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以甜瓜(Cumumis melo)品种‘GL~(-1)’为试验材料,在人工气候箱内采用基质栽培方式,研究了0.1~2 mmol·L~(-1)的外源亚精胺(spermidine,Spd)对低温胁迫[昼(12±1)°C/夜(6±1)°C]及恢复下甜瓜幼苗生长和活性氧代谢系统的影响,以探讨外源Spd调控低温胁迫对甜瓜幼苗伤害的可行性。结果显示:低温胁迫能显著影响甜瓜幼苗的生长和活性氧代谢系统的相关指标。适宜浓度的外源Spd能不同程度缓解甜瓜幼苗所受低温胁迫伤害,并以1 mmol·L~(-1) Spd处理效果最好,其显著促进了幼苗生长,提高了超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)、谷胱甘肽还原酶(GR)等抗氧化酶活性,同时也提高了还原型抗坏血酸(As A)、还原型谷胱甘肽(GSH)、可溶性蛋白和脯氨酸含量,降低了过氧化氢(H_2O_2)和丙二醛(MDA)的积累及超氧阴离子(O_2~-)产生速率。研究表明,外源Spd缓解甜瓜幼苗低温胁迫伤害具有剂量效应,以1 mmol·L~(-1) Spd效果最好。低温胁迫下,外源Spd处理可增强甜瓜幼苗抗氧化酶活性,提高抗氧化剂含量,维持As A-GSH循环系统的稳定性,降低H_2O_2和MDA的积累及O_2~-产生速率,从而减轻活性氧对甜瓜幼苗的伤害,保护细胞膜结构的稳定性,增强抗低温能力。
Taking Cumumis melo cultivar ’GL ~ (-1)’ as test material, substrate culture method was used in artificial climate chamber to study the effects of spermidine (0.1 ~ 2 mmol·L -1) , Spd) on the growth and active oxygen metabolism of muskmelon seedlings under low temperature stress (daylight (12 ± 1) ° C / night (6 ± 1) ° C] and recovery, in order to investigate the effect of exogenous Spd on low temperature stress on muskmelon seedlings Feasibility of injury. The results showed that: low temperature stress could significantly affect the growth of muskmelon seedlings and related indicators of active oxygen metabolism system. Exogenous Spd at appropriate concentrations could alleviate the damage of melon seedlings to low temperature stress to some extent, and the treatment with 1 mmol·L -1 Spd was the best, which significantly promoted seedling growth and increased the activity of superoxide dismutase SOD, POD, CAT, APX, DHAR, GR and other antioxidant enzymes But also increased the contents of As A, GSH, soluble protein and proline, and decreased the accumulation of hydrogen peroxide (H 2 O 2) and malondialdehyde (MDA) Superoxide anion (O_2 ~ -) production rate. Studies have shown that exogenous Spd alleviate melon seedling chilling injury with a dose-effect, with 1 mmol·L -1 Spd best. Under low temperature stress, exogenous Spd could enhance antioxidant enzyme activity, increase antioxidant content, maintain the stability of As A-GSH circulation system, reduce the accumulation of H 2 O 2 and MDA and the O 2 - production rate, thus reducing the reactive oxygen species Melon seedling damage, to protect the stability of the cell membrane structure, enhance anti-cryogenic capacity.