Effect Of Salt Stress On Raising Seedling And Physiological Characteristics Of Melia Azedarace L.

Taking fruit and annual seedlings in several families of Melia azedarach L. as research objects, morphological characteristics of fruit, growth, physiological and biochemical indexes of young seedlings under NaCl stress were studied. The results are summarized as follows:1 .Variation of fruit characters between families within populations was greater than that between populations. The broad heritability between families within populations was bigger than that between populations. Fruit characters were under the influence of both latitude and longitude, and latitude had more influence than longitude.2. With the increase of NaCl concentration, germination energy and germination rate of Melia azedarach L. families decreased on the whole. Seedling height and ground diameter increment, root range, length of main root, fresh weight of roots, fresh weight of stems, fresh weight of leaves, dry weight of roots, dry weight of stems, dry weight of leaves, total biomass decreased with the increase of NaCl concentration, but there was significant difference between families. With the increase of NaCl concentration, root-shoot ratio basically increased.3.With the increase of NaCl stress degree, damage degree of cell membrane of leaves increased, content of soluble proteins decreased, variation trend of POD activity was not significant, SOD activity increased except for Family H, content of MDA also increased. With the increase of stress concentration, activity of root system decreased.4.With the increase of NaCl concentration, chlorophyll content, net photosynthetic rate, stomatal conductance and transpiration rate decreased, variation trends of intercellular CO₂ concentration and water use efficiency were not significant.5.The comprehensive evaluation of the 26 indexes (seedling height increment, etc.) of the families by membership function method indicated that the salt-resistant ability of the families decreased in the order of Sheyang > Ganyu>Wulian>Weihai> Dongtai> Sihong.