关于玉米粒重的研究

玉米粒重由库容大小和库充实度决定,两者受籽粒和植株体内同化物供应和激素代谢水平的影响.在综述了粒重形成过程,介绍了各种环境因子(温度、水分、光照等)和栽培措施(营养元素、植物生长调节剂等)对库容建成和库充实度的影响的同时,分析了控制粒重增加的生理原因.     

源库关系改变对小麦灌浆期植株光合速率及~(14)C同化物运转分配的影响

选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种（大粒品种和小粒品种）千粒重、穗粒数、穗粒重、籽粒平均灌浆速率、单穗平均增重速率、植株光合速率及１４Ｃ同化物运转分配的影响。试验结果表明,去除顶端两个小穗后,两类品种的千粒重提高,穗粒数降低或基本不受影响,但降低比例明显低于去除小穗数的比例。籽粒平均灌浆速率和单穗平均增重速率（分别表征籽粒库容活性和穗粒库容活性）相应提高。结果,两类品种的穗粒重表现为补偿性增长。两类品种比较,小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌浆中后期的植株光合速率提高,使两类品种分配到籽粒中的１４Ｃ同化物比例增加。从而表明,无论是植株光合速率还是同化物的运转分配皆受穗粒库容活性的调控,调控方式和幅度因品种类型而不同。但提高其穗粒重的着眼点都应当是提高穗粒库容活性。     

小麦不同品种光合速率和^14C同化物分配对源库比改变的响应

选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种（大粒品种和小粒品种）穗部性状,粒粒平均灌浆速率,单穗平均增重速率,植株光合速率及＾１４Ｃ同位物运输分配的影响。试验结果表明,去除顶端两个小穗后,两类品种的籽粒平均灌浆速率和单穗平均增重速率（分别表征籽粒库容活性和穗粒库容活性）相应提高,穗粒重表现为补偿性增长。两类品种比较,小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌     

小麦不同品种光合速率和~(14)C同化物分配对源库比改变的响应

选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种（大粒品种和小粒品种）穗部性状、籽粒平均灌浆速率、单穗平均增重速率、植株光合速率及１４Ｃ同化物运输分配的影响。试验结果表明,去除顶端两个小穗后,两类品种的籽粒平均灌浆速率和单穗平均增重速率（分别表征籽粒库容活性和穗粒库容活性）相应提高,穗粒重表现为补偿性增长。两类品种比较,小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌浆中后期的植株光合速率提高,使两类品种分配到籽粒中的１４Ｃ同化物比例增加。从而表明,无论是植株光合速率还是同化物的运转分配皆受库容活性的调控,调控方式和幅度因品种类型而不同。     

水稻籼粳交DH群体籽粒充实度的遗传分析

籽粒充实度差是限制亚种间杂交稻产量潜力发挥的重要因素。作者对籼粳交（圭630／02428）DH群体的籽粒充实度进行了研究,结果表明,籽粒充实度是受多基因控制的数量性状,在该DH群体中发生分离的基因估计数为5－6对。通过估测三级（偏度）和四级（峰度）统计量,检测到控制籽粒充实度的多基因间存在重叠作用。DH群体中籽粒充实度表现出明显的超亲分离,表明基因重组可实现控制籽粒充实度的增效基因的聚合。籽粒充实度与单穗产量、穗均实粒数和干物质／总库容之比呈显著或极显著正相关,与千粒重、穗均颖花数和穗均总库容相关不显著。     

籼粳杂交稻籽粒库活性与其充实关系的研究

以两个籽粒充实程度不同的籼粳亚种间杂交稻ＰＣ３１１＊早献党１８（充实差）和测０３＊扬稻４号（充实好）材料,研究两组合的强、弱势粒发育过程中籽粒库活性与其充实之间的关系。结果表明：（１）充实好的亚杂组合强,、弱势粒干重、淀粉积累速率都盯应高于充实差的亚杂组合,两组合的强、弱势粒灌浆特性均表现异步型特征;（２）在灌浆早期,两亚杂组合强、弱热粒胚乳中蔗糖含量都比较高,且测扬要明显高于Ｐ早;在籽粒发育后期     

山茱萸种质资源数量性状分析及核心种质库评价

对从全国收集的75份山茱萸种质资源,从叶长、叶宽、果实横径、果实纵径、鲜果百粒重、种子千粒重、种子含水量、枣皮灰分、枣皮水分、水溶性浸出物和马钱素含量等表型性状,通过分析其变异系数和各性状间的相关性,采用欧氏系统聚类法抽取核心种质,并对构建的核心种质库进行评价。分析结果显示,75份山茱萸种质资源在叶长、叶宽、鲜果百粒重、种子千粒重、枣皮灰分和马钱素含量等性状上的变异系数均高于10%,说明这些性状变化范围较大,个体间性状不稳定,易受环境因素的影响;而果实横径、果实纵径、种子含水量、枣皮水分和水溶性浸出物的变异系数均低于10%,说明这些性状变异较小,表型性状比较稳定。相关性分析结果显示,各性状间都存在一定的相关性,其中果实纵径和果实横径与鲜果百粒重呈显著正相关(0.396b和0.312b),说明果实纵横径是影响果实重量的关键因素;水溶性浸出物大小与果实横径、果实纵径、马钱素含量呈现显著性正相关(0.481b、0.280a和0.372b),表明水溶性浸出物含量的高低与山茱萸有效成分马钱素含量和果实大小及形状密切正相关,这将为种质的筛选和评价提供依据。通过最小距离逐步抽样法抽出22份种质构成核心种质库（占初始种质库的29.33%）,采用欧氏距离聚类对抽样构成的初级核心种质库进行评价,结果显示,各性状均值t检验均不显著,并且极差符合率（CR%= 90.63%）大于80%,说明抽取的初级核心种质库能够很好地代表原有种质,从而达到了提高种质保存效率的目的,这将为进一步研究山茱萸核心种质库构建和其它药用植物构建核心种质提供参考。     

