水稻幼苗对纳米氧化铜的吸收及根系形态生理特征响应

以纳米氧化铜nano-Cu O(10,100mg/L)为研究对象,以微米氧化铜micron-Cu O(10,100mg/L)及铜离子Cu2+(1.4,2.3mg/L)为对照,通过水培实验,探讨水稻对nano-Cu O的吸收积累及其根系形态和生理特征响应.结果表明,各浓度(10,100mg/L)nano-Cu O处理条件下,水稻根部及地上部铜含量(根351~1444mg/kg dw;地上部9~45mg/kg dw)总体高于micron-Cu O处理(根248~817mg/kg dw;地上部1.57~1.60mg/kg dw)及Cu2+处理(根147~220mg/kg dw;地上部14~26mg/kg dw),且在水稻幼苗根及茎透射电镜图片中均观察到nano-Cu O的存在,指示水稻可通过纳米颗粒的形式吸收、转运nano-Cu O.Nano-Cu O在水稻根细胞中主要存在于核内体中,指示内吞作用是其进入根细胞的主要方式.Nano-Cu O对水稻幼苗根系有较强的毒性作用,对各根系形态指标的抑制率为28%~74%,其中总根长、根体积和比表面积为最敏感;nano-Cu O的吸收累积及纳米效应是其水稻根系毒性的主要原因.低浓度nano-Cu O(10mg/L)胁迫时,水稻幼苗根系活力显著提高,总吸收面积和活跃吸收面积无显著差异;高浓度nano-Cu O(100mg/L)胁迫时,水稻幼苗根系活力和总吸收面积显著降低.

Responses of morphological and physiological characteristics in rice (Oryza sativa L.) seedling roots to its uptake of CuO nanopaticles

Responses of morphological and physiological characteristics in rice (Oryza sativa L.) seedling roots to its uptake of nano-CuO (10, 100mg/L) were investigated using hydroponic experiments by setting micron oxide copper (micron-CuO) and copper ions (Cu2+) as control. Results showed that total copper contents in roots and shoots (roots 351~1444mg/kg dw; shoots 351~1444mg/kg dw) of rice seedlings in nano-CuO treatments (10, 100mg/L) were higher than those in micron-CuO treatments (roots 248~817mg/kg dw; shoots 1.57~1.60mg/kg dw) and Cu2+ treatments (roots147~220mg/kg dw; shoots 14~26mg/kg dw), and furthermore, nano-CuO was observed in TEM images of both root and stem cells, indicating rice seedling can uptake and transfer nano-CuO by the form of nano-CuO. A large amount of nano-CuOs observed in endosomes of rice seedling cells indicated that nano-CuO mainly relied on endocytic pathways to enter cell. The nano-CuO had toxic effects on rice seedling roots and the inhibitory rates on roots morphologies of nano-CuO ranged from 28% to 74%, and root length, root volume and root specific surface area were most sensitive indicators for nano-CuO toxicity. Both nano-CuO bioaccumulation in rice and nanoeffects resulted in toxicities of nano-CuO to rice seedling roots. Under low concentration of nano-CuO strees (10mg/L), root activities of rice seedlings significant improved but no significant differences were observed in its total roots absorbing area and actively absorbing area, compared with the control. Under high concentration of nano-CuO strees (100mg/L), root activities and total roots absorbing area of rice seedlings significantly decreased, compared with control.