Relative efficiency,ureide transport and harvest index in soybeans inoculated with isogenic HUP mutants of Bradyrhizobium japonicum

Summary Differences between isogenic uptake hydrogenase (HUP) mutants of Bradyrhizobium japonicum in terms of nodule efficiency, N₂ fixation and N incorporation into various plant parts were studied in a monoxenic greenhouse experiment in order to confirm previous results with soybeans and beans inoculated with various HUP⁺ and HUP^– strains. The HUP+ revertant PJ17-1 of a HUP^– mutant (PJ17) of strain USDA DES 122 showed a completely restored relative efficiency (100% versus 78±2% for the HUP^– mutant), higher nodule efficiency (N₂ fixed per g nodules), higher ureide-N transport rates, higher N contents in pods and higher N harvest indices. All these observations confirm previous experiments with HUP⁺ and HUP^– strains.     

土壤酸度对大豆、油菜生长和产量的影响

 两个盆栽试验结果显示，施用石灰石粉和钙镁磷肥能显著促进大豆生长和根瘤形成，并能提高产量，施用石灰增加了大豆植株Ca含量，但减少其K含量；施用磷肥增加植株的P含量，但减少植株的Ca的含量，大豆的根瘤数和籽粒产量与土壤pH、交换性Ca和Al及铝饱和度之间呈显著相关。10年的石灰石粉长期定位试验结果表明，在施用钙镁磷肥的条件下，施用3750kg/hm#+2石灰石粉即可使油菜获得高产，但适当过量施用石灰并未使油菜减产。要使红壤油菜获得最佳产量，必须使土壤pH值提高到5.9以上,而交换性铝降至1.0cmol(+)/kg以下。     

Novel Fertilizer as an Alternative for Supplying Manganese and Boron to Soybeans

Soybean (Glycine max) commonly experience Mn deficiencies in the coarse-textured soils of Coastal Plain Virginia, especially under high pH conditions. The objective of this study was to investigate the ability of a novel coated fertilizer to provide Mn and B to soybeans in soils where Mn deficiency is common and B deficiency, although far less common than with Mn, is possible. A 60-d greenhouse experiment was conducted with three treatments: control, uncoated KCl, and Mn +B coated KCl applied to Bojac and Dragston sandy loams. Soil and whole plant tissue samples were collected throughout the experiment. Bojac and Dragston soils treated with the coated KCl contained 12.0 mg kg^?1 and 15.8 mg kg^?1 more Mehlich 1 – Mn, 21.7 mg kg^?1 and 23.0 mg kg^?1 more Mehlich 3 Mn, and 4.5 mg kg^?1 and 4.6 mg kg^?1 CaCl₂ – Mn than the control and uncoated KCl, respectively. Coated KCl increased above ground tissue Mn by 42.9 mg kg^?1 compared to the control and the uncoated KCl treatments in the Bojac soil, while the Dragston soil showed no significant differences in Mn tissue concentration between treatments. Above ground tissue, Mn was much lower in the Dragston soil than the Bojac, probably due to greater organic matter which chelates Mn keeping it less plant available. Boron concentrations did not differ in plant tissue or soil, regardless of the extraction method. Results indicate that the coated KCl product could consistently provide increased Mn concentration in acidic sandy soils despite varying levels of organic matter, but is not effective for B.     

东北大豆脂肪、蛋白质含量的生态效应

采用 5个在各地都能够正常成熟的品质有差异的品种在东北三省有代表性的 11个地点种植 ,分析了解各地点脂肪、蛋白质含量的生态效应。结果表明 ,蛋白质含量、脂肪含量和蛋白脂肪总含量在品种间、地点环境间均存在极显著差异 ,而且存在品种×地点交互作用。三个品质特性均以品种效应的相对变异最大 ,品种×地点交互作用的相对变异次之 ,地点效应的相对变异最小。各生态地点的品质主效应和品种×地点交互作用有较大差异。     

利用“微创刷”法获得抗草甘膦转基因大豆

以发芽3 d的大豆成熟种子胚尖生长点为作用点,利用"微创刷"法将抗草甘膦基因(EPSPS)转入绥农22中,对转化植株T1代进行草甘膦筛选,对筛选后的抗性植株进行PCR检测,得到抗草甘膦转基因大豆。同时研究了不同浓度草甘膦对野生型绥农22与抗草甘膦转基因绥农22大豆植株的影响。结果表明:绥农22 T0代成株率为97.38%,对T1代具有草甘膦抗性的植株进行PCR检测,初步证明EPSPS基因成功转入大豆中,T1代转化效率为6.20%;对野生型绥农22与"微创刷"法获得的转基因绥农22大豆在不同浓度草甘膦进行相关生理指标测定,抗草甘膦转基因绥农22大豆在不同浓度草甘膦作用下叶片叶绿素含量指数、光合速率高于野生型绥农22大豆,莽草酸含量低于野生型绥农22大豆,进一步证明了大豆抗性植株对草甘膦的抗性。     

