Vegetative and physiological responses of purple seedlings to water stress

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Article Type:
Research/Original Article (دارای رتبه معتبر)
Abstract:
To investigate the effect of drought stress on the vegetative, physiological, and biochemical characteristics of purple seedlings, an experiment was conducted in the form of a completely randomized design with four levels of irrigation including 75% (mild stress), 50% (medium stress) and 25% (severe stress) of the field capacity (FC) and the control (100% FC) in greenhouse conditions. The results showed that severe drought stress significantly reduced vegetative traits such as seedling height growth (86.8%), the number of leaves, and total fresh and dry biomass by 93%, 46.2%, and 44.8%, respectively, but increased root volumetric growth (1034%). Also, drought stress affected all parameters of gas exchange and photosynthetic pigments. So that at the level of 25% FC, it caused a significant decrease in the rate of photosynthesis (1/20 µmolCo2m-2s-1), transpiration (0/65 mmolm-2s-1), stomatal conductance (106/2 mmolm-2s-1) and mesophilic (0/0088 mmolm-2s-1), intracellular carbon dioxide concentration (134/2 mmolCO2 m-2s-1) and carboxylation efficiency (0/00112 µmolCO2 mol-1H2O). The amount of photosynthetic pigments (chlorophyll a, b, total chlorophyll, and carotenoids) also showed a significant decrease at 25% FC (4.07, 1.96, 6.03 and 1.23 mg g-1 FW, respectively.). Also, drought stress increased the amount of proline and soluble sugar and showed the highest values at the level of 25% FC (respectively, 1.348 µmol g-1 FW of proline and 41.51 mg g-1 FW of soluble sugar). According to the above evaluations, it seems that the purple variety can tolerate drought stress up to 75% FC without causing damage to the plant tissue, but if the amount of water is reduced to the threshold of 25% FC, its growth and performance will be severely affected.
Language:
Persian
Published:
Journal of Forest Research and Development, Volume:9 Issue: 3, 2023
Pages:
349 to 363
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