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Table of Content

    12 June 2011, Volume 37 Issue 06
    • REVIEW
      Recent Findings in Plant Innate Immunity and Possible Impacts on Crop Disease-resistance Breeding
      ZHAO Kai-Jun, LI Yan-Qiang, WANG Chun-Lian, GAO Ying
      Acta Agron Sin. 2011, 37(06):  935-942.  doi:10.3724/SP.J.1006.2011.00935
      Abstract ( 3058 )   PDF (571KB) ( 5082 )   Save
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      Plants have been successfully living in such an environment in which there are myriads of potential microbial pathogens, indicating that plants possess an efficient immunity system. Recent studies have revealed that the plant immunity system consists of two layers of defense. The first layer, based on the sensitive perception of pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs) at the plant cell surface, is named as PAMP-triggered immunity (PTI). The second is called effector-triggered immunity (ETI), in which plants use additional receptors (such as R-gene products) to perceive pathogen virulence effectors that have evolved to suppress PTI. The conventional gene-for-gene resistance in plants belongs actually to ETI. For millions of years, natural selection has been driving pathogens to avoid ETI either by diversifying the recognized effectors or by acquiring additional effectors that suppress ETI. On the other hand, natural selection favors plant new R-genes that can recognize the newly acquired effectors in pathogen, resulting in new ETI to be triggered again. The latest studies have revealed the simple cipher that governs DNA recognition by TAL (transcription activator-like) effectors from plant pathogenic Xanthomonas. TAL effectors can specifically bind the target DNA of host plant with a novel protein-DNA binding pattern in which two amino acids recognize one nucleotide. Using this recognition code, TAL effectors can bind the promoter of target genes and induce the host diseases or resistance responses. Recent findings about plant innate immunity are reviewed in this paper and their possible applications in plant breeding for disease resistance are discussed.
      CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
      Response to Powdery Mildew and Detection of Resistance Genes in Wheat Cultivars from China
      LI Hong-Jie, WANG Xiao-Ming, SONG Feng-Jing, WU Cui-Beng, WU Xiao-Fei, ZHANG Ning, ZHOU Yang, ZHANG Hua-Yong
      Acta Agron Sin. 2011, 37(06):  943-954.  doi:10.3724/SP.J.1006.2011.00943
      Abstract ( 2287 )   PDF (280KB) ( 1567 )   Save
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      Wheat powdery mildew caused by Blumeria graminis (DC.) f. sp. tritici E.O. Speer is one of the major epidemic diseases threatening production of wheat (Triticum aestivum L.) in China. It is necessary to establish information on resistance to the disease in wheat cultivars and germplasm lines for parental selection in breeding, deployment of resistant germplasm, and application of resistant cultivars for controlling the disease. In this study, reactions to eight isolates of B. graminis (DC.) f. sp. tritici E.O. Speer were tested in commercial wheat cultivars, wheat lines involved in the national yield trials, and core collections. The presence of genes Pm4a, Pm8, and Pm21 for resistance to powdery mildew was detected using the gene-specific markers. Among 148 commercial wheat cultivars released since the 1980s, 16.9% exhibited resistance to multiple isolates, most of which were released in the 2000s. Over 50% of the cultivars released in different decades were susceptible to all the isolates tested. The frequencies of resistant cultivars from different wheat producing regions seemed to be associated with the significance of powdery mildew epidemic in a given region. Out of 1160 entries in the core collection, the proportions of entries resistant to isolate E09 were 3.4% and 4.2% in the landrace and improved cultivars, respectively. The Southwestern Autumn-Sown Spring Wheat Zone and the Xinjiang Winter-Spring Wheat Zone had higher percentages of E09-resistant cultivars than other wheat zones. None of the cultivar from the Southern Autumn-Sown Spring Wheat Zone, Northern Winter Wheat Zone, and Northern Spring Wheat Zone was resistant. The results of multiple-isolate test demonstrated that 33.7% were resistant among the 263 mini-core collection entries, most of which were resistant to one or two isolates. This indicates that there is a need to select resistant entries as recurrent parents for efficient use of existing core collection and to construct applied core collection for resistance to powdery mildew. Using the markers specific for resistance genes, the results of molecular detection demonstrated that 43.2% of the commercial cultivars contained gene Pm8. This gene was detected in the wheat lines involved in the national wheat yield trails at a high frequency. Genes Pm4a and Pm21 were detected mainly in the wheat lines or cultivars that were developed in the Yangtze River region. Some cultivars highly resistant to powdery mildew may possess other resistance genes that warrant further determination.
      Identification and Fine Mapping of a Semidwarf Gene iga-1 in Rice
      GUO Tao, HE Xing, RAO De-Hua, LIU Yong-Zhu, ZHANG Jian-Guo, CHEN Zhi-Jiang, WANG Hui
      Acta Agron Sin. 2011, 37(06):  955-964.  doi:10.3724/SP.J.1006.2011.00955
      Abstract ( 2331 )   PDF (456KB) ( 1511 )   Save
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      A semidwarf gene iga-1 of rice (Oryza sativa L.) by mutagenesis of outer space treatment from Texianzhan 13 was identified. The dwarf lines CHA-2 and CHA-2N which carried iga-1 showed great variation in agronomic traits. On the basis of the internode length of CHA-2 and CHA-2N, the mutant belongs to the dn type of dwarfing. GA3 treatment, endo-GA3 measurement and α-amylase activity analysis in endosperm showed that iga-1 is independent of gibberellin acid. Using a large F2 population derived from a cross between the CHA-2 and an japonica rice variety, 02428, the iga-1 gene was fine mapped into a 32.01 kb physical distance between two InDel markers, DL18 and DL19 on chromosome 5, where five open reading frames were predicted, one of which was the rice gibberellin-insensitive dwarf mutant gene D1. Sequence analysis showed that no variation in D1 locus was detected among CHA-2, CHA-2N and Texianzhan 13. Thus, D1 can not be the candidate gene of iga-1. Comparing the other dwarf genes on chromosome 5 showed that iga-1 is possibly allelic to the semidwarf gene sd-7.
