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Table of Content

    12 June 2008, Volume 34 Issue 06
    • REVIEW
      Research Outline on Some Related Characteristics of Brachypodium dis-tachyon as a New Model Plant Species
      YE Xing-Guo
      Acta Agron Sin. 2008, 34(06):  919-925.  doi:10.3724/SP.J.1006.2008.00919
      Abstract ( 2052 )   PDF (253KB) ( 1952 )   Save
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      Brachypodium distachyon, a monocot grass plant and widely distributed in temperate areas, has been regarded as an new potential model plant species and studied extensively in recent years because of its smaller genome, less chromosomes, shorter plant height, rapid life cycle, higher seed yield, undemanding growth requirements, and different ploidies similar to Triticum including diploid, tetraploid, and hexaploid. But, related research on this plant in domestic is just in initial stage. Cytogenetics, molecular genetics, genomics, mapping, tissue culture, and transformation of Brachypodium distachyon were reviewed in this paper, and its further investigation and application were briefly prospected at the same time in order to promote its study on the characteristics as model plant and benefit the structural and functional genomics research of some Pooideae species such as wheat and barley.
      CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
      Development and Chromosome Mapping of 81 New Wheat EST-SSR Markers and Application for Characterizing Rye Chromosomes Added in Wheat
      ZHUANG Li-Fang;SONG Li-Xiao;FENG Yi-Gao;QIAN Bao-Li;XU Hai-Bin;PEI Zi-You;QI Zeng-Jun
      Acta Agron Sin. 2008, 34(06):  926-933.  doi:10.3724/SP.J.1006.2008.00926
      Abstract ( 2258 )   PDF (712KB) ( 1708 )   Save
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      Genomic microsatellites (gSSR) have been widely used in cultivar fingerprinting, genetic diversity assessment, molecular mapping and marker assisted breeding, but development of SSR markers from genomic libraries is expensive and inefficient. With the availability of large numbers of expressed sequence tags (ESTs), development of EST-derived SSR (eSSR) markers is becoming an efficient and low-cost option for many plant species. To date, numerous eSSR markers have been developed and used in comparative and genetic mapping in many plant species, which showed a higher rate of transferability than gSSR markers. In wheat (Triticum aestivum L.), until January, 2007, more than 854 015 ESTs have been deposited in the public GenBank (http://www.ncbi.nlm.nih.gov), and more than 16 000 ESTs have been physically positioned on different bins of wheat chromosomes via Southern blotting analysis on a set of wheat deletions. Despite series of PCR based eSSR primers were designed, only a small number of them have been tested in wheat or its relative genomes. The purposes of our research were: 1) to develop and map of new eSSR markers of wheat; 2) to test the transferability of these markers in wheat relatives; and 3) to screen of new markers tagging different rye (Secale cereale L.) chromosomes. In this paper, 81 new EST-derived SSR markers were developed from salinity stressed and stem relative cDNA libraries of wheat. Of them, 67, 46, 18, and 61 markers produced 124, 72, 26, and 124 stable amplicons in genomes of wheat, rye, Haynaldia villosa L. Schur., and barley (Hordeum vulgare L.), respectively, indi-cating high transferability of these markers in wheat relatives. Twenty-two markers produced polymorphic amplicons between wheat landrace Chinese Spring and Huixianhong, and 23 markers produced polymorphic loci between barley cultivar Sileng Damai and Kuaiying Luomai, indicating potential use of these markers in genetic mapping and fingerprinting. Among the 67 eSSR markers with stable amplicons in wheat, 81 loci amplified by 43 markers were further mapped on 18 different wheat chro-mosomes using a set of wheat nulli-tetrasomics except 4B, 3D, and 6D. The other 24 markers could not be mapped on single chromosome of wheat mainly due to the possible duplications of gene occurred in wheat genomes. Of the 81 mapped loci in wheat, 29, 30, and 22 were assigned on A, B, and D genome, respectively. Of the 7 homoeologous groups of wheat, the mapped loci var-ied from 6-23, chromosomes of group 2 were found with the most loci (23) while group 5 with the least (6). For the single chro-mosome, the mapped loci varied from 1-11, chromosome 2B with the most (11) and 5A with the least (1). By amplified on ge-nomes of Huixianhong, rye cultivar ‘Jingzhou Heimai’and their amphiploid Jinghui 1, 30 out of 46 eSSR markers with stable amplicons in rye screened in the previous transferability test produced specific loci of rye in Huixianhong background. Using 11 Huixianhong-Jingzhou Heimai alien chromosome lines except 6R and 3RL, eight markers were further assigned on different sin-gle chromosomes including 1R (1), 4R (3), 5R (3) and R7 (1), 7 markers were assigned on more than one chromosome indicating possible duplication of gene occurred in rye genome, and 15 markers could not be mapped in the current wheat-rye alien chromo-some lines indicating potential use in other study.
      Test of Interaction between THL1 and SRK from Brassica oleracea L. in Self-Incompatibility Signaling Process
      GAO Qi-Guo;SONG Ming;NIU Yi;YANG Kun;ZHU Li-Quan;WANG Xiao-Jia
      Acta Agron Sin. 2008, 34(06):  934-943.  doi:10.3724/SP.J.1006.2008.00934
      Abstract ( 1816 )   PDF (676KB) ( 1277 )   Save
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      The SRK and THL1 from Brassica oleracea L. act probably with each other in self-incompatibility signal process. In present study, with an aim to testify the interaction, the coding sequences of THL1 and SRK kinase domain(named as SRKE1) were amplified from stigma mRNA of Brassica oleracea L., and inserted into the expression vector pET43.1 and yeast expression vec-tor pPIC9K to construct the recombinant plasma pET43.1-THL1, pET43.1-SRKE1, and pPIC9K-SRKE1. The recombinant protein were expressed in E. coli(BL21) and Pichia pastoris (GS115), respectively. Thioredoxin activity was tested by the ability of THL1 reducing insulin, showing that THL1 had oxidation/reduction activity. A new method was put forward for testing the interaction between proteins, through the method the interaction between SRKE1 and THL1 was analyzed, showing that SRKE1 and THL1 could act with each other to combine and form a stable complex. This research provides a theoretical and technical bases for fur-ther analysis of the interaction mechanism between SRK and THL1.
