Studies On Tissue Culture Using Shoot Tips And Adventitious Root Mechanism Of Castanea Mollissima Cv. 'Yanshanhong' In Vitro

Chinese chestnut (Castanea mollissima) is a popular fruit tree with broadly climate and soil condition. C. mollissima not only has economy value, but also has good nutrition and medicinal value. In present, tissue culture of C. mollissima is reported less with low rooting rate and influence of subculture time. But the mechanism of adventitious root is still blank in China. Therefore, it is very important to research of tissue culture using shoot tips and adventitious mechanism of C. mollissima. 'Yanshanhong'. At one time, it is important for expanding and propagation of seed in practicality value, and has also important significance of use for reference for other wood plant which are difficult to root.The rapid micropropagation technique of 2-3 month-old shoot tip of C. mollissima. 'Yangshan hong' in vitro were comeprehensively studied in this paper. The mechanism of adventitious root was studied in physiological and biochemical level.. The results were as follows:(1) The shoot tips used as explants were sterilized by immersion for 8-10min in 0.1 HgCl and inoculated in MS (1/2NO3^-) +0.5mg/L6-BA. Sterile system was achieved quickly. Browning can effectively control with 1 00mg/LPVP in medium. 0.5mg/L6-BA was the best concentration for shoots induction in multiplication culture. The excessive high concentration could induce more callus and effected microshoots differencation and regular growth.(2) Two step method was adopted in rooting culture and successfully inducted adventitious root formation. The microcuttings were cultured on 1/2MS (1/2NO3^-) +3mg/LIBA at dark condition for 5d, and then transfered to the 1/4MS (1/2NO3^-) with auxin-free, the rate of rooting reached 73.3%. After the subculture for 4 generations, the rooting rate gradually improved with the subculture times increasing. The 8th generations subculture was the best subculture time.(3) During the information of adventitious root , the ratio of IAA/ABA was a even more reasonable physiological biochemical indexes during adventitious root formation. The content of IAAgradually climbed and the content of ABA and GA₃ descended, which were favor of the information of adventitious root.(4) During the information of adventitious root, the activity of IAAO and POD gradually descended and the activity of PPO gradually climbed, which were favor of the information of adventitious root.