Studies on the Content Changes of Endogenous Phytohormones in Rice Calli for Genetic Transformation

Objective) In order to provide some reference frames for rational utilization of phytohormones or plant growth regulators in tissue culture, the dynamic changes of endogenous phytohormones in rice calli from four main processes of genetic transformation were studied. (Method) Using Guangjing No.1,Teqing and V20B as materials,endogenous ABA,IAA and Z in rice calli in four main stages of genetic transformation were analyzed by HPLC. (Result)IAA was found to be more abundant in the callus buds than in the mature embryos. High content of IAA reduced callus induction and growth. Z was found to be mainly existed in seed embroys, being crucial for callus induction. Calli could not be induced when Z content was too low, even the IAA levels were relatively high. High content of ABA was negative to callus induction,but might increase embryogenic callus in the process of callus regeneration. (Conclusion) The kinds, contents and harmonious balance of endogenous phytohormones are key factors to callus induction and differentiation for rice. The concentration of 2,4-D could influence the culture's strength of callus and the levels of endogenous phytohormones.