Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, China.
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, China.
Plant Physiol Biochem. 2018 Nov;132:652-659. doi: 10.1016/j.plaphy.2018.10.009. Epub 2018 Oct 10.
Our previous results showed that content of trans-zeatin (tZ) increases in leaves of heavy metal hyperaccumulators but decreases in non-hyperaccumulators growing in multiple heavy metal polluted soils. However, the relationship between arsenic (As) accumulation and endogenous forms of cytokinins (CTKs) in As hyperaccumulators remains unknown. Here a hydroponic experiment was conducted to compare the CTK forms in the As hyperaccumulator Pteris cretica var. nervosa and non-hyperaccumulator Pteris ensiformis under arsenate stress (0, 2, 5, and 10 mg L). A simple and cost-effective procedure for the determination of CTK forms in plants was established, and a stepwise regression analysis was used to study the relationship among total As contents and different forms of endogenous CTKs in fronds of two plants. The results showed that the optimized chromatographic parameters were Zobax SB-C18 column (5 μm × 4.6 mm × 250 mm), UV detection detector at 269 nm, a flow rate of 0.6 mL min, constant temperature of 45 °C and gradient elution with methanol-acetonitrile-1% acetic acid. Contents of chlorophylls in the fronds of P. ensiformis were significantly decreased with addition of As compared to P. cretica var. nervosa. Furthermore, the total As content in fronds of P. cretica var. nervosa was positively correlated to the contents of N6-(2-isopentenyl) adenine-7-β-D-glucoside (iP7G) and N6-(2-isopentenyl) adenosine (iPR). However, the total As content in fronds of P. ensiformis was negatively correlated to its trans-zeatin riboside (ZR) content. Therefore, iP7G and iPR could positively improve As accumulation by P. cretica var. nervosa.
我们之前的研究结果表明，在生长于多种重金属污染土壤中的重金属超积累植物的叶片中，反式玉米素（tZ）的含量增加，而非超积累植物的含量则降低。然而，砷（As）超积累植物中砷积累与细胞分裂素（CTKs）内源形式之间的关系仍不清楚。在这里，我们进行了一项水培实验，以比较砷酸盐胁迫（0、2、5 和 10mg/L）下砷超积累植物蜈蚣草（Pteris cretica var. nervosa）和非超积累植物凤尾蕨（Pteris ensiformis）中的 CTK 形式。建立了一种简单且具有成本效益的植物 CTK 形式测定方法，并采用逐步回归分析研究了两种植物叶片中总 As 含量与不同形式内源性 CTK 之间的关系。结果表明，优化的色谱参数为 Zobax SB-C18 柱（5μm×4.6mm×250mm）、269nm 紫外检测、流速 0.6mL/min、45°C 恒温、甲醇-乙腈-1%乙酸梯度洗脱。与蜈蚣草相比，砷处理后凤尾蕨叶片中的叶绿素含量显著降低。此外，蜈蚣草叶片中的总 As 含量与 N6-（2-异戊烯基）腺嘌呤-7-β-D-葡萄糖苷（iP7G）和 N6-（2-异戊烯基）腺苷（iPR）的含量呈正相关。然而，凤尾蕨叶片中的总 As 含量与其反式玉米素核苷（ZR）含量呈负相关。因此，iP7G 和 iPR 可能通过蜈蚣草提高 As 的积累。
