高温期喷施外源钙对甜瓜幼苗叶片生理特性的影响

【目的】研究不同浓度CaCl₂对秋季大田高温强光下甜瓜苗期的形态变化和生理特性的影响,为秋季大田甜瓜生产苗期管理确定CaCl₂最佳施用浓度、提高甜瓜幼苗的抗逆性和甜瓜全苗、壮苗率提供参考。【方法】以大田主栽品种西州密17号甜瓜为试材,设4个处理,以喷施清水为对照(CK),喷施20、10、5 mmol/L 3个浓度的CaCl₂,测定甜瓜苗期的生理特性指标,分析不同CaCl₂浓度处理对甜瓜幼苗生理特性的影响。【结果】在外界高温条件下,随着幼苗的生长和锻炼,甜瓜叶片可溶性蛋白含量总体呈“缓慢下降-迅速上升-缓慢上升”的三段式“S”曲线变化,叶绿素相对含量始终上升,抗氧化酶活性(SOD、POD、CAT)和MDA含量呈先升后降的趋势;从甜瓜幼苗1叶期至3叶期间可溶蛋白含量、抗氧化酶活性(SOD、POD、CAT)和MDA含量显著升高,在3叶期至5叶期之间均迅速下降,5叶期至9叶期之间缓慢下降或一定范围波动。【结论】高温环境下,喷施5 mmol/L CaCl₂,叶绿素相对含量和可溶蛋白含量分别比对照处理高17.70%和23.61%,SOD、POD、CAT活性分别比对照提高115.79%、57.42%、53.52%,MDA含量比对照降低22.13%,提高甜瓜幼苗耐热性效果显著。

Effects of Exogenous Calcium on Physiological Characteristics of Muskmelon Seedling Leaves during High Temperature Period

【Objective】 To study the effects of different concentrations of CaCl₂ on the morphological changes and physiological characteristics of muskmelon seedlings under high temperature and strong light in autumn field in Turpan area, so as to provide reference for determining the optimal application concentration of CaCl₂, and improving the stress resistance of muskmelon seedlings and the whole seedling and strong seedling rate of melon. 【Methods】 Four treatments were set up to study the physiological characteristics of muskmelon Xizhoumi 17, which were sprayed with 20, 10 and 5 mmol/L, respectively. The effects of different concentrations of CaCl₂ on physiological characteristics of muskmelon seedlings were analyzed. 【Results】 Under high temperature condition, with the growth and exercise of seedlings, the soluble protein content of muskmelon leaves showed a three-stage "S" curve of "slow decline-rapid rise-slow rise", the relative content of chlorophyll always increased, and the antioxidant enzyme activities (SOD, POD, CAT) and MDA content first increased and then decreased. Soluble protein content, antioxidant enzyme activities (SOD, POD, CATt) and MDA content increased significantly, then decreased rapidly from 3-leaf stage to 5-leaf stage, and slowly decreased or fluctuated in a certain range from 5-leaf stage to 9-leaf stage. 【Conclusion】 Spraying 5 mmol/L CaCl₂ can increase the relative content of chlorophyll and soluble protein by 17.70% and 23.61% respectively, and the activities of SOD, pod and cat are increased by 115.79%, 57.42% and 53.52% respectively, and the content of MDA is decreased by 22.13% compared with the control.