高温条件下空气湿度对番茄光合作用及生理性状的影响

目的]研究高温条件下不同空气湿度对番茄光合作用及生理性状的影响。方法]以番茄品种东圣1号为试材,将番茄幼苗置于35℃高温条件下进行低湿（30%～35%）、中湿（55%～60%）和高湿（85%～90%）3种空气湿度处理,测定幼苗不同处理天数的光合作用指标和生理生化指标。结果]高温条件下,番茄叶片的净光合速率随空气湿度的降低和处理天数的增加而下降,到处理第21天时,中、低湿度处理分别比高湿处理低13.0%、38.6%;随空气湿度降低,番茄叶片的叶绿素、可溶性糖、淀粉含量和超氧化物歧化酶（SOD）活性均下降,过氧化物酶（POD）活性略有上升,植物细胞浸提液的电导率显著增大,质膜透性变大,结果造成叶片光合作用能力下降,干物质积累减少。结论]提高空气湿度可使植株净光合速率、光合产物含量和SOD活性增大,有利于番茄幼苗的生长。

Effects of Air Humidity on Photosynthesis and Physiological Characters in Tomato under High Temperature

Objective]The purpose was to study the effects of air humidity on the photosynthesis and physiological characters in the tomato under high temperature.Method]With the tomato variety Dongsheng 1 as the tested material,the tomato seedlings were made for 3 treatments of air humidity as low humidity of 30%-35%,middle humidity of 55%-60% and high humidity of 85%-90% under the high temperature of 35 ℃ and the indexes of photosynthesis and physiology-biochemistry in the tomato seedlings treated for different days were determined.Result]Under high temperature,the net photosynthetic rate in the tomato seedlings was descended with the decrease of the air humidity and the treating days and after treatment for 21 d,that in the middle and low humidity treatments were 13.0% and 38.6% lower than that in the high humidity treatment.With the decrease of the air humidity,the chlorophyll,soluble sugar content,starch content and SOD activity in the tomato seedlings were all decreased,POD activity were slight higher,the conductivity of plant cell extract was increased obviously and the membrane permeability also became bigger,which caused the decrease of photosynthesis ability and reduction of the dry matter accumulation in plant leaf.Conclusion]Increasing the air humidity could increase the net photosynthetic rate,SOD activity and photosynthate,which was favorable to the growth of the tomato seedlings.