耐盐胁迫菜豆品种筛选及其苗期耐性生理研究

Screening of Salt Tolerant Common Bean Varieties and Studies on Their Salt Tolerance Physiology in Seedling Stage

采用营养液水培的方法,使用NaCl模拟盐胁迫,利用4个菜豆品种确定最适宜耐盐品种筛选的NaCl浓度,并对40个菜豆品种进行盐胁迫,以生长量、根冠比、株高、叶面积和净光合速率的相对值作为耐盐评价依据,采用加权隶属函数和聚类分析对不同菜豆品种耐盐性进行综合评价和耐盐等级划分,随后对高耐盐品种和盐极敏感品种进行生理指标测定。结果表明:150 mmol·L^(-1)的NaCl为最适宜进行耐盐品种筛选的盐浓度,苗期盐胁迫指标敏感程度表现为:相对生长量>相对净光合速率>相对根冠比>相对叶面积>相对株高,相对生长量、相对根冠比、相对叶面积、相对净光合速率与菜豆品种耐盐性最为密切,40个菜豆品种依照对盐胁迫耐受程度的强弱分为高耐盐、耐盐、较耐盐、盐敏感、盐极敏感5类,筛选出5个高耐盐品种P16152、P19023、P18009、P18012、P18051,对5个高耐盐品种和5个盐极敏感品种的生理指标测定结果表明,除POD活性外,SOD活性、活性氧生成速率和MDA含量在盐胁迫下盐极敏感型品种中差异显著的品种数量均高于高耐盐品种,SOD活性、活性氧生成速率和MDA含量相较于POD活性更适合评价菜豆耐盐性。

NaCl was used to simulate salt stress by hydroponic method of nutrient solution,4 common bean varieties were used to determine the most suitable NaCl concentration for variety screening.This experiment treated 40 common bean varieties with salt stress.Taking relative values of growth amount,rootshoot ratio,plant height,leaf area and net photosynthesis rate as basis for salt tolerance evaluation,adopting weighted membership function and cluster analysis,this experiment conducted comprehensive evaluation on salt tolerance of different bean varieties,and classified their salt tolerance grades.Then,the physiological indexes of these salt tolerant varieties were determined.The results showed that 150 mmol·L^(-1) NaCl was the most suitable salt concentration for variety screening.The sensitivity of salt stress index at seedling stage was:relative growth amount>relative net photosynthesis rate>relative root-shoot ratio>relative leaf area>relative plant height.The relative growth amount,relative root-shoot ratio,relative leaf area and relative net photosynthesis rate were most closely related to the salt tolerance of bean varieties.The 40 common bean varieties were divided into 5 categories according to their tolerant degree to salt stress:high salt tolerant,salt tolerant,rather salt tolerant,salt sensitive,salt extreme sensitive.Five high salt tolerant cultivars P16152,P19023,P18009,P18012 and P18051 were screened out.The results of determing physiological indexes of 5 high salt tolerant cultivars and 5 salt extreme sensitive cultivars indicated that except POD activity,the number of varieties with significant differences among extreme sensitive varieties in SOD activity,ros generation rate and MDA content under salt stress were more than varieties among high salt tolerant varieties.SOD activity,ROS generation rate and MDA content were more suitable than POD activity for evaluating salt tolerance of common beans.