外源Ca^(2+)、SA和ABA缓解甜瓜低温胁迫伤害的生理作用

Physiological effects of exogenous Ca^(2+),SA and ABA in alleviating low temperature stress of melon seedlings

以‘日本甜宝’甜瓜为试材,叶面喷施CaCl2、水杨酸(SA)和ABA溶液后进行15℃/10℃(昼/夜)低温处理6 d,研究低温胁迫过程中Ca2+、SA和ABA对甜瓜幼苗叶片生理生化指标变化的影响。结果表明:喷施一定浓度的Ca2+、SA和ABA均能缓解低温对幼苗的伤害。低温胁迫下,处理植株体内可溶性糖和可溶性蛋白含量变化不明显;3种物质均能减轻膜脂过氧化程度,尤其SA处理下MDA含量变化不明显,并能激活SOD、CAT、POD和APX 4种抗氧化酶的快速和长时间表达,其中5和10 mmol.L-1CaCl2、3 mmol.L-1SA和20 mg.L-1ABA处理的SOD活性一直维持较高水平,最高活性分别是胁迫前的1.94、2.30、2.10和3.42倍;3 mmol.L-1SA处理使CAT活性提高了1.36倍;ABA处理能激活POD活性,是胁迫前的1.48倍;1 mmol.L-1SA和40 mg.L-1ABA处理下的APX活性分别是胁迫前的1.53和2.12倍。表明,5和10 mmol.L-1CaCl2、1和3 mmol.L-1SA以及20 mg.L-1ABA处理可减轻低温对甜瓜生理指标的影响,有效提高甜瓜耐冷性。

Melon seedlings were sprayed with CaCl2,SA and ABA separately,and then plants were treated under 15 ℃/10 ℃ for 6 d to study the effects of exogenous Ca2+,SA and ABA on the physiological mechanism under low temperature stress.The results showed that pretreatments with certain concentrations of Ca2+,SA and ABA could alleviate cold damage.Soluble sugar and soluble protein contents in treatment seedlings changed insignificantly.Three substances pretreatments alleviated membrane lipid peroxidation especially salicylic acid best,and also activated rapidly the expression of SOD,CAT,POD,APX and the expression lasted longer time.Treatments of 5,10 mmol·L-1 CaCl2,3 mmol·L-1 SA and 20 mg·L-1 ABA kept SOD activity at higher levels which were respectively 1.94,2.30,2.10 and 3.42 times of those before stress.CAT acticity was enhanced by 1.36 times when sparyed with 3 mmol·L-1 SA.POD activity after treated with ABA was 1.48 times of that untreated;APX activities by the treatment of 1 mmol·L-1 SA and 40 mg·L-1 ABA were 1.53 and 2.12 times of those untreated.So the cold tolerance of melon seedling was enhanced with 5 and 10 mmol·L-1 CaCl2,1 and 3 mmol·L-1 SA and 20 mg·L-1 ABA treatment through alleviating low damages to physiology.