【摘要】 以超级杂交稻金优458为试验材料,利用人工气候箱设置17℃和15℃两个低温水平,对颖花分化期的盆栽水稻处理3d后(17℃3d和15℃3d分别为T1和T2),以大田盆栽为对照(CK),测定低温处理解除后0~32d早稻叶片气体交换参数、光响应参数、SPAD值及产量构成因子,以探讨低温对早稻叶片光合能力和产量的影响,以及低温解除后光合能力的恢复情况。结果表明:(1)低温处理显著降低了水稻叶片的净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr);T1处理低温解除后3d、T2低温解除后6d,水稻叶片气体交换能力均恢复至对照水平,但17d后Pn、Gs均明显下降,Tr显著增加。(2)低温解除后0~6d时T1处理光响应能力增强,而T2则显著下降,低温解除6d后其最大光合速率(Pm)恢复至对照水平,但至32d时T1和T2的Pm、表观量子效率(AQY)和半饱和光强(Ik)均降低,暗呼吸速率(Rd)显著增加。(3)低温处理显著降低了水稻叶片叶绿素含量,T1处理低温解除3d后及T2低温解除6d后,叶绿素含量恢复至对照水平。(4)低温处理导致早稻穗粒数、结实率和千粒重明显下降,空壳率和秕谷率显著增加,产量下降达25%。由此可见,颖花分化期低温会显著降低叶片气体交换能力,15℃低温还会显著降低光响应能力,低温解除后叶片光合能力出现一定程度恢复,但长期影响无法消除,最终产量也明显下降。研究结果可为水稻气象灾害影响评价和气象灾害指标制定等提供科学依据。更多还原

【Abstract】 Experiments were conducted under artificial climate chambers conditions to assess the photosynthetic responses and photosynthetic capacity recovery process of early rice(Oryza sativa L.,Jinyou458) to low temperature stress(T1 and T2,subjected to 17° C and 15° C for 3 days) at spikelet differentiation stage,by determined gas exchange and light response parameters,SPAD value,yield components.The results indicated that,(1) Pn,Gs,Ci,Trof T1 and T2 were decreased significantly compared with CK(control group,natural condition).Pnof T1 recovered3 days after stress,while T2 recovered 6 days later.However,Pnand Gswas decreased significantly on the 17 thday and 32 ndday after stress,while Trwas increased significantly.(2) Light response capacity of T1 enhanced 0- 6 days after stress,while T2 was decreased significantly.By the 6thday,T2 was recovered to the same level of CK,but Pm,AQY and Ikof T1 and T2 were decreased significantly by the 32 ndday.(3) SPAD value of T1 and T2 were decreased significantly.T1 was recovered to the same level of CK by the 3rdday,while T2 recovered by the 6thdays.(4) The grain No.per panicle,ripening rate,thousand-grain weight,and theoretical yield of T1 and T2 were decreased significantly,while unfilled and abortive grain rate were increased,which leaded to yield reduction rate of 25%.Obviously,low temperature stress at spikelet differentiation stage had negative effects on gas exchange activity and maximum photochemical capacity of early rice,thought recovered to some degree later,but the negative effects were irreversible for long,which leaded to lower yield.The results could support scientific foundations for meteorological disaster impact assessment and meteorological disaster indexes development.更多还原