1,2,4-三氯苯对水稻种子萌发及幼苗生长的毒性机理

以水稻为试材，采用水培方法研究了1,2,4-三氯苯(1,2,4-TCB)对水稻种子萌发、幼苗生长、叶绿素含量、蛋白质含量、脯氨酸含量、细胞膜通透性的影响.结果表明，水稻种子的萌发率和活力指数随1,2,4-TCB处理浓度的升高而逐渐降低，呈现一定的浓度-效应关系，高浓度(80和100 mg·L^-1) 1,2,4-TCB处理组水稻种子的活力指数仅为对照组的7. 89％和1.92％，水稻幼苗的株高和根长均受到抑制，表现出一定的浓度-效应和时间-效应关系.水稻叶片的叶绿素a、叶绿素b、总叶绿素和蛋白质含量均随1,2,4-TCB浓度的升高而降低.水稻叶片游离脯氨酸含量和细胞膜的通透性随处理浓度的升高而增加.当1,2,4-TCB处理浓度＞15 mg·L^-1时，游离脯氨酸含量和叶片细胞膜的通透性急剧增加，与对照组相比各组差异均显著(P＜0.01).这表明1,2,4-TCB对水稻幼苗的损伤是一个复杂的过程，其机理可能与1,2,4-TCB使植物细胞膜、细胞内蛋白质和细胞器结构和功能损伤有关.

Toxic effects of 1,2,4-trichlorobenzene on rice seed germination and seedling growth

By the method of water culture, this paper studied the effects of 1,2,4-trichlorobenzene (1,2,4-TCB) on the seed germination and seedling growth of rice, with the chlorophyll, protein and proline contents and cytomembrane permeability of seedling leaf measured. The results showed the seed germination rate and vigor index were decreased with increasing concentration of 1,2,4-TCB, showing a definite dose-response relationship, and the seedling growth and root length were inhibited, showing definite time-response and dose-response relationships. The chlorophyll a, chlorophyll b, total chlorophyll, and protein contents in seedling leaf decreased with increasing concentration of 1,2,4-TCB, while the free proline content and cytomembrane permeability had a sharp increase when the concentration of 1,2,4-TCB was higher than 15 mg x L(-1). All of these suggested that the damage of rice seedling was a complicated process, which might be related to the structural and functional damage of cellular membrane, protein, and organelles.