节水灌溉水稻叶片胞间CO_2浓度及气孔与非气孔限制

Intercellular CO_2 concentration and stomatal or non-stomatal limitation of rice under water saving irrigation

为了揭示节水灌溉水稻叶片光合作用的气孔与非气孔限制特征,在研究节水控制灌溉水稻叶片胞间CO2浓度的动态变化规律基础上,进一步探讨了气孔限制与非气孔限制情况。结果表明:水稻叶片胞间CO2浓度呈现v型的日变化规律,在12:00-14:00达到最低值,非气孔限制指标Ci/C与气孔限制值Ls变化规律相反;节水灌溉条件下未出现重度水分亏缺,没有改变胞间CO2浓度与光合作用速率的关系;较低的土壤含水率情况下,控制灌溉水稻的叶片气孔限制值Ls出现增加,非气孔限制没有增加,光合速率没有出现明显降低;气孔限制值增大、光合速率增加的现象表明Ls夸大了叶片光合作用的气孔限制情况。与常规灌溉相比,节水灌溉水稻叶片胞间CO2浓度的变化及其与影响因子间的关系并未发生变化,节水灌溉水稻叶片光合作用的气孔限制有所增加,但光合速率未出现明显降低。

In order to investigate stomatal and non-stomatal limitation on rice leaf photosynthesis rate under water saving irrigation,diurnal variations of intercellular CO2 concentration for rice leaves under water saving irrigation was analyzed.Then stomatal and non-stomatal limitation on rice leaf photosynthesis rate caused by water deficit under controlled irrigation was discussed based on the intercellular CO2 concentration variation.Intercellular CO2 concentration varied in v-style and got the daily minimum value at 12：00-14：00,but non-stomatal limitation index Ci /C varied the other way round with stomatal limitation index Ls.Moderate water stress under water saving irrigation did not result in change in relationships between intercellular CO2 concentration and photosynthesis rate.Stomatal limitation index Ls was found higher than flooding rice when soil moisture was lower in controlled irrigation paddy.But non-stomatal limitation index Ci /C and photosynthesis rate Pn made no difference when compared with flooding paddy rice.It indicates that stomatal limitation index Ls overestimated the stomatal limitation on photosynthesis.So,variation pattern of intercellular CO2 concentration and it correlations with environmental factors under controlled irrigation are same to those under flooding irrigation.Stomatal limitation is increased under controlled irrigation,but photosynthesis rate not.