低温弱光对西葫芦幼苗生长生理指标的影响

Effects of Low Temperature and Weak illumination on Physiological Indices of Summer Squash Seedlings

以西葫芦幼苗为试验材料,通过低温、弱光、低温弱光3种胁迫方式分别处理幼苗,测定西葫芦幼苗的光合作用相关参数,研究其在低温弱光逆境条件下叶片光系统受损伤的程度,以明确叶片内的细胞受损伤程度。结果表明:低温、弱光、低温弱光3种胁迫条件下,西葫芦幼苗叶片的叶绿素荧光参数(Fv/Fm、NPQ)、叶绿素含量、过氧化氢酶(CAT)活性以及超氧化物歧化酶(SOD)活性均有不同程度的降低,而丙二醛(MDA)和过氧化物酶(POD)活性均不同程度的升高。其中弱光条件下叶绿素荧光参数下降最多,而低温弱光在一定程度上缓解了弱光伤害。弱光胁迫下的西葫芦幼苗生理指标显著性差异最大,说明弱光对生物膜的影响最大。

The seedlings of summer squash were treated with low temperature, weak illumination and both low tem- perature and weak illumination. The photosynthesis parameters were determined to study the effects of low tempera- ture and poor light stress on photosystem of squash leaves and the damaged condition of cells inside the blade. The re- sults showed that under three stress conditions, the chlorophyll fluorescence parameters （Fv/Fm, NPQ）, chlorophyll content, catalase （CAT） activity and superoxide dismutase （SOD） activity decreased to varying degrees, while ma- londialdehyde （MDA） and peroxidase （POD） activity increased to varying degrees. Among them, the chlorophyll flu-orescence parameters decreased most under low light conditions, while both low temperature and weak illumination treatment could alleviate the damage of poor light to some extent. The physiological indicators of sum-mer squash seedlings under weak light stress showed the most significant difference, indicating that weak illumination had the greatest impact on biofilm of summer squash.