外源H2O2对盐碱胁迫下苹果矮化砧木幼苗生理特性的影响
投稿时间:2021-04-02  修订日期:2021-08-21  点此下载全文
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作者单位邮编
杜蕾 甘肃农业大学 园艺学院 730070
杨建宁 天水市麦积区果品产业局 741000
王星星 甘肃农业大学 园艺学院 730070
张德 甘肃农业大学 园艺学院 730070
赵婷 甘肃农业大学 园艺学院 730070
张瑞 甘肃农业大学 园艺学院 730070
王延秀 甘肃农业大学 园艺学院 730070
基金项目:国家自然科学基金(31960581)
中文摘要:以2年生苹果矮化砧木M9-T337为试材,采用盆栽实验法,设置浇灌清水(CK)和盐碱胁迫(0.1 mol/L NaCl+NaHCO3溶液)外加喷施5种浓度的H2O2处理[0(T1)、0.2 mmol/L(T2)、0.4 mmol/L(T3)、0.6 mmol/L(T4)、0.8 mmol/L(T5)],测定各处理叶片叶绿素含量、光合气体交换参数、渗透调节物质含量、抗氧化酶活性和细胞膜透性,并利用相关性与主成分分析进行综合评价,以探讨外源过氧化氢(H2O2)增强其盐碱耐性的生理机制。结果表明:(1)随着盐碱胁迫时间的延长,M9-T337幼苗叶片叶绿素a(Chl a)含量、叶绿素b (Chl b)含量、叶绿素总量(Chl t)、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、可溶性蛋白(SP)含量均呈逐渐下降趋势;胞间CO2浓度(Ci)、可溶性总糖(TSS)含量、脯氨酸(Pro)含量、过氧化氢酶(CAT)活性、抗坏血酸过氧化物酶(APX)活性、相对电导率(REC)、丙二醛(MDA)含量均呈上升趋势;超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性均呈先升后降趋势。与CK相比,外源H2O2处理后M9-T337幼苗叶片各指标均呈现不同幅度变化,且存在明显浓度效应,并以T3(0.4 mmol/L H2O2)处理叶片的Chl a、Chl b、Chl t、SP和Gs降幅最小,Ci、REC、MDA升幅最小,TSS、Pro、APX升幅最大。(2)M9-T337幼苗叶片Pn与Tr、Gs、Chl a、Chl b、Chl t、SP、SOD、POD呈显著正相关,与Ci、MDA、CAT、APX、REC呈显著负相关。(3)综合评价表明,各处理对M9-T337幼苗叶片生理特性的效应依次为:CK>T3>T4>T2>T5>T1。研究发现,叶面喷施适宜浓度H2O2可有效改善盐碱胁迫下M9-T337幼苗光合能力,显著提高抗氧化酶活性和渗透调节物质的含量,降低细胞膜透性,从而达到缓解盐碱胁迫的作用,并以0.4 mmol/L H2O2处理效果最佳。
中文关键词:苹果  矮化砧木  外源H2O2  盐碱胁迫  生理特性
 
Effects of Exogenous H2O2 Treatment on Physiological Characteristics of Salt-alkali Stressed Seedling of Apple Dwarf Rootstock
Abstract:Using 2-year old apple dwarf rootstock M9-T337 as test material, pot experiment method was adopted. Watering water (CK) and salt-alkali stress (0.1mol/L NaCl+NaHCO3 solution) were set, followed by spraying five concentrations of H2O2 treatment [0 (T1), 0.2 mmol/L (T2), 0.4 mmol/L (T3), 0.6 mmol/L (T4), 0.8 mmol /L (T5)], chlorophyll content, photosynthetic gas exchange parameters, osmotic adjustment substance content, antioxidant enzyme activity and cell membrane permeability of each treatment were measured, and comprehensive evaluation was conducted by correlation and principal component analysis, so as to explore the physiological mechanism of exogenous hydrogen peroxide (H2O2) enhancing saline-alkali tolerance. The results show that: (1) The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll (Chl t), net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and soluble protein (SP) of M9-T337 seedlings decreased gradually with the extension of saline-alkali stress. Intercellular CO2 concentration (Ci), soluble total sugar (TSS) content, proline (Pro) content, catalase (CAT) activity, ascorbate peroxidase (APX) activity, relative electrical conductivity (REC) and malondialdehyde (MDA) content all showed an increasing trend. The activity of superoxide dismutase (SOD) and peroxidase (POD) increased first and then decreased. Compared with CK, each index of M9-T337 seedling leaves changed in different amplitude after treatment with exogenous H2O2, and there was an obvious concentration effect. The decreases of Chl a, Chl b, Chl t, SP and Gs in leaves treated with T3 (0.4 mmol/L H2O2) were the smallest, and the increases of Ci, REC and MDA were the smallest. TSS, Pro and APX increased the most. (2) Leaf Pn of M9-T337 seedlings was positively correlated with Tr, Gs, Chl a, Chl b, Chl t, SP, SOD and POD, and negatively correlated with Ci, MDA, CAT, APX and REC. (3) Comprehensive evaluation showed that the effect of each treatment on the physiological characteristics of M9-T337 seedling leaves was in the order of CK>T3>T4>T2>T5>T1. The results showed that the suitable concentration of H2O2 could effectively improve the photosynthetic capacity of M9-T337 seedlings under salt-alkali stress, significantly increase the activities of antioxidant enzymes and the content of osmotic regulatory substances, and reduce the membrane permeability, so as to alleviate the salt-alkali stress, and 0.4 mmol/L H2O2 treatment had the best effect.
keywords:apple  dwarf stock  exogenous H2O2  saline-alkali stress  physiological characteristics
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