锑对甜瓜种子萌发及幼苗生理特征的影响

Effects of Antimony on Seed Germination and Seedling Physiology of Cucumis melo

为探索甜瓜(Cucumis melo)对锑(Sb^(3+))胁迫生理响应机制,以甜瓜品系‘10-06-3’为实验材料,通过种子萌发和幼苗水培实验,研究不同浓度Sb^(3+)(0、30、60、100 mg/L)胁迫对甜瓜种子萌发、幼苗期生理的影响。结果表明,低浓度Sb^(3+)对甜瓜种子萌发有促进作用,但对根的生长有抑制作用,也有利于幼苗生长,而高浓度Sb^(3+)明显对甜瓜种子萌发及幼苗生长有显著抑制作用;MDA浓度会随着Sb^(3+)浓度的上升而持续增加,可溶性糖含量以及CAT活性同MDA浓度呈显著正相关,随其增长而做出调节性增长。Sb^(3+)浓度低于60 mg/L时,可溶性蛋白含量、POD活性、SOD活性以及叶绿素相对含量会随着Sb^(3+)浓度升高而显著升高,但高于60 mg/L时,其活性及含量会急剧下降,一定浓度Sb^(3+)可激发甜瓜抗氧化调节反应,高浓度Sb^(3+)会抑制抗氧化酶活性;高浓度Sb^(3+)致使甜瓜叶片气孔导度、胞间CO_(2)浓度降低,从而影响甜瓜的光合速率、蒸腾速率;主成分分析中,主成分PC_1甜瓜可溶性糖含量、MDA浓度和CAT活性权重系数较大,主成分PC_(2)中可溶性蛋白、SOD的权重系数较大。研究表明,甜瓜在低浓度Sb^(3+)(30 mg/L)胁迫条件下通过提高可溶性糖以及可溶性蛋白等渗透调节物质的含量来增强抗逆能力,高浓度Sb^(3+)(60 mg/L)胁迫会损害防御系统,导致幼苗生长发育不稳定。

In order to explore the physiological response mechanism of Cucumis melo to antimony(Sb^(3+))stress,waterlogging tolerant melon strain‘10-06-3’was used as experimental materials to study the effects of Sb^(3+)(0,30,60,100 mg/L)stress at different concentrations on melon seed germination and seedling physiology through dish germination and hydroponic experiments.The results showed that low concentration antimony had a promoting effect on seed germination of muskmelon,but had an inhibitory effect on root growth and was also beneficial for seedling growth.However,high concentration antimony had a significant inhibitory effect on seed germination and seedling growth of muskmelon,affecting its development and growth.The concentration of MDA increased with the increase of antimony concentration,and the soluble sugar content and CAT activity were significantly positively correlated with MDA concentration,leading to a regulatory increase.When the concentration of Sb^(3+)was lower than 60 mg/L,the soluble protein content,POD activity,SOD activity,and relative chlorophyll content significantly increased with the increase of antimony concentration.However,when the concentration was higher than 60 mg/L,its activity and content sharply decreased.A certain concentration of Sb^(3+)could stimulate the antioxidant regulation reaction of muskmelon,while high concentration antimony inhibited antioxidant enzyme activity.High concentration of Sb^(3+)led to a decrease in stomatal conductance and intercellular CO_(2) concentration in melon leaves,which comprehensively affected the photosynthetic rate and transpiration rate of the melon.Principal component analysis showed that the weight coefficients of soluble sugar content,MDA concentration,and CAT activity in principal component PC1 were relatively high,while the weight coefficients of soluble protein and SOD in principal component PC_(2) were relatively high.This indicates that under low concentration Sb^(3+)(30 mg/L)stress conditions,sweet melons enhance their stress resistance by increasing the content of soluble sugars and soluble proteins as osmoregulatory substances.However,under high concentration Sb^(3+)(60 mg/L),nickel stress can damage their defense system,leading to unstable growth and development of seedlings.