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Table of Content

    12 February 2008, Volume 34 Issue 02
    • CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
      Geographical Sources of Germplasm and Their Nuclear and Cytoplasmic Contribution to Soybean Cultivars Released during 1923 to 2005 in China
      XIONG Dong-Jin;ZHAO Tuan-Jie;GAI Jun-Yi
      Acta Agron Sin. 2008, 34(02):  175-183.  doi:10.3724/SP.J.1006.2008.00175
      Abstract ( 2128 )   PDF (452KB) ( 1217 )   Save
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      It provides important and necessary information for future soybean breeding to estimate the genetic contribution from the end ancestors of the released cultivars. Based on the pedigree data of 1 300 soybean cultivars released during 1923−2005 in China, the nuclear and cytoplasmic contribution rates of the end ancestors to each of the cultivars were calculated and analyzed. The 1 300 cultivars were traced back to 670 nuclear and 344 cytoplasmic ancestors and had 45.44% (49.77%), 23.23% (26.31%), 7.33% (9.62%), 4.40% (4.62%), 0.87% (1.08%), and 0.55% (0.77%) of nuclear (cytoplasmic) germplasm from Eco-region I, II, III, IV, V, VI, 17.75% (7.00%) from foreign countries, and 0.45% (0.85%) from geographic-unknown sources, respectively, while the nuclear (cytoplasmic) germplasm of the cultivars mainly came from their own eco-regions released them. During the last decade (1996−2005), among 592 cultivars released, their nuclear (cytoplasmic) germpasm from foreign countries, eco-region VI and some geographic-unknown sources increased by 11.96% (8.85%), 0.89% (1.07%), and 0.22% (0.62%), but those from eco-region I−V decreased by 7.83% (4.22%), 3.66% (6.13%), 0.66% (0.34%), 0.64% (0.41%), and 0.27% (0.12%), respectively; 46 core end ancestors of the cultivars released during 1996−2005 were nominated on the basis of their nuclear and cytoplasmic contribution; the exchange and utilization of germplasm among eco-regions were improved but mostly still limited in their own eco-regions. Therefore, it is necessary to strengthen germplasm exchange among eco-regions for broadening genetic bases of the future cultivars.

      Cloning and Characterization of Maize ZmASK1, a Homologue to Shaggy/GSK-3-like Gene, Involved in Plant Responses to Abiotic Stresses
      ZOU Hua-Wen;WU Zhong-Yi;ZHANG Xiu-Hai;WANG Yong-Qin;YANG Qing;CAO Ming-Qing;HUANG Cong-Lin
      Acta Agron Sin. 2008, 34(02):  184-191.  doi:10.3724/SP.J.1006.2008.00184
      Abstract ( 1985 )   PDF (511KB) ( 1333 )   Save
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      Shaggy/GSK-3-like genes play important roles in plant development and stress responses. One full-length cDNA encoding a shaggy/GSK-3 homologue was isolated from maize (Zea mays L.) by RT-PCR and named as ZmASK1 (for abiotic stress-induced kinase). The predicted ZmASK1 protein has 426 amino acids with an estimated molecular mass of 48.5 kD and an isoelectric point of 8.7. RT-PCR analysis showed that the ZmASK1 expression was induced by mannitol, salt and abscisic acid (ABA). Furthermore, in different tissues the ZmASK1 showed different expression patterns and was most abundant in ovaries. These results suggest that ZmASK1 may play multiple roles in abiotic resistance pathways, as well as in plant reproductive development. This is the first shaggy/GSK-3-like gene associated with stresses and development reported in maize.

      Construction of cDNA Expression Library of Oilseed Rape and Screening and Identification of Interaction Partner of PG, A Virulence Factor from Sclerotinia sclerotiorum
      WANG Xin-Yu;YANG En-Dong;QI Cun-Kou;CHEN Song;ZHANG Jie-Fu;YANG Qing
      Acta Agron Sin. 2008, 34(02):  192-197.  doi:10.3724/SP.J.1006.2008.00192
      Abstract ( 1725 )   PDF (550KB) ( 1712 )   Save
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      Sclerotinia sclerotiorum (Lib.) de Bary is the fungus that causes stem rot disease in oilseed rape. To overcome plant cell wall, during early pathogenesis, the fungus secretes several types of cell wall-degrading enzymes such as polygalacturonases (PGs). The activity of these enzymes is crucial for the colonization of plant tissues, and these enzymes can be determinants of pathogenicity or virulence. PG can activate defense reactions in plants, having no relation to the enzyme activity. In order to understand PG signaling pathway, PG gene was cloned from Sclerotinia sclerotiorum by RT-PCR, the encoding region of PG was fused to the yeast GAL4 DNA-binding domain in yeast expression vector PGBKT7 and an oilseed rape cDNA expression library was constructed in yeast. PG-interacting proteins were screened in the library with PG as bait by yeast two-hybrid assay. An interacting protein was isolated, sequencing and BLAST analysis revealed that the protein contains a C2-domain and was predicted to be a Ca2+ binding domain. The protein shares 80.24% identity in amino acids with a C2-domain protein in Arabidopsis with unknown function. The expression levels of the C2-domain protein in floral, leaf and stem organs of oilseed rape were investigated by semi-quantitative RT-PCR, the results showed that the C2-domain protein was highly expressed in leaves after induced by Sclerotinia sclerotiorum. Comparison in C2-domain proteins between oilseed rape and other species suggested that aspartatic acid residues involving in Ca2+ binding were conserved.

      QTL Mapping and Correlations between Leaf Water Potential and Drought Resistance in Rice under Upland and Lowland Environments
      QU Yan-Ying;MU Ping;LI Xue-Qin;TIAN Yu-Xiu;WEN Feng;ZHANG Hong-Liang;LI Zi-Chao
      Acta Agron Sin. 2008, 34(02):  198-206.  doi:10.3724/SP.J.1006.2008.00198
      Abstract ( 1900 )   PDF (257KB) ( 1103 )   Save
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      To reveal the role and genetic mechanism of leaf water potential (LWP) to japonica rice under various water status, 120 recombinant inbred lines (RILs) derived from a cross between IRAT109, an upland japonica rice, and Yuefu, a lowland japonica rice, were planted under both upland and lowland environments for mapping QTL associated with high LWP. LWP was measured at pre-dawn and mid-day. Drought resistance was evaluated with index of drought resistance (IDR), which was the ratio of grain yield of upland treatment to that of lowland treatment at maturity. Significant variations of LWP were observed in RILs in both upland and lowland treatments. Correlation analysis indicated that LWP at mid-day in upland (WPU) was positively correlated (r = 0.256**; r = 0.259**) with IDR and yield per plant (YPU), and water potential variation in upland (WDU) negatively correlated (r = -0.280**; r = -0.260**) with IDR and YPU. For LWP, 6 additive QTLs including 2 for LWP at pre-dawn in upland (WPIU), 1 for WPU, 2 for WDU, and 1 for LWP variation in lowland (WDL) and 5 pairs of epistatic QTLs including 1 for WPU, 1 for WPIU, 1 for LWP at pre-dawn in lowland (WPIL), and 2 for WPL were detected, respectively. Among the 6 additive QTLs, the 2 for WPIU (wpiu1 and wpiu4) and 1 for WPU (wpu6), all donated by IRAT109, can explain 5.4%, 7.9%, and 10.0% of the phenotypic variances, respectively; the 2 for WDU, wdu6 from IRAT109 and wdy12 from Yuefu, can explain 11.6% and 9.5% of phenotypic variances, respectively. For IDR, 3 additive and 2 pairs of epistatic QTLs were identified. The broad heritability of LWP was low for direct selection in the field, but may be effective via marker-assisted selection.