地黄源库关系的变化及其与连作障碍的关系

通过正茬剪叶模拟连作地黄光合源不足条件下,测定分析植株源与库的关系,应用同位素示踪技术分析连作地黄光合产物的分配及内源激素的变化,以探讨地黄的连作障碍机制。结果表明:剪叶处理对植株的影响不能达到连作障碍程度,其库容及其活性大于连作地黄;连作地黄出现光合产物滞留于地上部,库的活性影响了植株光合产物向库的运输,在生长前期植株内源激素发生了变化;因此断定,连作地黄库容及其活性过低是限制地黄块根膨大的重要因素,库通过不同激素对源的反馈调节,抑制了地上源的光合能力及光合产物向库的分配,导致连作障碍。     

籼稻根系活力与地上部分的关系

1998年早季在广州研究了不同籼稻类型根系活力与地上部分一些性状的关系,结果表明:（1）所有参试品种的根系活力在全生育期中均呈单峰曲线变化,最高值出现在幼穗第2次枝梗原基分化期。两系法杂交稻在生长前期根系活力增幅大,叶面积指数发展快。（2）根系活力在分蘖期与叶绿素含量呈显著正相关;在分蘖期和孕穗期与叶绿素a/b值呈显著负相关,并在幼穗第2次枝梗原基分化期与叶面积指数呈显著正相关,说明在水稻生长发育前期根系活力的强弱与地上部分叶、蘖的发展是相对应的。（3）根系活力与灌浆成熟后期的籽粒充实度达极显著正相关,根系活力强的品种,后期充实度高,相反则充实度低。     

小麦不同品种光合速率和14 C同化物分配对源库比改变的影响

 选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种(大粒品种和小粒品种)穗部性状、籽粒平均灌浆速率、单穗平均增重速率、植株光合速率及14C同化物运输分配的影响。试验结果表明,去除顶端两个小穗后,两类品种的籽粒平均灌浆速率和单穗平均增重速率(分别表征籽粒库容活性和穗粒库容活性)相应提高,穗粒重表现为补偿性增长。两类品种比较,小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌浆中后期的植株光合速率提高,使两类品种分配到籽粒中的14C同化物比例增加。从而表明,无论是植株光合速率还是同化物的运转分配皆受库容活性的调控,调控方式和幅度因品种类型而不同。     

The parameters of grain filling and yield components in common wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) and durum wheat (<Emphasis Type="Italic">Triticum turgidum</Emphasis> L. var. <Emphasis Type="Italic">durum</Emphasis>)

Final grain dry weight, a component of yield in wheat, is dependent on the duration and the rate of grain filling. The purpose of the study was to compare the grain filling patterns between common wheat, (Triticum aestivum L.), and durum wheat, (Triticum turgidum L. var. durum), and investigate relationships among grain filling parameters, yield components and the yield itself. The most important variables in differentiating among grain filling curves were final grain dry weight (W) for common wheat genotypes and grain filling rate (R) for durum wheat genotypes; however, in all cases the sets of variables important in differentiating among grain filling curves were extended to either two or all three parameters. Furthermore, in one out of three environmental conditions and for both groups of genotypes, the most important parameter in the set was grain filling duration (T). It indicates significant impact of environmental conditions on dry matter accumulation and the mutual effect of grain filling duration and its rate on the final grain dry weight. The medium early anthesis date could be associated with further grain weight and yield improvements in wheat. Grain filling of earlier genotypes occurs in more temperate environments, which provides enough time for gradual grain fill and avoids the extremes of temperature and the stress of dry conditions.     

The Relationship between Polyamines and Hormones in the Regulation of Wheat Grain Filling

The grain weight of wheat is strongly influenced by filling. Polyamines (PA) are involved in regulating plant growth. However, the effects of PA on wheat grain filling and its mechanism of action are unclear. The objective of the present study was to investigate the relationship between PAs and hormones in the regulation of wheat grain filling. Three PAs, spermidine (Spd), spermine (Spm), and putrescine (Put), were exogenously applied, and the grain filling characteristics and changes in endogenous PA and hormones, i.e., indole-3-acetic acid (IAA), zeatin (Z) + zeatin riboside (ZR), abscisic acid (ABA), ethylene (ETH) and gibberellin 1+4 (GAs), were quantified during wheat grain filling. Exogenous applications of Spd and Spm significantly increased the grain filling rate and weight, but exogenous Put had no significant effects on these measures. Exogenous Spd and Spm significantly increased the endogenous Spd, Spm, Z+ZR, ABA, and IAA contents and significantly decreased ETH evolution in grains. The endogenous Spd, Spm and Z+ZR contents were positively and significantly correlated with the grain filling rate and weight of wheat, and the endogenous ETH evolution was negatively and significantly correlated with the wheat grain filling rate and weight. Based upon these results, we concluded that PAs were involved in the balance of hormones that regulated the grain filling of wheat.     