      Correlation and QTL Mapping of Biomass Accumulation, Apparent Har-vest Index, and Yield in Soybean
      HUANG Zhong-Wen;ZHAO Tuan-Jie;YU De-Yue;CHEN Shou-Yi;GAI Jun-Yi
      Acta Agron Sin. 2008, 34(06):  944-951.  doi:10.3724/SP.J.1006.2008.00944
      Abstract ( 2304 )   PDF (257KB) ( 1391 )   Save
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      Since soybean seed yield is the product of both biomass accumulation and harvest index, the objective of the present study was to measure the correlations of seed yield with the other two traits as well as with biomass accumulation at different seed development stages, to map their QTLs, and to reveal the QTL basis of the correlations. A RIL population, NJRIKY, derived from the cross between Nannong 1138-2 and Kefeng 1, quite diverse in biomass, harvest index and yield, was used to study the correla-tion among biomass accumulation, apparent harvest index and yield, to map the QTLs of the traits for revealing the genetic basis of the correlation among the traits. The results obtained were as follows: (1) Yield was closely and positively correlated with bio-mass accumulation and their correlation increased in the process of growth with the highest R2=0.76 at harvest stage. There ap-peared some negative exponential correlation between yield and biomass at R1, R3, and R5, with the biomass of 1 000, 2 300, and 5 500 kg ha-1 as the highest turning point, respectively. A linear correlation of yield with biomass at harvest stage [BM (H)] was detected, but without upper limit of the biomass found in the present experiment. There was an exponential correlation between yield and apparent harvest index, with 0.42 as the turning point, positive relationship as less than 0.42 and negative relationship as larger than 0.42. (2) 9, 10, and 10 QTLs for yield, apparent harvest index and BM (H) were detected in NJRIKY and 2, 3, and 3 QTLs of them respectively detected in both years. In addition, 6, 9, and 6 QTLs for biomass at R1, R3, and R5 were identified in the population, respectively, with 2 of them being detected across R1 through R5 in both years. (3) Among the 9 yield QTLs, 6 marker intervals were found to have QTLs conferring biomass and apparent harvest index, which implied a partially common genetic basis among the three traits.
      Epistatic Effects of QTLs and QE Interaction Effects on Oil Content in Soybean
      SHAN Da-Peng; QI Zhao-Ming;QIU Hong-Mei;SHAN Cai-Yun;LIU Chun-Yan;HU Guo-Hua;CHEN Qing-Shan
      Acta Agron Sin. 2008, 34(06):  952-957.  doi:10.3724/SP.J.1006.2008.00952
      Abstract ( 2325 )   PDF (470KB) ( 1395 )   Save
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      Soybean [Glycine max (L.) Merr., 2n=2x=40] is grown worldwide, especially in the United States, Brazil, Argentina, and China. Increasing oil content in soybean seeds is one of the main aims in soybean breeding. Oil content is quantitative traits controlled by multiple genes. Many researches have used molecular markers to map quantitative trait loci (QTL). Currently, SoyBase (2007) contains at least 68 QTL associated with oil content that have been mapped in many different populations and environments. The development of molecular tools has facilitated the task of identifying chromosomal regions related to particular traits. Song et al. (2004) developed an integrated genetic map spanning 2 523.6 cM across 20 linkage groups that contained 1 849 markers, including 1 015 SSRs, 709 RFLPs, 73 RAPDs, 24 classical traits, 6 AFLPs, 10 isozymes, and 12 others. In MAS, it would be more desirable to use confirmed QTL. For this purpose, it is necessary to conduct QTL, mapping studies in as many and as diverse environments and population as feasible. In this study, QTL of soybean oil content in five different years was analyzed with a recombination inbred lines (RIL) population derived from a cross between Charleston and Dongnong 594 by mixed linear model approach. 11 QTL with additive effects for oil content were mapped in the linkage groups A1, A2, B1, C2, D1a, D1b, F, H, and O. 15 QTL pairs with epistatic effects for oil content in the RIL were detected, and the general phenotypic variation was 17.84%. 9 QTL were detected from QTL× environment interaction, and the general contribution was 5.76%.
      Cloning, Expression, and Mapping of S-adenosyl-L-homocysteine Hydrolase (GhSAHH) cDNA in Cotton
      SHE Yi-Bin;ZHU Yi-Chao;ZHANG Tian-Zhen;GUO Wang-Zhen
      Acta Agron Sin. 2008, 34(06):  958-964.  doi:10.3724/SP.J.1006.2008.00958
      Abstract ( 1945 )   PDF (675KB) ( 1513 )   Save
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      S-adenosyl-L-homocysteine hydrolase (SAHH) is a key enzyme in the regulation of intracellular methylation reactions. Though the SAHH function has already been elucidated in various living creature bodies, it is still not explicit in growth and development of cotton fiber. Therefore, research of SAHH may provide effectively basis to clarify the mechanism of cotton growth and development. In this paper, we obtained a full length cDNA fragment of SAHH in cotton and further finished its expression, mapping and Southern blotting analyses. A cDNA clone encoding S-adenosyl-homocysteine hydrolase (Library No. g073a03a, GhSAHH) was isolated from cotton fiber cDNA library of 7235 germplasm line with elite fiber quality in Gossypium hirsutum L. The length of this cDNA clone was 1 598 bp. Further, a 318 bp-long-upstream fragment was obtained via 5′RACE technique. The full length of the cDNA clone was 1 916 bp with its open reading frame encoded 485 amino acids. The putative protein of this gene had an isoelectric point of 5.69 and a calculated molecular weight of 53.2 kD. Judging from its expression characters, GhSAHH is expressed in cotton cells, especially in root, hypocotyl and at early stage of fiber developmental period. Southern blotting analyses showed there was only one copy of GhSAHH in the genome of upland cotton. Using the BC1 mapping popula-tion with 140 individuals derived from the hybridization between the upland cotton standard line TM-1 and the sea-island cotton cultivar Hai7124, and TM-1 as recurrent parent, GhSAHH was localized on the chromosome 20. We have already constructed plant express vector and RNAi vector of GhSAHH, the transgenic research on cotton is undertaking.
      Construction on cDNA Library from Fertility-Related Genes of Male Sterile Wheat with Aegilops kotschyi Cytoplasm by SSH
      LI Hong-Xia;ZHANG Long-Yu;ZHANG Gai-Sheng;NIU Na;ZHU Zhan-Wang
      Acta Agron Sin. 2008, 34(06):  965-971.  doi:10.3724/SP.J.1006.2008.00965
      Abstract ( 2098 )   PDF (363KB) ( 1595 )   Save
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      Male sterility with Aegilops kotschyi cytoplasm has a great application potential in hybrid wheat (Triticum aestivum L.) breeding for its stable sterility and broad-spectrum of restoring gene resources. To further reveal the genetic mechanism of male sterility with Aegilops kotschyi cytoplasm, a male sterile line ms (Kots)-90-110(A) and its near isogenic line BC4F1 (fertility restored by rk5451) were employed to construct sterility and fertility cDNA libraries by suppression subtractive hybridization (SSH). Wheat anthers with pollen mother cells at dikaryophase were sampled for RNA extraction via microscopic examination. The two cDNA libraries were evaluated to be of good quality with high efficiency of SSH. Total 120 positive clones were randomly selected and sequenced from the 2 libraries, and 100 high quality sequences were obtained. According to BLAST screening and functional annotation, energy-related genes were identified with high frequencies in fertility cDNA library, while MADS-box transcriptional factor TaAGL7, ubiquitin-conjugating enzyme, and adenosine diphosphate glucose pyrophosphatase were detected in sterility cDNA library. The MADS-box transcription factor TaAGL7 plays important roles in regulating flower development. Immature spike ubiquitin-conjugating enzyme is likely to relate to apoptosis. The expression of adenosine diphosphate glucose pyrophosphatase directely affectes starch synthase and normal supply of energy. The genes detected in our study are probably important in fertility of wheat with Aegilops kotschyi cytoplasm.