      Cloning and Mapping of a New MYB Transcription Factor (GhTF1) in Cotton
      FANG Dong;LÜ Jun-Hong;GUO Wang-Zhen;ZHANG Tian-Zhen
      Acta Agron Sin. 2008, 34(02):  207-211.  doi:10.3724/SP.J.1006.2008.00207
      Abstract ( 1882 )   PDF (585KB) ( 1235 )   Save
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      Plant MYB transcription factors are characterized by containing a structurally conserved MYB domain, they play important roles in the regulation of plant development and metabolism. Of them, the R2R3 MYB proteins with two MYB domains are involved in regulating secondary metabolism and cellular morphogenesis. Cotton fibers are single-celled seed trichomes. So far, the molecular process of fiber initiation is poorly understood. However, some transcriptional factors such as MYB genes are responsible to fiber cell initiation. Just like in Arabidopsis, leaf trichome formation is mediated through positive and negative regulators such as GL1 and GL2 encoding MYB transcription factors.
      In cotton, several MYB transcription factors have been cloned. Expression of type I genes (GhMYB1, 2, and 3) was detected in all tissues tested, while type II genes (GhMYB4, 5, and 6) process involving many other pathways such as signal transduction and transcriptional regulation. Moreover, GhMYB109, a gene encoding a R2R3 MYB transcription factor, was expressed specifically in fiber initials and elongating fibers. And over-expression of GaMYB2 complemented gl1 phenotype as well as induced seed trichome development in Arabidopsis, suggesting a role of MYB-like transcription factors in cotton fiber cell differentiation. The objective of the study was to clone new MYB genes, further put a foundation to illustrate these genes function in cotton fiber developmental stages. In this paper, a MYB transcription factor gene, GhTF1 was isolated from developmentally different cotton fiber pools of elite material 7235 library. GhTF1 (GenBank No.: EF651783) is a 1 115 bp cDNA, its open reading frame is 771 bp, and encodes a polypeptide containing 256 amino acids. GhTF1 was expressed constitutively in every tissue with different expression levels, e.g. with higher levels in fiber cells at initiation and elongations stages. GhTF1 had conserved coding region in A and D diploid cotton species, G. herbaceum and G. raimondii, however, there existed a large DNA fragment insertion/deletion and base substitutions in their corresponding intron region. Southern blotting analysis showed that there were two copies of GhTF1 in the genome of upland cotton, deducing that the sub-genome A and sub-genome D contain each of them. Using the BC1 mapping population derived from the hybridization between the upland cotton standard line TM-1 and G. barbadense cultivar Hai7124, and TM-1 as recurrent parent, GhTF1 was located on the chromosome 10.

      A Novel STS Marker for Leaf Rust Resistance Gene Lr24 in Wheat
      ZHANG Na;CHEN Yu-Ting;LI Ya-Ning;ZHANG Li-Rong;MENG Qing-Fang;ZHANG Ting;YANG Wen-Xiang;LIU Da-Qun
      Acta Agron Sin. 2008, 34(02):  212-216.  doi:10.3724/SP.J.1006.2008.00212
      Abstract ( 2041 )   PDF (721KB) ( 1323 )   Save
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      Wheat (Triticum aestivum L.) leaf rust, caused by Puccinia triticina (formerly P. recondita f. sp. tritici), is one of the most destructive diseases on wheat production throughout the world. The use of resistant varieties is an economical, efficient and environmental-friendly way for minimizing the losses caused by wheat leaf rust. To date, about 90 leaf rust resistance genes have been found or identified in wheat and its relatives. The resistance gene Lr24, derived from Thinopyrum ponticum (2n = 70), confers very strong resistance to wheat leaf rust. Eight molecular markers of Lr24 have been developed, however more markers are needed for identifying and mapping the gene. In the present study, Xcwem17 was discovered as a new EST-SSR marker of Lr24 with the susceptible line Thatcher and 468 individuals of F2 progeny derived from a cross between TcLr24 and Thatcher. The wheat seedlings of parents and F2 generation were inoculated solely with leaf rust spores, and cultured in greenhouse at (20±5)℃. The infection types (IT) of all plant materials were scored in six grades with Roelfs’s system at the 14th day after inoculation. Twenty-two pairs of SSR and EST-SSR primer on wheat chromosome 3D were used to tag the resistance gene Lr24. One of the four polymorphism primers co-segregated with Lr24 was acquired after testing with 468 F2 individuals. Sequence analysis showed that Xcwem17 was 223 bp, in which from the 7th to 220th bp (coding 71 amino acid residues) showed 36% identity to a poly-protein gene of rice chromosome 5. The marker Xcwem17 was further converted into a STS marker, and tested together with a reported SCAR marker in the same population. The results showed that they both co-segregated with Lr24, and could amplify a single 310-bp (SCAR marker) or 180-bp (STS marker) band only in TcLr24 and Taishan 1 (a landrace carried Lr24). It suggests that the STS marker developed in the study can be used in MAS directly.

      Application Technique of Marker Grouping and Ordering in Genetic Linkage Map Construction Using Mapmaker/Exp

      XING Guang-Nan;ZHAO Tuan-Jie;GAI Jun-Yi

      Acta Agron Sin. 2008, 34(02):  217-223.  doi:10.3724/SP.J.1006.2008.00217
      Abstract ( 3244 )   PDF (579KB) ( 4574 )   Save
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      Mapmaker/Exp (3.0) is one of the most often used computer software packages for constructing genetic linkage map worldwide. It was found that the distances of the map constructed with the software were often exaggerated when large number of markers was involved. The present paper is to introduce our technical experiences in using Method 2 (marker number more than 500) of the software for a more reasonable linkage map. In Method 2 of Mapmaker/Exp (3.0), markers were usually grouped into linkage groups under an identical LOD value for all linkage groups; and then an “order” command followed by multiple “ripple” command was used to test the order with a window size of 5. The causes for the exaggerated map distances were found probably in two aspects in Method 2, i.e. the way of assignment of LOD value and utilization of “order” and “ripple” commands in marker grouping and marker ordering. Therefore, two innovations were taken in the application of Method 2 as: (1) different LOD values used for some specific linkage groups in addition to a common LOD value for the others; and (2) multiple “order” commands each followed with multiple “ripple” commands used for ordering markers in linkage groups, combined with some artificial adjustments when needed, for relatively higher likelihoods of the linkage groups. The innovations were used to construct a soybean genetic linkage map which showed more reasonable than that constructed with the old procedure with a better consistency to the soybean consensus map.

