Table of Content

12 February 2007, Volume 33 Issue 02

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ORIGINAL PAPERS

Effects of Nitrogen Application Regimes on Yield，Quality and Nitrogen Use Efficiency of Super Japonica Hybrid Rice

WAN Liang-Jun;ZHANG Hong-Cheng;HUO Zhong-Yang;LIN Zhong-Cheng;DAI Qi-Gen;XU Ke;ZHANG Jun

Acta Agron Sin. 2007, 33(02):  175-182. 

Abstract ( 2307 )   PDF (624KB) ( 1427 )   Save

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Effects of nitrogen application regimes, based on the proportion of base-tillering fertilizer to panicle fertilizer and leaf age of panicle fertilizer supply, were studied on yield，nitrogen use efficiency and quality in supper japonica hybrid rice, cv. Changyou 1, under the high grain yield at 225 kg ha^-1 of N condition during a whole growth stage. The result indicated that the yield was influenced significantly by nitrogen application regimes. The regime for highest yield was that the ratio of base-tillering fertilizer to panicle fertilizer was 58.34:41.66, and the split panicle fertilizers were equally applicated at 4th and 2nd leaf age from top. There were highly significantly positive correlations between yield and total N uptake，agronomic N use efficiency, apparent N recovery efficiency，physiological N use efficiency, and significantly quadratic relationships between yield and N kg 100 kg^-1 grain yield, N harvest index. With the decreasing of N rate of panicle fertilizer，head milled rice, protein content，chalky ratio and chalkiness were decreased; gel consistency and amylose content increased gradually. With postponing the time of N-applying leaf age, head milled rice and protein content were raised，and amylose content dropped. The gel consistency and apparent features were varied by different application proportions. On the whole，the proportion of N-application at 6:4 and the top dressing of panicle N-fertilizers with equal amount at 4th and 2nd leaf age from top might realize the coordination of supper high-yield，good quality and high N use efficiency.

Quantitative Trait Locus for Photosynthesis and Its Related Physiological Traits in Rice (Oryza sativa L.)

HU Mao-Long;ZHANG Yin-Xin;KONG Ling-Na;YANG Quan-Hai;WANG Chun-Ming;ZHAI Hu-Qu;WAN Jian-Min

Acta Agron Sin. 2007, 33(02):  183-188. 

Abstract ( 2173 )   PDF (470KB) ( 1364 )   Save

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In order to explore the genetic basis for photosynthesis and its related physiological traits, sixty-five chromosome segment substitution lines (CSSLs), derived from a cross between an indica cultivar IR24 and a japonica cultivar Asominori of rice (Oryza sativa L.), were utilized for mapping quantitative trait loci (QTL) for photosynthetic and its related physiological traits. Net photosynthesis (P_n), stomatal conductance (G_s), transpiration rate (T_r), intercellular CO₂ concentration (C_i), leaf chlorophyll (CHL), and total leaf nitrogen content (TLN) in flag leaves were measured at heading stage. The CSSLs showed transgressive segregation for many of the traits, and significant correlations were observed for most of the traits. In total, ten QTLs were detected on chromosomes 1, 3, 4, 5, 7, 8, and 10 with a range of percentages of variance explained (PVE) from 9.5% to 46.5%. LOD scores of these QTLs ranged from 2.77 to 8.42. A consistent location was mapped for a QTL controlling stomatal conductance (qGs-8) and leaf chlorophyll concentration (qCHL-8) in the vicinity of R727 on chromosome 8 and for a QTL controlling stomatal conductance (qGs-10) and intercellular CO₂ concentration (qCi-10) in the vicinity of C1166 on chromosome 10. No other overlapping loci associated with different traits were detected. These results indicated that the genetic mechanism of photosynthesis was complex in rice.

Dynamic Simulation Model for Photosynthesis and Dry Matter Accumulation in Rapeseed

TANG Liang;ZHU Yan;SUN Xiao-Fang;CAO Wei-Xing

Acta Agron Sin. 2007, 33(02):  189-195. 

Abstract ( 1940 )   PDF (475KB) ( 1244 )   Save

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Photosynthesis and dry matter accumulation are major determinants of the final yield in crop production. Based on eco-physiological processes, a simulation model for photosynthetic production and dry matter accumulation was established for rapeseed. The model used a ‘3 layer model’ for calculating the radiation interception by the layers of flowers, pods and leaves and light absorption by pods and leaves. Gaussian integration method was used to calculate the photosynthesis of pod and leaf layers, and the daily total canopy photosynthesis which was that of all layers of green organs. The effects of physiological age, temperature, nitrogen and water deficit factors on maximum photosynthesis rate were adequately quantified. The model calculated maintenance respiration and growth respiration which consume some photosynthate. Partition index of shoot was quantified by physiological development time (PDT) to calculate shoot dry matter from plant biomass. Then, plant biomass loss due to freezing was quantified by temperature effect. Testing of the model for dry matter accumulation with the field experiments of different genotypes, sowing dates, and nitrogen levels showed a good fit between the observed and simulated data. Thus, the present model appears to be favourable on mechanism explanation and reliable prediction.

Classification of Male Sterile Cytoplasm of CMS-P in Maize (Zea mays everta)

CHEN Wei;LIU Zhan-Xian;E Li-Zhu;YANG Hui;DAI Jing-Rui

Acta Agron Sin. 2007, 33(02):  196-200. 

Abstract ( 2170 )   PDF (1103KB) ( 1086 )   Save

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Application of cytoplasmic male sterility (CMS) materials makes an effective approach for utilization of heterosis, by which the seed pureness can be increased and the production cost can be reduced. A key problem for breeders is to identify unknown sterile cytoplasm and understand its characters. Using the combined methods of male fertility restoration testing, PCR of mtDNA and S1, S2 plasmid-like analysis, this study mainly dealt with classifying CMS-P selected from popcorn and finding the fertility diversity between CMS-P and others by pollen stain to understand the utilizing potential of CMS-P. The results indicated that CMS-P was classified to be the S-type CMS in maize. The PCR classifying method was quicker and exacter than others. And there was no difference between CMS-P and CMS-S in sequence of the special PCR fragment. The segregation proportion of pollen did not all accord with 1:1 by Chi-square test with pollen stain and CMS-P was much more fertile than CMS-Tangxu in restoring F₁. Pollen stain was diverse among the different nuclear backgrounds with same cytoplasm, the different cytoplasms and environments. The interaction between cytoplasm and nuclear minor gene maybe was the main factor that affects the fertility stability. We also found that HZ32 was a full restoring material with high restoring ability, and its rates of stained pollen were 96.4%, 94.2%, and 55.58% for CMS-T, CMS-C, and CMS-Tangxu, respectively. Ben7884 was a restoring line for S-type cytoplasm, but its restoring ability performed a fertility in 4–5 classes for C-type.

Isolation and Expression Analysis of Small GTP-Binding Protein Gene TaRab2 in Wheat

GUO Zhi-Ai;ZANG Qing-Wei;JING Rui-Lian;ZHAO Jun;CHANG Xiao-Ping;LI Run-Zhi;ZHAO Zhi-Li

Acta Agron Sin. 2007, 33(02):  201-207. 

