Study On Seed Germination And Stress-resistance Of Wild Apricot (Armeniaca Vulgaris Lam.) In XinJiang

This is a study on different types of wild apricot found in Xinjiang. Stratification combined with GA3 treatments was used in experiments on breakage of seed dormancy. Physiological studies were then carried out on freeze-resistance and drought-resistance characteristics.The main results are as follows:1. Seed germination experiments indicated that 100mg/LGA3 solutions for 12h combined with stratification treatment were effective in breakage of seed dormancy and the acceleration of radicle growth in both kinds of seeds. The effects of combined treatment were marked in apricots of sweet kernel type but not so in bitter types.α-amylase activity in sweet and bitter types was different.α-amylase activity of embryos in CK was higher than in other treatments, andα-amylase activity in fresh embryos per gram was higher than that in cotyledon.2. As to freezing injury during the flowering stage, a comprehensive analysis indicated that the degree of freezing injury in wild apricots is related to latitude, altitude and type of apricot, but that the abortive percentage and fruit set percentage are related particularly to the type. The resistance to cold of the wild sweet apricot was greater than that of the wild bitter one.3. The characteristics of drought-resistance of four types of wild apricot were as follows:(1) The effect of drought stress on absolute growth and leaf relative water content (LRWC) were different. Both of them were higher in wild sweet apricot 1 than in other types.(2) The total chlorophyll content of wild sweet and bitter apricot 1 increased constantly to day 21. The total chlorophyll content of wild sweet and bitter apricot 1 was markedly higher than in CK following drought stress , but not so in type 2.(3) During drought stress, peaking of proline content of the 4 wild apricot types appears at different times. By the 21st day, the proline content of the 4 types are all higher than the control, markedly so in bitter type 2. By day 21 the levels of soluble sugar and starch in the 4 types of apricot are all markedly lower than the control.(4) During drought stress,changes are seen both in MDA content and in levels of SOD, POD and CAT anti-oxidative enzymes activity. The MDA content of wild sweet apricot 1 is higher after drought stress at day 21, but in other types is lower. SOD activity peaks at different times in the 4 types."Sweet 1"has a tendency to increase during drought stress. By day 21 the SOD activity is higher than control, and in the other 3 markedly so. POD activity in each of the 4 types peaks on day 7 and then decreases slowly to day 21."Sweet 2"and"bitter 1"however still have a higher POD activity than control. The CAT activity increases with increased drought stress levels. That in"bitter 2"peaks on day 14, and the others on day 21, reaching 2 to 4 times the level of control. These bitter and sweet wild apricots thus both maintain high levels of enzyme activity in times of drought stress.