      An Efficient Culture System for Synchronization Control of Somatic Embryogenesis in Cotton (Gossypium hirsutum L.)
      CAO Jing-Lin;ZHANG Xian-Long;JIN Shuang-Xia;YANG Xi-Yan;ZHU Hua-Guo;FU Li-Li
      Acta Agron Sin. 2008, 34(02):  224-231.  doi:10.3724/SP.J.1006.2008.00224
      Abstract ( 1987 )   PDF (1877KB) ( 1232 )   Save
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      Low efficiency of somatic embryogenesis and asynchronous embryo development brings a lot of difficulties to the physiological, biochemical, and molecular biological studies of embryogenesis processes in cotton. In the present study, a simple and efficient method was developed to improve somatic embryogenesis frequency and synchronous development of mass somatic embryos from cultured cells of Gossypium hirsutum cv. Coker 201. The embryonic calli obtained after several rounds of subculture were scattered in liquid medium by shaking for 2 d and then resuspended in the same liquid medium after discarding the larger callus aggregates over 30 mesh-size-sieve. The suspensions cultured for 14 d were filtered through 50 mesh-size-sieve and then the aggregates over the sieve were inoculated onto the surface of Whatman filter paper placed on the solid medium containing 2.46 mmol L-1 IBA and 0.70 mmol L-1 kinetin to culture for 21 d followed by subculturing. The somatic embryo amount obtained by using new system was 15.5-fold higher than that by suspension culture and 3-fold higher than that by solid culture (without filter papers) at the same culture period, and in the different stages of somatic embryo development, 70.2% for globular, 52.3% for torpedo-shaped and 73.0% for cotyledonary embryos were obtained respectively during the culture. Suspension culture combined with solid culture with filter paper were considered to be beneficial for synchrony of somatic embryogenesis and mass embryo development.

      Analysis of Differential Expression of Mitochondrial Proteins between C-Type Cytoplasmic Male Sterility Line C48-2 and Maintainer in Maize
      XU Ke;CAO Mo-Ju;ZHU Ying-Guo;PAN Guang-Tang;RONG Ting-Zhao
      Acta Agron Sin. 2008, 34(02):  232-237.  doi:10.3724/SP.J.1006.2008.00232
      Abstract ( 2071 )   PDF (1238KB) ( 1307 )   Save
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      Cytoplasmic male sterility (CMS) in maize (Zea mays L.) is categorized into T-CMS, C-CMS, and S-CMS types based on the specific restoration of nuclear gene, in which C-CMS has a great application potential in maize hybrid breeding due to its stable sterility and resistance to Helminthosporium maydis Nisik. The sterile mechanism of C-CMS is not fully understood for its later discovery and utilization than these of T-CMS and S-CMS. The objective of the study was to give some evidences and explanations to the sterility reason of C-CMS in maize by analyzing the differential expression of anther mitochondrial proteome between a C-type sterile line (C48-2) and its maintainer (N48-2). The mitochondrial proteins in anthers of C48-2 and N48-2 were separated firstly by two-dimensional electrophoresis with immobilized pI (3-10, non-linear) gradients and then by SDS-PAGE. The coomassie brilliant blue-stained protein spots were analyzed using PDQUEST software, there were about 260 detectable spots on each 2D-gel. With direct MALDI-TOF mass spectrometry analysis and protein database searching, only 2 out of 10 protein spots were identified with significative data, which were up-regulated in mononuclear phase of C48-2. They were identified as glutamate dehydrogenase (GDH) and voltage-dependent anion channel protein-1 (VDAC1), respectively. The GDH exists mainly in mitochondria of higher plants and plays an important role in nitrogen metabolism. Once the GDH is up-regulated at any phase of plant development, the normal supply of energy will be affected, probably leading to cytoplasmic sterility. The VDAC1 plays an essential role not only in the permeability of the mitochondrial membrane, but also in apoptosis mediated by the mitochondrial pathway. Overexpression of VDAC1 in a variety of cells induced apoptotic cell death, indicating VDAC1 as a conserved mitochondrial element of the death machinery. Our research suggests that the GDH and VDAC1 in mitochondria probably cause the sterility in C-CMS in maize.

      Changes in Chloroplast Proteome of Chinese Cabbage Seedlings Induced by PSⅡInhibiting Herbicide Atrazine

      LI Xue-Mei;ZHANG Wei-Jia;WANG Yan;WANG Zhen-Ying;PENG Yong-Kang

      Acta Agron Sin. 2008, 34(02):  238-242.  doi:10.3724/SP.J.1006.2008.00238
      Abstract ( 1762 )   PDF (348KB) ( 1054 )   Save
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      To investigate the mechanism with which the herbicides works, chloroplast proteome was analyzed in Chinese cabbage seedlings treated with PSⅡinhibiting herbicide Atrazine by using 2-DE techniques and MALDI-TOF MS. The results indicated that 23 protein spots showed significant and reproducible changes in treated-seedlings, of which 4 protein spots were down–regulated (spots 15-18) and 5 protein spots up-regulated (spots 19-23). Fourteen protein spots showed qualitative changes between control and treated samples. Ten out of 14 proteins (spots 5-14) were newly synthesized in the treated seedlings. Four out of 14 protein spots (spots 1-4) disappeared treated with high concentration Atrazine (10 mg L-1), and not with low concentration Atrazine (0.01, 0.1, and 1 mg L-1, respectively). From the 14 protein spots, spots 1, 2, 5, 6, 8, 10, and 13 were respectively identified as glycos-transf-Ⅰ, isoprene synthase, hypothetic protein, proline dehydrogenase, putative 6-phospho-fructo kinase isozymeⅡ, calcium transporting ATPase, and maturase K, respectively. Changes in chlorophyll content and soluble protein content were also determined in treated seedlings. It was found that chlorophyll a content decreased, while chlorophyll b content showed a little increase without significant difference. The soluble protein content increased with increasing treatment concentration.