      Genetic Diversity in Main Parents of Sweetpotato in China as Revealed by ISSR Marker
      LI Qiang;LIU Qing-Chang;ZHAI Hong;MA Dai-Fu;WANG Xin;LI Xue-Qin;WANG Yu-Ping
      Acta Agron Sin. 2008, 34(06):  972-977.  doi:10.3724/SP.J.1006.2008.00972
      Abstract ( 2127 )   PDF (219KB) ( 1471 )   Save
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      As an important material of industry and new energy resource crop as well as food and forage, increase in production of sweetpotato[Ipomoea batatas (L.) Lam.] is desired, but this goal is often limited by a narrow genetic background of the parents in conventional hybridization. It is, therefore, necessary to assess genetic diversity in main parents of sweetpotato. In this study, 62 main sweetpotato parents in China were assessed by using inter-simple sequence repeat (ISSR) marker to understand their genetic difference for exact parent selection in breeding. Seventeen ISSR primers generated 490 polymorphic bands with an average of 28.8 polymorphic bands per primer, indicating that ISSR marker was one of efficient methods to analyze the genetic diversity of sweetpotato. Wide genetic variations, ranged from 0.158 to 0.924 with an average genetic distance of 0.574, were found among the tested cultivars. The UPGMA cluster analysis classified the materials into 2 groups, domestic and exotic cultivars. These main parents had high genetic diversity, and domestic cultivars were far from exotic cultivars in terms of genetic distance. The genetic diversity of Asian cultivars was higher than that of the cultivars originally from Africa and America. The cultivars from Chinese mainland had the smallest genetic distance (0.419), and were close to the cultivars from Taiwan, China, but far from exotic Asian cultivars. These results suggest that crosses between domestic and exotic parents should be emphasized in sweetpotato breeding in China.
      Construction of Potato Plastid Transformation Vector and Transient Ex-pression of GFP Gene in Tuber
      DING Yu-Mei;YANG Zheng-An;ZHOU Xiao-Gang;ZHANG Shao-Song;SUN Mao-Lin
      Acta Agron Sin. 2008, 34(06):  978-983.  doi:10.3724/SP.J.1006.2008.00978
      Abstract ( 2008 )   PDF (449KB) ( 1938 )   Save
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      Plastid transformation in higher plants offers several advantages over nuclear transformation, including maternal inheritance of transgenic, lack of position effects and gene silencing, and high levels of transgenic expression, because the high ploidy level of the plastome in cells and the genes of interest are integrated into the plastome via homologous recombination. Based on the highly conservative features of trnI and trnA genes during the plastid genome evolution of higher plants, we described a distinct construction protocol of species-specific transformation vector of potato. We designed the primers and PCR-amplified the trnI-trnA targeting region from total genomic DNA of potato line of ‘Hui-2’. After sequencing and digesting the amplifed 2.7 kb fragment, which was used as homologous targeting sequences, we constructed the potato-specific plastid expression vector named pBMLSIA-GFP that carries the expression cassette of Prrn-gfp-aadA-TpsbA. Then, verified by digestion with restriction enzymes, the vector pBMLSIA-GFP was transformed into potato tubers using PDS-1000/He biolistic particle delivery system. The fluorescence upon excitation with 365 nm light 2 days after bombardment was observed, the results indicated that the transient expression of GFP gene was in high efficiency under the regulation of plastid promoter Prrn and signals TpsbA. Tubers bombarded twice at 1 100 psi pressure and a target distance of 6 cm emitted the most intensive fluorescence. The analysis results of SDS-PAGE electrophoresis showed that GFP protein in high-level expression was up to 15.4–30.2% of the total soluble protein in potato tubers. It indicated that this potato-specific plastid expression vector pBMLSIA-GFP is highly effective and desirable to be applied in traits improvement of potato via plastid genetic transformation.
      Overexpression of W6 Gene Increases Salt Tolerance in Transgenic To-bacco Plants
      LU Yan;XU Zhao-Shi;ZHANG Rui-Yue;LIU Li;LI Lian-Cheng;CHEN Ming;YE Xing-Guo;CHEN Yao-Feng;MA You-Zhi
      Acta Agron Sin. 2008, 34(06):  984-990.  doi:10.3724/SP.J.1006.2008.00984
      Abstract ( 2162 )   PDF (400KB) ( 1613 )   Save
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      Ethylene responsive factors (ERFs) are important plant-specific transcription factors. Some of them have been identified to interact with the ethylene-responsive GCC box and the dehydration responsive element (DRE). They usually play very important regulatory roles in response to biotic and abiotic stresses in plants. In our study, an ERF gene W6 was isolated from wheat (Xiao baimai) cDNA library, which belongs to ERF IV subfamily. Full-length W6 cDNA encoded an ERF protein containing a conserved ERF DNA-binding motif, two putative nuclear localization sequences and a C-terminal acidic transcription activation domain. W6 expression in wheat can be induced by various treatments such as cold, drought, salt, ABA and fungal pathogens. We constructed transgenic vector (35S::pBI121::W6) containing CaMV 35S promoter and then obtained W6-overexpresed tobacco plants by Agrobacterium-mediated transformation in order to identify the function of W6. Under the treatment with 200 mmol L-1 NaCl for 50 d, the transgenic plants grew well but the control plants nearly died. The root length of transgenic tobacco plants was between 1.40 cm and 3.93 cm, while that of the control only 0.20 cm. The root weight of transgenic tobacco plants was between 2.41 g and 7.79 g, while that of the control only 0.06 g. SOD activity and chlorophyll content in transgenic plants increased markedly compared to the control. All results the above showed that the overexpression of W6 improved tobacco’s salt tolerance, and W6 may act as a connector among different signal transduction pathways. The overexpression of W6 activated the expression of GCC box-containing genes PR2, PR3, PR5, and DRE/CRT genes NtERD10A and NtERD10C under normal growth conditions, and the tolerance to salt stress was improved in transgenic tobacco plants, which suggested that W6 regulates osmotic tolerance by activation of downstream gene expression through interaction with the GCC box or DRE.
      Sampling Method on Grain Yield Evaluation Based on Maize Regional Trials
      PU Shao-Jing;JIN Wen-Lin;BAI Qiong-Yan;ZHANG Lian-Ping;CHEN Li-Jun;ZHAO Bo;ZHONG Lian-Quan
      Acta Agron Sin. 2008, 34(06):  991-998.  doi:10.3724/SP.J.1006.2008.00991
      Abstract ( 2169 )   PDF (352KB) ( 1116 )   Save
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      The current design for maize regional trials on the number of rows in plot and plants of yield estimate mostly depends on experiences instead of sufficient, and it was short of statistical foundation. Sampling method for grain yield based on common regional trials was studied in the known population of 7 200 plants in an area of 1 209.60 m2 with summer maize cultivar Jingyu 11 in Changping District, Beijing through the “Sampling Software” designed by Jin and Li, and number of sampling rows (lines) and sample size were approached as key points. Sampling with four sorts of sample sizes of 60, 120, 180, and 240 by random piece sample of 1–6 rows and 10 rows, according to the comparative analysis of variance of sample means, sampling method of 3–6 rows was better than that of 1–2 rows and 10 rows. Frequency distribution of the means of 500 samples showed that for dif-ferent sample sizes, the sampling should choose a different number of rows, and for the sample size of 60, 120, 240, and 420, 3, 4, 5, and 6 rows were the better sampling number of rows respectively. Considering precision and labor load, sampling 4–6 rows was better than sampling 3 rows. In labor-saving strategy with lower precision, sample size of 120 was suggested for sampling 4–6 rows; while in higher precision strategy, sample size of 420 was better for sampling 4 and 6 rows, and that of 480 for sampling 5 rows. Sampling methods with different number of rows and sample sizes were significantly different in frequency distribution of the sample means and the variance of sample means, and the better sampling methods could be distinguished from the others. Comprehensive analyses of the above results indicate that the best methods are sampling 6 rows with 420 plants for high precise trials, and 4 rows with 120 plants for common trials lower in precision.
