To ascertain the safety of herbicides in peach production, we examined the effects of two herbicides (glyphosate and paraquat) on vegetative growth, root structure, root-tip cell mitosis and photosynthesis in rootstock Prunus persica seedlings. The results showed that the growth of both shoot and root of the P. persica seedlings was significantly inhibited under the glyphosate treatment. Compared with the control, plant height decreased by 31.5%, total root length, root surface area, root volume and the number of root tips decreased by 39.5%, 39.5%, 49.8% and 44.6%, respectively. The paraquat treatment had no significant differences compared with the control. The mitotic index of root tip cells decreased by 38.0% and 35.9% under both herbicide treatments, respectively. The proportion of cells at metaphase against the total number of mitotic cells in the root tips was significantly reduced by glyphosate treatment compared with the control and the paraquat treatment. Root tip cells of peach were sensitive to both kinds of herbicides. The leakage of electrolytes from the cells in root tips was significantly higher than that of the control from the second day to the thirtieth day after treatments. After five days of glyphosate treatment, electrolyte leakage rate of leaves was raised, the bases of young leaves turned yellow, and spread to leaf tips, parts of which ultimately withered. Net photosynthetic rate, stomatal conductance, and transpiration rate were reduced more strongly under the glyphosate treatment than the paraquat treatment. In conclusion, both kinds of herbicides reduced cell mitotic index of root tip cells and leaf net photosynthetic rate, increased the electrolyte leakage rate of the root tip cells in P. persica seedlings. Glyphosate had a greater effect on vegetative growth and leaf photosynthesis, which could cause young leaves yellowing and leaf tips scorching.
以砧木毛桃幼苗为研究对象,通过土施草甘膦和百草枯研究2种桃园常用除草剂对毛桃营养生长、根系结构、根尖细胞分裂、叶片光合特性等的影响,为除草剂在桃生产中的安全使用提供科学依据。结果表明: 草甘膦处理显著抑制毛桃地上部和根生长,与对照相比,株高降低31.5%,总根系长度、总根表面积、总根体积和总根尖数分别降低了39.5%、39.5%、49.8%和44.6%,而百草枯处理以上指标与对照差异均不显著;草甘膦和百草枯处理后毛桃根尖细胞有丝分裂指数分别降低38.0%和35.9%,且草甘膦处理分裂中期细胞数占分裂细胞总数的比例显著低于对照和百草枯处理;毛桃根尖细胞对2种除草剂响应迅速,从处理第2天开始根尖细胞电解质渗漏率始终显著高于对照。叶片细胞电解质渗漏率则从处理5 d后开始显著升高,且草甘膦处理出现幼叶基部变黄并向叶尖蔓延,同时部分叶尖逐渐焦枯的现象;2种除草剂处理导致毛桃叶片净光合速率、气孔导度、蒸腾速率有不同程度的降低,其中草甘膦处理下降更明显。综上,使用草甘膦和百草枯均会降低毛桃幼苗根尖细胞分裂指数,提高根尖细胞电解质渗透率,总体降低叶片净光合速率。草甘膦对毛桃营养生长、叶片光合作用影响更大,而且会造成幼叶变黄、叶尖焦枯等现象。.
Keywords: glyphosate; paraquat; peach; photosynthesis; root structure; vegetative growth.