Comparative Study On Salt Tolerance Of Five Annual Medics Under NaCl Stress

The annual medic is a new and high quality resource of legume which has been introduced from external recent years, to study its salt tolerance is the important base for its introduction, breeding and extending, and it is also very beneficial to explore the salty soil of the northern area in China. The integrated salt tolerance of five Species of annual medics was tested under 0, 0.2%, 0.4%, 0.6% and 0.8% salt concentration of NaCl by measuring the physiological and biochemical indexes such as relative germination tendency and relative germination rate of the seeds and relative speed of growth, cell membrane permeability, chlorophyll content, free proline and MDA content, soluble sugar content and protective enzyme of the plants. The results as follows:1. Most physiological and biochemical indexes of annual medics have changed greatly under salt stress, and the amount of variety is different in terms of materials and indexes. The pertinence between different indexes from the same species and the NaCl concentration is dissimilar as well as the same index from different species and the NaCl concentration. The result will be not completely consistent when selecting different indexes to appraise the salt-tolerance of five annual medics. So, it is reasonable to estimate the annual medics, salt tolerance by synthetizing many different indexes instead of using a single index.2. NaCl stress has obviously restrained the germination of annual medics which were adopted in the test, made the relative germination rate and germination tendency of its seeds descendent evidently, especially when the NaCl concentration is equal to or above 0.4%, the relative germination rate and germination tendency decreased more than 63.0% and 14.0% so as to almost all the seeds could not germinate under 0.8% NaCl stress. It can be concluded that the response of annual medics, seeds are relatively sensitive to NaCl stress.3. According to the results of integrated grade, it is believed primarily that the order from strong to weak of salt tolerance of Species for experiment is snail medic, barrel medic, burr medic, black medic, strand medic. But the conclusion need to be...