马铃薯蕾花果脱落与内源激素和光照的关系

以乌Ｈ_４比的母本０８１和父本ＮＳ４０－３７为材料,通过田间和室内试验,对马铃薯蕾花果脱落过程中内源激素变化进行研究,阐明了内源激素的变化规律及ＩＡＡ、ＧＡ_３、ＡＢＡ、Ｚ、ＺＲ对蕾花果脱落的具体作用方式;同时研究了不同光周期和光照强度与脱落的关系及所引起的内源激素的变化。结果表明,蕾花果中ＡＢＡ含量升高是引起脱落的主要原因,不利的外界因素可诱发ＡＢＡ的变化,而长光周期和充足的光照有助于减少蕾、花、果的脱落。     

土壤养分因子与马铃薯产量和商品薯率相关及通径分析

研究了不同生态条件下，土壤养分因子对马铃薯产量和商品薯率作用效果．结果表明，马铃薯产量在不同生态条件下，其参数有所不同，一般在干旱条件下，速效钾与产量关系密切，相对重要性大，决定程度也最高；在丰水条件下，速效氮与产量关系密切，相对重要性大，决定程度也最高．不论在干旱或丰水生态条件下，速效氮与商品薯率关系最密切作用最大．通过研究，提出了适应不同生态条件栽培马铃薯选地标准和施肥结构方案．     

大豆抗除草剂特性的遗传及其利用

本文综述了大豆抗除草剂特性的研究现状。分别就大豆品种对八种(类)除草剂的抗性反应作了概述,并列出了已发现的大豆抗、感除草剂基因名单,讨论了抗(耐)性基因的利用方式。     

蓖麻生育产量与气象条件关系

三年分期播种试验结果，结合水分等其它试验数据，通过统计分析，得出栽培蓖麻从播种至成熟中各发育阶段的单因子和复因子（光、温、水）与阶段发育天数间的关系方程，可用于发育期予报。并相应得出各发育阶段的温度下限指标。与此同时还建立了蓖麻籽实产量和产油量与气象因子的关系方程，可用于产量和产油量的估测。通过盆栽试验得到南麻幼苗冻害温度指标。     

耐阴与不耐阴大豆茎叶性状的变异及差异比较研究

大豆不耐阴品种的性状变异大于耐阴品种,茎叶性状中,叶形指数的变异最小、柄角的变异最大,表明叶形性状较稳定、柄角性状易受环境影响,对照单作,大豆间作后,节长增加,节径和柄茎变细,比叶鲜,干重下降,两类型大豆有着基本一致的消长趋势,但在消长平准上,不耐阴品种比耐阴品种显著。柄角,柄长和叶片的长、宽及面积等五性状,在中、高节位上的叶层变化及差异,表现了不耐阴品种对弱光环境反应的敏感和耐阴品种的钝性。耐阴     

THE YIELD AND UPTAKE OF PHOSPHORUS BY GRASSES AND CLOVERS

When perennial ryegrass and wild white clover are grown in a phosphorus-deficient soil, there is a difference in the extent to which they use the added phosphorus, especially when the phosphorus supply (potential) is small. In these circumstances the clover makes the better use of the phosphorus. The similarity of the Larsen values obtained with these two species, however, indicates that this must be largely due to the species absorbing the phosphorus at different rates, and not to any interspecific difference in ability to utilize the supply. Both perennial ryegrass and cocksfoot gave higher L values for the hay than for the pasture variety, indicating that slowly-exchangeable phosphorus might be more accessible to the former than the latter. Perennial ryegrass, cocksfoot, timothy, wild white clover and red clover showed minimum values for L at varying times after sowing which were characteristic of the species. This is explained in terms of the isotopic exchange reactions taking place.     

THE YIELD AND UPTAKE OF PHOSPHORUS BY GRASSES AND CLOVERS

The yield and phosphorus uptake of grasses and clovers from Welsh soils were studied in 6-inch flower pots. Attempts were made to relate the phosphorus that the plants had been able to absorb to various measurements of the labile phosphorus in the soil. It is shown that in these'phosphate fixing' soils, absorption is not related to the exchangeable phosphorus as measured by equilibration. The values obtained for the latter are very high compared with the small amounts of phosphorus that the plants have been able to absorb, giving support to the view that the conversion of phosphorus to insoluble forms is not the main feature of'fixation' in these soils. Absorption of phosphorus by the grass was, however, related to the Larsen (L) values. In previously unfertilized soils, the fact that the L values were also related to the acetic-soluble phosphorus content confirmed the belief that acetic extraction is a suitable means for assessing the abilities of such soils to provide the necessary phosphorus for plant growth. In soils containing reserves of residual phosphorus, however, much of the phosphorus that contributed to the L values was not extracted by acetic acid, and this method of extraction is unsuitable for use with such soils. Placement of the applied phosphorus near the root zone led to a decrease in L values.     

MATERIALS AND METHODS

Rice germplasm A total of 208 indica P/TGMS lines were selected for analysis from the National Mid-term Genebank for Rice, Hangzhou, China (Supplemental Table 2), and 100 typical indica and 100 japonica accessions to identify the indica/japonica component of them were also from the National Mid-term Genebank for Rice, Hangzhou, China (Supplemental Table 5).