Abstract ( 1842 )   PDF (1299KB) ( 1075 )   Save

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Wheat (Triticum aestivum L.) is an important crop in the world. However, drought greatly affects its yield in many areas. Discovering and cloning genes related to drought tolerance are the foundation for improving the drought tolerance in crops with genetic modification, which also plays a crucial role in understanding the genetic mechanism of drought tolerance in crops. The small GTP binding protein Rab plays an important role in vesicular transport in eukaryotic cells. The transportation of newly synthesized proteins from the endoplasmic reticulum to the Golgi complex and to secretory vesicles involves the movement of carrier vesicles. By the reverse Northern screening, some candidate ESTs were isolated from the cDNA libraries which were constructed from the 2-leaf seedlings of Hanxuan 10，a wheat cultivar with strong drought tolerance，treated with 24 h and 48 h water stress. One of them was highly identified with small GTP binding protein Rab2. The EST was extended using CAP3 software in the lab local net. Based on the extended sequence, a pair of primer was designed in the two side regions of its predicted ORF. Using RT-PCR method, an 824 bp cDNA was isolated from Hanxuan 10, which contains a complete 633 bp ORF and encodes a putative protein composed of 210 amino acids. The full length cDNA was named as TaRab2 (Accession No. AY851657). TaRab2 contains conserved structure of small GTPase including four conserved domains for guanine nucleotide binding and an effector domain. Multiple alignment analysis on the putative protein indicated that TaRab2 was more than 90% homologous to the small GTP-binding proteins Rab2 in maize, rice, Arabidopsis and Sporobolus stapfianus. Northern blots showed that TaRab2 was an up-regulated gene induced by water stress in wheat, but the expression levels were different in the different time points. The highest expression level was induced by the 6 h water stress. The longer the stress duration, the lower the expression level. The expression level of TaRab2 returned to original quantity by the 72 h water stress. Therefore, TaRab2 was inferred to possibly play a certain role in drought tolerance of plants.

Characteristics of Nutrient Absorption in Super-High-Yielding Mid-Season and Late-Maturity Japonica Rice

DU Yong;LIU Hui;YANG Cheng;WANG Zhi-Qin;YANG Jian-Chang

Acta Agron Sin. 2007, 33(02):  208-215. 

Abstract ( 1780 )   PDF (595KB) ( 1049 )   Save

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Rice is one of the most important food crops in China. Elucidation of nutrient requirement and absorption has great significance in the realization of high-yielding, good quality and high efficiency in rice. The objective of this study was to investigate the characteristics of nutrient absorption in super-high-yielding cultivation (SHYC, grain yield >11 t ha^-1) and in high-yielding cultivation as the control (grain yield > 7.5 t ha^-1) using two mid-season and late-maturity japonica rice cultivars, Huaidao 68 and Zhendao 88. The absorption and accumulation of nitrogen (N), phosphorus (P) and potassium (K) in the plants were analyzed. The results showed that plants in SHYC absorbed and accumulated less N before the critical stage of productive tillers and more N after the jointing stage, when compared with the those in control. The amount of P absorbed in SHYC was more than that in the control at each growth stage, especially at later growth stages. There was no significant difference in K absorption and accumulation between the SHYC and the control before the critical stage of productive tillers, whereas the plants in SHYC absorbed more K than in the control from jointing to maturity. Input of N balanced the output in SHYC, but the control showed more input than output in N. There were more outputs than inputs in P and K for both SHYC and high-yielding cultivation, especially the former. The amount absorbed of N, P, K for the production of 1 000 kg grains was 21.6–21.9 kg, 6.7–7.2 kg, and 24.8–25.6 kg, respectively in SHYC, and 23.8–24.3 kg, 6.8–7.3 kg, and 27.4–29.0 kg, respectively, in the control. The results indicated that the mid-season japonica rice with SHYC absorbed nutrients less at early growth stages whereas more during the later growth period, and increased the internal nutrient efficiency. The characteristics of nutrient absorption and optimized nutrient management for mid-season japonica rice with SHYC were discussed.

Effects of Shading in Field on Photosynthetic Characteristics in Summer Corn

ZHANG Ji-Wang;DONG Shu-Ting;WANG Kong-Jun;HU Chang-Hao;LIU Peng

Acta Agron Sin. 2007, 33(02):  216-222. 

Abstract ( 1901 )   PDF (576KB) ( 1144 )   Save

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The summer corn (Zea mays L.) in Huanghuaihai region of China grows under high temperature and low light in the season of the year, and there is a large area of corn intercropping with winter wheat in Shandong Province. With the change of ecological factors and productive conditions, corn is shaded by winter wheat at the seedling stage, and grow under high temperature and low light at grain forming stage, which decreased grain yield. However, there are few reports on the effects of shading on photosynthesis of corn. This research attempted to study the photosynthetic foundation for the effects of shading on grain yield of corn, and provide theoretical evidence to improve yield and quality of summer corn. Effects of different shading degrees and different shading stages in field on photosynthetic characteristics of summer corn were studied. The field was shaded by the nets with 50% and 90% shading over the plants. The positions of the nets were raised with the growth of corn plant, and the distance between the nets and the top of corn plants remained in about 2.5m. So that only the illumination intensity condition was changed, while the aeration condition and relative humidity were not changed. Other environmental changes might be due to the change of illumination intensity. The results showed that there were significant effects of shading in field on photosynthetic characteristics of summer corn, so that grain yield of corn were decreased significantly. When shaded by 50% and 90%, grain yield of ND108 decreased by 16.9% and 24.5% respectively from seedling to jointing stage, by 34.1% and 55.3% respectively from jointing to flowering stage, and by 67.5% and 79.4% respectively from flowering to maturity stage. Correspondently, leaf area index of corn were decreased by 53.6% and 64.3%, 22.1% and 23.0%, 66.2% and 79.4% respectively, net photosynthesis rate of corn were decreased by 28.6% and 49%, 36.6% and 59.6%, 43.9% and 64.7% respectively in three shading stage. Both ribulose-1,5-bisphosphate carboxylase (PEPCase) and phosphoenolpyruvate carboxylase (RuBPCase) activities of corn leaves were decreased significantly in different shading treatments. Effects of different shading stages on photosynthetic characteristics of corn were significantly higher than those of different shading degree.

QTL Analysis for Flag Leaf Length in a Rice DH Population under Multi Environments

CAO Gang-Qiang;GAO Yong-Ming;ZHU Jun

Acta Agron Sin. 2007, 33(02):  223-229. 