      Analysis of Nuclear Gene Codon Bias on Soybean Genome and Transcriptome
      ZHANG Le, JIN Long-Guo, LUO Ling, WANG Yue-Ping, DONG Zhi-Min, SUN Shou-Hong, QIU Li-Juan
      Acta Agron Sin. 2011, 37(06):  965-974.  doi:10.3724/SP.J.1006.2011.00965
      Abstract ( 2279 )   PDF (246KB) ( 2256 )   Save
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      Research of soybean nuclear gene codon composition, usage pattern and influencing factors can provide theoretical basis for applying genetic engineering techonology to improve soybean varieties. A total of 46 430 high confidence coding sequences predicted from soybean genome and 2 071 full-length transcripts were used to analyze the composition and characteristics of soybean nuclear gene codons. CodonW software was applied to calculate the nucleotide composition, relative synonymous codon usage and other parameters of soybean genome and transcriptome. The result indicted that gene expression level was significantly and positively correlated with G+C and GC3s contents, and genes with high G+C and GC3s contents had high codon preference. UCC and GCC were identified as optimal codons in soybean. Analysis of coding sequences with different length showed that codon preference reduced as the coding sequence (CDS) length increased, and longer CDS tend to select codons randomly. CDS length between 400 to 600 bp had the highest expression level among the transcriptome data. The preference and expression level were almost the same between leaf-specific and seed-specific genes. But seed-specific genes had significantly higher G+C and GC3s contents than leaf-specific genes, and the contents of aromatic amino acids encoded by seed-specific genes were highly significantly lower than these by leaf-specific genes.
      Pyramiding Resistance Gene Pi-ta, Pi-b, and Stv-bi by Marker-assisted Selection in Rice (Oryza sativa L.)
      WANG Jun, YANG Jie, CHEN Zhi-De, FAN Fang-Jun, ZHU Jin-Yan, YANG Jin-Huan, ZHONG Wei-Gong
      Acta Agron Sin. 2011, 37(06):  975-981.  doi:10.3724/SP.J.1006.2011.00975
      Abstract ( 2723 )   PDF (283KB) ( 1348 )   Save
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      The blast and stripe disease are two major diseases of rice in Yangtze River japonica cultivating area. Breeding resistant cultivars is the most effective way to prevent these two major diseases. Wuyujing 8, containing both Pi-ta and Pi-b, was crossed with Zhendao 42 which carried rice stripe disease resistance gene Stv-bi. Two gene-markers, Pita and Pib, and one SCAR marker tightly linked with Stv-bi were used for marker-assisted selection in each segregating generation. After the multi-generation breeding and identification of resistance, three resistance genes were put together finally. One new rice stable line, 74121 was obtained which conferred good agronomic characteristics containing high-yield, good quality and multi-resistance. These results indicated that marker-assisted selection could not only be a simple and effective way but also provide genetic resources for breeding new rice multi-resistant varieties.
      GmAREB Gene Improves Tolerances to Drought and Oxidation in Transgenic Arabidopsis
      GAO Shi-Qing, CHEN Ming, XU Zhao-Shi, TANG Yi-Miao, LI Lian-Cheng, MA Wei-Zhi, ZHAO Chang-Ping
      Acta Agron Sin. 2011, 37(06):  982-990.  doi:10.3724/SP.J.1006.2011.00982
      Abstract ( 2101 )   PDF (613KB) ( 1581 )   Save
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      Abiotic stresses such as drought, high-salt and low temperature severely affect the yield and quality of crops. It is reported that subfamily A of alkalescence leucine zipper transcription factors (basic leucine zipper, bZIP) mainly participated in response to ABA, drought, high salt and oxidative stresses, plays vital roles in stress signal transduction, downstream gene expression regulation and improvement of anti-adversity in plants. In this study, soybean (Glycine max) cv. Tiefeng 8 with salt tolerance was used to isolate and obtain a bZIP transcription factor gene by electronic assembly methods, which was named as GmAREB (Glycine max ABA responsive element binding protein). This gene was composed of 1,317 nucleotides and encoded 439 amino acids. Sequence analysis showed that there were four putative phosphorylation sites (C1, C2, C3, C4), a nuclear localization signal region (KVVE) and a conservative bZIP domain. Homology and phylogenetic trees displayed that GmAREB had the higher homology and more close relationships with Arabidopsis ABF2 and rice TRAB1. To study the combining characteristics of transcription factors and DNA, we carried out electrophoretic mobility shift assay (EMSA) experiment and the results displayed thatGmAREB could specifically bind the ABRE cis-element in vivo. Functional identification of stress treatments showed that the survival rate of 35S::GmAREB transgenic plants treated by drought was higher (50%) than that (5%) of wild type. Stomatal observation displayed that the stomatal aperture of transgenic Arabidopsis (0.8 μm) was less than that of control (2.6 μm) under the drought stress for 2 h. The 35S::GmAREB transgenic plants were treated by methyl viologen (MV) to identify the oxidative stress tolerance of the GmAREB gene. Statistical analysis showed that transgenic Arabidopsis maintained the higher chlorophyl content (7.3 mg g–1 FW) than that of the wild-type. RT-PCR analysis of transgenic Arabidopsis showed that GmAREB overexpression enhanced the expression of downstream stress-related target genes (ABI1, ABI2) and suppressed the stomatal opening-related target genes (KAT1, KAT2). Therefore, the results above illuminated that GmAREB overexpression effectively regulated the expression of downstream target genes, accelerated the stomatal closure, reduced the moisture to evaporate, decreased chlorophyll degradation and enhanced the tolerance to drought and oxidative stresses in transgenic Arabidopsis.
