油菜和小麦种苗根系对乙草胺的耐性差异分析

为揭示油菜和小麦根系对乙草胺耐药性差异的原因,采用水培法研究了梯度浓度乙草胺对油菜和小麦种苗根系形态、根尖生理代谢和解剖结构的影响。结果表明,1 mg/L乙草胺对油菜根长抑制率为33.63%,而对小麦根长抑制率可达55.22%;100 mg/L乙草胺对油菜侧根抑制率为63.03%,而对小麦侧根抑制率达100.00%;经0.01 mg/L乙草胺处理后的油菜根尖细胞膜透性高于小麦,当乙草胺浓度高于0.1 mg/L后,小麦根尖细胞膜透性剧烈增加且高于油菜;在较高浓度乙草胺胁迫下,小麦根尖抗氧化酶活性均低于油菜;10 mg/L乙草胺处理下,小麦根尖的解剖结构变异较油菜明显,表现为细胞排列松散、混乱,根冠变形,分生组织细胞染色程度变浅,伸长区细胞分化提前,中柱鞘细胞木质化。研究表明,小麦的根系建成比油菜更容易受乙草胺抑制,且侧根数比根长更敏感;油菜和小麦对乙草胺耐药性差异可能与细胞膜透性、抗氧化酶活性以及根尖细胞组织分化等差异有关。

Analysis of acetochlor tolerance in root of Brassica napus L. and Triticum aestivum L.

To study the mechanism of acetochlor tolerance in Brassica napus L. and Triticum aestivum L., the effects of different concentrations of acetochlor on seedling root morphology, root tip physiological metabolism and anatomical structure were determined by using hydroponic experiments. The results showed that the root length inhibition rates of B. napus and T. aestivum treated by 1 mg/L acetochlor were 33.63% and 55.22%, respectively; the lateral root number inhibition rate of B. napus and T. aestivum treated by 100 mg/L acetochlor were 63.03% and 100.00%, respectively; root tip membrane permeabilities of B. napus treated by 0.01 mg/L acetochlor were higher than that of T. aestivum, while the index of T. aestivum surged and surpassed that of B. napus when acetochlor concentrations exceeded 0.1 mg/L; antioxidant enzyme activities of T. aestivum treated by high concentration acetochlor were lower than that of B. napus. Under 10 mg/L acetochlor treatment, various abnormalities of anatomical structure were observed in root tip of T. aestivum more than B. napus, the arrangement of cell was loose and disordered, deformation of root cap, lighter staining of meristematic cells, early differentiation of elongation region and lignification of pericyclic cells. The results indicated that root of T. aestivum was more sensitive to acetochlor than B. napus, and lateral root number was more sensitive than root length; the acetochlor tolerance difference in B. napus and T. aestivum had related to the differences on cell membrane permeability, antioxidant enzyme activity and root tip cell and tissue.