      Detection of Rice Fragrant Gene by Allele-Specific Amplification
      LU Yan-Ting;LIU Qing-Long;WANG Jun-Min;YAN Wen-Chao;YU Fa-Ming;JIN Qing-Sheng
      Acta Agron Sin. 2008, 34(02):  243-246.  doi:10.3724/SP.J.1006.2008.00243
      Abstract ( 1837 )   PDF (324KB) ( 1537 )   Save
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      The technically simplified approach of marker-assisted selection has directly and practically used in rice breeding. Fragrance in rice, a recessive trait, has been known to be due to an 8 bp deletion and 3 SNPs difference in a gene on chromosome 8. Rice breeders have an interest in gaining access to a simple and inexpensive method for distinguishing between fragrant and non-fragrant rice. Allele specific amplification (ASA) is a low-cost, robust technique that can be utilized to discriminate between the alleles. We used a single tube ASA assay which allows discrimination between 9 fragrant and 3 non-fragrant rice varieties and 3 F1 plants to identify homozygous fragrant, homozygous non-fragrant, and heterozygous non-fragrant individuals. The research showed that using tetras-primer amplification refractory mutation system PCR could result in three possible outcomes. External primers generated a fragment of approximately 580 bp as a positive control for each sample. Internal and corresponding external primers produced a 355 bp fragment from a non-fragrant allele, a 257 bp fragment from a fragrant allele and both 355 bp and 257 bp fragment from a heterozygous allele allowing simple analysis on agarose gels. A single tube allele specific PCR which allows determination of the genotypic status of an individual rice plant, either homozygous fragrant, homozygous non-fragrant or heterozygous has practical utility for rice breeders worldwide.

      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Changes in Growth Duration of Rice with Altitude and Its Temperature Accumulation Effect in Panxi Region, China
      YUAN Ji-Chao;YANG Shi-Min;WANG Ming-Tian;WU Yong-Cheng;ZHU Qing-Sen;YANG Jian-Chang
      Acta Agron Sin. 2008, 34(02):  247-253.  doi:10.3724/SP.J.1006.2008.00247
      Abstract ( 1936 )   PDF (453KB) ( 1082 )   Save
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      There have been a lot of studies on the influencing factors of rice growth duration and its predicting models in plain and hilly regions with a low altitude, but few studies involving the relationship between rice growth duration (or the effective temperature accumulation it needed) and altitude in mountain areas. In order to study the variation of rice growth duration with altitude and its temperature accumulation effect, a group of field experiments at 8 sites with different altitudes from 540 to 1 800 m in Panxi region, Sichuan province were conducted, in which, 3 sowing dates and 5 cultivars including hybrid indica rice, indica rice, and japonica rice were selected. The experimental results were as follows. The rice growth duration in days was not only different with the cultivars used, but also strongly influenced by therm-photo environment. The duration in days from sowing date to full heading period and the effective temperature accumulation it needed had largely instability at the sites selected. They were mainly and certainly related with altitude and latitude of the sites. A series of lineal regression equations of growth duration in days from sowing to full heading and the total growth duration (y) responding to latitude (x1) and altitude (x2) of the sites were founded. However, the relationship between the effective temperature accumulation needed (y) and the latitude (x1) and altitude (x2) obeyed a quadratic function. With the altitude ascending, the duration in days from sowing date to full heading period prolonged, while the effective temperature accumulation it needed increased firstly and decreased secondly. effective temperature accumulation was the highest in the middle altitude region which was about 1 200 m to 1 300 m.

      Changes of C/N Ratio in the Subtending Leaf of Cotton Boll and Its Relation- ship to Cotton Boll Dry Matter Accumulation and Distribution
      HU Hong-Biao;ZHANG Wen-Jing;CHEN Bing-Lin;WANG You-Hua;SHU Hong-Mei;ZHOU Zhi-Guo
      Acta Agron Sin. 2008, 34(02):  254-260.  doi:10.3724/SP.J.1006.2008.00254
      Abstract ( 1822 )   PDF (281KB) ( 985 )   Save
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      To study changes of the C/N ratio in the subtending leaf of cotton boll and its relationship with boll dry matter accumulation and distribution, 14 cotton cultivars with significant differences in yield were chosen as materials. The results showed that dynamic changes of the C/N ratio in the subtending leaf of cotton boll could be simulated with quadratic: y=at2+bt+c [y stands for the C/N ratio and t stands for boll age (d)]. Correlation analysis indicated that a, b, c and the maximum C/N ratio were significantly correlated with dry weight per boll (the total of boll shell, seed and fiber dry matter weight per boll) and boll weight (the total of seed and fiber dry matter weight per boll), but not with lint percentage and boll shell percentage. Therefore, a, b, c and the maximum C/N ratio were selected as the variables for clustering analysis. The 14 cotton cultivars were clustered into 3 groups: GroupⅠ(including American Cotton-33B etc.), GroupⅡ(including Ke Cotton 1 etc.) and GroupⅢ(including China Cotton Re-search Institute 35 and China Cotton Research Institute 38). There were significant differences in dynamic changes of the C/N ratio and dry weight per boll among three groups. The C/N ratio of the GroupⅢwas much higher than that of GroupⅠ&Ⅱ during the period from 10 to 17 days of boll age and still maintained around 2.5 after 24 days of boll age, showing a widest changing range and a highest average value during the whole boll developing stage. The boll dry matter accumulation of GroupⅢ had the longest speedy rising period with the lowest velocity, which resulted in the highest final dry weight per boll and boll weight. However, there existed no significant difference in dry matter distribution in each part of cotton boll among three groups and no visible connection between the final lint percentage as well as lint yield and the characters of the C/N ratio in the subtending leaf of cotton boll. In conclusion, dynamic characters of the C/N ratio in the subtending leaf of cotton boll are significantly different among different genotypes, and the C/N ratio declined dramatically from 10 to 17 days of boll age and maintained at a relative higher level after 24 days of boll age, and that is favorable to cotton boll dry matter accumulation.

      Effect of Polyamines on Chilling Tolerance in Seed Imbibition and Seed Germination in Maize
      ZHENG Yun-Ye;CAO Dong-Dong;ZHANG Sheng;GUAN Ya-Jing;HU Jin
      Acta Agron Sin. 2008, 34(02):  261-267.  doi:10.3724/SP.J.1006.2008.00261
      Abstract ( 2267 )   PDF (323KB) ( 1480 )   Save
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      Chilling injury caused by low temperature happens frequently during seed imbibition in maize (Zea mays L.). Polyamines (PAs) such as putrescine (Put), spermindine (Spd), and spermine (Spm) are accumulated in plants, maintaining the stability and integrality of membrane under low temperature stress and eliminating free radicals in cells. They have been used by presoaking and leaf spray in barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) respectively to improve the tolerance to abiotic stresses. In the present study, Spd and Spm were used as an inducer to investigate chilling tolerance during seed imbibition and seed germination in maize. Seeds of maize inbred lines ‘Hung C’ (chilling-tolerant) and ‘Mo17’ (chilling-sensitive) were soaked with 0.25 mmol L-1 of Spd and Spm, respectively for 72 h under dark at 15℃, and the control was not treated with PAs. Part of the seeds were germinated for 7 d under 25℃ after imbibition for 48 h under 5℃ in dark. The germination rates were tested every day with 4 replicates (25 seeds per replicate) each. Other part of seeds were imbibed for 0, 12, 24, 36, and 48 h, respectively at 5℃ in dark. The embryos were separated from the seeds for testing the activities of peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidese (APX) as well as the contents of proline (Pro), soluble protein, and nucleic acid in embryo leakage. All measurements repeated 3 times with 15 seeds each time. Under chilling stress, both Spd and Spm treatments increased the activities of POD, CAT, SOD, and APX, raised soluble protein and Pro contents, and reduced nucleic acid content in embryo leakage. The treatments also increased seed germination percentage and shortened the mean germination time (MGT) which increased by 18.5% and 14.0%, and decreased by 1.21 d and 1.14 d for Spd and Spm treatments, respectively as compared with those of control. During the imbibition under chilling stress, the activities of POD, CAT, SOD and APX, Pro and soluble protein contents in embryos and germination percentage were higher, whereas the content of nucleic acid and MGT were lower in untreated Huang C seeds than in untreated Mo17 seeds. The results suggested that Spd and Spm treatments can improve the chilling tolerance during seed imbibition, and enhance the germination of maize seeds.

