【作者】 周磊；

【导师】 王根轩；

【作者基本信息】 浙江大学 ， 生态学， 2011， 硕士

【摘要】 作物在遭受水分胁迫后复水,其生长会得到一定程度补偿,如果水分处理适当,会弥补胁迫期间所受的生长损失,甚至出现超补偿效果。作物这种缺水补偿节水机制对农业生产具有重要的理论意义和应用价值。本论文通过在水稻分蘖后期设置一系列不同的水分干旱梯度和密度梯度,处理结束后在同一时间复水,研究干旱期间及复水后的生理生态变化响应,探究其内在的补偿节水机理。本研究的水分处理分为干旱5天、10天和充分供水三个水平,密度分别为15株/m2、45株/m2和90株/m2。实验期间分别测定水稻的分蘖数、株高、生物量、籽粒重等形态学指标,光合作用、蒸腾速率、气孔导度、叶绿素含量等生理指标,RuBP羧化酶和PEP羧化酶活性等分子指标,研究水稻分蘖后期的水分亏缺补偿节水的变化规律。结果显示：(1)在水稻分蘖后期进行水分调控,可以减少水稻的无效分蘖和生长冗余,有利于提高水稻的产量和水分利用效率。在水分亏缺和复水期间我们定期测定了水稻的分蘖数目,并在收获后测定其地上生物量、产量和收获指数等指标。在水稻收获时,经过水分干旱处理的地上生物量要低于对照,产量高于对照或有少量降低,收获指数则均高于对照。(2)水稻分蘖后期进行适当的水分胁迫,在生理生态方面存在着明显的补偿效应,且受阈值限制。在控水期间,水稻的光合作用、蒸腾速率和气孔导度在超出其承受的阈值后均显著降低,水稻分蘖数减少,地上生物量生长被抑制,地下生物量和根冠比增大。在复水之后,水稻的光合作用、蒸腾速率和气孔导度升高,地上生物量得到补偿生长,地下生物量和根冠比降低。(3)水分胁迫可能诱导产生水稻的C4光合途径。在水分胁迫期间,RuBP羧化酶和PEP羧化酶的活性得到提高,在复水之后,Rubp羧化酶、PEP羧化酶活性在一定时间内仍高于对照,这对同化物质的合成和积累补偿起着重要作用。通过水稻分蘖后期的水分和密度处理,我们认为中等密度45株／m2干旱10天左右的水分亏缺补偿节水效果最好。实验期间对水稻的光合作用相关参数、光合酶活性等生理分子变化机制的研究为水稻水分亏缺补偿节水提供了理论支持。更多还原

【Abstract】 The growth of crop could be compensated when it is rewatered after water stress. The losses which it suffered during drought period will be made up, or even be excessive compensated if the water treatment is appropriate. The mechanisms of water deficit compensation and water- saving in crop are meaningful for applying in agriculture. We set different moisture gradient and densities to study the molecular physio-ecological responses of rice to water deficit and rehydration during the period of late-tillering. The inner mechanisms of compensatory water-saving are explored in this paper.The water treatments of this research are divided into three levels, which are well-watered,5-day drought and 10-day drought. The densities were 15 plants,45 plants and 90 plants in every square metre. We measured morphological indices such as tillers number, height, biomass, grain yield, physiological indicators such as photosynthesis, transpiration, stomatal conductance, water use effeciency, molecular indicators such as the activity of RuBP carboxylase and PEP carboxylase and so on. The results are as follows.(1) The invalid tillers and growth of rice could be reduced through the regulation of watering. The water use effeciency and grain yield could be improved. We measured the number of tillers during the period of water stress and rehydration. The aboveground biomass of water treatment groups were lower than the control after the harvest of rice, but the grain yield were a small amount of lower or even higher than the control. The harvest index of water treatments were all higher than the control.(2) The compensatory effect and threshold were significant in the physio-ecological aspects after appropriate water deficit during the period of late-tillering in rice. The photosynthesis, transpiration rate and stomatal conductance in excess of the threshold exposure were significantly lower, the number of tillers reduced, the growth of shoot biomass was inhibited, root biomass and root to shoot ratio increased during water stress period. The photosynthesis, transpiration rate and stomatal conductance increased, the aboveground biomass compensated in some extent, belowground biomass and root to shoot ratio decreased after the resumption of water.(3) The photosynthetic circle of C4 could be induced by the water stress and rehydration in rice. The activities of RuBP carboxylase and PEP carboxylase increased during the period of water deficit. The activities of RuBP carboxylase and PEP carboxylase were still higher than the control in a certain period after water recoverWe find that the water deficit compensatory effect of 10-day drought in density of 45/m2 was the best by the treaments of water and densities during the period of late-tillering in rice. The changeable mechanisms of experiment parameters such as photosynthetic indices and activities of enzymes provide a theoretical support for the study of water deficit compensatory effect and water-saving technology in rice.更多还原