Studies On The Dynamic Abortion Of Embryo And The Rescuing Technique Of Tetraploid Robinia Pseudoacacia

In the studies, both the ovule and mature embryo of Tetraploid Robinia pseudoacacia were employed to investigate and discuss the relationship between embryonic development and changes of endogenous hormones in ovules; the variation and the physiology and biochemical mechanism of mature embryo; the rescuing technique by culture in vitro. The results indicates that:(1) At both 10d and 100d after anthesis, abortion was more serious than other points with a frequency of 60%～70%. At 30d after anthesis the abortion was the lowest with a frequency 27%. So the abortion mainly happened during younger and older stage of embryo development. From the growth curve of embryo's diameter and weight, the peak period of growth happened during 15d to 50d, and tended to be flat till 55d.(2) During the whole development, the contents of ABA,IAA,GA3 in normal ovules reached their highest level on the 5th day after anthesis, and then decreased, but the contents of IAA and GA3 increased again during 30～70d, ABA content in aborted ovules maintained a relatively high level, but the contents of IAA and GA3 dropped to the lowest level. In the aborted ovule, ABA/(IAA+GA3) was always higher than that of normal ovule.(3) The results of saving young embryos in different development stages by culture in vitro indicate that preferable sterilization was to dip the young legumen in 70% alcohol for 60s, the frequency of pollution drops to 9.4%; the suitable stage for ovule culture is 30d after anthesis and the embryo's culture-response-rate is of 47.7%; the suitable development medium for ovule is Nitsch+6-BA0.5mg/L+ IBA2 mg/L +GA30.5mg/L and the ovules's culture-response-rate is of 63.6%; the efficient medium for inducing callus from young embryo is MS+ 2,4-D3.0mg/L+6-BA0.5mg/L+NAA 0.2mg/L and the callus-inducing rate is 38.6%; the suitable medium for differentiation is 6-BA3.0mg/L+NAA0.5mg/L+ KT3.0mg/L and on which some buds are induced from callus, the differentiation rate reached 16%; the callus anatomy showed that the proliferation growth of young embryo callus mainly originates from inner.(4) Within the seeds, the frequency of embryo is 37.77%, yet the abnormal embryo were classified into 6 groups, he frequency accounts for 92.31%.. From the physiological and biochemical properties, and studies from ploidy showed that between Diploid and Tetraploid Robinia pseudoacacia, the content of soluble protein and MDA, the activity of POD, and the vitality of embryo, which are associated with embryo's germination, were different. By ploidy identification, most of the embryos of vitality were tetraploid. (5) The results of rescuing the mature seeds and embryos by culture in vitro indicate: after the treatment of 10%H2O2 24h,5mg/l GA3 6h, 7mg/l NAA 6h, the average frequency of germination is 5.5%, and the peak value is 6.0%. Meanwhile, a small proportion of the mature embryos can germinate after 7d.