      Genetic Analysis and Fine-Mapping of the ygl98 Yellow-Green Leaf Gene in Rice
      SUN Xiao-Qiu, WANG Bing, XIAO Yun-Hua, MO Chun-Mei, DENG Xiao-Jian, WANG Beng-Rong
      Acta Agron Sin. 2011, 37(06):  991-997.  doi:10.3724/SP.J.1006.2011.00991
      Abstract ( 2370 )   PDF (461KB) ( 1597 )   Save
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      A yellow-green leaf mutant ygl98 was isolated by chemistry mutagenesis. Its whole plant exhibited yellow-green trait throughout the growing period. Compared with its wild-type parent 10079, the contents of chlorophyll and carotenoid decreased by 45.3% and 45.6%; and at the maturity, the number of productive panicles per plant, seed setting rate and plant height reduced by 14.4%, 10.7%, and 7.4%, respectively. The result of electron microscopic observation revealed that the chloroplasts in the ygl98 mutant were out-of-shape. A lot of cystic structures and poor thylakoids were observed in the chloroplasts of the ygl98 mutant, and grana stacks appeared to be less dense compared to those of wild type. Genetic analysis showed that the yellow-green leaf trait of the ygl98 mutant was controlled by one pair of recessive nuclear genes. Genetic mapping of the mutant gene was conducted by using 771 yellow-green leaf individuals from the F2 mapping population of ygl98/Zhefu 802. Finally, the mutant gene was mapped between InDel markers I3 and I4 on the long arm of chromosome 3, with genetic distances of 0.07 and 0.19 cM, respectively, and with physical distance of 44.2 kb, in which eight predicted genes had been annotated. Sequencing analysis of these candidate genes between the mutant and its wild-type revealed the single base change (G1522A) of the gene for magnesium-chelatase ChlD subunit resulted in a missense mutation (A508T) in the encoded product. The same gene mutation caused by OsChlD(Chlorina-1) was documented previously. The Chlorina-1 mutant displays a severe yellowish-green leaf phenotype only at the seedling stage, and the abnormal leaf color is ?rst observed on the leaves of 2- to 3-week-old seedlings, while the ygl98 mutant exhibits yellow-green trait throughout the growing period. The different phenotypes of the two mutants may be caused by the different mutational sites of OsChlD genomic sequence.
      Identification and Functional Analysis of a Wheat Resistance Analogous Gene BRG1
      LI Ning, HUANG Qian, LIU Yan, ZHAO Dan, LIU Yan, HUANG Tie-Jing, ZHANG Ceng-Yan
      Acta Agron Sin. 2011, 37(06):  998-1004.  doi:10.3724/SP.J.1006.2011.00998
      Abstract ( 2325 )   PDF (332KB) ( 1293 )   Save
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      Barley yellow dwarf virus (BYDV) can cause wheat yellow dwarf. In this study, we isolated a fragment of a wheat resistance analogous gene, tentatively named BYDV response gene1 (BRG1),which was expressed in the BYDV resistant wheat-Thinopyrum intermedium translocation line YW642 but was not expressed in the BYDV susceptible wheat Zhong 8601 by using cDNA-AFLP technique.The full-length cDNA sequence of the gene BRG1 was obtained by rapid amplification of cDNA end (RACE) and RT-PCR methods. The gene BRG1 encodes a NBS-LRR protein consisting of 645 amino acid residues,which possesses one typical NB-ARC domain and three leucine-rich domains. The result of expression analysis by Q-RT-PCR method indicated that the expression of BRG1 gene was predominant in the BYDV resistant translocation line YW642 and induced by BYDV infection, reached the peak at 48 hour post inoculation with BYDV, whereas the express level of the gene in the susceptible wheat parent Zhong8601 was lower than that in the resistant wheat YW642, and showed a decline tendency with BYDV infection time. The mRNA expressionof BRG1 gene in YW642 wasup-regulated by salicylic acid (SA) and jasmonate (JA). Virus induced gene silencing technique was used to conduct functional analysis on the gene BRG1. The results showed that after BYDV infection, BYDV relative content in BRG1 knocked-down YW642 was higher than that in YW642 expressing BRG1 gene, whereas the silenced BRG1 gene did not obviously alter the plant phenotype to BYDV infection, suggesting that the gene BRG1 may be involved in the host response to BYDV infection but not be an important gene.
      Silicon and Its Uptaking Gene Lsi1 in Regulation of Rice UV-B Tolerance
      FANG Chang-Jun, WANG Qing-Shui, YU Pan, HUANG Li-Kun, WU Xing-Chun, LIN Wen-Xiong
      Acta Agron Sin. 2011, 37(06):  1005-1011.  doi:10.3724/SP.J.1006.2011.01005
      Abstract ( 2076 )   PDF (438KB) ( 1045 )   Save
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      Silicon (Si) has beneficial function in enhancing plant resistance to biotic and abiotic stresses. Rice is a typical Si-accumulating plant. In this research, UV-B tolerant rice accession Lemont, UV-B sensitivity rice Dualr and their low silicon rice gene 1 (Lsi1) transgenic lines were used to explore the relationships between silicon and rice UV-B tolerance. It was found that rice cultured in Si-deficiency solution had lower gene transcript levels of phenylalanine ammonia lyase (PAL), photolyase (PL), and lower contents of total phenolics and flavonoids in leaves than that in Si-containing solution. The same tendency was found in the case when the rice accessions were supplementarily exposed to UV-B radiation, although both gene expression level and antioxidants concentrations were increased. Further, Lsi1-suppressed or overexpressedtransgenic rice lines of Lemont, and Lsi1-overexpressed transgenic rice line of Dular were also detected in the same treatments. The results showed that gene transcript level of PAL and PL was increased in Lsi1-overexpressed transgenic line, but down-regulated in Lsi1-RNAi line of Lemont as compared with their wild types (WT) under normal light condition. The expression level of the two genes in all entries was enhanced after UV-B radiation treatment, and it was the highestin Lsi1-overexpressed line of Lemont, followed by their WT, and lowest in Lsi1-RNAi line. The same tendency was also found in the content of total phenolics and flavonoids. The similar results were further confirmed in the overexpression of Lsi1 in Dular.The findings suggested that rice UV-B tolerance could be effectively mediated by enhancing/inhibiting expression of Lsi1.
