A Leaf Disc Assay for Evaluating the Response of Tea (Camellia sinensis) to PEG-Induced Osmotic Stress and Protective Effects of Azoxystrobin against Drought.

Yu-Chieh Chiu,Chang-Chang Chen,Bo-Jen Chen,Yen-Shuo Su,Wen-Dar Huang

doi:10.3390/plants10030546

Abstract

Tea (Camellia sinensis), 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 (Fv/Fm), 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−1) 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−1) reversed Fv/Fm, 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.

Highlights

Introduction published maps and institutional affilTea (Camellia sinensis) is an important beverage crop with expanding plantation areas and boosting production in the world [1]
Components of chlorophyll fluorescence can be used to evaluate the status of photosystem II (PSII) in plant tissue
The response of Fv /Fm in leaf discs collected from PEG-induced osmotic stress for a period of 5 days is presented in Figures 1A and 2A

Summary

Introduction

Tea (Camellia sinensis) is an important beverage crop with expanding plantation areas and boosting production in the world [1]. Tea plants are cultivated in a wide range of climatic environments, tea plants prefer a warm and humid climate. In. Taiwan, tea is the most important beverage crop, and C. sinensis var. Sinensis is the major cultivated tea variety that contributed to over 90% of tea production. Sinensis) cultivar “Taiwan Tea Experiment Station No. (TTES No.12)”, which is called “Jhinhsuan”, is one of the most widely grown tea cultivars in Taiwan. Areas receiving less than 1250 mm rainfall per year are inadequate for industrial production, major nations of tea cultivation are iations

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Conclusion