      Effects of Soil Moisture and Irrigation Patterns during Grain Filling on Grain Yield and Quality of Rice and Their Physiological Mechanism

      LIU Kai;ZHANG Hao;ZHANG Shen-Feng;WANG Zhi-Qin;YANG Jian-Chang

      Acta Agron Sin. 2008, 34(02):  268-276.  doi:10.3724/SP.J.1006.2008.00268
      Abstract ( 2046 )   PDF (480KB) ( 1310 )   Save
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      The objective of this study was to investigate whether a moderate soil-drying or an alternate wetting and moderate-drying irrigation during the grain filling period could improve the grain quality and increase yield in rice. Two rice cultivars, Wuyujing 3 (japonica) and Yangdao 6 (indica), were grown in pots and cement tanks. Three soil moisture treatments and three irrigation patterns, well-watered (WW, well-watered) and conventional irrigation (CI, continuous flooding), moderate soil-drying (MD, soil water potential at – 10 ~ – 30 kPa) and alternate wetting and moderate-drying irrigation (W-MD, re-watered when soil water potential reached at – 25 kPa), and severe soil-drying (SD, soil water potential at – 40 ~ – 60 kPa) and alternate wetting and severe-drying irrigation (W-SD, re-watered when soil water potential reached at – 50 kPa), were imposed during grain-filing. Compared with WW or CI, MD or W-MD significantly increased grain weight, peak viscosity, and breakdown values, and re-duced chalkiness and setback values. The results were reversed for SD or W-SD treatments. Activities of sucrose synthase (SuS), adenine diphosphoglucose pyrophosphorylase (AGP), starch synthase (StS), and starch branching enzyme (SBE) in grains in mid-dle and late grain-filling stages were significantly enhanced, whereas ethylene revolution rate of grains decreased, under MD or W-MD. The SD or W-SD had the opposite effects. The results indicate that both MD and W-MD can improve rice quality, resulting from the physiological mechanism of enhancing activities of SuS, AGP, StS, and SBE and decreasing ethylene production in grains.

      Dynamic Changes of Endogenous GA3 and ABA Contents in Tea Cultivars with Different Phenological Characters and Their Impact on the Regulation Axillary Buds Sprouting

      YU Li-Jun;SHI Yun-Feng;XIAO Hai-Yun;LIU Fu-Zhi;LIU Zhong-Hua

      Acta Agron Sin. 2008, 34(02):  277-283.  doi:10.3724/SP.J.1006.2008.00277
      Abstract ( 1960 )   PDF (226KB) ( 1126 )   Save
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      By using Enzyme Linked Immunity Absorb Assay (ELISA) method, the dynamic changes of endogenous GA3 and ABA contents in leaves of 5 tea cultivars were determined before and after the sprouting of axillary buds from 8 Mar. 2003 to 25 Mar. 2006. Results showed that the dynamic change of GA3 concentration in mature leaves of various cultivars in the period of 8 Mar. 2003 to 25 Mar. 2006 showed a “sharply decreasing-slightly increasing-decreasing-sharply increasing” pattern with the growth of tea plant in every year. The first ascending time of GA3 concentration appeared earlier in early-sprouting cultivars, and later in late-sprouting cultivars. The lowest ABA concentration also appeared earlier in early-sprouting cultivars and later in late-sprouting cultivars. The annual average GA3 concentration in mature leaves of five tea cultivars was higher in early-sprouting cultivars than in medium-sprouting cultivars and much higher than in late-sprouting cultivars. During the dormancy of tea plant in winter season, the GA3 concentration in mature leaves in the lowest level in the whole year, and the ABA concentration in mature leaves was in the highest level. From Nov. 2003 to Jan. 2006 this three years, the average concentrations of GA3 and GA3/ABA ratio in mature leaves were closely related with the sprouting period of overwintering buds. The research data showed that the GA3 concentration in axillary buds during the sprouting period in spring was higher than that of in mature tea leaves, however, the ABA concentration in the axillary buds was lower than that of in mature tea leaves.

      Effects of Green-Revertible Albino Gene on the Agronomy Traits and Appearance Quality in Rice

      ZHANG Yi;LÜ Jun;LI Yun-Feng;YANG Kun;SHEN Fu-Cheng;ZHANG Qiao-Lin;PENG Qi-Lian;ZHOU Ya-Lin;HE Guang-Hua

      Acta Agron Sin. 2008, 34(02):  284-289.  doi:10.3724/SP.J.1006.2008.00284
      Abstract ( 1898 )   PDF (329KB) ( 1373 )   Save
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      Chlorophyll content mutants are important genetic material for photosynthesis and cytoplasmic-nuclear interaction studies, and useful breeding materials for identifying and improving the purity of hybrid seeds. A variant of green-revertible albino (gra) was discovered among the progenies from a crossing of G46B (indica)×Sirio (japonica). A pair of near-isogenic lines (NILs) of Gra and gra were bred by continuously heterozygote self-crossing. The near-isogenic level was evaluated through analysis of polymorphism detected by 120 InDels markers and the results indicated that Gra and gra is a good pair of NILs. Comparative analysis on agronomic and appearance quality traits of NILs indicated that the gra(t)-gene reduced half of the content of chlorophyll at 4–5th leaf stage, and significantly decreased the white root number at transplanting stage, leaf producing speed, tillering ability as well as available spike number and yield per plant. The gra(t)-gene also significantly influenced the length of 2, 3–5, 7, and 9–11th leaves and the width of 3–7 and 9th leaves. However, the gra(t) gene didn’t affect the other agronomic traits and the appearance quality of the milled rice investigated in this study.

