Contribution of incident solar radiation on leaves and pods to soybean seed weight and composition

The weight and composition of soybean seeds (Glycine Max L. Merrill) depend on changes in carbon and nitrogen assimilate supply during grain filling. Soybean pods and seeds are green, evidencing their capacity to capture light. However, the current physiological knowledge does not consider any effect of incident solar radiation reaching the pods on seed weight and composition. The objective of this work was to investigate the response of seed weight and composition to changes in assimilate supply from leaves, to the incident solar radiation reaching the pods and to the combination of both, changes in assimilate supply from the leaves and incident solar radiation on pods of soybean plants. Field experiments were performed during two growing seasons at Balcarce, Argentina. Treatments modified the amount of assimilates supplied by the leaves (plant shading, defoliation), the solar radiation reaching the pods (pod shading) or both (defoliation and pod shading) during seed filling. Plant shading and defoliation reduced seed weight, oil concentration and oil and protein content and increased the concentration of saturated and poli-unsaturated fatty acids while reduced oleic acid percentage. Pod shading increased the concentration of stearic acid and reduced the concentration of linolenic acid. When pods were shaded on defoliated plants, seed weight and oil and protein content decreased while fatty acid composition was similar to values obtained under defoliation treatment. Based on these results, a conceptual model that considers photoheterotrophic nature of reproductive structures of soybean is proposed. Seed weight, oil and protein content and oil fatty acid composition depended on assimilate availability for the seeds. The response of oil and protein content to assimilate supply depended on whether leaves were present or not. The effect of solar radiation incident on pods depended on the amount of assimilates available for the seeds: (i) when carbon allocated was low (defoliation treatments), pods contributed to seed carbon economy but solar radiation incident on them did not affect fatty acid composition; (ii) when carbon allocated to the seeds was high (intact plants), contribution of pods to seed carbon economy was not significant, but the amount of solar radiation incident on pods produced significant changes in fatty acid composition.     

芝麻黄化突变体YL1的叶片解剖学及光合特性

表型性状标记在作物遗传育种中具有重要的应用价值。在芝麻地方种质"庙前芝麻"中发现了能够稳定遗传的黄化突变体YL1,对该突变体的叶片解剖特征、光合特性及农艺性状的比较分析表明,突变体YL1黄化心叶和平展叶在各个发育时期的叶绿体结构均与同时期野生型存在明显差异,下表皮气孔保卫细胞数是正常叶的2倍左右。YL1的叶绿素a、总叶绿素、类胡萝卜素含量均只有同时期正常含量的30%~40%,叶绿素b含量只有正常叶的20%;光合速率在初花期及以前均显著低于同期正常叶,但到终花期与正常叶相当;YL1的生育期和初花期显著推迟,株高和单株蒴果数明显降低,每蒴粒数和千粒重略微降低。显微观察表明,YL1的叶绿体形态结构发育不规则,基粒和基粒片层数目明显少于野生型,使得叶绿素含量过低,属于叶绿体发育异常导致的叶绿素缺少型突变体。     

大豆高产优质施肥研究与应用

本文概述了大豆营养特性与施肥的研究结果，提出了高产施肥的关键技术。大豆营养特性：一是对主要营养元素的吸收量较稻、麦作物高（等量籽粒产量），生产100kg大豆约吸收6.5~8.5kg N，1.8~2.8kg P2O5，2.7~3.7kg K2O，3.5~4.8kg CaO，1.8~2.9kg MgO，4.5~9.5g Zn。二是对主要营养元素的吸收积累高峰在花荚期，N、P、K的60~70%在在此期吸收，而不同于稻麦等作物。三是总氮源的40~60%来源共生固氮，而共生固氮又受土壤N、P、K、Ca、Mo、Zn等及土壤PH值影响。四是大豆成熟阶段营养器官的养分向籽粒转移率高，Ｎ、Ｐ、Ｋ分别达58~77%，60~75%，45~75%。大豆施用N、P、K、Zn、Mo、B肥均显著提提高产量，合理配合施用可达到180~300kg/亩。N、P提高籽粒蛋白质含量，K与Zn提高脂肪含量，P、K、Zn、Mo及少量N肥可提高结瘤固氮率。N、P、K和多种微肥可减轻东北连作大豆的不利因子危害，大幅度增加产量。大豆高产施肥，一是根据土壤、植株养分含量确定施肥数量，二是有机肥与N、P、K肥及多种微肥配合施用，三是注重前茬作物施肥，增肥土壤，四是根据土壤条件、耕作制度、大豆品种特性确定施肥数量、方法、时期。中等肥力高产施肥一般应施用N 8，P2O5 4，K2O 4，ZnSo4 1.5(kg/亩)，钼酸铵20~30g/亩，P、K、Zn用作底或种肥，N肥钼肥种肥花期追肥各半，另于花荚期喷施P、N、Mo肥二次     

泌乳后期奶牛干物质及部分营养需要研究

选择15头中国荷斯坦奶牛,随机分成三组,研究河北农区泌乳后期奶牛干物质及部分营养需求模型。结果表明:泌乳后期奶牛干物质采食量DM(kg)=0.0685W0.75+0.45(0.4×M+15×fat);所需产奶净能NE(LkJ)=376.45W0.75+3138×(0.4×M+15×fat)+ΔW×25100;可消化蛋白质DCP(g)=3.44W0.75+M×CP%/0.6+ΔW×325;各项指标略高于中国奶牛饲养标准(NY/T34-2004)。     

5个椰子品种形态特征的比较研究

对5个椰子品种茎、叶、花的23个形态特征进行了比较研究。结果表明:有15个数量性状和5个质量性状在5个品种间有显著性差异,而小叶形状、小叶边缘颜色和小叶边缘形状这3个性状在品种间无显著性差异。通过综合分析这20个性状,可以将供试品种进行初步区分。     

Molecular Cloning and Characterization of a Novel Gene Involved in Fatty Acid Synthesis in Brassica napus L.

