儿茶素对蝴蝶兰叶片离体培养褐变发生的影响

Effect of Catechin on Browning of Leaf Explants in Tissue Culture of Phalaenopsis sp.

用0.3 g/L儿茶素处理蝴蝶兰叶片外植体,在MS+3 mg/L 6-BA(pH 5.8)培养基上培养4 d,外植体褐变率高于对照227.6%。用香草醛-盐酸溶液染色反应法发现鞣质分布在维管束和细胞间隙。叶片剪切的外植体(培养0 d)鞣质含量较高,培养4 d降低,8 d后再升高。儿茶素处理的外植体鞣质含量明显高于对照。在培养期间,儿茶素处理的外植体PPO、POD和PAL活性高于对照外植体,其中POD活性在第8天达到最大值,PPO和PAL活性在培养第12天达到高峰。

The browning percentage of leaf explants of Phalaenopsis sp. ,treated with 0. 30 mg/L of catechin and cultured in MS medium containing 3 mg/L 6-BA （pH 5. 8） for first four days, were higher 227. 6% than that of the controls. 8% （w/v） vanillin-hydrochloric acid assay confirmed that tannins were distributed in intraeellular fractions and vascular hundle of leaf explants. Cutting of leaf explants caused more accumulation of tannin in them cultured 0 day. Tannin contents reduced in the first four days, and then increased after first eight days. It was found that increased activities of PPO, POD and PAL, as well as the more tannin contents in catechin treated leaf explants resulted in promotation of browning development,leaf explants treatment with cateehin had a high POD activity in them culture at 8^th days , while the activities of PPO and PAL were higher cultured at 12th days.