      Characteristics of Growth and Development of Winter Wheat under Zero-tillage in North China Plain

      LI Su-Juan;CHEN Ji-Kang;CHEN Fu;LI Lin;ZHANG Hai-Lin

      Acta Agron Sin. 2008, 34(02):  290-296.  doi:10.3724/SP.J.1006.2008.00290
      Abstract ( 2082 )   PDF (260KB) ( 1180 )   Save
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      The agro-ecosystem in North China Plain is challenged by water shortage, environmental pollution with burning crop stalks and high cost. Practice of conservation tillage is very essential in North China Plain for saving water, reducing environment pollution and tillage cost, increasing the crop productivity and organic matter content of soil. With the extension of conservation techniques, zero-tillage arouses more and more attention in the area. Some investigators found yield increasing with zero-tillage, but some experiments indicated the weaker seedling and revival stage delaying of winter wheat under zero-tillage as compared with conventional tillage. The objectives of this study were to evaluate the growth and development of winter wheat under zero-tillage treatment in North China Plain and to explore the reason of the influence of zero-tillage. The experiment using the winter wheat cultivar “Kenong 9204” with three tillage treatments including conventional tillage with stubble incorporating (CT), rotary tillage with residue returning (RT), and zero-tillage with stubble direct drilling (ZT) was conducted in Luancheng Ecological Experimental Station of Chinese Academy of Sciences during 2004–2006 growth seasons. To keep similar rate of seedling emergence in all treatments, seeding rate was from 165.0 kg ha-1 (in CT and RT treatments) increased to 262.5 kg ha-1 in ZT treatment. In addition to the characteristics of growth and development of wheat, the plough layer temperature and soil water con-tent were measured. Soil temperature was measured by thermoelectric couple every day. Soil moisture was observed by TDR (plough layer soil) and neutron instrument (deeper than 20 cm) every 14 d during winter and every 7 d for the rest time. The basic seedling and tillers in three treatments ranked significantly as ZT<RT<CT (P≤0.05), but the percentage of seed-setting tillers in ZT treatment was higher than that in CT treatment. The number of basic seedling in ZT was lower than that in CT by 28.9% and 11.7% in 2004–2005 and 2005–2006 growth seasons, and lower than that in RT by 11.7% and 10.0%, respectively. The plant height, leaf area index, dry weight of wheat shoot and grain yield were the lowest in ZT treatment because of the deficient population. In ZT treatment, the maximum leaf area indices were 2.9 and 6.0 in two growth seasons, respectively. Grain yield of ZT reduced by 30.1% and 27.2% as compared with that of CT in the two growth seasons and decreased by 15.3% and 25.2% than that of RT, respectively. The water content in 0–30 cm soil layer in ZT treatment was significantly higher (P<0.05) than that in CT treatment during the whole growing period. The topsoil temperature was the lowest in ZT treatment from seedling to revival stages, indicating ZT had a “lower temperature effect”, which delays the emergence and revival of seedlings and reduce tillering rate in winter wheat. The time of seedling emergence and revival in ZT was late 1–3 and 4–5 d than that in CT and RT, respectively.

      Growing Characteristics of Rice Seedlings of Over-Optimum Age for Mechanical Transplanting
      ZHANG Zu-Jian;WANG-Jun;LANG You-Zhong;YU Lin-Hui;XUE Yan-Feng;ZHU Qing-Sen
      Acta Agron Sin. 2008, 34(02):  297-304.  doi:10.3724/SP.J.1006.2008.00297
      Abstract ( 1973 )   PDF (461KB) ( 1149 )   Save
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      The rice seedlings grown for a long time and not suitable for mechanical transplanting are called as “seedlings of over-optimum age”. In this study, Yangjing 9538 was planted in seedling raising plates with different treatments of seedbed soil fertilizing levels. In the stage of 28 days after sowing, the above ground parts of seedlings could still maintain a few growth, seedling dry weight and the dry weight perunit of seedling height still had a little increment. But leaf color (SPAD) descended quickly. The roots grew stagnantly, root length and number of roots stopped increasing, the activity of root and root/shoot ratio descended quickly, and obviously. In the stage of 36 days after sowing, the seedling height increased quickly none the less, the dry weight per unit of seedling height descended significantly, seedling leaf color kept in a low level. The activity of root was low and the root system growth activity was in the lowest level. The seedling sugar metabolism was sensitive to the stage when the seedlings were at over-optimum age, while nitrogen metabolism was blunt, so the ratio of seedling sugar to nitrogen in the stage of 36 days after sowing descended significantly. The characteristics of seedling growth in the stage when the seedlings were at over-optimum age affected significantly by different fertilization levels. Under high level of fertilization, the basal part width of shoot wasn’t changes obviously, but seedling height increased quickly, so the dry weight per unit of seedling height descended quickly; the roots grew weakly than these under low level of fertilization, root number and root length were less, the root system growth activity de-scended quickly, root/shoot ratio descended obviously. The seedbed soil fertilization level affected carbon and nitrogen metabo-lisms obviously, nutrition decreased largely under high level of fertilization. The above results showed that, rice seedling growth in the stage of 28 days especially 36 days after sowing was decided by the growing condition in a very great degree. The rice seedling in the low fertilization level can maintain higher sugar to nitrogen ratio in the stage when the seedling were at over-optimum age, and keep better nourishment for seedling growth.

      Effects of Seed Soaking with Glycinebetaine on the Salt Tolerance of Cotton Seedlings
      LI Yu-Jing;SONG Xian-Liang;YANG Xing-Hong;LIU Juan;LI Xue-Gang;ZHU Yu-Qing;SUN Xue-Zhen;WANG Zhen-Lin
      Acta Agron Sin. 2008, 34(02):  305-310.  doi:10.3724/SP.J.1006.2008.00305
      Abstract ( 1990 )   PDF (431KB) ( 1283 )   Save
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      Cotton is a main agricultural product in the world and salty soils have a tremendous impact on farmers livelihood. Finding ways to increase salt tolerance of cotton is crucial in agricultural. Glycinebetaine (GB) is an amino-acid derivative accumulated in certain plants under water stress, which has been studied as an osmoprotectant in the adaptation to water, salt and cold stress. The adaptation varies with and depends on numerous factors including types of crop, timing and rate of fertilizer application, and environmental conditions. Exogenous GB may help to reduce the negative effects of salt stress in cotton production. The objective of this study is to determine the effects of seed soaking with GB on the salt tolerance of cotton seedlings whether under salt stress or not. Two transgenic insect resistant cotton cultivars 99B and LMY28 abroad generalized in production were used in these examinations. Some of the seeds of the two cotton cultivars were soaked with 400 μg mL-1 GB for 15 h and others with water for 15 h, and then cultured with Hoagland solution or Hoagland solution containing 0.4% NaCl in pots under field conditions. The results indicated that seed soaking with GB promoted the synthesis of chlorophyll, but decreased the value of Chl a/b; increased the chlorophyll fluorescence dynamic parameters Fv/Fm, Fv/Fo, photosynthetic electron transport rate (ETR) and actual quantum efficiency (ΦPSⅡ), which improved the photosynthetic capacity of cotton seedlings, leaves consequently. In addition, seed soaking with GB also increased the soluble sugar content in leafs and stems of cotton seedlings, increased the proline content in leafs of cotton seedlings, but decreased the relative electrical conductivity of cotyledon, indicating that seed soaking with GB can promote osmotic adjustment ability and alleviate the harm caused by salt stress. Seed soaking with GB also promoted N metabolism through increasing the activity of NR of cotyledon. Two cotton cultivars had the same reaction trend to GB treatment.

