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Potassium improves photosynthetic tolerance to and recovery from episodic drought stress in functional leaves of cotton (Gossypium hirsutum L.)

Author:
Zahoor, Rizwan, Zhao, Wenqing, Dong, Haoran, Snider, John L., Abid, Muhammad, Iqbal, Babar, Zhou, Zhiguo
Source:
Plant physiology and biochemistry 2017 v.119 pp. 21-32
ISSN:
0981-9428
Subject:
Gossypium hirsutum, antioxidants, cotton, cultivars, drought, enzyme activity, leaf water potential, leaves, lipid peroxidation, photosystem II, potassium, proline, stomatal conductance, water stress
Abstract:
To investigate whether potassium (K) application enhances the potential of cotton (Gossypium hirsutum L.) plants to maintain physiological functions during drought and recovery, low K-sensitive (Siza 3) and -tolerant (Simian 3) cotton cultivars were exposed to three K rates (0, 150, and 300 K2O kg ha−1) and either well-watered conditions or severe drought stress followed by a recovery period. Under drought stress, cotton plants showed a substantial decline in leaf water potential, stomatal conductance, photosynthetic rate, and the maximum and actual quantum yield of PSII, resulting in greater non-photochemical quenching and lipid peroxidation as compared to well-watered plants. However, plants under K application not only showed less of a decline in these traits but also displayed greater potential to recover after rewatering as compared to the plants without K application. Plants receiving K application showed lower lipid peroxidation, higher antioxidant enzyme activities, and increased proline accumulation as compared to plants without K application. Significant relationships between rates of photosynthetic recovery and K application were observed. The cultivar Siza 3 exhibited a more positive response to K application than Simian 3. The results suggest that K application enhances the cotton plant's potential to maintain functionality under drought and facilitates recovery after rewatering.
Agid:
5829050