Abstract ( 2130 )   PDF (426KB) ( 1028 )   Save

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A double haploid rice population from IR64/Azucena was used to dissect the quantitative inheritance of flag leaf length. The QTL mapping method based on mixed linear model approaches was employed for detecting QTLs with additive and epistatic effects as well as their QE interaction effects in 4 years. The results revealed that altogether 18 QTLs for leaf length were detected on 11 chromosomes, and all of them were involved in epistasis. 3 QTLs were involved in epistasis but without detectable additive effects, such loci might play the role of modifying agents that tend to activate other loci or modify the action of other loci. The same locus could get involved in interactions with more than one other locus, as might indicat the possibility of multi-QTL associations in the formation of complex traits. QTL and epistasis could have both genetic main effects that expressed stably in every environment and QE interaction effects. Some QTLs had QE effects under multi-environments but without genetic main effect, as might suggest expression of this kind of QTLs could be modified by environmental factors easily. And also some QTLs had only genetic main effect, so would not easily be affected by environment. Epistasis had wider range of epistasis × environment effects than that of main effects, might indicate that some digenic interactions were more easily subjected to environmental influence. Compared with indirect mapping method with QE effects but without epistatic effects, more QTLs were detected in the present study, but no major QTL was found. The QE effects were treated as random effects, so the sum of QE effects would be zero in theory, and multi environments were suitable for estimating genetic main effects better.

Light Energy Utilization Efficiency of High Oil Corn 115 at Grain Filling Stage

ZHUANG Ke-Zhang;GUO Xin-Yu;WANG Ji-Hua;WANG Kong-Jun;WU Zheng-Feng;LIU Peng;DONG Shu-Ting;ZHANG Ji-Wang

Acta Agron Sin. 2007, 33(02):  230-235. 

Abstract ( 1984 )   PDF (393KB) ( 956 )   Save

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High oil corn is a value-added corn type，which contains more oil and higher quality protein than normal corn. At present high oil corn has not been widely planted by farmers because its grain yield is lower than that of normal corn. The yield of high oil corn is restricted by lower net photosynthetic rate. A field experiment with a planting density of 30 000 plants ha^-1 was carried out to reveal the reason of lower net photosynthetic rate of high oil corn. The technique of chlorophyll fluorescence was used to measure light energy utilization efficiency of high oil corn. Light energy utilization and dissipation of upper, middle and basal leaves of high oil corn 115 in grain filling stage was studied. Compared with ND108，net photosynthetic rate (P_n), transpiration rate (T_r), stomal conductance (G_s) of were significantly lower（P<0.05）; intercellular CO₂ concentration (C_i) and water use efficiency of HOC115 (WUE) were slightly lower in ND108 (P>0.05). PSⅡ maximal photochemical efficiency (F_v/F_m) of HOC115 was lower significantly than that of ND108. PSⅡ activity (F_v/F_o) of HOC115 was slightly lower than that of ND108 (P>0.05). Apparent relative electron transportation rates of HOC115 were lower than that of ND108. Compared with ND108, the proportion of light energy used in heat dissipation by HOC115 was higher when light energy was constant. This result indicated that light energy utilization efficiency of HOC115 is lower than that of ND108. The largest light utilization efficiency difference between HOC115 and ND108 was observed in middle leaves. In conclusion, photosynthetic rate of HOC115 is lower mostly due to lower light energy utilization efficiency. In high oil corn breeding and cultivation, we should select high photosynthetic inbred lines and improve the growing conditions with suitable fertilizer and irrigation to enhance their light use efficiency.

Biological Control of Plant Diseases and Plant Growth Promotion by Bacillus subtilis B931

ZHANG Xia;TANG Wen-Hua;ZHANG Li-Qun

Acta Agron Sin. 2007, 33(02):  236-241. 

Abstract ( 1835 )   PDF (461KB) ( 1207 )   Save

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Bacillus subtilis B931, a biological control bacterium isolated from wheat field, protects plants against many soil-borne diseases and promotes plant growth. A mutant library of B931 containing over 3 000 Tn917 mutants was constructed by transposon mutagenesis with plasmid pTV1::Tn917. Six mutants defective in antibiotic production (B931-A－) were selected by dual culture test with Gaeumannomyces graminis var. tritici on PDA plates. Another six mutants which over-produced or less-produced phytohormones 3-Indoleacetic acid (IAA), gibberellin (GA₃) or cytokinin (CTK), respectively, were selected by ELISA and HPLC methods. Greenhouse experiments showed that, compared with the wild type, the antibiotic-defective mutant was less effective in biological control of wheat take-all caused by G. graminis var. tritici and cotton damping-off caused by Rhizoctonia solani, indicating that the antibiotic production played a major role in the biocontrol activity of B931. The mutants that over-produced or less-produced phytohormones had no significant influence on seedling growth of wheat and cotton. However, the mutants that overproduced IAA or CTK could significantly promote root growth of sweet potato seedlings.

Allelic Variations of Puroindoline a and Puroindoline b Genes in New Type of Synthetic Hexaploid Wheats from CIMMYT

LI Gen-Ying;XIA Xian-Chun;ZHANG Ming;ZHANG Yong;HE Zhong-Hu;SUN Qi-Xin

Acta Agron Sin. 2007, 33(02):  242-249. 

Abstract ( 2426 )   PDF (919KB) ( 883 )   Save

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Triticum dicoccoides and Aegilops tauschii are important germplasm resources of rich genetic variability for improvement of hexaploid wheat (T. aestivum). This variability can be accessed by utilizing synthetic hexaploid wheat lines with genomes from Ae. tauschii and T. dicoccoides. Two methods can be employed to incorporate Triticum dicoccoides and Aegilops tauschii genes into a hexaploid wheat. One is the direct cross method of hybridization between Ae. tauschii and hexaploid wheat, another is an indirect method of synthetic hexaploids by crossing tetraploid wheat with Ae. tauschii. Genes from tetraploid wheat and Aegilops tauschii are then available via direct crossing of synthetic hexaploids to T. aestivum. The CIMMYT (International Maize and Wheat Improvement Center) has produced two types of synthetic hexaploids. One is the progeny of T. turgidum ssp. durum crossing with Ae. tauschii, another is the new type synthetic wheat which produced by crossing Triticum dicoccoides with Aegilops tauschii.
Grain hardness is a major factor influencing the end-use quality. Genes for grain hardness in common wheat reside on Ha locus of chromosome 5DS. The wild-type alleles (Pina-D1a, Pinb-D1a) determine soft endosperm, while the hard phenotypes result from mutations in either Pina or Pinb. In order to understand the evolution of genes for grain hardness, studies have focused on the wild relatives of common wheat, particularly on Ae. tauschii, the supposed donor of the D genome in common wheat. Puroindoline a in Ae. tauschii contained 99.3% amino acid sequence homology to the wheat cultivar ‘Penawawa’ and 90.5% amino acid sequence homology in puroindoline b. Among 50 Ae. tauschii accessions, four alleles of puroindoline a and four alleles of puroindoline b were identified, encoding two and three different proteins, respectively. However, the effect that these sequence polymorphisms may have on kernel texture is unknown, as no test method of texture has been developed for Ae. tauschii. The incorporation of Ae. tauschii into synthetic hexaploid facilitates the analysis of puroindoline sequence polymorphism and other genetic effects on kernel texture, using testing methods designed for hexaploid wheat, such as the Perten single kernel characterization system (SKCS). Analysis of synthetic hexaploid can also facilitate the analysis of the effect of the A and B genomes, contributed by the tetraploid wheat parent on kernel texture. Studies on Ae. tauschii and synthetic hexaploid wheat derived from hybridization of T. turgidum ssp. durum with Ae. tauschii demonstrated a number of novel Pina and Pinb sequences. However, none of these Pina and Pinb mutations produced a hard endosperm texture in synthetic wheat. To further understand the mechanism of grain hardness formation in Ae. tauschii and synthetic wheat, a total of 57 new type synthetic hexaploid lines derived from the crosses T. dicoccoides×Ae.tauschii were employed to evaluate the SKCS hardness and detect puroindoline alleles using gene specific PCR primers. Four allelic variations of Pina and Pinb were identified, i.e., Pina-D1a, Pina-D1c, Pinb-D1h, and Pinb-D1j. Eight lines were Pina-D1a/Pinb-D1j types, accounting for 14%, and 49 were Pina-D1c/Pinb-D1h types, accounting for 86%. Kernel texture differed significantly among the synthetic hexaploid lines, ranging from 10.5 to 42.6, with significant difference among the parental types, T. dicoccoides or Ae. tauschii. The interactions between parental genotypes had also a significant influence on kernel texture. These results indicated that there might be some genes besides Ha locus associated with the kernel texture.

