水分胁迫对两系杂交稻籽粒充实的影响

Effect of Water Stress on Grain Filling of Two-line Hybrid Rice

以2个两系杂交稻为材料,设充分灌溉、适度水分胁迫和重度水分胁迫3种水分处理,研究大田和盆栽条件下抽穗后9 d至成熟期水分胁迫对水稻籽粒充实的影响。结果表明:植株趋向成熟的过程中,剑叶叶绿素含量和光合速率的下降速度,适度水分胁迫和重度水分胁迫处理比充分灌溉处理更快,表明水分亏缺可加速植株衰老。水分胁迫处理与充分灌溉处理相比,储藏性碳和14C固定的碳从茎秆向籽粒运转分别增加15％～20％和55％～67％;水分胁迫处理灌浆期缩短5～17 d,籽粒灌浆速率增加0.09～0.27 mg·(d·粒)-1。盆栽和大田试验的适度水分胁迫处理籽粒增产8.2％～10％,盆栽试验中重度水分胁迫处理导致籽粒减产。

Two two-line indica hybrids were grown in both the pot and field. Three levels of soil water potential, well watered (WW) , moderate water deficit (MD) , and severe water deficit (SD), were imposed from 9 d after anthesis to maturity in both pot and field experiments. Results showed that chlorophyll content and photosynthetic rate of the flag leaves declined more quickly as plants approached maturity for MD and SD plants than for WW plants, indicating the water deficits enhanced senescence. The remobilized carbohydrate reserve and reallocation of pre-fixed 14C from stems to grains increased by 15% to 20% and 55% to 67% , respectively, for water deficit plants, when compared with WW plants. The water deficit treatments shortened the grain-filling by 5 to 17 d and increased the grain-filling rate by 0. 09 to 0. 27 mg · (d · grain)-1. The grain yield of MD plants in both experiments was increased by 8. 2% to 10% but that of SD plants in the pot was reduced.