高温胁迫对设施甜瓜幼苗光合特性参数的影响

Effects of High Temperature Stress on Photosynthetic Characteristics of Facility Muskmelon Seedlings

以厚皮甜瓜“西州密25号”和“耀珑25号”为试材,采用单因素随机区组试验,设置30、35、40、45℃4个处理,以25℃为对照在人工气候箱内模拟7月设施温湿度条件,研究了高温胁迫对甜瓜幼苗电导率、丙二醛、叶绿素荧光参数和光合气体交换参数的影响,以期为甜瓜抗逆栽培和耐热机理提供参考依据。结果表明:电导率和丙二醛与温度均呈正相关。“耀珑25号”在35、40、45℃时的电导率较对照升高19.03%、36.12%和54.28%。丙二醛含量在25、30、35、40、45℃较对照升高40.72%、58.46%、81.04%和132.66%;甜瓜的叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)与温度呈极显著负相关,胞间CO_(2)浓度(Ci)与温度呈极显著正相关,Gs降低时Ci反而升高。光合指标初始荧光(Fo)、最大荧光(Fm)、PSⅡ活性(Fv/Fo)、PSⅡ最大光能转化效率(Fv/Fm)与温度呈极显著负相关。高温胁迫下,“耀珑25号”甜瓜较适宜在温室内种植。

The melons variety‘Xizhoumi No.25'and‘Yaolong No.25'were used as test materials,a one-way randomized block test was conducted with four treatments of 30℃,35℃,40℃,45℃,25℃was used as CK,and the temperature and humidity conditions of the facility were simulated in an artificial climate chamber in July,the effects of high temperature stress on the electrical conductivity,malondialdehyde,chlorophyll fluorescence parameters and photosynthetic gas exchange parameters of melon seedlings were studied,in order to provide reference for the stress-resistant cultivation and heatresistant mechanism of melon.The results showed that the conductivity and malondialdehyde were positively correlated with temperature.The electrical conductivity of‘Yaolong No.25'at 35℃,40℃and 45℃increased by 19.03%,36.12%and 54.28%compared with the control.Malondialdehyde was increased by 40.72%,58.46%,81.04%and 132.66%compared with the control.Chlorophyll content,Pn,Gs and Tr of melon were negatively correlated with temperature,while Ci was positively correlated with temperature.Ci increased when Gs decreased.Photosynthetic indices Fo,Fm,Fv/Fo and Fv/Fm were significantly negatively correlated with temperature.Under high temperature stress,the melon variety‘Yaolong No.25'was more suitable for growing in greenhouse.