Improving Organic Phosphate Utilization in Transgenic White Clover by Overexpression of Aspergillus niger PhyA Gene

HAN Sheng-Fang;GU Jun-Tao;XIAO Kai

Acta Agron Sin. 2007, 33(02):  250-255. 

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The open reading frame (ORF) of phytase (PhyA) and cDNA part of patatin signal peptide were PCR amplified separately with DNA of Aspergillus niger and potato. The binary expression vector fused PhyA ORF and potato patatin signal peptide was constructed. Using the cotyledon of white clover as explants, the transgenic white clover lines ectopic expression of the PhyA gene were established based on Agrobacterium tumefaciens-mediated transformation method. The wild type plants without transformed (CK) and ten randomly selected transgenic lines were used for PCR amplification analysis to detect the target gene in the transgenic lines. It was found that the tested transgenic lines all showed positive PCR. The transgenic line 1 to line 4 were used for further Southern blot and Northern blot analysis. The results indicated that the genome of above four lines all contained low copies of PhyA. The line 1 and line 3 had higher levels of PhyA expression, indicating that it is effective to conduct genetic transformation of ectopic target genes in white clover by using agrobacterium tumafeciens-mediated method.The line 1 and line 3 with higher level of PhyA expression were used to assay the phytase activities in root and its intercellular space. When the phytate was the only phosphorus source, the phytase activities in root in line 1 and line 3 were 31.43% and 44.76% higher than those in control plants (CK), respectively. Meanwhile, the phytase activities in the intercellular space of root in line 1 and line 3 were 3.3-fold and 5.12-fold higher than those in CK, respectively. Therefore, the PhyA products in line 1 and line 3 could be secreted into the intercellular space of root by the direction of patatin signal peptide. Similarly, under the condition with phytate as the only source of phosphorus, the phosphorus concentration of plants, the accumulative phosphorus amount per plant, plant fresh weight and plant dry weight were all much higher in line 1 and line 3 than in CK. Among them, for line 1 and line 3 the phosphorus concentration of plant was 30.23% and 34.88% higher than CK, the accumulative phosphorus amount per plant was 2.90-fold and 3.54-fold, the plant fresh weight was 2.25-fold and 2.79-fold and the plant dry weight was 2.22-folf and 2.79-fold, respectively compared with the CK. Thus, it was clearly shown that ectopic expression of Aspergillus niger PhyA gene can significantly increase the ability for white clover to utilize organic phosphate under P_i-deficient condition.

Mapping of One Fiber Factor 1 Gene Based on Single Nucleotide Polymorphisms in Gossypium

HAN Zhi-Guo;GUO Wang-Zhen;ZHANG Tian-Zhen

Acta Agron Sin. 2007, 33(02):  256-261. 

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Marker-assisted selection (MAS) has been an important way for practical plant breeding, and more available markers are required, especially those linked to the genes of some agronomical important traits. Many kinds of molecular markers are being used in cotton genetic mapping, but there is little report on SNP markers development of cotton genes. FIF1 is predominantly expressed early in developing cotton fibers and identified to be a key regulator of cotton fiber development. In this paper, FIF1 genes from G. hirsutum cv. TM-1 and G. barbadense cv. Hai7124 were cloned on the basis of its published sequence in G. arboreum L. Based on the SNPs between FIF1 genes from two tetraploid cotton, SNP and CAPs markers were developed, and the gene was mapped on our allotetraploid cotton genetic map. This result indicates that SNP marker development is feasible and effective in Gossypium.

Fertility Photo-Thermo Characteristics in PTGMS Rice C815S and Its Homologous Plant Lines

HE Qiang;CHEN Li-Yun;DENG Hua-Feng;TANG Wen-Bang;XIAO Ying-Hui;YUAN Long-Ping

Acta Agron Sin. 2007, 33(02):  262-268. 

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The study of the fertility change mechanism of PTGMS has been a hot topic since 1989, and the prevenient achievements have revealed the fertility alteration models of PTGMS rice in response to photoperiod and temperature condition. There have been mainly four models: the suppose of three developing phase and two photoperiod-sensitive stages, the model of light and temperature in fertility changes, the quantitative model of fertility changes and the three dimensional coordinate model of fertility conversion, and these models and theories had higher utilization values in directing two-line hybrid production. In this paper, fertility photo-thermo characteristics, developmental photo-sensitivity and their relationships in PTGMS rice C815S and its homologous plant lines were studied in 12 controlled combination treatments of 3 daylength with 4 lower temperature, treatments of shading, and short photoperiod, and the treatments of different rowing date. The results showed that C815S and its homologous plant lines were a type of typical lower thermo-sensitivity sterile line and their low critical temperature was below 23.0℃. In Changsha, there were no obvious fertility fluctuation and alteration from sterility to fertility under the long daylength condition while there was slight fertility fluctuation under the short daylength condition. The different degrees of photoperiod sensitivity sterility in C815S and its homologous plant lines were a result of the interaction of daylength ×temperature, and there would be some internal relation between the interaction and developmental photoperiod sensitivity. The interaction of daylength ×temperature was further discussed and the interdynamic effect model of daylength and temperature, being of the quantitative fertility response to photoperiod and temperature, was supposed. This hypothesis can offer the corresponding temperature for fertility alteration under the determinate daylength, being used in the selection of PTGMS, hybrid seed production and propagation of PTGMS scientifically. According to this hypothesis, the breeding strategy of selecting the practical two-line genic sterile line can be put forward in the corresponding environment.

Effects of Soil Water Conditions on Wheat Xylem Vulnerability and Leaf Ultrasound Acoustic Emission

JIA Xiu-Ling;WANG Zhen-Lin;MA Rui-Kun;ZHANG Li-Hua;ZHANG Quan-Guo;YANG Li-Hua

Acta Agron Sin. 2007, 33(02):  269-277. 

