以超级杂交稻组合天优998为材料,通过人工气候箱模拟高温胁迫,于抽穗开花期至灌浆结实期的不同生育阶段(抽穗期、乳熟期、蜡熟期和黄熟期)分别对其进行不同程度(日最高气温分别为32、35、38、40和42℃,日较差为6℃)的高温处理,以研究高温对超级杂交稻源库特性的影响.结果表明,高温胁迫下,剑叶SOD酶和POD酶活性逐渐下降,MDA含量逐渐上升,光合活性降低,蜡熟期和黄熟期尤为严重.另外,高温胁迫导致水稻结实率下降,籽粒可溶性糖和可溶性蛋白含量上升,其中以抽穗期籽粒以及乳熟期中下部籽粒的变幅最大.抽穗期和乳熟期剑叶显著受损的日最高温度为38℃,籽粒则为35℃；而35℃以上处理主要使蜡熟期和黄熟期剑叶光合能力显著降低,对籽粒影响不大.这表明抽穗期和乳熟期日最高温度38℃以上对水稻的源和库影响均较大,但在蜡熟期和黄熟期主要影响剑叶光合活性.%Super hybrid rice Tianyou 998 was investigated under different high temperature levels ( daily highest temperature was 32, 35, 38,40 and 42℃ , the daily range 6℃ ) in climate chambers during different growth stages (heading,milk, soft dough, and hard dough stage). The results showed that SOD( Superoxide Dismutase) and POD (Peroxidase) enzyme activities decreased gradually but the content of MDA ( Malondialdehyde ) increased. The flag leaf photosynthetic activity was affected adversely, especially in the soft dough stage and hard dough stage. Meanwhile, the seed setting rate decreased, and the content of soluble sugar and protein of spikelets increased. The development process of upper - middle - basal sink in heading stage was seriously disturbed, and so did middle - basal sink in milk stage. When the daily highest temperature was up to 38 ℃ ,both heading and milk stage' s flag leaf was damaged significantly, compared with grain in 35 ℃. The flag leaf photosynthetic activity of the soft and hard dough stage declined significantly when the daily highest temperature was above 35℃ , while the influence on grain was not serious. It was suggested that when the daily highest temperature was above 38℃ ,the source and sink of the rice was affected seriously in heading and milk stages,but mainly affected the photosynthetic activity in soft dough and hard dough stages.
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