Based on the sequence of a novel expressed sequence tag (EST), the full-length cDNA of 1 017 nucleotides was cloned from Brassica napus cv. Xiangyou 15 through rapid amplification of cDNA ends (RACE). The gene was designated as Bnhol34 (HQ585980), encoding a protein of 338 amino acids. BLAST analysis showed no high degree of sequence identity to any known gene. The calculated molecular weight of the Bnhol34 protein was 36.23 kDa, and the theoretical isoelectric point was 8.74. The Bnhol34 was also cloned from a high oleic acid mutant 854-1 through homologous cloning. There was no difference between the two Bnhol34 genes. Bnhol34 was localized in a tissue-specific manner in B. napus, and its expression level was about eight-fold greater in Xiangyou 15 seeds than in 854-1. The promoter region sequences of Bnhol34 were then isolated from Xiangyou 15 and 854-1, and a 93-bp deletion was found to occur in the Bnhol34 promoter region of 854-1. Three abscisic acid-responsive cis-elements (ABRE) were identified in the promoter region of Xiangyou 15. Real-time PCR analyses revealed that exogenous abscisic acid increased Bnhol34 expression by about four-fold in Xiangyou 15 seeds, yet did not change Bnhol34 expression in 854-1. It appeared that Bnhol34 might be abscisic acid insensitive in 854-1.     

转基因油菜TOPAS 19/2质粒分子多家协同实验及不确定度评定

质粒分子是转基因产品核酸定量检测的一类新型标准物质,具有易制备、周期短、成本低等特点。采用实时荧光定量PCR技术,并协同7家实验室对转基因油菜TOPAS 19/2质粒分子进行了基因组的可替代性研究、协同实验研究及不确定度评定。T检验表明,质粒和基因组所产生的内源和外源基因标准曲线的斜率和线性相关系数没有显著性差异。对多家定值的数据进行了统计分析得出,TOPAS19/2质粒分子的量值结果0.910,扩展标准不确定度（K=2）为0.013。     

Regulatory Network of Transcription Factors in Response to Drought in Arabidopsis and Crops

Drought is one of the most important environmental constraints limiting plant growth, development and crop yield. Many drought-inducible genes have been identified by molecular and genomic analyses in ...     

The role of peroxidase in the resistance of sunflower against Orobanche cumana in Russia

We present the results of a histochemical study comparing seedlings of races C and D of Orobanche cumana Wallr. (syn. O. cernua Loefl.) attacking sunflower (Helianthus annuus L.) in southern Russia. Three groups of O. cumana seedlings were distinguished according to the peroxidase content of the cells in the radicles: (1) those with neither extracellular nor intracellubr peroxidase and whose radicles have a smooth apex (these were classified as non-infective): (2) those with a high peroxidase content of the nuclei and the cytoplasm layer adjacent to the cell wall, as well as excretion of peroxidase from the apex of the radicles: (3) those with a similarly high peroxidase activity in the parasite cells, but without extracellular excretion. The apices of the radicles of the last two groups are swollen. It is suggested that these belong to O. cumana races C and D respectively. The extracellular peroxidase in O. cumana race C reacts with phenolic compounds, which are lignin precursors of the host, resulting in host resistance due to the formation of lignin layers in sunflowers possessing the Or3 gene for resistance. The absence of extracellular peroxidase in O. cumana race D prevents lignin formation and enables the parasite to attach to the host vascular system. Comparison of these data with the information on the earlier O. cumana races A and B, and older sunflower cultivars, points to a crucial role of peroxidase in the process of breeding new sunflower cultivars and the evolution of new O. cumana races.     

A high-throughput glasshouse bioassay to detect crown rot resistance in wheat germplasm

A high-throughput and reliable seedling bioassay to screen wheat germplasm for crown rot resistance was developed. Single wheat seedlings were grown in square seedling punnets in a glasshouse and inoculated with a monoconidial Fusarium pseudograminearum isolate 10 days after emergence. The punnets were laid horizontally on their side and a 10- µ L inoculum droplet placed on the stem base. Seedlings were incubated at near-saturated relative humidity, and crown rot severity was assessed 35 days after inoculation. Studies on the duration of incubation period, inoculum concentration and temperature were carried out to optimize these parameters. Seedling growth at 25/15(±5)°C in a glasshouse and 48-h incubation at near-saturated RH in darkness gave the best results. When crown rot resistance rankings of 16 Australian cultivars from the bioassay were compared with their field performance, Spearman's rank correlation coefficient was highly significant. This indicated that the seedling bioassay mimicked field resistance to crown rot in adult plants. A bootstrap resampling analysis showed little or no improvement in the coefficient of variation with an increasing number of replications, indicating a high level of precision and reproducibility. By detecting small but consistent differences in crown rot severity, the bioassay proved effective in large-scale screening for partial resistance: already over 1400 wheat genotypes have been screened. The high degree of precision makes this an invaluable tool in the understanding of pathogen aggressiveness, host specialization and parasitic fitness.