      Genetic Diversity of Peanut RILs and Enhancement for High Oil Geno-types
      LIAO Bo-Shou;LEI Yong;WANG Sheng-Yu;LI Dong;HUANG Jia-Quan;JIANG Hui-Fang;REN Xiao-Ping
      Acta Agron Sin. 2008, 34(06):  999-1004.  doi:10.3724/SP.J.1006.2008.00999
      Abstract ( 2036 )   PDF (207KB) ( 1386 )   Save
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      Peanut (Arachis hypogaea L.) is one of the important sources of vegetable oil and enhancement of peanut oil content is a key objective of breeding. In this study, peanut recombined inbreed lines (RILs) were constructed from Yuanza 9102 ´ Zhonghua 5 using a seed descent method and oil content and DNA polymorphism among the RILs were analyzed. The oil range of the RILs was 50.85–62.11%, which was much wider than the two parents of 53.13–57.07%, indicating that there was heterobeltiosis for oil content. The highest oil content in the RILs was higher than that of the high oil parent Zhonghua 5 by 5%. Through DNA diversity analysis using SSR approach, there was wider DNA polymorphism among the RILs. The high oil recombined lines existed in various clusters with considerable genetic distance. The high oil content was found not linked with other important traits such as 100-pod weight and resistance to bacterial wilt. Three line-pairs with zero genetic distance and similar oil content and agronomic characteristics but different in resistance to bacterial wilt were found, which might be desirable genetic materials for molecular marker research or gene cloning. Three elite lines with high oil content, desirable agronomic characters and bacterial wilt resistance were identified and they would be soon tested in regional varietal trials.
      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Effects of Nitrogen Nutrition on Grain Yield of Upland Rice and Paddy Rice under Different Cultivation Methods
      ZHANG Ya-Jie;ZHOU Yu-Ran;DU Bin;YANG Jian-Chang
      Acta Agron Sin. 2008, 34(06):  1005-1013.  doi:10.3724/SP.J.1006.2008.01005
      Abstract ( 2053 )   PDF (362KB) ( 1386 )   Save
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      Upland rice and dry-cultivated paddy rice have been attracted more and more attention because of limited water resources in China. Researches on interaction between water and nitrogen supplies for crop resistance to drought stress has become the hot topic regarding regulation on nutritional physiology. However, there is little information available on effect of nitrogen (N) nutrition on grain yield and its components of upland rice and paddy rice under different cultivation methods. The objective of this study was to evaluate the difference between upland rice and paddy rice and interaction between cultivation methods and N levels. One upland rice cultivar Zhonghan 3 (japonica) and one paddy rice cultivar Yangjing 9538 (japonica) were grown under moist cultivation (MC, control) or bare dry-cultivation (DC) with three N levels, low amount of N (LN, 100 kg ha-1), normal amount of N (NN, 200 kg ha-1), and high amount of N (HN, 300 kg ha-1). The results showed that, compared with NN, the grain yield under HN was lower for both upland and paddy rice under DC and for paddy rice under MC, whereas higher for upland rice under MC. With the increase in N levels, upland rice and paddy rice showed higher productive tillers, more or fewer spikelets per panicle, lower percentage of ripened grains under two cultivation methods. However, the percentage of ripened grains was reduced more for paddy rice than for upland rice. There was no significant difference in 1 000-grain weight for upland rice among three N levels, whereas grain weight was reduced with the increase in N levels. Compared with MC, DC showed no significant difference in grain weight for upland rice, whereas a significant decrease for paddy rice. DC significantly increased the percentage of ripened grains for both upland and paddy rice, and that were more for upland rice than for paddy rice. Compared with paddy rice, upland rice showed less number of adventitious roots, lower nitrogen absorption ability and lower productive tillering ability, fewer pani-cles, fewer spikelets per panicle and lower grain yield. However, upland rice exhibited quicker increase in adventitious roots and slower declining in leaf nitrogen content from jointing to heading, and a faster declining speed in chlorophyll content (SPAD value) after flowering. Also, upland rice had less negative response to water stress and more positive response to N. The results suggest that the response to cultivation methods and N levels varies largely between upland rice and paddy rice. The approaches to in-crease the grain yield of both paddy and upland rice were discussed.
      Effects of Straw Mulching Plus Nitrogen Fertilizer on Nitrogen Efficiency and Grain Yield in Winter Wheat
      ZHAO Peng;CHEN Fu
      Acta Agron Sin. 2008, 34(06):  1014-1018.  doi:10.3724/SP.J.1006.2008.01014
      Abstract ( 2015 )   PDF (187KB) ( 1673 )   Save
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      Long-term application of nitrogen fertilizer is approved to cause low nitrogen use efficiency in crops and environmental pollution by NO3--N accumulation in soil. Straw returning to field takes the advantages of improving physical and chemical characteristics and nutrition status of soil, resulting in yield promotion of crops. The nitrogen managements for straw mulching cultivation have been studied well in single cropping system. The wheat (Triticum aestivum L.)-maize (Zea mays L.) double cropping system is typical in North China Plain, however, nitrogen fertilizer application regimes in straw-mulching double-cropping system extended rapidly in the region are poorly studied. In the current fixed-plot field experiments, we aimed at the changes of nitrogen use efficiency and grain yield under straw mulching plus a series of amount of nitrogen fertilizer in winter wheat, and provided some advices on nitrogen application regime in mulch farming. A wheat cultivar, Zhoumai 14, was used in a two-factor randomized block design with 3 replicates. A total of 10 treatments were coded as N0, N90, N180, N270, and N360 for only nitrogen fertilizer applied (0, 90, 180, 270, and 360 kg ha-1, respectively) and S+N0, S+N90, S+N180, S+N270, and S+N360 for straw mulching plus nitrogen applications (nitrogen rates as above), respectively. About 7 500 kg ha-1 straw residue from previous cropping season was ploughed into soil. Compared with no straw mulching treatments, S+N treatments increased dry matter accumulation during wheat growth. The S+N treatments showed the amount and proportion of dry matter accumulation lower before heading than N treatments, but significantly higher at the period of heading to maturity. Under the same nitrogen fertilizer rates, grain yields of S+N90, S+N180, S+N270, and S+N360 were higher than those of corresponding N treatments by 7.1%, 8.4%, 11.1%, and 10.2%, respectively. The S+N270 treatment had the largest amount and increasing ratio of grain yield with significant differences from other S+N and those of N treatments, indicating that S+N270 might be the proper treatment in wheat production. Nitrogen fertilizer use efficiency, nitrogen use efficiency, and agronomic nitrogen use efficiency in S+N treatments were higher than those of N treatments by 3.3–9.2%, 0.7–4.0, and 2.7–7.3 kg kg-1, respectively. Our results indicate that returning straw to field has positive effects on winter wheat under the experimental conditions, and straw mulching plus nitrogen fertilizer has larger productivity than only applying nitrogen fertilizer.
