Studies On The Differences In Biological Characters Of Seeds, Seedlings And Salt-tolerance Of Melia Azedarach L. From Different Provenances

The biological characters of seeds, growth rhythm and cold-resistance of one-year seedlings of chinaberry (Melia azedarach L.) which originated from 10 different phenological areas were studied. And the seedlings of 6 typical provenances were tested to select provenances with strong salt-tolerance and fast growing rate for reforestation in coast areas of Jiangsu province and other saline-alkali areas nearby. The results were shown as follows:1. There were significant differences in the length, width, length-width ratio and 1000-seed weight of chinaberry seeds with and without endocarps, which were from 10 different provenances. And germination percentage, germination index, vigor index , respiration rate and moisture content had also significant differences among different provenances. There were strong relationships between respiration rate and vigor index, showing that respiration rate could be an index for substituting other vigor indices to some extent. The nutrient contents were also significantly different among different provenances. The seed qualities of Yangling Shaanxi, Pingtan Fujian and Nanning Guangxi were better than those of Huanggang Hubei, Changsha Hunan and Hangzhou Zhejiang.2. The one-year seedling height growth and caliper growth in different provenances was significantly different and the growth rhythm of both height and caliper appeared to be a"S"curve. The seedlings originated from low latitude grew faster than those originated from high latitude. The provenances with relatively high biomass of one-year seedlings were Pingtan Fujian, Nanning Guangxi and Changsha Hunan. And those with relatively low biomass were Huanggang Hubei, Yangling Shaanxi and Zhongmou Henan. The cold-resistance of chinaberry seedlings was weak and they could be injured seriously by low temperature. The seedlings of different provenances had different degrees of freezing damage and there was a strong negative linear relationship between degrees of damage and seedling caliper in the same provenance. The seedlings from high latitude generally had stronger cold-resistance than those from low latitude.3.The morphological, physiological, photosynthetic and chlorophyll fluorescence indices of chinaberry were affected significantly under salt stress.The seedling from different provenances had different salt-tolerance caused by genetic variation. The synthetic evaluation by using the subjection functions combined with morphological, physiological and chlorophyll fluorescence indices showed that the salt-tolerance could be arranged from strong to weak as Pingtan Fujian>Zhongmou Henan>Hangzhou Zhejiang>Yangling Shaanxi>Nanning Guangxi> Changsha Hunan.