      Cloning and Expression of GhSAMS Gene Related to Salt-tolerance in Gossypium hirsutum L.
      ZHOU Kai, SONG Li-Yan, YE Wu-Wei-*, WANG Jun-Juan, WANG De-Long, FAN Bao-Xiang
      Acta Agron Sin. 2011, 37(06):  1012-1019.  doi:10.3724/SP.J.1006.2011.01012
      Abstract ( 2107 )   PDF (677KB) ( 1251 )   Save
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      As one of main abiotic stresses in nature, salt stress does great harm to plants, and seriously affect plant growth and development. Simultaneously, the crops cultivated in the saline land undergo a wide range of yield decline. To excavate salt-tolerance gene, we cloned the cDNA of S-adenosyl-L-methionine synthetase gene from Gossypium hirsutum by RACE and RT-PCR, which was named GhSAMS, with the cDNA full length of 1 576 bp, ORF of 1 182 bp, and coding 393 amino acid residues. Bioinformatics analysis showed GhSAMS has the similarity of 91%, 93%, and 93% with Arabidopsis thaliana, Suaeda salsa, and Oryza sativa, respectively. Phylogenetic analysis showed GhSAMS was the closest to Suaeda salsa,and Real-time PCR suggested that GhSAMS was induced by salt stress, while the induction was postponed in salt sensitivity material. It showed lower gene expression level on salt sensitive material Zhong S9612 relative to salt resistance material Zhong 9835. At the same time, we established protokaryotic expression vector pET28-GhSAMS and transformed GhSAMS into E. coli after IPTG induction, showing a successful gene expression.
      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Changes in Morphological and Physiological Traits of Roots and Their Relationships with Grain Yield during the Evolution of Mid-season Indica Rice Cultivars in Jiangsu Province
      ZHANG Hao, HUANG Zuan-Hua, WANG Jing-Chao, WANG Zhi-Qin, YANG Jian-Chang
      Acta Agron Sin. 2011, 37(06):  1020-1030.  doi:10.3724/SP.J.1006.2011.01020
      Abstract ( 2328 )   PDF (614KB) ( 1294 )   Save
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      Roots are involved in acquisition of nutrients and water, synthesis of plant hormones, and anchorage of plants. However, little is known what changes in root physiology and morphology during the evolution of rice cultivars. In this study, 13 typical mid-season indica rice cultivars (including hybrid combinations) applied in the production in Jiangsu Province during the last 60 years were used, which were classified into four types of early tall cultivars, dwarf cultivars, semi-dwarf cultivars, and super rice cultivars according to their application times, plant types and genotypes. All the tested cultivars were grown in the field and changes in morphological and physiological traits of roots and their relationships with grain yield during the evolution of cultivars were investigated. Results showed that the root dry weight, root weight density, root length, root length density and root diameter were increased with the evolution of the cultivars at main growth stages. From the heading stage, the shoot dry weight was increased with the evolution of the cultivars. Compared with other cultivars, the root-shoot ratio of super rice cultivars was increased at the mid-tillering and panicle initiation stages, but showed no significant differences among the four types of cultivars at latter growth stages. Specific root length was decreased with the evolution of the cultivars at the mid-tillering stage, and showed no significant differences among the four types of cultivars at other growth stages. The root oxidation activity, leaf photosynthetic rate, total absorbing surface area and active absorbing surface area of root, and the content of cytokinins (zeatin + zeatin riboside) in root bleeding and grain yield wereincreased with the evolution of the cultivars. Increase in grain yield was attributed mainly to the increase in total number of spikelets, which resulted mainly from a large panicle. Regression analysis showed that the root dry weight, root length, root diameter, root oxidation activity, total absorbing surface area and active absorbing surface area of root very significantly correlated with grain yield. The results suggest that the improved root and shoot growth increases grain yield of the modern cultivars, especially super rice cultivars.
      Effects of Asymmetric Warming on Key Enzyme Activities of Starch Synthesis in Superior and Inferior Grains of Winter Wheat under FATI Facility
      TIAN Yun-Lu, CHEN Jin, DONG Wen-Jun, DENG Ai-Xin, ZHANG Wei-Jian
      Acta Agron Sin. 2011, 37(06):  1031-1038.  doi:10.3724/SP.J.1006.2011.01031
      Abstract ( 2156 )   PDF (301KB) ( 1244 )   Save
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      Using Yangmai 11 as the material, we investigated the impacts of asymmetric warming on the key enzyme activities in starch synthesis in winter-wheat superior and inferior grains based on field study with FATI (Free Air Temperature Increased) facility. The results showed that the activities of sucrose synthase (SS), ADP-glucose pyrophosphorylase (AGPase), and starch branching enzyme(SBE) were higher in superior grains than in inferior grains, and also higher in the daytime than at night. In the control during the grain filling stage, the average activities of SS, AGPase, and SBE were 72.9%, 111.4%, and 7.8% higher in superior grains than in inferior grains. In superior grains, the SS activities in all-day warming, daytime warming and nighttime warming treatments were 8.4–31.2% higher than those in the ambient control in the daytime, and 11.1–20.3% higher than those in the control at night. In inferior grains, the increased percentages were 9.7–20.3% in the daytime and 6.1–32.0% at night. In inferior grains, the AGPase activities were elevated significantly compared to the control with 54.2–124.4% in the daytime and 20.7–99.3% at night. The SBE activities were also higher in the warming treatments than in the control with the increase of 3.9–12.1% in the daytime and 1.0–7.6% at night. Besides, the correlations existed between the activities of AGPase and SBE and the 1000-grain weight were positive and significant. This result indicated that elevation of AGPase and SBE activities plays an important role in the enhancement of 1000-grain weight.