      Activities of Enzymes Involved in Sucrose and Starch Synthesis during Grain Filling and the Relation to Nitrogen Metabolism in Strong- and Weak-Gluten Wheat Cultivars
      LI Jian-Min, WANG Zhen-Lin, GAO Rong-Qi, LI Sheng-Fu, CAI Rui-Guo, YAN Su-Hui, YU An-Ling, YIN Yan-Ping
      Acta Agronomica Sinica. 2008, 34(06):  1019-1026.  doi:10.3724/SP.J.1006.2008.01019
      Abstract ( 2139 )   PDF (454KB) ( 1373 )   Save
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      The strong- and weak-gluten cultivars are two typical patterns of high-quality wheat for different end-uses, between which many differences exist in the synthesis, accumulation, concentration, and components of both protein and starch in grain. The experiment was conducted at Tai’an experimental station of Shandong Agricultural University in 2005–2006 growth season. A strong-gluten cultivar Gaocheng 8901 and a weak-gluten cultivar Yumai 50 were used to compare the contents of NO3−-N, NH4+-N and activities of enzymes relating to nitrogen metabolism, sucrose and starch syntheses and the starch accumulation dur-ing grain filling, and to characterize the relationship between nitrogen and carbon metabolisms during grain development. The results indicated that the activities of sucrose synthase (SS), sucrose-phosphate synthase (SPS), adenosine diphosphorate glucose pyrophrylase (AGPP), soluble starch synthase (SSS), granule-bound starch synthase (GBSS), and starch branching enzyme (SBE) performed in the pattern of a single-peak curve during grain filling. The peak values of SS, SPS, SSS, GBSS, and SBE activities were higher in Yumai 50 than in Gaocheng 8901 except AGPP. The accumulation rate of amylopectin was highly significantly correlated with the activities of SS (r=0.9377**), SPS (r=0.8857**), AGPP (r=0.6489**), and SBE (r=0.5980**) in Gaocheng 8901, however, the accumulation rate of amylose was highly significantly correlated with the activities of SS (r=0.7616**) and SPS (r=0.7750**). The accumulation rate of amylopectin was significantly or highly significantly correlated with the activities of SS (r=0.8182**), SPS (r=0.6762**), AGPP (r=0.7028**), GBSS (r=0.8749**), and SBE (r=0.5433*) in Yumai 50, and the accumulation rate of amylose was highly significantly correlated with the activities of SS (r=0.8528**), SPS (r=0.8428**), and SBE(r=0.8603**). The activities of both nitrate reductase (NR) and glutamine synthetase (GS) exhibited a gradually decreased trend in the processs of grain filling in both cultivars, the activities of NR and GS in Gaocheng 8901 were higher than those in Yumai 50. The contents of NO3−-N and NH4+-N were highly significantly positively correlated with the activities of NR and GS in both cultivars. In Gaocheng 8901, the activities of NR and GS were negatively correlated with the activities of SS and SPS, but in Yumai 50 only the negative correlation of the activities between GS and SPS was significant (r = -0.5212*). Based on the results mentioned-above it was found that the starch synthesis and accumulation in grains of the different cultivars were influenced by the activities of the enzymes involved in nitrogen metabolism. The higher activity of NR caused the activities of both SS and SPS to be decreased, resulting in the decline of starch accumulation rate. This finding here supported the assumption that the ratio of SPS to NR plays an important role in starch synthesis and accumulation in wheat grains.
      Effects of Nitrogen Application Rates on Accumulation, Translocation, and Partitioning of Photosynthate in Winter Wheat at Grain Filling Stage
      MA Dong-Yun;GUO Tian-Cai;WANG Chen-Yang;ZHU Yun-Ji;SONG Xiao;WANG Yong-Hua;YUE Yan-Jun
      Acta Agron Sin. 2008, 34(06):  1027-1033.  doi:10.3724/SP.J.1006.2008.01027
      Abstract ( 1960 )   PDF (368KB) ( 1366 )   Save
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      Grain yield is mainly contributed by photosynthate post anthesis in wheat (Triticum aestivum L.), but assimilate accumulation before flowering also plays an important role, especially under stress conditions. The effects of nitrogen fertilizer on assimilation and partitioning of carbohydrate at maturity have been studied in different experiments with different conclusions. To evaluate the dynamic changes of assimilation and carbohydrate partitioning in wheat organs under different nitrogen application rates, a poly-spike cultivar Yumai 49-198 and a large-spike cultivar Lankao Aizao 8 were used in a pot experiment in 2005–2006 growth season. The nitrogen fertilizer was applied (half basic application and half topdressing at jointing) at two levels of 18 g m-2 and 36 g m-2 respectively. Flag leaves were labeled by 14CO2 at pre-anthesis stage. The results indicated that the 14C assimilates photosynthesized at pre-anthesis mainly distributed in stem and sheath, next in grain at maturity. The proportion of 14C partitioned to stem and sheath, grain was 44.31–60.96% and 31.81–40.67% respectively. In comparison, the proportion of 14C partitioned to grain was increased, while to stems and sheath was reduced by increased N application. The percentage of assimilated 14C in stems and sheaths of Lankao Aizao 8 was greater than that of Yumai 49-198. There was 34.94% of the assimilates in grains de-rived from the reallocation of assimilate stored at pre-anthesis and 65.06% from photosynthate post anthesis. Moreover, transloca-tion amount, translocation proportion and contribution of assimilates before flowering to grains decreased with higher nitrogen application rate, while the contribution of assimilates post anthesis and grain weight per spike increased. The results also showed that the percentage of post anthesis assimilation to grains was 77.84% and 56.29% for Lankao Aizao 8 and Yumai 49-198, respec-tively, indicating that assimilates photosynthesized post anthesis in Lankao Aizao 8 was greater than that in Yumai 49-198. Finally, grain yield in 36 g m-2 N treatment was higher than that in 18 g m-2 N treatment. Meanwhile, increase range in grain yield of Lankao Aizao 8 both in treatments of 36 g m-2 and 18 g m-2 was greater than that of Yumai 49-198, indicating that the effect of nitrogen fertilizer on Lankao Aizao 8 was significantly greater than that of Yumai 49-198.
