大穗型水稻品种抽穗开花期遭遇高温后的结实表现

培育大穗型水稻品种是进一步提高水稻产量的途径之一,但是大穗型水稻的颖花受精和籽粒灌浆易受环境影响而产生波动。以大穗型水稻品种BL006和R-农白为试验材料,中穗型品种黄华占为对照,利用人工气候室模拟湖北典型高温天气的昼夜温度变化,研究大穗型水稻在抽穗开花期遭遇高温（日平均气温30℃和33℃）后的结实表现。结果表明：高温处理后,各品种的颖花受精率显著降低;30℃处理后,BL006、R-农白和黄华占的颖花受精率分别下降10.37、10.05和7.24个百分点,33℃处理后,分别降低53.17、65.38和8.17个百分点;30℃高温处理后,弱势颖花受精率的降幅较大,33℃高温处理后,强势颖花受精率的降幅较大;颖花受精率的变化与品种的光合特征有关。与常温相比,30℃高温处理后,BL006和R-农白的千粒重均降低1.69%,黄华占升高2.45%;33℃处理后,BL006和黄华占分别降低18.38%和11.65%,R-农白升高3.10%。此外,千粒重的变化也受粒位影响。因此,选育强耐高温的大穗型水稻品种,要整体提升穗部颖花的高温耐性水平和品种的光合能力。     

牡丹开花前后碳水化合物的分配与光合速率的关系

以牡丹( Paeonia suffruticosa ) 品种‘肉芙蓉’为材料, 研究其开花过程中碳水化合物的分配及其对有花枝上叶片( FL) 与无花枝上叶片(NFL) 净光合速率( Pn) 的影响。结果表明: 在花衰败前,有花枝Pn明显低于无花枝, 但可溶性糖含量却高于无花枝。与前一天17时相比, 经过一夜消耗后, 早晨8时有花枝可溶性糖含量没有显著差别, 而无花枝的则较低, 说明除光合作用外, 还有其他途径为有花枝提供可溶性糖。花衰败后, 两种枝叶Pn和可溶性糖含量的差异逐渐消失。与花衰败前不同, 经过一夜消耗后, 早晨8时两种枝叶的可溶性糖含量比前一天17时都降低, 表明为有花枝提供可溶性糖的其他途径在花衰败后停止工作, 推测这一途径极可能与花的生长发育有密切联系。     

我国主要玉米自交系开花期耐旱性差异及改良

通过对37份我国主要玉米自交系两年的开花期耐旱性鉴定, 筛选出耐旱系12份(K22、 SH15、 X178、 P138、中自01、中自451、金黄96B、齐319、旱23、东91、临京11、 CA156). 在干旱胁迫下, 果穗吐丝延迟, 雌雄开花间隔增大, 结穗率下降, 籽粒产量严重降低; 雌雄开花间隔天数和结穗率与籽粒产量均呈极显著相关, 是可供耐旱性选择     

闭颖授粉水稻CL01的抗逆性及其相适应的生理特点

本文对开颖授粉水稻材料T168和闭颖授粉水稻材料CL01进行了比较研究. 发现在连续人工降雨和低温处理条件下, CL01的结实率受影响较小; 相反, T168的结实率随着处理天数的增加而迅速降低, 说明CL01的抗逆性较强. 通过对从开花前5天到开花当天的花药和花丝的长度、浆片的大小以及在开花过程中浆片的鲜重和干重的变化的研究, 揭     

水稻开颖机理的探讨 Ⅴ不育系与可育系浆片和花丝结构的比较

用电子显微镜观察了不育系珍汕97A与保持系珍汕97B的浆片和花丝的超微结构及其在开、闭颖过程中的变化，发现开颖前浆片和花丝细胞的质体中含有淀粉粒，临开颖时，淀粉粒消失。浆片和共丝的薄壁细胞吸水后，内膜系统破裂，释放出水解酶，细胞开始自溶，解体物通过导管等质外体向小穗轴撤离。另外还发现：不育系的浆片中的维管     

The importance of the period immediately preceding anthesis for grain weight determination in wheat

