干旱和复水对冬小麦光合产物分配格局的影响

Influence of drought and rewatering on the pattern of photosynthate partitioning of winter wheat

于2005—2006年在中国科学院封丘农田生态实验站研究了不同水分处理下冬小麦光合产物分配格局及其动态。实验设全生育期干旱处理和充分供水处理以及干旱后拔节期、孕穗期、开花期复水处理。结果显示:不同生育期复水对冬小麦由于干旱胁迫引起的生物量下降有补偿作用;干旱和复水能改变器官水平上光合产物的分配格局;干旱胁迫引起叶、穗分配降低,并使茎、叶鞘和根分配指数上升;拔节期复水使叶光合产物分配指数增加、茎分配指数下降;孕穗期和开花期复水能提高光合产物在茎和穗中的分配;不同时期复水对干旱胁迫引起的产量下降均有不同程度的补偿作用,拔节期复水主要提高小麦单株穗数、孕穗期和开花期复水以提高千粒重为主。

In 2005--2006, two experiments were carried out to study the effect of drought stress on photo- synthate partitioning patterns of winter wheat, as well as ecophysiological responses of winter wheat to drought and rewatering, at the Fengqiu Agro-ecological Experimental Station, Chinese Academy of Sciences. Jimai20 and Zhoumail8, two winter wheat cultivars differing in sensitivity to drought stress, were grown in the field under a retractable awning. In experiment, plants were subjected to severe drought stress at the reviving stage, and then rewatered respectively at the jointing stage （ Wrl ） , the booting stage （Wr2） and the flowering stage （ Wr3 ）. Rewatering had compensatory effects on losses in winter wheat biomass induced by drought stress. Rewatering at the jointing stage had the greatest stimulating effect on biomass. Compensatory growth however did not lead to a full recovery of leaf area lost during the drought period. Rewatering at first suppressed root growth, and then stimulated it. Drought stress led to reduced photosynthate allocation in leaves and spikes, and increased photosynthate alloca- tion in the stem, leaf sheaths and roots. Rewatering at the jointing stage, the booting stage and the flowering stage boosted photosynthate accumulation in leaves, the stem and grains respectively. Rewatering at all stages allowed full recovery of drought induced yield loss, by increasing number of spikelets at the jointing stage or 1 000 kernel weight at the booting and flowering stages.