College of Science, Northwest A&F University, Yangling 712100, China.
College of Life Sciences, Northwest A&F University, Yangling 712100, China.
Int J Environ Res Public Health. 2018 Jul 11;15(7):1467. doi: 10.3390/ijerph15071467.
Kenaf ( L.) with high tolerance to chromium (Cr) can be used in the phytoremediation of chromium-contaminated soil. However, the mechanisms of chromium accumulation and tolerance in kenaf are still unclear. A hydroponic experiment was taken to screen two kenaf cultivars with Cr tolerance among nine kenaf cultivars via a tolerance index. This is first time the ascorbate-glutathione (AsA-GSH) cycle and chloroplast structural changes involved in Cr tolerance of two kenaf cultivars are explored. This study indicated that enhancement of chromium concentrations reduced nine kenaf growth rates and plant biomass. In addition, in all the nine cultivars, the roots had higher Cr accumulation than the shoots. Cr-tolerant cultivar Zhe70-3 with the maximum tolerant index had the significantly higher enzymatic activities of ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and mono- dehydroascorbate reductase (MDHAR) in non-enzymatic antioxidant system compared to Cr-sensitive cultivar Zhe77-1. In addition, higher GSH and AsA contents and lower damages of chloroplast ultrastructure were observed in Zhe70-3 under Cr treatment. In conclusion, Cr stress can cause less oxidative stress and destruction of chloroplast ultrastructure in Cr-tolerant cultivar Zhe70-3, and the AsA-GSH cycle may play a crucial role in kenaf Cr tolerance.
苎麻（ L.）对铬（Cr）具有高耐受性，可用于受铬污染土壤的植物修复。然而，苎麻对铬的积累和耐受机制仍不清楚。本研究通过耐受指数，从 9 个苎麻品种中筛选出 2 个具有 Cr 耐受能力的苎麻品种进行水培实验。这是首次探讨了 2 个苎麻品种的抗铬机制中抗坏血酸-谷胱甘肽（AsA-GSH）循环和叶绿体结构变化。本研究表明，铬浓度的增加降低了 9 个苎麻品种的生长速度和生物量。此外，在所有 9 个品种中，根的 Cr 积累量均高于地上部分。具有最大耐受指数的 Cr 耐受品种 Zhe70-3 具有更高的非酶抗氧化系统中的抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）、脱氢抗坏血酸还原酶（DHAR）和单脱氢抗坏血酸还原酶（MDHAR）的酶活性。此外，在 Cr 处理下，Zhe70-3 中的 GSH 和 AsA 含量更高，叶绿体超微结构损伤更小。综上所述，Cr 胁迫下，Cr 耐受品种 Zhe70-3 中的氧化胁迫和叶绿体超微结构破坏程度更小，AsA-GSH 循环可能在苎麻的 Cr 耐受中起关键作用。
