脱乙酰几丁质对烟草叶片一些生理生化特性的影响

Effect of Chitosan on Some Physiological and Biochemical Roles of Tobacco (Nicotiana tobacum)

以温室栽培生长7～8周的烟草（Nicotianatobacum）第4片真叶为材料，测定了脱乙酰几丁质对细胞膜透性的影响。结果发现，脱乙酰几丁质处理的烟草叶片的电解质、可溶性蛋白质的外渗量和胞外可溶性过氧化物酶的活性均比对照组大，并且随所用的脱乙酰几丁质浓度增加而增大。Mg2＋、Ca2＋、Al3＋能抑制脱乙酰几丁质诱导的蛋白质外渗。脱乙酰几丁质（500μgml-1）处理的烟草叶片的几丁醇和β－1，3－葡聚精酶的活力，在处理6h后开始上升，至36h活力达最高峰，分别是对照组的1．88倍和1．51倍。5mmolL-1Ca2＋对这种诱导具有抑制作用。伴随着对几丁酶和β-1，3-葡聚糖酶的诱导，处理组的可溶性蛋白含量也在处理后36h达到最高峰。

Treatment of the forth Nicotiana tobacum leaves with chitosan resulted in the increment of the Permeability of cell membranes as shown by the leakage of electrolytes, proteins into the medium and the increment of peroxidase activity in the medium. The amount of leakagewas in relation to the concentration of chitosan and time of treatment. 5mmol/L Ca2+ could inhibit this action to some extent as shown by inhibiting the leakage amount of proteins. The activities of chitinase and β - 1, 3 - glucanase of the leaves treated with 500μg/ml chitosan for36hr were 1. 88 and 1. 51 times of those of the leaves untreated respectively. With the induction of chitinase and β - 1, 3- glucanase, the protein content Of the leaves treated with 500μg/ml chitosan for 36 hr was also much higher than that of the leaves untreated. 5mmol/L Ca2+ could partially inhibit the induction of chitinase and β- 1, 3 - glucanase by chitosan .