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Mesophyll cells’ ability to maintain potassium is correlated with drought tolerance in tea (Camellia sinensis)

Zhang, Xianchen, Wu, Honghong, Chen, Linmu, Wang, Ningning, Wei, Chaoling, Wan, Xiaochun
Plant physiology and biochemistry 2019 v.136 pp. 196-203
Camellia sinensis, breeding, drought, drought tolerance, ion channels, leaves, mesophyll, potassium, stress tolerance, tea, water stress
Tea plant is an important economic crop and is vulnerable to drought. A good understanding of tea drought tolerance mechanisms is required for breeding robust drought tolerant tea varieties. Previous studies showed mesophyll cells’ ability to maintain K+ is associated with its stress tolerance. Here, in this study, 12 tea varieties were used to investigate the role of mesophyll K+ retention ability towards tea drought stress tolerance. A strong and negative correlation (R2 = 0.8239, P < 0.001) was found between PEG (mimic drought stress)-induced K+ efflux from tea mesophyll cells and overall drought tolerance in 12 tea varieties. In agreement with this, a significantly higher retained leaf K+ content was found in drought tolerant than the sensitive tea varieties. Furthermore, exogenous applied K+ (5 mM) significantly alleviated drought-induced symptom in tea plants, further supporting our finding that mesophyll K+ retention is an important component for drought tolerance mechanisms in tea plants. Moreover, pharmacological experiments showed that the contribution of K+ outward rectifying channels and non-selective cation channels in controlling PEG-induced K+ efflux from mesophylls cells are varied between drought tolerant and sensitive tea varieties.