Although individual grain weight is an important source of variation forgrain yield, there is still poor understanding of the causes determining finalgrain weight. Almost all studies conducted for understanding thedeterminants of grain weight have been focused on the post-anthesis period.However, there is important evidence that pre-anthesis conditions couldalso modify final grain weight. Three experiments including different sowingdates, genotypes and temperature regimes between booting and anthesis,were carried out in Argentina and Mexico to analyse the effect oftemperature and associated traits during the pre- and post-anthesis periodson grain weight under field conditions. In these experiments final grainweight could not be explained by average or maximum temperature duringthe post-anthesis period. However, average temperature between bootingand anthesis was closely related to the observed grain weight differences,probably as a consequence of the effects of this factor on carpel growth.Differences in grain weight between genotypes and grain position weresuccessfully explained by differences in carpel weight at anthesis. Theseresults suggest that our knowledge to determine grain weight could improveif the immediately pre-anthesis period conditions were taken into account.     

Pollination behaviour of Nardostachys jatamansi DC., an endangered medicinal and aromatic herb

Nardostachys jatamansi is a perennial, endangered medicinal and aromatic herb of family Valerianaceae, distributed in subalpine to alpine areas. Being an endangered species it should be conserved through in situ as well as ex situ methods. Study of reproductive biology is necessary for effective conservation of endangered plants and pollination behaviour is an integral part of reproductive biology. Present study deals with pollination behaviour of N. jatamansi. Parthenocarpy, passive autogamy, active autogamy, geitonogamy and xenogamy experiments were applied in this study. Flowering (peak) takes place during the month of July–August and anthesis between 7:00–11:00 h. Anthers disperse pollen grains after 24 h of anthesis. Stigma is of protogynous type. Fruit set recorded in above experiments was 40% in passive autogamy, 70% in active autogamy, 53.33% in xenogamy and 86.67% in geitonogamy as well as open pollination experiments. The species is self-pollinated but dependent on pollinators for optimum pollination. Cross pollination may have adaptive value for species as it compensate failure of autogamy and also maintains genetic variability in the population. Crop improvement program may be initiated through xenogamy.     

玉米开花期耐旱相关性状的遗传及育种策略

玉米对干旱的反应取决于新陈代谢能力、形态结构和生育阶段.开花期逢遇干旱使玉米产量下降幅度最大.随着产量下降,环境方差所占比例增大,遗传力降低,直接选择效率不高.在干旱条件下,寻找遗传力高且与产量高度相关的第二类性状,构建选择指标,可提高耐旱选择效率.雌雄开花间隔天数(ASI)和单株穗数是可供利用的第二类性状,对其选择所获得的产量增益,在干旱和正常水分条件下均可表现出来.耐旱育种目的在于改变基因型对干旱环境的反应,实现耐旱丰产目标.根据目标环境特征,设计适宜的耐旱选择程序,结合分子标记辅助选择技术,鉴定和利用现有优良耐旱种质和CIMMYT耐旱群体,是我国进行耐旱育种和种质改良的可选途径。     

玉米雌雄穗开花间隔与产量关系研究

以2个热带玉米群体Pool 16、 Pool 18的不同世代种质为材料, 分别种植在开花期充足灌水、中度水分胁迫和严重水分胁迫3种水分梯度条件下, 研究玉米的雌雄穗开花间隔(ASI)与产量及其其它性状间的关系. 研究表明, 随水分胁迫程度的加强, 产量与ASI间的相关性增强. 在严重胁迫条件下, 二者的相关系数r=-0.529**; 在胁迫条件下,     

花后高温对春小麦种子活力的影响

[目的]探索花后高温对春小麦种子质量的影响,为减缓高温危害提供理论依据。[方法]以春小麦宁春4号和繁08-3为供试材料,盆栽条件下,花后10～25 d在自制的温箱中进行高温处理,研究花后高温对春小麦种子淀粉酶活性和种子活力的影响。[结果]花后高温显著降低了春小麦种子的发芽率、种子活力和淀粉酶活性,使宁春4号的发芽率降低了2.08%,种子活力降低了22.25%;使繁08-3的发芽率降低了4.08%,种子活力降低了22.94%。[结论]花后高温降低了春小麦种子的活力,从而影响种子的出苗率,最终影响春小麦的产量。