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| Screening of Salt Tolerant Common Bean Varieties and Studies on Their Salt Tolerance Physiology in Seedling Stage |
| LI Mengdi1，FENG Guojun2，YANG Xiaoxu2，LIU Chang2，YAN Zhishan2，LIU Dajun2* |
| 1College of Life Sciences，Heilongjiang University，Harbin 150081，Heilongjiang，China；2College of Modern Agriculture and Ecological Environment，Heilongjiang University，Harbin 150081，Heilongjiang，China |
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Abstract 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．
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Received: 21 April 2021
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