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Water stress-induced xylem embolism has important physiological consequences for plant growth and survival in most species. Effects of soil water conditions on leaf xylem cavitation and embolism occurrence were investigated throughout the major growth stages in field-grown winter wheat (Triticum aestivum L. cv. Shixin 733) plants. The xylem cavitation and embolism were measured by monitoring ultrasonic acoustic emission (AE) from leaf xylem. It was found that daily AE generally started around 6:00–8:00 a.m. and ceased between 21:00 p.m. and 3:00 a.m. of the following day. Embolism occurred to a much greater extent in leaves of water stress (WS) plants than in well-watered (WW) control. The total number of AE occurred in a period of 24 hours (24 h AEs) from WS plants was higher than that from WW control between jointing and mid grain filling stage. The difference between treatments peaked between anthesis and initial grain filling, with 24 h AEs being 4.6 times greater in WS than in WW plants. The number of 24 h AEs from WS plants, however, dropped greatly to values similar to or even lower than that of WW plants under more severe soil water stress after mid grain filling, which phenomenon is termed “AE depletion”. Vulnerability curves, which were fitted to Logistic function by plotting cumulative AEs versus corresponding leaf water potential (Ψl), showed that leaf xylem vessels were generally most vulnerable at Ψl of about －1.00 MPa. Soil water stress led to much more vulnerable leaf xylem, which greatly reduced leaf embolism resistance and consequently impaired xylem safety. The higher degree of cavitation and embolism occurrence in WS plants resulted basically from a more vulnerable water conducting system, and much less from the greater xylem water tensions, as compared with WW control.

Effects of Long-Term Fertilization on Activities of Key Enzymes Related to Nitrogen Metabolism (ENM) of Maize Leaf

LIU Shu-Yun;DONG Shu-Ting; ZHAO Bing-Qiang; LI Xiu-Ying;ZHANG Zhen-Shan

Acta Agron Sin. 2007, 33(02):  278-283. 

Abstract ( 1947 )   PDF (599KB) ( 1084 )   Save

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In order to understand the effect of long fertilization to nitrogen metabolism, we studied the effects of long-term(13 years) fertilization on activities of key enzymes (NR,GS,GOGAT and GDH) related to nitrogen metabolism (ENM) of maize leaf. The experiment was conducted in the base of soil fertility and fertilizer effect monitoring in fluvo-aquic soil in Changping County, Beijing, China with 8 treatments as CK(no fertilizer), NPK(N, P, K fertilizers), NPKM(N, P, K fertilizers and manure), NPKS(N, P, K fertilizers and stalk mulching), N(only N fertilizer), PK (P, K fertilizers), NK(N, K fertilizers), NP(N, P fertilizers). The rates of fertilizer application were 150 kg N ha^-1, 75 kg P₂O₅ ha^-1 and 45 kg K₂O ha^-1 per cropping season, and the manure and maize stalk were applied with 22.5 t ha^-1 and 2.25 t ha^-1 per year. The key enzymes related to nitrogen metabolism were measured. Yield investigation showed that NPKM treatment had the highest grain yield, and N treatment had the lowest one. Balanced fertilization treatments such as NPK, NPKM and NPKS had higher activities of enzymes related to nitrogen metabolism (ENM) of maize leaves during the grain filling phase and higher yields than the treatments of imbalanced fertilization systems (N, NK, NP and PK treatments). Long-term imbalanced fertilization systems such as NP, N, NK, PK and CK did not well match the high activities of enzymes related to nitrogen metabolism (ENM) with high grain filling phase, resulting in lower active growth and lower yields. The high activity of only some single enzyme had little effect on maize yield and quality. That all the key enzymes related to nitrogen metabolism (ENM) of maize leaf had higher activities could be effective on maize yield and quality formation. Even if the Glutamine sybthetase (GS), Glutamate synthase (GOGAT) and Glutamate dehydrogenase (GDH) activities on average of N and CK treatments were higher than others, the grain yields of these treatments were lower markedly than others. Different enzymes have different roles in the formation of grain yield and quality, so the study on all enzymes related to the activities of nitrogen metabolism (ENM) will help to understand the nitrogen metabolism of maize and improve the efficiency of fertilizer utilization.

Effects of Wheat Residue Incorporation and Nitrogen Management Techniques on Formation of the Grain Yield of Rice

XU Guo-Wei;WU Chang-Fu;LIU Hui;WANG Zhi-Qin;YANG Jian-Chang

Acta Agron Sin. 2007, 33(02):  284-291. 

Abstract ( 2286 )   PDF (609KB) ( 1203 )   Save

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The annual total amount of crop residue straw exceeds billion tons in China. However, about 45%–60 % of them are burnt or discarded, which not only wastes organic fertilizer source, but also pollutes the environment. Meanwhile, heavy use of nitrogen fertilizer has become a serious problem in rice production in this country. The purposes of this study were to investigate the effects of wheat straw incorporation to soil and site-specific nitrogen management (SSNM) on the growth and grain yield of rice. Two mid-season japonica rice cultivars, Wuxiangjing 14 and Yangjing 9538, were field-grown with three nitrogen (N) fertilizer treatments, no nitrogen application, farmers’ fertilizer-N practice (FFP), and SSNM base on chlorophyll measurement meter (SPAD) readings. The results showed that, compared with FFP, SSNM reduced N application by 40.0%–41.7% and increased grain yield by 3.81%, on average. The grain yield in the wheat residue-incorporated treatment was 2.49%, on average, higher than that in the residue-removed treatment. The agronomic efficiency, recovery efficiency and physiological efficiency of nitrogen fertilizer under wheat residue incorporation were higher than those under the residue-removed. In comparison with those under the residue removal and FFP, the number of stems and tillers, leaf area index, and biomass accumulation were less or lower under the residue incorporation and SSNM during the early growth period, but the differences were reduced at heading and thereafter. Both the residue incorporation and SSNM increased the percentage of productive tillers, photosynthetic rate of flag leaves and root activities during grain filling. The results suggest that both the residue incorporation and SSNM benefit the photosynthetic production of rice during the later growth period and an increase in the production efficiency. Wheat residue incorporation and SSNM increased nitrogen harvest index and agronomic efficiency, recovery efficiency, physiological efficiency, and partial factor productivity. Reasons for the characteristics of the grain yield, growth and development and nitrogen fertilizer use efficiency under the residue incorporation and SSNM were discussed.

Cloning and Sequence Analysis of Novel Drought-Tolerance Gene Coding LEA3 Protein in Tibetan Hulless Barley

QIAN Gang;ZHAI Xu-Guang;HAN Zhao-Xue;PAN Zhi-Fen;DENG Guang-Bing;YU Mao-Qun

Acta Agron Sin. 2007, 33(02):  292-296. 