Studies on the nature of relationships between grain size,spikelet number,grain yield and spikelet filling in late duration varieties of rice (Oryza sativa L.)

Summary Studies on the nature of relationship between grain size (in terms of thousand grain weight), grain number, rate of filling and yield have been worked out with late duration (140–150 days) rice varieties. Grain number per m², grains per panicle and yield showed a negative relationship with grain size. There was no compensatory balance between grain size and grain number within a range of thousand grain weight of 15 to 30 g. Based on the peaks in grain filling activity, the varieties were classified into four groups. There was no relationship between grain size and rate of grain filling thereby suggesting that grain filling is determined by inherent endogenous factors.     

Effect of Plastic Film Mulching on the Grain Filling and Hormonal Changes of Maize under Different Irrigation Conditions

Plastic film mulching (PM) is widely utilized for maize production in China. However, the effect of PM on the grain yield of crops has not been established, and the biochemical mechanism underlying the increase or decrease in grain yield under PM is not yet understood. Grain filling markedly affects the grain yield. The objective of this study was to investigate the effects of PM on maize grain filling under different irrigation levels and the relationship of such effects with hormonal changes. In the present study, PM was compared with traditional nonmulching management (TN) under 220 mm, 270 mm and 320 mm irrigation amount, and the grain filling characters of the grains located in various parts of the ear and the hormonal changes in the grains were measured. The results indicated that at 220 mm irrigation, PM significantly increased the grain filling rate of the middle and basal grains and decreased the grain filling rate of the upper grains. At 270 mm irrigation, the PM significantly increased the grain filling rate of the all grains. At 320 mm irrigation, the PM only significantly increased the grain filling rate of the upper grains. The IAA, Z+ZR and ABA content in the grains was positively correlated with the grain weight and grain-filling rates; however, the ETH evolution rate of the grains was negatively correlated with the grain weight and grain-filling rates. These results show that the effect of PM on maize grain filling is related to the irrigation amount and that the grain position on the ear and the grain filling of the upper grains was more sensitive to PM and irrigation than were the other grains. In addition, the PM and irrigation regulated the balance of hormones rather than the content of individual hormones to affect the maize grain filling.     

Hormones in the grains in relation to sink strength and postanthesis development of spikelets in rice

Inferior spikelets usually exhibit a slower grain filling rate and lower grain weight than superior spikelets in a rice (Oryza sativa L.) panicle. This study investigated whether the variations in grain filling between the two kinds of spikelets were attributed to their sink strength and whether the sink strength was regulated by the hormonal levels in the grains. Using two field-grown rice genotypes, the division rate of endosperm cells, hormonal levels in the grains, and grain weight of both superior and inferior spikelets were determined during the grain filling period. The results showed that superior spikelets had dominance over inferior spikelets in endosperm cell division rate and cell number, grain filling and grain weight. Changes in zeatin (Z) and zeatin riboside (ZR) contents paralleled and were very significantly correlated with the cell division rate and cell number. Cell division rate and the content of indole-3-acetic acid (IAA) in the grains were also significantly correlated. Gibberellin (GAs; GA₁+ GA₄) content of the grains was high but ABA levels were low at the early grain filling stage. ABA increased substantially during the linear phase of grain growth and was very significantly correlated with grain dry weight during this period. Application of kinetin at 2 through 6 days post anthesis (DPA) significantly increased cell number, while spraying ABA at 11 through 15 DPA significantly increased the grain filling rate. The results suggest that differences in sink strength are responsible for variations in grain filling between superior and inferior spikelets. Both cytokinins and IAA in the grains may mediate cell division in rice endosperm at early grain filling stages, and therefore regulate the sink size of the grain, whereas ABA content correlates with sink activity during the linear period of grain growth.     

不同生育时期水分有限亏缺对冬小麦产量及其构成因素的影响

利用温室盆栽试验研究了施Ｎ与不施Ｎ（施肥）条件下不同生育阶段水分有限亏缺对冬小麦产量及其构成因素的影响。结果表明,在小麦苗期、拔节期、灌浆期进行水分亏缺胁迫处理。对其经济学产量,生物学产量,每盆有效穗数、每穗粒数、千粒重等影响达显著或极显著水平。苗期和灌浆期为水分亏缺不敏感期,拔节期为亏缺敏感期。在施底肥条件下拔节期水分亏缺使每穗粒数、千粒重显著减少,或低于对照水平。从补偿角度看,苗期是生物学产量