      The Inhibitory Effects of Auxin and Cytokinin on Dark- and ABA-induced Stomatal Closure in Broad Bean
      ZHANG Bei;SHE Xiao-Ping;ZHANG Guang-Bin;MENG Zhao-Ni;SONG Xi-Gui
      Acta Agron Sin. 2008, 34(06):  1034-1041.  doi:10.3724/SP.J.1006.2008.01034
      Abstract ( 2242 )   PDF (626KB) ( 1220 )   Save
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      In the present studies, the effects and mechanisms of natural and synthetic auxin IAA, NAA, 2,4-D, cytokinin ZT, KT, 6-BA on dark- and ABA-induced stomatal closure were investigated by means of stomatal bioassay and using laser-scanning confocal microscopy. Isolated epidermal strips of Vicia faba were incubated with IAA (10 mmol L-1), NAA (10 mmol L-1), 2,4-D (10 mmol L-1), ZT (0.1 mmol L-1), KT (0.2 mmol L-1), 6-BA (0.2 mmol L-1), NO scavenger c-PTIO (200 mmol L-1), Hb (100 mmol L-1), NOS inhibitor L-NAME (25 mmol L-1), H2O2 scavenger AsA (100 mmol L-1), CAT (100 U mL-1), inhibitor of H2O2-generating enzyme NADPH oxidase DPI (10 mmol L-1) for 3 h, in darkness or in light in the presence of ABA (1 mmol L-1), respectively. The results showed that auxin, cytokinin, as well as c-PTIO, Hb, L-NAME, AsA, CAT, and DPI, reversed dark- and ABA-induced stomatal closure significantly. Epidermal strips treated with auxin and cytokinin were loaded with NO-fluorescent dye DAF-2DA or H2O2-fluorescent dye H2DCF-DA. The results indicated that darkness and ABA could induce an intense DAF-2DA or H2DCF-DA fluorescence in guard cells. However, dark- and ABA-induced DAF-2DA and H2DCF-DA fluorescence were largely prevented by auxin and cytokinin tested. Similarly, the treatments of c-PTIO, Hb, L-NAME and AsA, CAT, DPI also substantially suppressed dark- and ABA-induced DAF-2DA and H2DCF-DA fluorescence, respectively. These results provide the evidence that auxin and cytokinin tested lessen assuredly NO and H2O2 levels induced by dark and ABA in guard cells. Considering synthetic auxin, cytokinin NAA, 2,4-D, KT, 6-BA and natural IAA, ZT were used in the present work and IAA, ZT are representative of endogenous auxin and cytokinin respectively, the effects of auxin, cytokinin tested on dark- and ABA-induced stomatal closure and NO, H2O2 level can be attributed to an universal effect of auxin or cytokinin.
      Changes of Main Agronomic Traits with Genetic Improvement of Soybean [Glycine max (L.) Merr.] Cultivars in Jilin Province, China
      ZHENG Hong-Bing;XU Ke-Zhang;ZHAO Hong-Xiang;LI Da-Yong;YANG Guang-Yu;LIU Wu-Ren;LU Jing-Mei
      Acta Agron Sin. 2008, 34(06):  1042-1050.  doi:10.3724/SP.J.1006.2008.01042
      Abstract ( 2015 )   PDF (421KB) ( 1316 )   Save
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      Soybean yield in Jilin Province has increased approximately 1.12% per year since early 1920. Our objective was to investigate the changes in agronomic traits associated with yield increase in the selection of historical cultivars using 30 soybean cultivars cultivated and genetically improved from 1923 to 2005. The experiments were performed with randomized complete block design with at least three replicates in Changchun (43.53°N, 125.10°E), Jilin Province in 2005–2006. The results indicated that according to the regression equation, soybean yield exhibited a linear increase with genetic improvement, from 1 197.80 kg ha-1 in 1923 to 2 305.54 kg ha-1 in 2005, with average increase of 14.60 kg ha-1(1.12%) per year. With the increasing of soybean yield, plant height and branches shortened; stem diameter and number of pods and seeds increased. Yield was positively correlated with number of pods and seeds per plant, stem diameter, leaf area per plant, leaf area index (LAI), and the number of leaves (P<0.05) while negatively correlated with plant height, number of branches, and lodging index (P<0.05). This study demonstrated that genetic improvement enhances the resistance to lodging, the sink capability and the assimilation ability which results in a consecutive yield increase in soybean.
      Effects of Nitrogen Application on Forage Maize Planted in Two Soil Types in Agriculture-Animal Husbandry Ecotone of North China
      DU Xiong;ZUO Qi-Hua;FENG Li-Xiao;ZHANG Wei-Hong;DOU Tie-Ling;BIAN Xiu-Ju;ZHANG Li-Feng
      Acta Agron Sin. 2008, 34(06):  1051-1059.  doi:10.3724/SP.J.1006.2008.01051
      Abstract ( 2517 )   PDF (264KB) ( 1016 )   Save
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      To solve the actual problems of shortage and bad quality of forages in current agriculture-animal husbandry ecotone of North China, a field experiment was conducted to study the effects of nitrogen application rate on biomass yield, forage quality, fertilizer and water use efficiencies of forage maize (Zea mays L.) in meadow chestnut and sand chestnut soils. The results indicated that nitrogen application increased the forage maize biomass yield by 36.1% and 106.0% in meadow chestnut and sand meadow chestnut soils, respectively, and significantly improved nitrogen absorption in forage maize plant. The nitrogen content in plant increased by 108.0% and 81.9% compared with that without nitrogen application, and the extravagant absorption of nitrogen by plant occured in meadow chestnut soil. Nitrogen application also increased the phosphorus content in forage maize plant by 10.9% in meadow chestnut soil, but decreased in sand chestnut soil. In the two soil types, the content and yield of crude protein and crude fat of the forage maize were enhanced significantly with the increase of nitrogen application. The yields of crude protein and crude fat increased by 1.60 and 2.10 times in meadow chestnut soil, and by 2.74 and 1.36 times in sand chestnut soil, respectively. The nitrogen application increased the water use efficiency (WUE) of the forage maize by 27%–45%, equivalent to a surplus supply of 82.5–135.7 mm water in meadow chestnut soil, and by 95%–97%, equivalent to a surplus supply of 294.9–258.5 mm water in sand chestnut soil. Thus it concluded that nitrogen for forage maize is an effective technique to improve biomass, nutrition quality, and fertilizer and water utilization efficiencies in the area, nitrogen applications of less than 200 kg ha-1 in meadow chestnut soil and more than 135 kg ha-1 in sand chestnut soil were appropriate to ensure high yield and good quality as well as high nitrogen fertilizer and water use efficiencies of forage maize.