Abstract ( 2197 )   PDF (1439KB) ( 1034 )   Save

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Late embryogenesis abundant (LEA) proteins were major group of proteins that were prominent in the stress response in various organisms including plants, algae, yeasts and bacteria. LEA3 protein was hydrophilic and accumulated in higher plants under conditions of extreme desiccation, during the last stage of seed formation, and during periods of water deficit in vegetative organs. In the present study, the most contrasting drought-tolerant genotypes were screened for comparing the differential sequences of gene coding LEA3 protein in Tibetan hulless barley, based on scoring of water loss rate (WLR), maldondialdehyde and proline measured. And Dongqing 8 with the highest scores and Pinbi 14 with the lowest ones were selected for analyzing the differences between the genes coding LEA3 protein in Tibetan hulless barley. Total RNA of two selected barley cultivars was extracted after treating with dehydration for 12 hours, and the first strand cDNA was synthesized by mRNA reverse transcription based on the primers designed according to the homologous sequence from Hordeum vulgare L. regiesterd in GenBank (No. X78205). RT-PCR products of gene coding LEA3 protein were cloned to pMD18-T vector. The recombinant pMD18-T plasmids, inserted interesting gene, were identified by PCR and restriction digestion, respectively. Results of sequence analysis revealed that both genes coding LEA3 protein contained entire open reading frames. The ORF of gene coding LEA3 protein from Dongqing 8 was composed of 606 bp, contrasting with 639bp from Pinbi 14. Accordingly, the deduced LEA3 protein in drought-tolerant genotype, Dongqing 8, was composed of 202 amino acid residues, while that of 213 amino acid residues in drought-sensitive genotype, Pinbi 14. The deduced LEA3 protein in the most tolerant genotype contains 8 repeats of an 11-amino acid motif that form amphiphilic α-helical structure, accordingly it shares the same characteristics as the third group of LEA protein. Comparing with LEA3 protein of the most sensitive genotype, the deduced LEA3 protein in Dongqing 8 was absent of the fourth motif because of absence of 33 nucleotides. In addition, there was a mutation of 6 differential amino acid residues appeared between in Dongqing 8. The polarity of LEA3 protein in drought-tolerant genotype could be stronger than that in Pinbi 14, due to those 6 mutant amino acid residues. Respectively, both materials shared 94.38% and 92.02% similarity by DNA and amino acid sequence homological comparison. In the present study, differential number of repeated motifs was related to the most contrasting drought-resistant genotypes in Tibetan hulless barley. The differential hydrophilic capability of LEA3 protein could be related to differential number of repeated motifs, mostly to the polarity of mutant amino acid residues. Accordingly, it was suggested that differential configuration of drought-tolerant proteins may be contributed to capability of drought resistance in plants.

Relationship between Leaf Nitrogen Contents and Fluorescence Parameters in Wheat

MA Ji-Feng;ZHU Yan;YAO Xia;TIAN Yong-Chao;LIU Xiao-Jun;CAO Wei-Xing

Acta Agron Sin. 2007, 33(02):  297-303. 

Abstract ( 2046 )   PDF (548KB) ( 997 )   Save

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It is very important for using non-destructive method to determine nitrogen status and growth characters of crop plants. Remote sensing has been successfully applied in assessing crop biophysical and biochemical variables, such as leaf area index, chlorophyll, nitrogen and so on. Chlorophyll fluorescence is a new non-destructive instrumentation for predicting leaf nitrogen content of crop. In this study, two experiments were carried out at Nanjing to investigate the correlative relationship of leaf nitrogen content to fluorescence parameters in wheat (Triticum aestivum L.). Experiment one was conducted with two cultivars (Ningmai 9 and Huaimai 20) and five nitrogen rates of 0, 75, 150, 225 and 300 kg ha^-1 in 2003. Experiment two included two cultivars (Ningmai 9 and Yumai 34) with three nitrogen rates of 0, 90, 270 kg ha^-1 in 2004. The change patterns of leaf nitrogen contents and fluorescence parameters across growth stages in different wheat cultivars were determined under different nitrogen levels, the correlative relationships of leaf nitrogen contents to fluorescence parameters were established, and the regression equations for predicting leaf nitrogen contents were formulated. The results showed that the leaf nitrogen contents and fluorescence parameters at different leaf positions of wheat increased with raised nitrogen applications. From booting to maturity, fluorescence parameters Fv/Fm and Fv/Fo of wheat leaves initially increased and then decreased with growth process of time. Leaf nitrogen contents of different leaf positions in wheat had significant positive correlations with fluorescence parameters Fm，F_v，F_v/F_m，F_v/F_o，F_s and F_o’, especially the correlation in the 1st and 2nd leaves from top was the best. Nitrogen contents of two top leaves in different wheat cultivars were significantly related to F_v/F_m and F_v/F_o, with average R₂ of 0.66 and 0.61, respectively. For different types of cultivar with low, medium and high grain protein contents, an integrated regression equation could be used to describe the dynamic change pattern of leaf nitrogen contents at the two top leaves with fluorescence parameter (F_v/F_o).

Effects of Nitrogen Application Rate on Grain Quality in Wheat Cultivars GC8901 and SN1391

CAI Rui-Guo;YIN Yan-Ping;ZHANG Min;DAI Zhong-Min;YAN Mei-Ling;FU Guo-Zhan;HE Ming-Rong;WANG Zhen-Lin;

Acta Agron Sin. 2007, 33(02):  304-310. 

Abstract ( 2070 )   PDF (528KB) ( 1163 )   Save

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Application of nitrogen fertilizer (N) is one of the most important measures to increase grain yield and improve the end-use quality of wheat. It is generally accepted that the protein content and nutrition quality of wheat grain could be improved by reasonably N application. But the effect of N rate on protein component and processing quality of wheat grain varied with cultivars and cultivation conditions. The strong-gluten wheat cultivars of wheat are obviously different from the weak-gluten cultivars in many quality parameters of grain, such as grain protein content, protein component, grain starch content, starch component. In the present study, a strong-gluten wheat (Triticum aestivum L.) cultivar GC8901 and a weak-gluten wheat cultivar SN1391 were used to investigate the effect of N rate on the grain quality. The experiment was conducted in a pool culture on the Experimental Farm of Shandong Agriculture University from 2002 to 2004 with three nitrogen application rates, 12(N₁₂), 24(N₂₄) and 36(N₃₆) g m^-2. The results showed that properties of starch and protein, and processing quality in both wheat cultivars could be markedly influenced by N application. As compared with the N₁₂ treatment, the N₂₄ treatment significantly increased amylopectin contents, decreased amylose contents and the ratio of amylose to amylopectin, promoted the starch accumulation and improved the paste properties. When the N application rate reached 36 g m^-2, amylopectin contents and starch accumulation decreased, however, the amylose content increased. The albumin, globulin, glutenin and protein content of GC8901 enhanced, but the gliadin content reduced with the increase of N application. The gliadin, gluten and protein content of SN1391 were much lower in the N24 treatment than those in the other two N treatments. The albumin content of SN1391 decreased and globulin increased with the increase of N rate. An appropriate N rate was beneficial to increased grain hardness, but excessive N application had an adverse effect. The volume weight of wheat grain declined with the increase of N application. The dough whiteness of GC8901 rose with increasing nitrogen, but that in N₂₄ treatment was lower than that in the other two treatments of SN1391. As for GC8901, with the increase of nitrogen application rate, the content and quality of wheat gluten, the development time, stability time, extension area and extensibility of the dough were all enhanced, leading to the improvement of food processing quality of strong-gluten wheat cultivars, but those for SN1391 were low resulting in the better processing quality of weak-gluten wheat cultivars. When the N application was 36 g m^-2, the quality of two cultivars went inferior. The results reveal that the N application rate affects protein, starch, and their component contents in grain, resulting in the changes of the processing quality of wheat.

