不同青贮玉米品种耐盐性比较

为筛选耐盐青贮玉米种质资源材料,在宁夏平罗县不同盐含量的试验地种植5个青贮玉米品种,通过测定蜡熟期各品种的光合气体交换参数、生理生化指标和农艺性状进行耐盐性鉴定,并利用主成分分析和隶属函数法对各青贮玉米品种的耐盐性强弱进行综合评价,结果表明:不同青贮玉米品种的生理指标、光合特性及农艺性状均存在一定差异。随着盐胁迫程度的加剧,过氧化氢酶(CAT)活性有所提高,当胁迫程度达到一定限度后呈下降趋势。对于叶片温度(T_L)而言,表现为重度胁迫时最高,轻度胁迫时最低。5个不同品种在不同盐胁迫程度下的表现不一致,中度胁迫时,玉米品种H14/A18的气孔导度(Gs)、蒸腾速率(Tr)及胞间CO_2浓度(Ci)和胞间CO_2浓度/大气CO_2浓度(Ci/Ca)最高;重度胁迫下,玉米品种H_242/1523的以上4个指标最高;而轻度胁迫时,玉米品种北21/1522的以上4个指标最高。相关性分析发现,抗氧化保护酶活性中过氧化物酶(POD)活性与CAT活性、超氧化物歧化酶(SOD)活性之间呈显著性正相关,Gs与Ci、Tr及Ci/Ca呈极显著正相关。对不同盐胁迫程度下的各项指标进行综合分析,按照综合评价值(D值)的大小,5个青贮玉米品种在重度胁迫时耐盐性强弱依次为:H_242/1523桂青贮1号北21/1522H14/1528H14/A18;中度胁迫时耐盐性强弱依次为:H14/A18桂青贮1号北21/1522H_242/1523H14/1528;轻度胁迫时耐盐性强弱依次为:北21/1522H14/1528H_242/1523桂青贮1号H14/A18。

Comparison of Saline Tolerance of Different Kinds of Silage Maize

In order to screen the germplasm resources of salt-tolerant silage maize,five silage maize varieties were planted in Pingluo County of Ningxia with different saline-alkali content.Based on the values of photosynthetic gas exchange parameters,physiological indexes and agronomic traits measured in ripening stage,the salt tolerance for the five maize genotypes was evaluated through principal component analysis and the subordinate function method.The results showed that physiological indexes,photosynthetic gas exchange and agronomic traits were different among the five genotypes.The activity of catalase(CAT)was increased with the increase in severity of salt stress,and then decreased when the degree of stress reached a certain limit.The leaf temperature(TL)showed maximum when it was under severe stress,minimum under mild stress.The performance of five different varieties under different salt stress levels was inconsistent,under the condition of moderate stress,the highest values of stomatal conductance(Gs),transpiration rate(Tr),intercellular CO2 concentration(Ci) and intercellular CO2 concentration/atmospheric CO2(Ci/Ca) were H14/A18;under severe stress,H242/1523 was the highest in all four cases.In the case of mild stress,the highest value of the four was Bei 21/1522.It was found that activity of peroxidase(POD)was significantly and positively correlated with activity of CAT and superoxide dismutase(SOD) through correlation analysis.There was a extremely significant positive correlation of Gs with Ci,Tr and Ci/Ca.After the comprehensive analysis of the degree of each index under different saline stress,the salt tolerance of severe stress was ranked as follows:H242/1523>Gui silage Number 1>Bei 21/1522>H14/1528>H14/A18;The order of salt tolerance in moderate stress was: H14/A18>Gui silage Number 1>Bei 21/1522>H242/1523>H14/1528;The salt tolerance of mild stress was ranked as follows: Bei 21/1522>H14/1528>H242/1523>Gui silage Number 1>H14/A18 according to the value of comprehensive evaluation value(D value).