      Dry-Matter Accumulation and Nitrogen Absorption and Utilization in Middle-Season Indica Super Hybrid Rice
      WU Wen-Ge;ZHANG Hong-Cheng;CHEN Ye;LI Jie;QIAN Ying-Fei;WU Gui-Cheng;ZHAI Chao-Qun
      Acta Agron Sin. 2008, 34(06):  1060-1068.  doi:10.3724/SP.J.1006.2008.01060
      Abstract ( 2216 )   PDF (373KB) ( 1219 )   Save
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      The field experiment was conducted in 2006 to research the difference of characteristics of dry matter accumulation and nitrogen uptake and utilization between five super rice cultivars and the control—Shanyou 63. The dry matter production of middle-season indica super hybrid rice was started from the beginning of elongation stage, and with the rice growing, the comparative advantage of dry matter accumulation was gradually speeded up. The middle-season indica super hybrid rice had apparent advantage in biomass accumulation after heading. Total amount of nitrogen absorption was 196.5 (184.3–200.8) kg ha-1 in super rice cultivar, which was 20.0 kg ha-1 higher than that of control. The amount of nitrogen absorption of middle-season indica super hybrid rice cultivar corresponded to that of control before jointing stage, however, increased 9.2 kg ha-1 more than that of CK from jointing stage to heading stage, 4.9 kg ha-1 more than that of CK at 25 days after heading stage, and 4.3 kg ha-1 more than that of CK from 25 days after heading stage to maturity. The Nitrogen uptake rate reached its peak at booting stage, and the middle-season indica super hybrid rice was 3.68 (3.44–3.96) kg N ha-1 d-1 while the control was 3.55 kg N ha-1 d-1. And then, the nitrogen uptake was slower and slower after booting stage, and at 25 days after heading and at maturing stage, the N-uptake rate was 0.36 kg N ha-1 d-1 in super rice, whereas it was almost zero in the control. It can be seen that middle-season indica super hybrid rice held high N rate in the leaf blade after heading stage, which was beneficial to chlorophyll contents stability and photosynthate accumulation so that the super high yield of the rice could become true. The result also showed that the super hybrid rice should absorb about 1.83 kg N per hundred kilogram grain when its yielding level was 10.5 t ha-1.
      Discrimination of Numerous Maize Cultivars Based on Seed Image Process
      YANG Jin-Zhong;HAO Jian-Ping;DU Tian-Qing;CUI Fu-Zhu;SANG Su-Ping
      Acta Agron Sin. 2008, 34(06):  1069-1073.  doi:10.3724/SP.J.1006.2008.01069
      Abstract ( 2192 )   PDF (188KB) ( 1438 )   Save
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      Seed identification plays a crucial role in seed quality testing and breeding programs in maize (Zea mays L.). Machine vision of seed surface features performances well based on a few experiments in maize. But the sample numbers in these studies were only 3–7 cultivars. To further examine the feasibility of image process application in discriminating numerous maize cultivars, six models were created and validated by means of principle component analysis and statistical discrimination analysis. The models comprised 4 categories or their combinations of 46 morphological traits extracted from scanned two-side images of 50 kernels each of 193 maize cultivars from Northeast and North China in recent years. Models of size, shape, texture, color, plus combination of latter 3 categories and combination of all 4 categories could correctly recognize cultivars at rates of 25%, 33%, 39%, 95%, 95%, and 95%, respectively, when cross-validated with all 9 650 kernels. Average refuse error rates were 90%, 90%, 86%, 45%, 47%, and 42%, respectively, and acceptance error ones were 92%, 92%, 88%, 46%, 48%, and 43%, respectively. These two error rates were highly and positively correlated between each other (r = 0.83**-0.91**). Machine vision wins the ad-vantages of low cost and high speed over manual or biochemical detecting methods, and is feasible to be applied to identification of numerous maize cultivars. The combination of shape, texture and color is the best model. Model performance may be promoted further with optimizing samples and structure.
      Relationship between SDS-Unextractable Glutenin Polymeric Protein and Mixograph Parameters
      ZHANG Ping-Ping;XIAO Yong-Gui;LIU Jian-Jun;MA Hong-Xiang;HE Zhong-Hu
      Acta Agron Sin. 2008, 34(06):  1074-1079.  doi:10.3724/SP.J.1006.2008.01074
      Abstract ( 2205 )   PDF (256KB) ( 1396 )   Save
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      Improvement of end-use quality has become a major breeding objective in China. In order to further improve gluten quality, effective selection parameter in early generation is necessary in wheat quality breeding program. In total, 108 wheat (Triticum aestivum L.) varieties and advanced lines were used to test kernel hardness, protein content, sedimentation value, mixogragh parameters, glutenin polymeric protein content by biuretium protein fraction procedure, and the amount and ratio of gluten protein fractions by size-exclusion high-performance liquid chromatography method (SE-HPLC). The relationship between flour protein content, sedimentation volume, and mixograph parameters and gluten protein fractions in quantity were investigated. The results showed that broad variations for quality traits and quantitativedata for protein fractions were observed in this set of germplasm. The range of mixograph peak time was 1.12–7.19 min, and the range of SDS-unextractable polymeric protein was very broader than that of SDS-extractable polymeric protein. There were less correlation between grain hardness, flour protein content, whole meal sedimentation value, and mixograph peak time with r of 0.24–0.49. The amount of gliadin was not significantly correlated with mixograph parameters, while the ratio of gliadin to glutenin (Gli/Glu) was crucial in determining mixograph parameters [r = (–0.52)– (–0.61), P<0.001], which was independent of flour protein content. The strong associations between percent SDS-unextractable fraction in total polymeric protein (%UPP) and mixograph parameters were observed with r of 0.70–0.85 (P<0.001). %UPP and Gli/Glu tested by SE-HPLC can be used as effective parameters for early generation selection to improve wheat gluten strength due to their automatic micro-analyzing method.
      Effects of Nitrogenous Fertilizer Application Model on Culm Lodging Re-sistance in Winter Wheat
      WEI Feng-Zhen;LI Jin-Cai;WANG Cheng-Yu;QU Hui-Juan;SHEN Xue-Shan
      Acta Agron Sin. 2008, 34(06):  1080-1085.  doi:10.3724/SP.J.1006.2008.01080
      Abstract ( 2374 )   PDF (364KB) ( 1461 )   Save
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      Culm lodging is a common problem in wheat (Triticum aestivum L.) production causing yield loss and quality deterioration of grain. Weak mechanical strength of the 1st and 2nd basal internodes of culm is the major reason for wheat lodging during late growth period. It is well known that the mechanical strength is closely related to cellulose and lignin contents in culm, which are easily affected by nitrogen fertilizer. Accordingly, lodging resistance can be improved through proper nitrogen application. However, few reports have been found on it so far. We attempted to set up a nitrogen application regime for increasing longing resistance in high-yielding winter wheat through measuring the structure parameters of culm, chemical components of culm cell walls, and the culm lodging resistance index (CLRI). In the present experiment, we employed a wheat cultivar “Yannong 19” with high yield and strong-gluten content in the field with basic nutrition status in 0–20 cm soil layer as organic matter of 2.13%, total N of 1.5 g kg-1, available N of 115.6 mg kg-1, available P of 22.8 mg kg-1, and available K of 142.5 mg kg-1. N fertilizer treat-ments were set up by randomized block design with three application rates (202.5, 270.0, and 337.5 kg ha-1, respectively) and three basal-topdressing ratios at pre-sowing, jointing, and booting stages (3:5:2, 5:5:0, and 7:3:0, respectively). The planting den-sity was 2.25´106 plants ha-1. The results showed that N fertilizer application model significantly affected lodging-resistant capa-bility. Lengths of the 1st and 2nd basal internodes and their N contents increased with the increase of nitrogen levels, especially the basal nitrogen proportion. The cell wall cellulose and lignin contents, and culm lodging resistance index showed the trend of low-high-low in the 3 N levels, but kept decreasing when more basal nitrogen was applied. CLRI was positively correlated with the diameter of basal internodes (r = 0.9254**), thickness of culm wall (r = 0.9087**), filling degree (r = 0.9218**) and mechanical strength (r=0.9662**) of culm, but negatively correlated with the length (r = -0.8421**) and the nitrogen content (r = -0.8658**). The study also indicated the potential of CLRI for wheat lodging evaluation.
