| China is the origin center of Chinese cabbage-pe-tsai (Brassica campestris L. ssp. pekinensis (Lour.) Olsson, syn. B. rapa L. ssp. pekinensis), which forms leafy head serving as nutritorium under the co-effects of natural evolution and artificial selection. The styles of leafy head are various, its tight degree is one of the important horticultural characteristics. Since leaf head consists of a number of head leaves, we can't understand the law of leaf head development until we know the mechanism for leaf to bend. The accumulating plant physiological information shows that plant hormones, especially such as IAA, play very important roles during head leaf development, The experiment that transfering auxl and aux2 genes (respectively encode trytophan monooxygenase and indoleacetamide hydrolase, which are needed for two-step synthesis of IAA) into Chinese cabbage-pe-tsai proves such supposal. Dr. He's laboratory screened out a new gene named as BcpLH by differential hybridization during the stage between the end of rosette and the start of heading leaf differntiation. After computer alignment matching BcpLH to the domains of double-stranded RNA binding (DBRM), the homologous regions were recognized between BcpLH and human and mouse double-stranded RNAbinding protein TRBP. PCR expression analysis shows that during vegetative growth BcpLH gene was expressed preferentially in folding leaves at folding stage. Transcripts of BcpLH gens were increased when plants were sprayed with IAA. It is deduced that BcpLH gene may be related to initiation of folding leaf and leafy head and induced by auxin in the aspect of transcriptional expression. HYL\ gene in Arabidopsis thaliana also has the domains of double-stranded RNA binding, its mutant is characterized by shorter stature, delayed flowering, leaf hyponasty, reduced fertility, decreased rate of root growth, and an altered root gravitropic response. It also exhibits the different corresponding to plant exogenous hormones. Based above information, by vacuum infiltration and micro-injection methods we transferred anti-sense gene of BcpLH into Chinese cabbage-pe-tsai and nonhead Chinese cabbage (B. campestris L. ssp. chinensis (L.) Makino var. communis Tsen et Lee ) in order to obtain more clues about the functions of this gene. The morphological characters and corresponding to plant hormones such as IAA, 6-BA and ABA were compared between transformants and nontransformant. Meanwhile the factors affecting efficiency of transformation in the transformation systems mentioned above were primarily studied also. Seven main conclusions were following :(1) The morphology of transgenetic plants had been changed. They exhibit the increasing innumber of leaf, darker leaf color, curled leaf surface, more leaf thorn, leaf hyponasty, shorter distance between leaves, delayed flowering (about 10 d), reduced fertility individually, mutated flower (so called nested flower model).(2) Plant exogenous hormones affected organ growth of transformant during seedling, leaf color became lighten after spraying IAA, the growth of leaf, leaf stalk, hypocotyl and primary root is less sensitive than control.(3) When concentration of 6-BA was below 0.1 mM it promoted leaf growth of tranformant, The expending effect of cell in transformant leaf is less than one in control under the low concentration of 6-BA, otherwise it is opposite under the high concentration of 6-BA.The growth of both leaf and leaf stalk of tansformant is more sensitive to 6-BA than that in control, but the growth of hypocotyl and primary root is less sensitive than one in control. The turning point of 6-BA concentration is 0.1 mM, it speeds the growth of transformant primary root under low concentration, but it hampers the primary root growth under high concentration.(4) ABA has the same effects on leaf index and leaf stalk of both transformant and nontransformant.,but it plays more intensive inhibiting effect on the transformant than on the control, that indicates that the sensibility to ABA in thes...
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