Chiu Yu-Chieh, Chen Bo-Jen, Su Yen-Shuo, Huang Wen-Dar, Chen Chang-Chang
Department of Agronomy, National Taiwan University, Daan, Taipei 101, Taiwan.
Tea Research and Extension Station, New Taipei 22391, Taiwan.
Plants (Basel). 2021 Mar 13;10(3):546. doi: 10.3390/plants10030546.
Tea (), a globally cultivated beverage crop, is sensitive to drought, which can have an adverse effect on the yield and quality of tea. Azoxystrobin (AZ) is one kind of fungicide considered as an agent to relieve damage caused by stress. Initially, the response of tea plant to osmotic-gradient stress was evaluated using leaf disc assays with PEG-induced osmotic stress. The decline of the maximum quantum yield of PSII (F/F), actual photosynthetic efficiency of PS II (Y(II)), total chlorophylls, carotenoids, DPPH radical scavenging capacity, reducing power, total phenols, and the increase in MDA was observed in leaf discs treated with a gradient of PEG solutions (22.8, 33.2, 41.1% PEG, and blank). These results revealed that efficiency of photosystem II (PSII), photosynthetic pigments, and antioxidant ability in leaf discs were inhibited with an aggravated lipid peroxidation under PEG-induced osmotic stress, and indicated leaf disc assay with moderate PEG iso-osmotic condition would reflect a portion of tea plant response to drought stress. Therefore, the protective effect of AZ (0.125 and 1.25 g a.i. L) on tea plants suffering from drought was evaluated using leaf disc assays with 22.8% PEG iso-osmotic condition. Pretreatment of AZ (0.125 a.i. g L) reversed F/F, Y(II), DPPH radical scavenging capacity, and reducing power with reduced MDA in PEG-treated leaf discs, but photosynthetic pigments, total phenols, and ascorbate peroxidase activity were irresponsive to AZ. An Alleviated physiological damage in tea leaf with AZ applying was preliminarily revealed in this study. A Rapid screening of agents for tea plants against drought was developed to assist in the selection of protective agents.
茶叶是一种全球广泛种植的饮料作物，对干旱敏感，干旱会对茶叶的产量和品质产生不利影响。嘧菌酯（AZ）是一种被认为可缓解胁迫造成损害的杀菌剂。最初，利用聚乙二醇（PEG）诱导的渗透胁迫叶盘试验评估茶树对渗透梯度胁迫的响应。在用不同梯度PEG溶液（22.8%、33.2%、41.1%PEG以及空白对照）处理的叶盘中，观察到PSII最大量子产率（F/F）、PSII实际光合效率（Y(II)）、总叶绿素、类胡萝卜素、DPPH自由基清除能力、还原力、总酚含量下降，丙二醛（MDA）含量增加。这些结果表明，在PEG诱导的渗透胁迫下，叶盘中光系统II（PSII）的效率、光合色素和抗氧化能力受到抑制，脂质过氧化加剧，这表明在中等PEG等渗条件下的叶盘试验能反映茶树对干旱胁迫的部分响应。因此，利用22.8%PEG等渗条件下的叶盘试验评估了AZ（0.125和1.25 g a.i. L）对遭受干旱的茶树的保护作用。AZ（0.125 a.i. g L）预处理可使PEG处理的叶盘中F/F、Y(II)、DPPH自由基清除能力和还原力恢复，MDA含量降低，但光合色素、总酚和抗坏血酸过氧化物酶活性对AZ无反应。本研究初步揭示了施用AZ可减轻茶叶的生理损伤。开发了一种快速筛选茶树抗旱剂的方法，以协助选择保护剂。