      Estimation of Canopy Leaf Nitrogen Status Using Imaging Spectrometer and Digital Camera in Cotton
      WANG Fang-Yong, WANG Ke-Ru, LI Shao-Hun, GAO Shi-Ju, XIAO Chun-Hua, CHEN Bing, CHEN Jiang-Lu, LV Yin-Liang, DIAO Mo-Yang
      Acta Agron Sin. 2011, 37(06):  1039-1048.  doi:10.3724/SP.J.1006.2011.01039
      Abstract ( 2263 )   PDF (443KB) ( 1180 )   Save
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      Leaf nitrogen content is an important index to evaluate and estimate crop growth status, yield and quality. Real-time and non-destructive measurement of nitrogen nutrition status of plants is useful for nitrogen fertilizer management in cotton (Gossypium hirsutum L.) production. The objectives of this study were to determine the relationships of ground–based canopy spectral reflectance, spectral index and color parameters obtained by using common digital camera (Olympus C-5060) and imaging spectrometer (MSI200), with canopy leaf nitrogen content, and to develop regression models for estimating leaf nitrogen content in cotton. The results showed that canopy spectral reflectance decreased with increasing leaf nitrogen content, and the bands sensitive to leaf nitrogen content occurred the green and red regions mainly. Furthermore, the models to retrieve canopy leaf nitrogen contents using DI (R580, R680) and G–R were most feasible with the maximum determination coefficients (R2) and the minimum standard error (SE) for two visible sensors, respectively. Additional, b* (CIE 1976 L*a*b* color model) and H (HSI color model) were the optimum color parameters. On the whole, for the fitting effects, the spectral index was superior to color parameters for the same sensor, and MSI200 superior to digital camera. Then, the prediction performances of the spectral indices of digital camera were validated by using independent dataset. We found that difference indices DI (R580, R680) and G–R were the optimum indicators of canopy leaf nitrogen content with the highest predictive precision (0.8131 and 0.7636, respectively) and accuracy (1.0149 and 0.9661) and the lowest RMSE (2.3313 and 2.7406 mg g–1, approximately 6.52% and 8.24% of the mean). Hence, canopy spectral parameters in visible region may provide an effective and feasible means of estimating canopy leaf nitrogen contents quantitatively in cotton field.
      Effects of Planting Density and Soil Moisture on Flag Leaf Photosynthetic Characteristics and Dry Matter Accumulation and Distribution in Wheat
      JIA Lan-Beng, YU Zhen-Wen-*, WANG Dong, ZHANG Yong-Li, SHI Yu
      Acta Agron Sin. 2011, 37(06):  1049-1059.  doi:10.3724/SP.J.1006.2011.01049
      Abstract ( 2504 )   PDF (455KB) ( 1835 )   Save
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      Water shortage is one of the major problems in wheat (Triticum aestivum L.) production in northern plain in China. Water-saving technique is most important in wheat cultivation. In this study, we adopted water-controlled irrigation based on measuring soil moisture to improve the fixed-amount irrigation strategy in previous studies. Using wheat cultivar Jimai 22, we measured the photosynthetic performance of flag leaf and dry matter accumulation and distribution in plant under two plant densities and three irrigation treatments. In the 2008–2009 growing season, the plant densities were 150 (M1) and 225 (M2) seedlings per square meter, and the irrigation treatments were designed as relative soil moisture (SM) of 65% at jointing and 60% at anthesis (W0), SM of 75% at jointing and 75% at anthesis (W1), and SM of 75% at 7 d after jointing and 75% at 7 d after anthesis (W2). In the 2009–2010 growing season, only one plant density (M1) was adopted, which showed better performance in yield and water use efficiency (WUE) in the 2008–2009 growing season. Besides, the irrigation treatments were adjusted to SM of 75% at jointing and of  60% at anthesis (W’0), SM of 85% at jointing and 75% at anthesis (W’1), and SM of 85% at 7 d after jointing and SM 75% at 7 d after anthesis (W’2). Under the same irrigation treatment, maximal photochemical efficiency of PSII (Fv/Fm) and actual photochemical efficiency of PSII (ΦPSII) under M1 density were higher than those under M2 density from middle to late grain-filling stage, and dry matter accumulation amount after anthesis and dry matter translocation amount tograins in M1 treatment were significantly higher than those in M2 treatment. Compared with W1 treatment, Fv/Fm and ΦPSII of W2 treatment were significantly higher from middle to late grain-filling stage, and photosynthetic rate (Pn), evapotranspiration (Tr), leaf water use efficiency (WUEL), and stomatal conductance (Gs) were also higher in W’2. Under the M1 plant density, the dry matter accumulation amount after anthesis and its contribution to grains were higher in W2 than in W1 treatment, whereas the grain yield and WUE of W2 treatment were significantly higher than those in W1 treatment. The changing tendency of dry matter accumulation and distribution, grain yield, and WUE were similar in both growing seasons. In wheat growing environment similar to the condition of this experiment, we propose the best plant density is 150 seedlings per square meter and the best irrigating both at jointing and anthesis is SM (0–140 cm soil layer) of 75% at 7 d after both stages.
