低温胁迫下籽用西瓜幼苗生理变化与耐冷性的研究

以三叶一心期的籽用西瓜幼苗为材料,采用10℃低温胁迫的方法,研究了黑籽瓜兰州大片(wb10)和红籽瓜巢湖红(wb7)随着处理天数的延长幼苗的耐冷性、光合特性、生理特性的变化规律,以探讨籽用西瓜耐低温的生理机制,从而为籽用西瓜的引种栽培和抗寒品种选育提供理论依据。结果表明:不同品种籽用西瓜幼苗的叶绿素含量、Pn、Tr、Gs、Ci随低温胁迫时间的延长而逐渐降低;Pro、MDA、相对电导率随低温胁迫时间的延长而升高。两品种的冷害指数存在一定差异,耐冷性表现为wb10>wb7。低温胁迫下,耐冷性较强的wb10幼苗叶片中的叶绿素含量、Pn、Tr、Gs、Ci均高于耐冷性较弱的wb7,而耐冷性较强的wb10幼苗叶片中MDA含量、脯氨酸含量、相对电导率均低于wb7。综合试验中各项指标认为,耐冷性与品种的来源、类型及在低温下植株的冷害指数、光合特性和细胞膜稳定性有关。

Study on Relationship between Physiological Changes and Chilling Tolerance in Seed-used Watermelon Seedling under Low-temperature Stress

The effects of 10℃ low temperature treatment on chilling tolerance,photosynthesis characteristics and protective system against active oxygen of 3 leaf stage seedlings of two seed-used watermelon varieties,one is black(wb10),the other is red(wb7),were investigated under low temperature stress.The research aim at supply theory basis for introduction and cultivation,improving Chilling tolerance of seed-used watermelon.The results showed that compared with control,chlorophyll content,the photosynthetic rate(Pn),stomatal conductance(Gs)and intercellular CO2 concentration(Ci),transpiration rate(Tr) were declined with the time extension of low temperature treatment,the leakage of electrolytes,the content of proline and the content of MDA were increased in all the four varieties.There was a considerable difference of chilling tolerance among different varieties;Chilling tolerance from being strong to weak is wb10>wb7,seedlings of variety wb10 and wb7 with stronger chilling tolerance had lower electrolytic leakage(%),lower MDA content,higher proline content in leaves than those of variety wb10 and wb7 with weaker chilling tolerance.Therefore,chilling tolerance may be related to chilling injury index、photosynthesis characteristics and membrane stability in the plants.