Estimation Models of Cotton Aboveground Fresh Biomass Based on Field Hyperspectral Remote Sensing

BAI Jun-Hua;LI Shao-Kun;WANG Ke-Ru;SHUI Xue-Yan;CHEN Bing

Acta Agron Sin. 2007, 33(02):  311-316. 

Abstract ( 1917 )   PDF (442KB) ( 1064 )   Save

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Aboveground fresh biomass is an important colony qualitative index of cotton, and so it is significant for production management and yield estimation in cotton to establish the monitoring model based on hyperspectral parameter. The wavelength variation coefficient of cotton canopy hyperspectrum on aboveground fresh biomass and the correlation between the aboveground fresh biomass and reflective spectrum, the first derivative spectrum showed that the biggest value of hyperspectral variation coefficient of cotton canopy reflectance in the visible light region was in 672 nm. The biggest value of correlation coefficient between the aboveground fresh biomass and reflectance spectrum at the visible light region was in 589–700 nm and at the near infrared red region in 865-919 nm, and the former was larger than latter. The correlation coefficient between the aboveground fresh biomass and the first derivative value in the visible light had three high-value areas including 524–528 nm, 552–588 nm and 710–755 nm. According to the analysis above, the nineteen hyperspectral characteristic parameters were used to establish the hyperspectral remote sensing estimation models of the aboveground fresh biomass in cotton. The tested result of models expressed the parameters veracity of estimating the aboveground fresh biomass in cotton, including reflectance of 682 nm and 629 nm and the combination forms, was up 80%. Among them, F629[Y = 9.7914 exp(－20.738 F629)]in single band reflectance parameters was better, its veracity reached to 83.9%, RMSE was 0.64 kg m^-2, and the correlation coefficient between the estimated value and measured value was 0.94**; The monitoring model of [629, 901] [Y = 0.0986 exp(4.3696 [629, 901])] was best, and its veracity reached to 84.0%, RMSE was 0.55 kg m^-2, and the correlation coefficient between the estimated value and measured value was 0.96**, the two models above were the best among the elected models estimating cotton aboveground fresh biomass.

DNA Sampling Strategy and Calculation of Genetic Distance between Maize (Zea mays L.) Populations

HOU Ben-Jun;WANG Tie-Gu;CHEN Yan-Hui;WU Lian-Cheng;KU Li-Xia

Acta Agron Sin. 2007, 33(02):  317-321. 

Abstract ( 2067 )   PDF (405KB) ( 1162 )   Save

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SSR is a good molecule marker with broad application. Bulk sampling is feasible to analyze genetic diversity of maize population by SSR. It is necessary to study influence of genetic distance as using bulk sampling. In present study, the genetic distances between two populations were compared and analyzed by 50 pairs of SSR primers, checked by inbred lines Huangzao 4 and Mo17, and using 60 individuals DNA samples of Golden Queen and Yuzong 5 maize populations with six treatments (the individual DNA samples, the mixed DNA samples with 5 individuals, 10 individuals, 15 individuals, 20 individuals, and 30 individuals, respectively). The results indicated that using the individual DNA samples can detect the alleles with very low frequencies, and make the detected allele number decreased gradually and the frequency of missing alleles increased with the increase of mixed individuals in the treatmen. The results of the genetic distance between two populations calculated by three models suggested that the genetic distances GD, GD(J) and GD(N) showed a gradually increasing trend with the increasing of the mixed individual number, but the increasing extent of GD(J) and GD(N) was wider. There was an obvious deviation between GD(J), GD(N) from mixed samples and the GD from 60 individual DNA samples based on allele frequency. The results and the comparison of the genetic distances based on different calculation methods suggested that the 10 individuals’ DNA mixture is the best sampling strategy when genetic diversity and polymorphism in maize populations are studied by SSR.
If the Nei’s genetic distance GD(N) and Jaccord’s genetic distance GD(J) are calculated according to 0, 1 data, (GD(N)+GD(J))/2 will be calculated close to the genetic distance by allele frequency of individuals. Gene frequency can be studied by using capillary electrophoresis and SSR fluorescence detection. There will be a broad application prospect about bulk sampling strategy with SSR marker.

Binding Characteristics of Granule-Bound Starch Synthase (GBSS) with Starch in Wheat Cultivar Chinese Spring

GUO Hua;WANG Xian-Ze;LI Hai-Lei;GAO Ai-Ying;TIAN Ji-Chun

Acta Agron Sin. 2007, 33(02):  322-325. 

Abstract ( 2232 )   PDF (943KB) ( 910 )   Save

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The factors affecting the binding characteristics of GBSS with starch granule were studied using a wheat (Triticum aestivum) cultivar Chinese Spring with different temperature treatments. After sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis, we got GBSS concentration by coomassie brilliant blue G-250(CBB G-250) method. The results showed that the temperature affected the binding of GBSS and starch granule. In 50–80℃, the concentration of GBSS unbound from starch increased with the temperature rising, which the maximal concentration was 11.361 μg mL^-1 at 80℃, while that was reduced when the temperature was 85–95℃. Furthermore, Mg²⁺ could also affect the quantity of GBSS unbound from starch. When Mg2+ concentration was lower than 1.75 mmol L^-1, the concentration of GBSS unbound increased. The lower Mg²⁺ concentration, the higher the concentration of GBSS unbound. However, when Mg2+ concentration was higher than 2.5 mmol L^-1, it could restrain GBSS unbinding. These results showed that GBSS bound starch granule by non-covalent bonds. The best GBSS extracting conditions were 55 mmol L^-1 Tris-HCl (pH 6.8), 0.75 mmol L^-1 MgCl₂, 2.3% SDS, 5% 2-ME and 10% glycerol, 15 min in boiling water, or 55 mmol L^-1 Tris-HCl (pH 6.8), 0.75 mmol L^-1 MgCl₂, 2.3% SDS, 5% 2-ME and 10% glycerol, 80℃ 30 min. The results are helpful to investigate 3-D structure of biological activated GBSS and mechanism of GBSS binding with starch granule.

RESEARCH NOTES

Expression and Characterization of a Novel Vacuole Na+/H+ Antiporter Gene in Rice (Oryza sativa)

LIU Zhu-Ling;HAN Sheng-Fang;XIAO Kai

Acta Agron Sin. 2007, 33(02):  327-332. 

