【目的】基于林地除草导致的草甘膦残留问题,通过杉木盆栽探究杉木对土壤残存草甘膦的形态学和生理学响应,分析土壤残存草甘膦对杉木养分吸收的影响机制,为林业生产中草甘膦的合理施用提供理论依据,为杉木人工林的可持续经营提供基础资料。【方法】参考土壤残存草甘膦含量在培养基质中添加不同浓度草甘膦(0、2、5、10、20、50 mg·kg~(-1)),通过盆栽试验,测定杉木对草甘膦的形态学和生理学响应,分析草甘膦对杉木养分吸收的影响机制。【结果】草甘膦对杉木幼苗的生长发育产生影响,在高浓度草甘膦处理下,杉木幼苗生物量增量显著低于对照,同时叶片出现黄化现象。不同浓度草甘膦处理下杉木幼苗叶片生理学指标表现为:随着草甘膦浓度增加,叶片相对电导率、MDA含量、SOD活性、POD活性、脯氨酸含量总体均呈上升趋势,可溶性蛋白呈下降趋势,叶绿素a、叶绿素b和叶绿素总量均先升后降,而莽草酸含量无显著变化。草甘膦对杉木根系和叶片元素的吸收和利用影响显著,随着草甘膦浓度增加,杉木幼苗根系Cu、Mg和Ca含量均呈上升趋势。杉木叶片Cu含量增加,Mn含量先上升后下降,Zn含量则呈先降后增。【结论】高浓度草甘膦对杉木生长有负面作用,造成杉木幼苗生理紊乱,引起其养分吸收失衡,最终导致杉木幼苗生长量和成活率降低,因此在林业除草过程中应合理控制草甘膦用量,且在抚育过程中喷施草甘膦应远离杉木根系,以减少根系对草甘膦的吸收,降低其不利影响。
[ Objective ] Glyphosate is usually more or less left over forest land after using for weeding. To explore effects of the glyphosate residues on Chinese fir, a pot experiment was conducted to determine the physiological mechanism of Chinese fir in responses to residual glyphosate in soil, and the effect of glyphosate on the nutrient uptake of Chinese fir. This study aimed to provide the theoretical basis for the rational application of glyphosate in forestry production, and to provide the basic data for the sustainable management of Chinese fir plantation. [ Method] Chinese fir seedlings were planted in sand with addition of different glyphosate levels (0, 2, 5, 10, 20, 50 mg~ kg-1 ). Morphological and physiological features of Chinese fir were measured, and the nutrient content was determined. [ Result ] The results showed that under high concentrations of glyphosate, biomass of Chinese fir significantly decreased compared to the control (P 〈 0.05 ), and fir leaves showed chlorosis. At glyphosate level of 50 mg ~ kg-1, seedlings all died. Physiological parameters of seedlings showed that increasing glyphosate levels led to increased relative conductivity, MDA content, SOD activity, and POD activity in leaves, and decreased pi'oline and soluble protein content. Chlorophyll a, chlorophyll b and total chlorophyll content first rose then declined, while shikimic acid content showed no significant change. The macro and micronutrient accumulation in roots and leaves of Chinese fir seedlings were affected by glyphosate. With the increase in glyphosate, Cu, Ca and Mg levels increased in the roots, while there was no significant change in the accumulation of Mn, Fe and Zn. In addition, the accumulation of Cu in Chinese fir leaves increased and Mn increased first and then decreased, and Zn increased after decline. [ Conclusion] Overall, we found that glyphosate had negative effect on Chinese fir growth, led to physiological disorder, disturbed plant nutrient absorption, and negatively influenced seeding growth