热激处理对甜柿外植体总酚含量和PAL、PPO、POD活性的影响

摘要

The explants of Diospyros vaki is easy to occur browning during tissue culture process. In order to prevent browning, explants should be treated by heat shock before cultivation. Phenols content and activities of PAL, PPO and POD in D. vaki c.v. ‘Baohuatianshi’ leaves were researched, and physiological mechanism of heat shock treatment preventing browning was discussed. The results showed that browning degree of leaves was decreased significantly after heat shock treating, and total phenol content and activities of PAL and PPO were also lower than the control. But preventing effect of hot shock treatment on POD activity was not obvious. It suggested that heat shock treatment could inhibit synthesis and oxidation of phenols, and decreased quinones content, which was browning production, through reducing activities of PAL and PPO in explants. So heat shock treatment could effectively prevent browning.%甜柿在组织培养过程中极易褐化，为了防止褐变，在培养之前应对外植体进行热激处理。文中研究了热激处理后的宝华甜柿叶片在培养过程中其酚类物质含量和苯丙氨酸解氨酶（PAL）、多酚氧化酶（PPO）、过氧化物酶（POD）活性的变化情况，并对热激处理抑制组培褐变的生理机制进行了初步探讨。结果表明：热激处理后，宝华甜柿叶片的褐变程度比没有处理的明显减轻，其总酚含量与苯丙氨酸解氨酶（PAL）及多酚氧化酶（PPO）活性均有所降低，但热激处理对其过氧化物酶（POD）活性的抑制效果并不明显，说明热激处理通过降低外植体的PAL及PPO活性，抑制酚类物质的合成及氧化，减少了褐变产物——醌类物质的形成，从而有效抑制了褐变现象的发生。