      Combined Effects of Nitrogen and Sulphur Fertilization on Content and Size Distribution of Glutenin Macropolymer in Wheat Grain
      CAI Tie, WANG Zhen-Lin, YIN Yan-Ping, LI Yong, CHEN Xiao-Guang, WANG Beng, CHEN Er-Ying, GUO Dun-Xiang, NI Yang-Li, YANG Wei-Bing
      Acta Agron Sin. 2011, 37(06):  1060-1068.  doi:10.3724/SP.J.1006.2011.01060
      Abstract ( 1983 )   PDF (367KB) ( 1053 )   Save
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      The content and size distribution of glutenin macropolymer (GMP) play key roles in grain quality of wheat (Triticum aestivum L.). The aims of this study were to analyse the relationship between the content and size distribution of GMP and evaluate combined effects of nitrogen and sulphur fertilization on the content and size distribution of GMP in wheat grain. In the study, Shannong 15 was used in a field experiment with three nitrogen (N) application levels (120, 240, and 360 kg ha−1) and three sulphur (S) application levels (0, 60, and 90 kg ha−1). HMW-GS and LMW-GS were firstly separated using the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and each of the subunits was then extracted before quantitative measurement by colorimetric analysis. The result showed that, in certain ranges, contents of GMP, HMW-GS, and LMW-GS were significantly increased with more application of nitrogen fertilizes. The increasing application of sulphur showed no significant effect on GMP content, but reduced contents of HMW-GS and D-LMW-GS and promoted contents of B-LMW-GS and C-LMW-GS. The content of small GMP particle (diameter less than 12 μm) was significantly reduced with the increase of nitrogen and sulphur fertilization, and the content of large GMP particle (diameter no less than 12 μm), tended to increase with the increase of nitrogen application and sulphur application. However, the distribution of GMP particle number was not affected by the nitrogen and sulphur treatments. According to correlation analysis, C-LMW-GS content was negatively correlated with the content of small GMP particle. These results suggested that increasing nitrogen application had the effect on the absolute content of GMP, while increasing sulphur application affected relative content of GMP. Nitrogen and sulphur fertilization have positive modulation on the content of large GMP particle, and C-LMW-GSplays an important role in the development of large GMP particle.
      Regulation of Nitrogen Level on Photosynthetic Energy Partitioning in Wheat Leaves under Elevated Atmospheric CO2 Concentration
      ZHANG Xu-Cheng, YU Xian-Feng, WANG Hong-Li, MA Yi-Fan
      Acta Agron Sin. 2011, 37(06):  1069-1076.  doi:10.3724/SP.J.1006.2011.01069
      Abstract ( 1997 )   PDF (365KB) ( 981 )   Save
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      The objective of this study was to understand the regulatory mechanism of nitrogen (N) application on photosynthetic acclimation under elevated atmospheric CO2 concentration. The ambient atmospheric CO2 concentration was 400 μmol mol−1, and the elevated CO2 concentration was 760 μmol mol−1, which was simulated with Top Open Chambers. Wheat (Triticum aestivum L.) cultivar Ningchun 4 was grown in pots under both CO2 concentrations and treated with low (0 mg pure N per kilogram soil, N0) and high (200 mg pure N per kilogram soil, N200) N application levels. The photosynthetic electron transport rate was estimated using the response curve between photosynthetic rate (Pn) and intercellular CO2 concentration (Ci) and chlorophyll fluorescence parameters. The leaf nitrogen concentrations were also measured at jointing and heading stages. Compared to that under the ambient CO2 concentration, the leaf nitrogen concentration of wheat was decreased significantly under the elevated CO2 concentration, and the percentage of decrease in N200 treatment was 335.7% higher at heading than jointing stage. The values of maximal quantum yield under irradiance (Fv′/Fm′), actual PSII efficiency under irradiance (ΦPSII), photochemical fluorescence quenching (qP) were higher in N200 treatment than in N0 treatment; however, the value of non-photochemical fluorescence quenching (NPQ) was higher in N0 treatment than in N200 treatment. Under elevated atmospheric CO2 concentration, the electronic transport rate of photochemistry (Jc) and Rubisco carboxylation rates (Vc) were increased significantly, but the electronic transport rate of photorespiration (Jo) and Rubisco oxygenation rate (Vo) were decreased significantly. N application tended to promote the values of Jc, Jo, Vc, and Vo, especially for Jc and Vc, which had significant increase compared to those in N0 treatment. When the atmospheric CO2 concentration elevated from 400 μmol mol−1 to 760 μmol mol−1, the rations of Jo/Jc and Vo/Vc decreased significantly. Under the elevated atmospheric CO2 concentration, N application decreased Jo/Jc and Vo/Vc significantly at jointing stage, but increased Jo/Jc at heading stage and remained Vo/Vc with no significant difference. The leaf nitrogen concentration was positively correlated with Jc (P < 0.01), Jo, (P < 0.05) and Vo (P < 0.05), and the sensitivities of Jc, Jo, and Vo in response to leaf N concentration were decreased under elevated atmospheric CO2 concentration. The opening ratio of PSII reaction center was increased under elevated atmospheric CO2 concentration, and the non-photochemical energy dissipation was decreased simultaneously, resulting in more photosynthetic electron transported to photochemical process in wheat leaf. N application had a positively effect on photosynthetic function and changed its energy partitioning through increasing leaf N concentration. This might be one of the key reasons for photosynthesis acclimation of C3 plant to N sufficient application under elevated atmospheric CO2 concentration.
