Lavin Babaei; Mohammad Mehdi Sharifani; Reza Darvishzadeh; Naser Abbaspour; Mashhid Henareh
Abstract
To investigate photosynthetic response of some pear (Pyrus spp.) species to drought stress, a pot experiment was conducted using as factorial experiment based on completely randomized design (CRD) with three replication under greenhouse condition. The factors included five pear species including: P. ...
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To investigate photosynthetic response of some pear (Pyrus spp.) species to drought stress, a pot experiment was conducted using as factorial experiment based on completely randomized design (CRD) with three replication under greenhouse condition. The factors included five pear species including: P. biossieriana, P. communis, P. glabra, P. salicifolia and P. syriaca and three levels of drought stress [(100%, 60% and 30% of field capacity (FC)]. According to the obtained results, different levels of drought stress significantly restricted morphological and physiological responses in all studied species. Increasing drought stress intensity reduced leaf relative water content (RWC), net photosynthetic rate, stomatal conductance, transpiration rate and intercellular carbon dioxide concentration when compared to their values in control plants. However, root/shoot dry weight ratio, specific leaf weight and stomatal density per unit of area were increased. In P. glabra exposed to severe stress (30% of FC), the values of root/shoot dry weigh ratio (0.85 g), specific leaf weight (23 mg cm-2), stomata density per unit of area, relative water content (73%) and net photosynthetic rate (3.9 µmol CO2 m-2 s-1) were significantly higher than the other species. P. syriaca, P. salicifolia, P. biossieriana and P. communis were placed in the next ranks, respectively based on their response to drought. In conclusion, P. glabra is reported as a more effective species in mitigating the adverse effects of drought by boosting its protective mechanisms than the other pear species.
Nasser Abbaspour; Lavin Babaee
Abstract
Adaptation and defense responses are the consequences of exposure to drought stress in plants. Salicylic acid (SA) as a natural signaling molecule poses a significant impacts on various aspects of plant growth and development. This study investigates the effects of SA on carotenoids content, lipid peroxidation ...
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Adaptation and defense responses are the consequences of exposure to drought stress in plants. Salicylic acid (SA) as a natural signaling molecule poses a significant impacts on various aspects of plant growth and development. This study investigates the effects of SA on carotenoids content, lipid peroxidation rate and antioxidant enzymes activities. A pot experiment was conducted using a factorial pattern based on a randomized complete block design with three replications under greenhouse conditions. The variables in the experiment included grapevine cultivars (‘Rasheh’ and ‘Bidane Sefid’), irrigation periods (5, 10 and 15 day intervals) and SA concentrations (0, 1 and 2 mM). Results showed that with increasing the drought stress levels, increase in carotenoids, malondialdehyde (MDA) contents, catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) enzymes activities were detected. Carotenoids content, catalase (CAT) and ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) enzymes activities were higher in the Rasheh cultivar compared with the ‘Bidane Sefid’ cultivar. Carotenoids content, CAT, APX and GPX enzymes activities increased by application of salicylic acid. . According to the obtained results, the Rasha cultivar showed a greater tolerance to water stress in comparison with Bidane Sefid cultivar, suggesting that SA is capable of inducing drought stress tolerance in plants.
