Bhupendra Koul, Devindra Vijay Amla, Indraneel Sanyal, Ruchi Singh
Plant Transgenic Lab, CSIR-National Botanical Research Institute, P.O. Box 436, Rana Pratap Marg, Lucknow-226 001, India
Plant Physiology Lab, CSIR-National Botanical Research Institute, P.O. Box 436, Rana Pratap Marg, Lucknow-226 001, India
Key words: Cicer arietinum (L.), Water stress, Terminal drought, Relative water content, Leaf water potential, Photosynthesis rate
Drought is one of the major abiotic stresses in agriculture for losses in crop productivity worldwide. Three chickpea (Cicer arietinum L.) varieties namely P362, P1103 and SBD377 were assessed for response to drought tolerance during vegetative stage, in stress and non-stress environments, under contained conditions. Several physiological parameters including gas exchange, photosynthesis rate, fluorescence, stomatal conductance and water loss per day were monitored simultaneously. P362 variety showed maximum photosynthesis rate in irrigated as well as in drought conditions. This variety also maintained its relative water content (RWC) and water potential (WP) during imposition of similar duration of drought. Due to the maximum elasticity of leaf cells, it maintained its cell turgidity upto 68% RWC to protect itself from water stress, compared to variety P1103 and SBD377. The effective solute concentration and osmotic potential in the irrigated controls at full turgor was lowest in P362 variety, compared to the other two varieties. Osmotic adjustment (OA) was assessed as a capacity factor which is rate of change in turgor pressure with RWC. P362 variety showed a maximum OA value of 0.27 while the values for SBD377 and P1103 were 0.22 and 0.21, respectively. During water stress, the chlorophyll content was minimally reduced in P362 variety, therefore effective quantum yield of photosystem II (Fv/Fm) and photosynthesis rate was maximally maintained. The higher photosynthesis rate under irrigated conditions and maintenance of higher RWC under drought conditions makes P362 variety a promising option for optimum yield under prolonged terminal drought or under rain-fed conditions.
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