      Effects of Fruiting Branch Position, Temperature-Light Factors and Nitrogen Rates on Cotton (Gossypium hirsutum L.) Fiber Elongation
      ZHAO Wen-Jing, MENG YA-Li, CHEN Mei-Li, LI Wen-Feng, ZHOU Chi-Guo
      Acta Agron Sin. 2011, 37(06):  1077-1086.  doi:10.3724/SP.J.1006.2011.01077
      Abstract ( 1880 )   PDF (449KB) ( 934 )   Save
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      Cotton fiber length is one of the important criteria of cotton quality, and fiber elongation is influenced by many factors. To study effect of fruiting-branch position, temperature-light factor and nitrogen rates on dynamic changes of cotton fiber length, we carried out the field experiments in Nanjing (118º50′E, 32º02′N, middle lower reaches of Yangtze River Valley) and Xuzhou (117°11′E, 34°15′N, Yellow River Valley). Cotton cultivars of Kemian 1 and NuCOTN 33B were used. Two sowing dates and three nitrogen application levels were applied, thus cotton fiber developing process can be arranged at different fruiting-branch position and ecological conditions. The results showed that cotton bolls developed in the middle-branch position produced longer fiber than that in lower- and upper-branch positions, but the dynamic changes of fiber length were not significant among different fruiting branches. PTP can be an indicator assessing temperature-light effect during cotton fiber elongation period. The maximum elongation rate (Vmax) and duration of fiber speedy elongation period (T) were linearly corelated with PTP, while the theoretical maximum of cotton fiber length (Lenm) was quadratic with PTP. The longest Lenm (30.94 and 30.31 mm for Kemian 1 and NuCOTN 33B, respectively) was obtained at PTP of 335 MJm2 in cotton fiber elongation period (333.3 and 337.9 MJ·m2 for Kemian 1 and NuCOTN 33B,respectively), when Vmax was 1.3 mm d–1 and T was 16 d. There exists an interaction between N fertilization and PTP on fiber elongation. As N fertilization increased, values of PTP for obtaining the longest Lenm decreased. And when PTPwas greater than 240 MJm2 (237.6 and 241.6 MJm2 for Kemian 1 and NuCOTN 33B, respectively), NA under 240 kg N ha1 was more suitable for the elongation of cotton fiber; while PTP was less than that value, NA under 480 kg N ha1 was more appropriate.
      Effects of Cultivar and Environment on Nutritional Quality of Chinese Naked Oats
      LIN Wei-Jing, TUN An-Feng, LI Chun-Gong, WANG Yan, ZHOU Su-Mei
      Acta Agron Sin. 2011, 37(06):  1087-1092.  doi:10.3724/SP.J.1006.2011.01087
      Abstract ( 2261 )   PDF (206KB) ( 1485 )   Save
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      To understand the status of nutritional quality of Chinese naked oat (Avena sativa L.) cultivars used in oat production, we collected 58 samples of 38 cultivars from six major production areas in China, which were harvested from 2007 to 2009. The nutritional compositions, including grain moisture, crude protein, crude fat, crude fiber, β-glucan, and starch, were analyzed and compared among cultivars, planting sites, and harvest years. These quality parameters varied greatly among cultivars. The content of crude fat had the largest variation coefficient, which was 21.38%. In contrast, starch content had the least variation among cultivars with the variation coefficient of 6.23%. Oleic acid and linoleic acid were the main components of unsaturated fatty acids in oat oil and their proportions were similar, showing a roughly 1:1 ratio. Moreover, there were differences of contents of oleic acid and linoleic acid among cultivars. In the amino acid components, sulfur amino acids (consisted of methionine and cysteine) had the largest variations among cultivars. The integrated quality of oat samples from Gansu Province was higher than that form other planting sites due to its higher contents of protein, β-glucan, linoleic acid, and lysine. Planting year had less effect on nutritional quality of oats compared with cultivar and planting site. According to cluster analysis, a few cultivars with rich β-glucan, protein, linoleic acid, lysine, or sulfur amino acid were screened out, which were propitious to oat breeding and rough material selection in oat processing industry.
      Effect of Shading Post Anthesis on Anthocyanin Accumulation and Activities of Related Enzymes in Colored-Grain Wheat
      WANG Hai-Wei, WANG Zhen-Lin, WANG Ping, WANG Shu-Gang, HUANG Wei, WU Yu-Guo, SUN Lan-Zhen, YIN Yan-Ping
      Acta Agron Sin. 2011, 37(06):  1093-1100.  doi:10.3724/SP.J.1006.2011.01093
      Abstract ( 2004 )   PDF (456KB) ( 1452 )   Save
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      To understand the pathway of anthocyanin accumulation during grain filling of wheat (Triticum aestivum L.) and its response to light, we used three red-gain, two black-grain, and one white-grain (control) varieties/lines to investigate the dynamic changes of anthocyanin accumulation and activities of related enzymes during grain filling. Shading treatments were conducted during the whole filling stage (14–34 d post anthesis, treatment T1) and at early (14–24 d post anthesis, treatment T2) or late filling stage (24–34 d post anthesis, treatment T3), and natural light condition without shading was used as the control. The effects of treatments T1 and T3 on anthocyanin content were larger than that of treatment T2, indicating that late grain filling period is critical for anthocyanin biosynthesis. The changing degree of anthocyanin content induced by shading varied across varieties with larger changes in D4 Hong (red grain), Hong 5 (red grain), and Heixiaomai 76 (purple red grain). In the treatment T1, the grains of three red-grain varieties with anthocyanin content less than 1U g-1 were colorless, similar to the white-grain control “Jimai 19”. In the treatment T2, the anthocyanin began to be synthesised after the shading was removed in late grain filling period. The anthocyanin contents of black-grain wheat varieties Changyi Heimai and D4 Hei were significantly reduced in shading treatments, but the absolute content was higher than 2 U g-1 in the treatment T1. This result suggested different pathways of anthocyanin biosynthesis probablylight-dependent in red-grain wheat. While both light-dependent and non-light-dependent pathways in black-grain wheat, of which the latter was the main pathway. In colored-grain wheat, the activities of plenylalanine ammonialyase (PAL) and chalcone ismoerase(CHI) were low in early grain-filling period, and increased to a higher level in middle to late filling period. However, the activity of polyphenol oxidase (PPO) varied from a high level in early filling period to a low level in middle to late filling period.In the control treatment without shading, the activities of PAL and CHI were positively associated with anthocyanin content at a significant level, indicating that CHI and PAL are the key enzymes in anthocyanin biosynthesis. The PPO activity was negatively correlated with anthocyanin content in black-grain wheat rather than red-grain wheat. Under the shading conditions, the activities of PAL, CHI, and PPO were not closely associated with the anthocyanin content. Therefore, it is inferred that the effect of light on anthocyanin biosynthesis is not based on the direct regulations of PAL, CHI, and PPO activities.