      A Simulation Model of Leaf Elongation Process in Rice

      CHANG Li-Ying;GU Dong-Xiang;ZHANG Wen-Yu;YANG Jie;CAO Wei-Xing;ZHU Yan

      Acta Agron Sin. 2008, 34(02):  311-317.  doi:10.3724/SP.J.1006.2008.00311
      Abstract ( 2099 )   PDF (544KB) ( 1348 )   Save
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      Modeling leaf growth dynamics in rice is of significant importance for realizing virtual and digital plant growth. Based on time-course observations on leaf morphological properties (leaf length and leaf width) on main stems and tillers under different nitrogen rates and water regimes with four rice cultivars, the change patterns of leaf morphology with growth progress and environmental factors were characterized, and a dynamic model was developed to simulate time-course growth characters of different leaves on rice plant. The growth dynamics of leaf length on stem and tiller could be described with a logistic model, leaf width with conic equation, and leaf shape with exponential function and quadratic equation. The effects of nitrogen and water conditions on leaf growth were quantified by the effective values of leaf nitrogen concentration and water content. The model was validated with independent field experiment data of different nitrogen rates, and the mean RMSEs of dynamic leaf length were 3.60 cm and 3.96 cm, those of leaf width were 3.15 cm and 3.56 cm on main stem and tillers, respectively. The results indicated that the present model had a good performance in predicting morphological growth of leaf on stem and tiller in rice plant.

      Border Cells Alleviating Aluminum Toxicity in Soybean Root Tips
      LI Rong-Feng;CAI Miao-Zhen;LIU Peng;XU Gen-Di;LIANG He;ZHOU Zhu-Gui
      Acta Agron Sin. 2008, 34(02):  318-325.  doi:10.3724/SP.J.1006.2008.00318
      Abstract ( 2015 )   PDF (388KB) ( 1242 )   Save
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      Root border cell (BC) is a group of cells from the apex of root, which has been considered to play a vital role in protecting root tip from extracellular biotic and abiotic stresses. It is known that the BC may secrete saccharide to chelate Al3+ and alleviate cell damage under aluminum stress. In this paper, we aimed to reveal the effects of root BC on alleviation of aluminum toxicity to root tips with soybean [Glycine max (L.) Merrill] cultivar Zhechun 3 during the development of roots. The BC number, activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) as well as protein content were measured under 0 (CK), 50, 100, 200, and 400 μmol L-1 Al3+ stress for 12 and 24 h respectively, with static culture (to maintain border cells adhered to root tips) and shaking culture (to remove border cells from root tips completely). The results showed that the viable border cells accounted for 60%–80% when root length was 5 mm. 50–400 mmol L-1 Al3+ treatment for 12 h increased the number of border cells, but inhibition of border cell development by Al3+ turned up after 200, 400 mmol L-1 Al3+ treatment for 24 h. When soybean roots were cultivated by shaking to remove border cells from root tips, root elongation was decreased with increasing Al3+ concentrations. However, this kind of inhibition of root growth was alleviated under static culture. At the same time, POD, CAT (under Al stress for 12 h), SOD activities and protein content were higher significantly than those under shaking culture withlower Al3+ concentration (0–100 mmol L-1 Al3+ treatment for 12 h and 0, 50 mmol L-1 Al3+ treatment for 24 h) stress. And no significant difference in POD, SOD activities and protein content was observed between static culture and shaking culture under higher Al3+ concentration (200, 400 mmol L-1 Al3+ treatment for 12 h and 100–400 mmol L-1 Al3+ treatment for 24 h) (P>0.05). The results suggested that border cells adhered to the root tips can significantly affect root relative elongation rate, POD, CAT, SOD activities and protein content of soybean root tip, and alleviate the toxicity Al3+ to plant root tips through increasing the number of border cells, enhancing the protein content of root tips and maintaining higher POD and SOD activities.

      Effects of Oligochitosan on Photosynthetic Parameter of Brassica napus Seedlings under Drought Stress
      LI Yan;ZHAO Xiao-Ming;XIA Xiu-Ying;LUAN Yu-Shi;DU Yu-Guang;LI Feng-Lan
      Acta Agron Sin. 2008, 34(02):  326-329.  doi:10.3724/SP.J.1006.2008.00326
      Abstract ( 2117 )   PDF (383KB) ( 1408 )   Save
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      Effect of oligochitosan on enzyme activities associated with the resistance to epiphyte and bacteria diseases of plants has been reported. Oligochitosan was prepared in our labarotory. Brassica napus L. seedlings without or with oligochitosan treatment under drought stress were determined with PP-Systems company CIRAS-2 portable Photosynthetic apparatus in the trial. The result indicated that the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) decreased significantly (P < 0.05), while stomatal limitation (Ls) increased significantly (P<0.05) in Brassica napus L. seedlings under drought stress. The Pn, Gs, and Ci increased, while Ls decreased when Brassica napus seedlings treated with 50 mg L-1 oligochitosan under drought stress. It indicated oligochitosan treatments are beneficial to reduce the drop of Pn caused by stomatal limitation in Brassica napus L. seedlings under drought stress. The dry weight of roots of rapes also increased by spraying oligochitosan under drought stress.

      RESEARCH NOTES
      Expression of the MADS-Box Gene GmAGL15 in Seed Development of Soybean

      WANG Xiao-Lin;CHEN Yan-Ping;YU De-Yue

      Acta Agron Sin. 2008, 34(02):  330-332.  doi:10.3724/SP.J.1006.2008.00330
      Abstract ( 2092 )   PDF (341KB) ( 1367 )   Save
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      AGL15 (AGAMOUS-like 15) is the only MADS domain regulatory factor identified to date that is expressed in a highly preferential manner in developing plant embryos. In this study, an AGL15–like gene was obtained from soybean by homology-based cloning method, here named as GmAGL15. Sequence analysis indicated that Arabidopsis AGL15 and GmAGL15 shared 61% of identity at amino acid level, especially 84.3% in the MADS domains, 63.2% in the K domains. RT-PCR analysis showed that GmAGL15 expressed only in embryos. A real-time PCR was performed to observe the expression profiling of GmAGL15 in developing seeds, and the results indicated that the expression of GmAGL15 appeared two peak values, at 15 DAF (days after flowering) and at 30 DAF. GmAGL15 was expressed at approximately 10-fold higher levels at the 30 DAF than other time of seed development. Based on these data, we suggest that GmAGL15 is likely to be an important component of the regulatory circuitry directing seed specific processes in soybean.

