Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China.
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China.
Ecotoxicol Environ Saf. 2018 Aug 30;158:37-43. doi: 10.1016/j.ecoenv.2018.04.009. Epub 2018 Apr 12.
Cytokinins (CTKs) are effective in alleviating abiotic stresses on plants, but little information is available regarding the effects of CTKs on arsenic (As) accumulation and changes of chloroplast ultrastructure in plants with different As-accumulating ability. Here a hydroponic experiment was designed to evaluate the effects of different concentration of kinetin (KT, 0-40 mg/L) on growth and chloroplast ultrastructure of As hyperaccumulator Pteris cretica var. nervosa and non-hyperaccumulator Pteris ensiformis treated by 5 mg/L arsenate for 14 days. The growth parameters, As accumulation, contents of photosynthetic pigments and chloroplast ultrastructure were examined. The results showed that KT promoted the growth of two plants, and significantly increased As accumulation and translocation in P. cretica var. nervosa and P. ensiformis at 5 and 20 mg/L, respectively. Additionally, the contents of chlorophyll a and carotenoid in two plants showed no significant difference at 20 mg/L KT compared to the control. Chloroplast ultrastructure of P. cretica var. nervosa was integral with KT application. Comparatively, the swollen chloroplasts were increased, plasmolysis appeared, and chloroplast grana slice layers and stroma lamellas were clearly separated or distorted at 5 mg/L KT in P. ensiformis. The length and width of chloroplasts in P. cretica var. nervosa were significantly increased with KT addition compared to the control. However, the length of chloroplasts in P. ensiformis was significantly decreased but their width showed no significant change. Furthermore, the deterioration of chloroplast ultrastructure in P. ensiformis was ameliorated by 40 mg/L KT. These results suggested that KT increased As accumulation and was beneficial to maintain the photosynthetic pigments for a good growth of plants. Therefore, KT could maintain and reorganize the ultrastructure integrality of As-stressed chloroplasts to some extent for the two plants, especially at high concentration.
细胞分裂素（CTKs）在缓解植物非生物胁迫方面效果显著，但关于 CTKs 对不同砷积累能力植物砷积累和叶绿体超微结构变化的影响的信息却很少。在这里，我们设计了一个水培实验，以评估不同浓度的激动素（KT，0-40mg/L）对 5mg/L 砷酸盐处理 14 天后的砷超积累植物蜈蚣草（Pteris cretica var. nervosa）和非砷超积累植物凤尾蕨（Pteris ensiformis）生长和叶绿体超微结构的影响。检测了生长参数、砷积累、光合色素含量和叶绿体超微结构。结果表明，KT 促进了两种植物的生长，并显著增加了 P. cretica var. nervosa 和 P. ensiformis 对砷的积累和转运，分别在 5 和 20mg/L 时达到最高。此外，与对照相比，两种植物在 20mg/L KT 时叶绿素 a 和类胡萝卜素的含量没有显著差异。KT 处理后 P. cretica var. nervosa 的叶绿体超微结构完整。相比之下，在 5mg/L KT 处理下，凤尾蕨的叶绿体膨胀，出现质壁分离，类囊体片层和基质片层明显分离或扭曲。与对照相比，KT 处理后蜈蚣草的叶绿体长度和宽度显著增加。然而，凤尾蕨的叶绿体长度显著减小，但宽度没有显著变化。此外，40mg/L KT 改善了凤尾蕨叶绿体超微结构的恶化。这些结果表明，KT 增加了砷的积累，有利于植物的良好生长维持光合色素的含量。因此，KT 可以在一定程度上维持和重组砷胁迫下叶绿体的超微结构完整性，特别是在高浓度下。