      RESEARCH NOTES
      Changes of Some Leaf Characteristics in Rice (Oryza sativa L.) Varieties Released from 1958 to 2005 in Jilin Province
      ZHAO Guo-Chen, JIANG Nan, XU Ke-Zhang, LING Feng-Lou, WU Zhi-Hai, DI Yu-Ting
      Acta Agron Sin. 2011, 37(06):  1101-1108.  doi:10.3724/SP.J.1006.2011.01101
      Abstract ( 1966 )   PDF (371KB) ( 1309 )   Save
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      In order to understand the changes of leaf characteristics associated with yield during the genetic improvement of rice, 33 japonica rice varieties released from 1958 to 2005 were planted under same field conditions. Some indexes related to leaf characteristics, such as leaf number, leaf area per plant, leaf area duration (LAD), length, width and area of top three leaves, chlorophyll content index (CCI) and specific leaf weight (SLW) of flag-leaf were measured at 10d after heading. The results showed that the grain yield was increased from 7 756.6 kg ha-1 in 1958 to 12 807.3 kg ha-1 in 2005, with the increase of 65.11% in 47 years and an annual increase rate of 1.39% according to the calculation of regression equation. The increasing of grain yield was mainly attributed to the increase of leaf number, leaf area per plant and LAD with years of release. By studying on the top three leaves of plant, our results showed that the significant decrease of flag-leaf length resulted in the decline of flag-leaf area; the changes of top second leaf area was not obvious; as the increase in the length and width of top 3rd leaf, significantly increased was found in its area with years of release. Leaf number, leaf area per plant and LAD were all positive correlated with years of release significantly. CCI and SLW of flag-leaf were positively correlated with year of release and with yield significantly. Our results showed that the increase of plantleaf area and LAD were resulted from the increase ofleaf number and the area of top 3rd leaf. CCI and SLW of flag-leaf were increased with years of release. We suggested that leaf number, leaf area per plant, LAD, and CCI as well as SLW of flag-leaf at 10d after heading could be as potential indices in the future high yield rice breeding.
      Comparison of Aging Characteristics and Longevity of Wheat Seeds in Vacuum and Non-vacuum Packages Storage in Mid-term Low-Temperature Genebank
      WU Shao-Yun, ZHOU Guo-Yan
      Acta Agron Sin. 2011, 37(06):  1109-1115.  doi:10.3724/SP.J.1006.2011.01109
      Abstract ( 2077 )   PDF (302KB) ( 1155 )   Save
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      To validate the effect of vacuum and sealed package on seed viability and longevity after long-time storage in mid-term low-temperature (−2±2°C) genebank, we sampled 89 accessions of common wheat seeds (89 samples) to compare their survival status, rate of seeds deterioration (1/σ), seeds initial quality (Ki), half-life period (P50), and storage longevity (log σ) with the same accessions that in non-vacuum packages during the 11-year storage. The survival frequencies and aging characteristics of 89 samples in both packages followed the normal distributions according to chi-square tests. In a few genotypes, the rate of seeds deterioration and longevity characteristics showed obvious differences between the vacuum and non-vacuum package treatments. Wheat genotypes with identical initial moisture and prestorage environment showed different rates of significant deterioration in the two-package treatments, of which vacuum packaging treatment presented lower rate and lightened degree of seed aging. Therefore, vacuum and sealed package has the effect on lessening seed deterioration and maintaining seed longevity compared to the non-vacuum package. We also observed the higher value of Ki in the vacuum and sealed packaging treatment than in the non-vacuum packaging treatment. However, it seems not to support the hypothesis of Ki as the indicator for seed initial quality.
      Establishment of DNA Fingerprintings of Kenaf (Hibiscus Cannabinus L.) Germplasm Resources with ISSR Molecular Markers
      HONG Bin, QI Wei, LAN Chao, CHEN Hui-Duan, XU Jian-Tang, SU Jian-Guang, LI Ai-Jing, QI Jian-Min
      Acta Agron Sin. 2011, 37(06):  1116-1123.  doi:10.3724/SP.J.1006.2011.01116
      Abstract ( 2339 )   PDF (827KB) ( 1215 )   Save
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      Kenaf (Hibiscus cannabinus L.) is an important economic crop in China. To identify germplasm resources and establish the data base of DNA fingerprintings, we adopted six kenaf germplasm resources to screen 80 ISSR primers, 20 of which were polymorphic. Then 20 ISSR primers were used to amplify 84 kenaf germplasm resources introduced and preserved from home and abroad. Totally 230 bands were produced,the average number of DNA bands amplified by each primer was 11.5, and the number of polymorphic DNA bands was 185. The polymorphic proportion of DNA bands was 80.43%, which indicated the abundant genetic diversity of kenaf germplasm resources preserved. Based on the DNA bands amplified from 84 kenaf germplasm resources, the Excel data base for PCR amplified bands of the kenaf germplasm resources was established. According to the principle of uniqueness of the fingerprintings, the DNA fingerprints of 82 kenaf germplasmwere constructed with five ISSR primers (UBC813, UBC825, UBC836, UBC888 and UBC889) selected from 20 polymorphic primers, using the analyzing software designed by our laboratory programmed and based on image manipulation. The fingerprintings provide a basis of the molecular identification of kenaf germplasm resources. In this research, the DNA fingerprintings system was proved to be feasible and reliable.

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:
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