Abstract ( 1843 )   PDF (1174KB) ( 971 )   Save

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Using a cDNA fragment PCR amplified from Arabidopsis AtNHX1 as the probe, a novel vacuole Na⁺/H⁺ antiporter gene (OsANT1) in rice was obtained based on the screening of a cDNA library made from leaves of rice plants treated with 200 mmol L^-1 NaCl. The results indicated that the full-length of OsANT1 cDNA was 2 178 bp. The open reading frame (ORF) of OsANT1 was
1 608 bp with 535 translated amino acids. OsANT1 had 15 exons and 14 introns with a total length of 4 835 bp at the DNA level. It was found that OsANT1 contained 12 transmembrane domains and had high similarities with other vacuole Na⁺/H⁺ antiporters from plant species, such as Arabidopsis thaliana, Oryza sativa, Triticum aestivum, Zea mays, Hordeum vulgare, Iris lacteal, and Phragmites australis. The expression of OsANT1 in leaf, stem and root was all induced by NaCl and the expression levels were increased with the increase of NaCl concentration applied and the elongation of NaCl treatment time. Taken together, it is suggested that OsANT1 is functional for rice to withstand NaCl under salt stress.

Analysis of Gene Expression Profile Responsed to Water Stress in Wheat (Triticum aestivum L.) Seedling

PANG Xiao-Bin;MAO Xin-Guo;JING Rui-Lian;SHI Jun-Feng; GAO Ting;CHANG Xiao-Ping;LI Yan-Fang

Acta Agron Sin. 2007, 33(02):  333-336. 

Abstract ( 1911 )   PDF (290KB) ( 950 )   Save

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To understand the gene expression characteristics, which involved in drought tolerance, five cDNA libraries were constructed using suppression subtractive hybridization (SSH) method with wheat seedlings sampled at 1, 6, 12, 24 and 48 hours of water stress, respectively. By sequencing, 6 733 ESTs were obtained from the cDNA libraries. The gene expression profile induced by water stress in wheat seedling has been preliminarily constructed after assembling, homologous comparing, annotating and classifying the EST sequences. The dynamic characters and 4 patterns of gene expression during water stress treatment were found. The expression pattern 1 in which the most genes were detected at the initial stage, but the number of genes decreased to the least at 12th hour of water stress, then gradually increased with water stress undergone continuously, included genes involved in repair and protection from damage. The pattern 2 with the fewer genes at the initial stage, but the gene number increased-decreased-increased gradually with the water stress process of time, which was protein synthesis-related genes. The pattern 3 was that gene number was fewer at the initial stage, but gradually increased to the most at 12^th hour, then gradually decreased, such as protein kinase gene. Number of genes in the pattern 4 was higher at the initial stage, and then decreased-increased-decreased gradually along with the water stress elongation, to which protein phosphatase gene belongs. Among 648 uni-genes of known function annotation, the proportion of transcription factor genes was 6.17%, protein phosphatase genes 2.16%, protein kinase genes 4.01%, genes involved in repair and protection from damage 19.90%, genes of macromolecule protection factor 2.0%, membrane protein genes 9.11%, which may be important gene classifications related to drought resistance. The result was helpful to completely comprehend genetic mechanism of drought resistance in wheat, to discover and utilize key genes in the improvement of crop drought resistance.

Effects of Different Irrigation Regimes on Protein Components and Dough Rheology of Wheat

YAN Mei-Ling;CAI Rui-Guo;JIA Xiu-Ling;WANG Jiang-Chun;WANG Zhen-Lin

Acta Agron Sin. 2007, 33(02):  337-340. 

Abstract ( 1998 )   PDF (49KB) ( 1063 )   Save

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Two winter wheat cultivars, GC8901with strong-gluten and SN1391 with weak-gluten, were employed in the field experiment to investigate the effects of irrigation regimes on grain quality, including protein content, protein component contents, farinograph parameters and extensograph parameters. The results showed that the grain albumin and globulin contents of both cultivars were enhanced by irrigation. An appropriate amount of irrigation made the contents of gliadin and glutenin enhance in strong-gluten cultivar GC8901, but decline in weak-gluten wheat SN1391. GC8901 was superior to SN1391 in terms of GMP and HMW-GS contents, flour sedimentation value, farinograph parameters and extensograph parameters. Irrigation improved the flour sedimentation value, farinograph parameters and extensograph parameters in strong-gluten cultivar GC8901, but not in weak-gluten cultivar SN1391, which was closely associated with the influence of irrigation on gliadin, glutenin, GMP and HMW-GS contents in the two cultivars.

SSR Linkage Map Construction and QTL Identification for Plant Height and Ear Height in Maize (Zea mays L.)

ZHANG Zhi-Ming;ZHAO Mao-Jun;RONG Ting-Zhao;PAN Guang-Tang

Acta Agron Sin. 2007, 33(02):  341-344. 

Abstract ( 2144 )   PDF (285KB) ( 1257 )   Save

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A mapping population consisting of 229 F₂ individuals derived from the cross between maize (Zea mays L.) inbreds R15 and Ye 478 was used in this study. Plant height (PH) and ear height (EH) of 229 F_2:4 population individual plants were measured at two locations by random block design in 2003. A genetic linkage map was constructed containing 146 simple sequence repeat (SSR) markers, which covered 1 666 cM of the maize genome, with an average distance of 11.4 cM. Composite interval mapping identified eight QTL for PH located on chromosomes 2, 3, 4, 5 and 8, and three QTL for EH located on chromosome 4, with explained phenotypic variation ranging from 6.67% to 11.59% and from 10.46% to 12.15%, respectively.

Genetic Analysis of Flowering Time and Photoperiod Sensitivity in Rapeseed (Brassica napus L.)

CAI Chang-Chun;CHEN Bao-Yuan;FU Ting-Dong;TU Jin-Xing

Acta Agron Sin. 2007, 33(02):  345-348. 

Abstract ( 2000 )   PDF (295KB) ( 1016 )   Save

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One doubled haploid (DH) population derived form F1 plants of the cross between DH401 (P₁) and Q2 (P₂) was used to study the inheritance of flowering time and photoperiod sensitivity of spring Brassica napus in this study. Two parents had exhibited a low and high sensitivity to photoperiod, respectively. Days to flower (DTF) were investigated in the P₁, P₂ and DH population at Hezheng (Gansu Province) with a long day in summer and at both Zhaoqing (Guangdong Province) and Wuhan (Hubei Province) with a short day in winter for consecutive two years. Photoperiod sensitivity index (PSI) was calculated according to DTF obtained from Hezheng and Zhaoqing. The means of DTF and PSI were analyzed by applying a mixed major gene and polygene inheritance model. The results showed that DTF at Hezheng, Wuhan and Zhaoqing was controlled by 3, 2, and 2 pairs of major genes with additive and epistatic effect plus polygenes, duplicate effect plus polygene, respectively. Heritability values of the major genes at the three locations were 91.13%, 63.05% and 62.02%, and those of polygenes were 4.43%, 1.58%, and 22.71%, respectively. The PSI was conditioned by 2 pairs of major genes with epistatic recessiveness effect and some polygenes. The heritability values of the major genes and polygenes were 50% and 37.5%, respectively. Other genetic parameters were also estimated. Therefore, it is speculated that both flowering time and photoperiod sensitivity in this DH population were controlled by 2 or over 2 pairs of major genes and polygenes, and the plants might have some different interaction models among flowering genes under different photoperiods. Meanwhile, how to use the results for Brassica napus breeding was discussed.