      RESEARCH NOTES
      Sequence Analysis and Characterization of Four GL2 Homologous Genes in Cotton (Gossypium hirsutum L.)
      YANG Xia;HOU Lei;XIAO Yue-Hua;LI De-Mou;ZHANG Guo-Fang;PEI Yan
      Acta Agron Sin. 2008, 34(06):  1086-1091.  doi:10.3724/SP.J.1006.2008.01086
      Abstract ( 2084 )   PDF (692KB) ( 1717 )   Save
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      Arabidopsis GLABRA2 (AtGL2), a transcription factor, plays critical roles in the differentiation of trichome cells and root hair cells. However, the function of GL2 homologous genes in cotton fiber differentiation and development is still unclear. In this paper, transcription profiles of four putative cotton HOX ORFs homologous with AtGL2 were investigated. Multiple sequence alignment revealed that these 4 GhHOX proteins shared 95%, 71%, 72%, and 63% identity with AtGL2 in the homeobox conserved domain, respectively. Real-time RT-PCR analysis indicated that GhHOX1, GhHOX3 and GhHOX4 expressed in cotton elongating fiber cells preferentially. Moreover, GhHOX3 showed significant higher expression level in the ovules of Xuzhou 142 than in its fuzz-free and lint-free mutant ovules at the initiation stage. The results suggested that the GL2 homologous genes of cotton may play important roles in fiber initiation and elongation.
      Effect of High Temperature during Grain Filling on Starch Accumulation, Starch Granule Distribution, and Activities of Related Enzymes in Wheat Grains
      YAN Su-Hui;YIN Yan-Ping;LI Wen-Yang;LIANG Tai-Bo;LI Yong;WU Yun-Hai;WANG Ping;GENG Qing-Hui;DAI Zhong-Min;WANG Zhen-Lin
      Acta Agron Sin. 2008, 34(06):  1092-1096.  doi:10.3724/SP.J.1006.2008.01092
      Abstract ( 2152 )   PDF (390KB) ( 1428 )   Save
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      In order to investigate the effects of high temperature at early grain filling stages (5–9 d after anthesis) on grain starch formation of wheat (Triticum aestivum L.), cultivars Jimai 20 (weak heat tolerance) and Lumai 21 (strong heat tolerance), were used with a heat stress treatment in the field by plastic sheds. Starch accumulation, starch granule distribution, and changes of enzymes activities involved in starch synthesis were examined. The results showed that heat stress after anthesis remarkably reduced starch accumulation at maturity. The total starch and amylopectin contents decreased significantly, but amylose content increased in heat treatments compared to control. Accordingly the ratio of amylose to amylopectin of heat treantment was significantly higher than that of control. The effect of high temperature on starch accumulation in Jimai 20 was greater than that in Lumai 21. The volume, number, and surface area percentage of A type starch granule were enhanced significantly, but those of B type starch granule reduced greatly under high temperature. After 5 d heating stress, the sucrose content, the activities of sucrose synthase (SS), adnosine diphosphate glucose pyrophosphorylase (AGPP), soluble starch synthase (SSS), and granule-bounded starch synthase (GBSS) increased in heat-treated grains of Lumai 21, but changed slightly in treated grains of Jimai 20 with no significant difference to control. These indexes of Jimai 20 and Lumai 21 became lower than those of control at 15 and 20 d post anthesis (6 and 11 d after heat stress removal), respectively. The GBSS activity was affected slightly by heat treatment. The results indicate that the changes in grain sucrose content and the activities of SS, AGPP, SSS, and GBSS are companied with the changes in grain starch accumulation, and high temperature restrains starch synthesis at middle and late grain filling stages, which is caused by inferior sucrose providing capacity and low activities of enzymes (SS, AGPP, SSS, and GBSS) involved in starch synthesis.
      Isolation and Sequence Analysis of α-gliadin Genes from Dasypyrum breviaristatum
      LI Guang-Rong;REN Zheng-Long;LIU Cheng;ZHOU Jian-Ping;YANG Zu-Jun
      Acta Agron Sin. 2008, 34(06):  1097-1103.  doi:10.3724/SP.J.1006.2008.01097
      Abstract ( 1943 )   PDF (641KB) ( 1161 )   Save
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      PCR was carried out on the genomic DNA from Dasypyrum breviaristatum using the conserved primers specific forα-gliadin genes. The PCR products were cloned and sequenced. Total 7 sequences were obtained with length of 999 to 1 018 bp containing coding regions from 283 to 290 amino acids and their GenBank accession number are EU186102 to EU186108 respectively. BLAST search showed that these sequences belong to a-gliadin super-family. Searching for 4 different T cell stimulatory epitopes for celiac disease patient, it is found that 5 of 7 sequences contained the Glia-a-2 epitopes at the C terminal region. The phylogenetic trees indicated that all the sequences could not be clustered into the group of a-gliadin genes from the A, B, and D genomes of wheat (Triticum aestivum), but presented in a new group. On the basis of the a-gliadin gene sequences, a pair of AS-PCR primer was designed. PCR results indicated that the AS-PCR primers allow to specifically amplify the D. breviaristatum and wheat-D. breviaristatum partial amphiploid, which thus can be used as a marker to trace the D. breviaristatum derived a-gliadin genes in wheat-Dasypyrum introgression lines.
      Effects of Exogenous Chromosomes on Root Characteristics in Triticum aestivum-Lophopyrum elongatum with Chinese Spring Background
      PENG Yuan-Ying;SONG Hui-Xing;ZHONG Zhang-Cheng
      Acta Agron Sin. 2008, 34(06):  1104-1108.  doi:10.3724/SP.J.1006.2008.01104
      Abstract ( 1912 )   PDF (443KB) ( 928 )   Save
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      The effects of exogenous chromosomes on root morphology were studied with the disomic substitution series of Triticum aestivum L. cv. Chinese Spring-Lophopyrum elongatum (Host) A. Löve. Scanner-based image analysis was used to investigate total root length, surface area, mean diameter, and number of root per plant. The fractal dimensions of young root systems were also calculated. Compared with Chinese Spring, there were fewer roots per plant in 3Ee, 5Ee, and 7Ee substitutions and larger total root length and surface area in 1Ee, 2Ee, and 4Ee substitutions, indicating that genes associate with the above characteristics on the corresponding chromosomes respectively. But the genes controlling average diameter were found on every chromosome of L. elongatum. The fractal dimension of seedling root systems was significantly correlated with the above 4 root parameters included in root growth models (0.757**≤r≤0.845**). It is suggested that the fractal dimension can be used as an integrated index for summarizing root morphological characteristics of Chinese Spring and its substitutions after further studies.

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)
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https://www.sciencedirect.com/journal/the-crop-journal
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E-mail: cropjournal@caas.cn
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