      Relationship between Changes of Na+, K+, and Ca2+ Contents during Seed Germination and Salt Tolerance in Maize
      SHANG Xue-Fang;DONG Shu-Ting;ZHENG Shi-Ying;WANG Li-Yan
      Acta Agron Sin. 2008, 34(02):  333-336.  doi:10.3724/SP.J.1006.2008.00333
      Abstract ( 2063 )   PDF (292KB) ( 978 )   Save
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      Maize (Zea mays L.) seeds of a salt tolerant cultivar Denghai 9 and a salt sensitive cultivar Jundan 18 were germinated and grown in 1/4 and 1/2 Hoagland solutions with 0, 50, 100, 150, and 200 mmol L-1 NaCl, respectively. The contents of Na+, K+, and Ca2+ in testa, embryo, endosperm, roots, root crown, and leaf were measured by ICP Mass. The Na+ content increased accordantly with the NaCl concentration in culture solution. In young seedlings, Na+ content in root and root crown was higher than that in leaf; in germinating seeds, it was significantly higher in embryo than in testa and endosperm. The capacity of Na+ accumulation in roots was strong, while the capacity of Na+ rejection in embryo was weak. The testa could also accumulate some Na+. The K+ and Ca2+ contents in germinating seeds and young seedlings of maize decreased obviously under NaCl stress, and the Ca2+ content showed changes in a large scale, which was 38.4%–55.9% in Denghai 9 and 65.6%–78.2% in Jundan 18. The capacities of Na+ accumulation and rejection as well as the Ca2+ selective absorption might be related to salt-tolerance of maize cultivars

      Cloning and Sequence Analysis of Partial Fragments of Critical Genes Involved in Flax Lignin Synthesis
      GAO Yuan;CHEN Xin-Bo;LONG Song-Hua;DENG Xin;ZOU Jie;LIU Ai-Ling
      Acta Agron Sin. 2008, 34(02):  337-340.  doi:10.3724/SP.J.1006.2008.00337
      Abstract ( 2093 )   PDF (280KB) ( 1349 )   Save
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      Flax is an important bast fiber crop. High content of lignin in the fiber greatly reduces fiber quality after degumming. The cDNA fragments of the critical genes involved in flax lignin biosynthesis were amplified from the flax bark mRNA by RT-PCR using the degenerate primers designed from conservative regions of existing homologous gene sequences. Thirteen distinct bands were obtained from agarose gel electrophoresis. The fragments from these bands were ligated to T-vector. The recombinant plasmids were transformed into E. coli. Five to eight separate clones transformed from each band were chosen to be sequenced. Sequence analysis and GenBank BLAST revealed eight new sequences, including two CCoAOMT (EF214740, EF214741) genes, three 4CL (EF214737, EF214738, EF214739) genes, and three F5H (EF214745, EF214746, EF214747) genes. This implies that these are multi-gene families for the genes encoding the three key enzymes in flax lignin biosynthesis. These partial cDNA sequence data are useful for cloning full length cDNA and characterizing the functions and regulations of the critical genes involved in flax lignin biosynthesis.

      GISH Analysis of Sweet Potato Wild Relative Ipomoea trifida (4x)
      XIANG Su-Qiong;WANG Wei-Xing;LI Xiao-Lin;CHEN Yao;GUO Qi-Gao;HE Qiao;LIANG Guo Lu
      Acta Agron Sin. 2008, 34(02):  341-343.  doi:10.3724/SP.J.1006.2008.00341
      Abstract ( 2076 )   PDF (299KB) ( 1024 )   Save
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      Using genomic DNA of I. trifida (2x) as probe, I. trifida (4x) lines 695104 and 697288 were analyzed with genome in situ hybridization (GISH). The results showed that the two liness were very closely related to I. trifida (2x) based on hybridization signals. Bright and even hybridization signals were observed on all chromosomes of 695104, showing that I. trifida (4x) 695104 should be from doubling of I. trifida (2x) chromosome set. Hybridization signals of 697288 differed from those of 695104 in brightness and region size. It displayed there types: the first was that 41 chromosomes appeared bright and even signals on whole chromosomal; the second was that 14 chromosomes presented even signals almost on whole chromosome but weaker than the first; the third was that 5 chromosomes displayed more weaker signals than those of both the first and the second. Therefore 697288 might derived from I. trifida (2x), but through recombination and variation.

      Effects of Nitric Oxide on Root Growth and Absorption in Wheat Seedlings in Response to Water Stress
      WEN Yu;ZHAO Xiang;ZHANG Xiao
      Acta Agron Sin. 2008, 34(02):  344-348.  doi:10.3724/SP.J.1006.2008.00344
      Abstract ( 1993 )   PDF (294KB) ( 1550 )   Save
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      To investigate the effects of exogenous NO donor sodium nitroprusside (SNP) on root growth and absorption in wheat seedlings (Triticum aestivum L.) under water stress, we cultured Yumai 49 seeds in Hoagland solution for 8 days, and then treated them for 2 days in Hoagland solution (CK) and Hoagland adding 50 μmol L-1 SNP, 25% PEG-6000 ( Ó0.8 MPa), and 50 μmol L-1 SNP+25% PEG-6000, respectively. The results showed that 50 mmol L-1 SNP increased the length of primary roots and the number of lateral roots by 11.94% and 83.78% respectively, and enhanced the root activity by 55.88%. Meanwhile, the K+ content in wheat roots increased by 42.52%. In the patch-clamp experiment, SNP increased the inward-rectifying K+ current of wheat root cells under water stress and the NO specific scavenger c-PTIO reversed the effect above. The results above indicated that exogenous NO enhanced wheat drought resistance possible by improving wheat roots growth, increasing root activity to enhance K+ influx by activating root inward-rectifying K+ channels.

Co-sponsored:
the Crop Science Society of China
the Institute of Crop Science, CAAS
China Science Publishing & Media Ltd.
Published: Science Press
Editor-in-chief: Wan Jian-min
Associate Editors-in-Chief:
Chen Xiao-ya Yang Jian-chang Zhang Xian-long Wang Jian-kang Xu Ming-liang Liu Chun-ming Wang Dao-wen Sun Chuan-qing Ding Yan-feng Jin Wei-wei Chu Cheng-cai Cheng Wei-hong
Director of the editorial department:
Cheng Wei-hong
CN 11-1809/S
ISSN 0496-3490
Post subscription code: 82-336

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  • Started in 2013
  • Covered by SCIE
  • Open access in ScienceDirect

Editor in chief: Wan Jian-min
CN 10-1112/S
ISSN 2095-5421, 2214-5141(online)
Online published:
https://www.sciencedirect.com/journal/the-crop-journal
Submission: https://www.editorialmanager.com/cj/
E-mail: cropjournal@caas.cn
Tel: 8610-82108548

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