河西荒漠灌区不同耕作方式对作物产量的影响

在河西荒漠灌区比较了小麦、玉米、大豆3种作物在连作、轮作、间作方式下的产量,结果表明,小麦产量以小麦与玉米轮作最高,为6 839.3 kg/hm2,较连作增产23.6%;玉米产量以小麦与玉米间作(小倒茬)最高,为12 915.0 kg/hm2,较连作增产50.8%;蚕豆产量以玉米与蚕豆间作(连作)最高,为3 654.0 kg/hm2,增产率达50.2%。     

不同大豆杂交后代新品系产量性状的主成分分析

对来源于不同亲本组合的13个大豆新品系产量相关性状和遗传距离进行综合分析,旨在为区域性大豆生产中品种更新、筛选和亲本选配工作提供理论依据。通过主成分分析探讨了各产量相关性状以及各品系综合主成分值的大小与产量高低的关系;根据品系间的遗传距离,通过聚类分析将13个品系分为4类,结果表明亲本来源与遗传距离没有必然联系。在选择大豆品种时,应根据育种目标确定各个主成分值的大小;在评价品种间遗传差异时,应根据育种过程中对品种的选择方向和环境因素进行综合评价。     

Weed Competition in Soybeans (Glycine max L.)

The present investigation was conducted to determine the critical period of weed competition in soybeans at Giza, Egypt. Weed flora in the experimental site at Giza contained a wide range of species during both seasons of study (1990 and 1991). Total weed dry weight increased progressively with time up to 12 WAE (182.0 g/m²). Weed-free and weedy periods exhibited significant effects on soybeans height, number of pods per plant, stand at harvest, biological and seed yields. Optimum seed yields were produced by weed-free durations for 6 WAF up to all season (3.229–3.545 t/ha). Whereas, weedy periods for 2, 4, 6, 8, 10 and 12 WAF reduced seed yield by 14.9, 28.0, 35.3, 45.1, 48.1 and 51.1 %, respectively. Weed competition for the entire season caused 56.1 % reduction in soybean seed yield. The obtained results indicate that weed competition during the early stages of growth, adversely affected soybeans. At least 6 WAE of weed-free period was required to insure optimum soybean growth and yield. However, oil and protein contents were not affected by weed competition.     

The use of nitrogen-15 natural abundance and nitrogen yield of non-nodulating isolines to estimate nitrogen fixation by soybeans (Glycine max L.) across three elevations

Summary Dissimilarities in soil N uptake between N₂-fixing and reference non-N₂-fixing plants can lead to inaccurate N₂ fixation estimates by N difference and ¹⁵N enrichment methods. The natural ¹⁵N abundance ( ¹⁵N) method relies on a stabilized soil ¹⁵N pool and may provide reliable estimates of N₂ fixation. Estimates based on the ¹⁵N and differences in N yield of nodulating and non-nodulating isolines of soybean were compared in this study. Five soybeans from maturity groups 00, IV, VI, and VIII and their respective non-nodulating isolines were grown at three elevations differing in ambient temperature and soil N availability. Despite large differences in phenological development and N yield between the non-nodulating isolines, the ¹⁵N values measured on seeds were relatively constant within a site. The ¹⁵N method consistently produced lower N₂ fixation estimates than the N difference method, but only in three of the 15 observations did they differ significantly. The average crop N derived from N₂ fixation across sites and maturity groups was 81% by N difference compared to 71% by ¹⁵N. The magnitude of difference between the two methods increased with increasing proportions of N derived from N₂ fixation. These differences between the two methods were not related to differences in total N across sites or genotypes. The low N₂ fixation estimates based on ¹⁵N might indicate that the nodulating isolines had assimilated more soil N than the non-nodulating ones. A lower variance indicated that the estimates by N difference using non-nodulating isolines were more precise than those by ¹⁵N. Since the differences between the estimates were large only at high N₂ fixation levels (low soil N availability), either method may be used in most situations when a non-nodulating isoline is used as the reference plant. The ¹⁵N method may have a comparative advantage over N difference and ¹⁵N enrichment methods in the absence of a suitable non-N₂-fixing reference plant such as a non-nodulating isoline.     

抗盐碱转基因大豆对根际与非根际土壤氨氧化古菌多样性的影响

采用PCR—DGGE技术,研究了抗盐碱转基因大豆（SRTS）对根际与非根际土壤氨氧化古菌（AOA）群落多样性的影响。结果表明,在非根际土壤中,SRTS的氨氧化古菌DGGE条带数、多样性指数显著高于其受体亲本黑农35和其他两种大豆处理,而均匀度指数较低;在根际土壤中,SRTS的DGGE条带数和多样性指数均高于其受体亲本,但并不显著,其均匀度指数则显著高于其他处理;每种大豆自身根际与非根际比较显示,SRTS非根际氨氧化古菌DGGE条带数、多样性指数明显高于根际,均匀度指数却低于根际,而其受体亲本与其他两个处理反之。聚类分析结果表明,SRTS的DGGE带谱与其他大豆处理差异较大,且自身非根际与根际处理差异显著,与其受体亲本黑农35相似性很低。测序结果表明,在SRTS处理中特有条带12、15和优势条带13、14均属于Uncultured crenarchaeote。在盐碱土壤生态系统中,SRTS提高了非根际土壤氨氧化古菌群落的多样性,但对根际土壤中氨氧化古菌的群落多样性有一定的抑制作用。