the effects of sucrose and some regulators on freezing tolerance in chickpea studied. four weeks in vitro explants were cultured in three different ms media without growth regulators and with normal level of sucrose (30 gl-1) (a), without growth regulators and with reduced sucrose (10 gl-1) (b) and medium supplemented with lmg gl-1 bap and 0.1 mgi1 iba and with 30 gi-1sucrose (c) for two weeks....

The snow-cover on soil, the factor that protects wheat from the biting cold, has generally declined; on the other hand, the surface air temperature has warmed. It is not clear whether these changes decrease winter-killing of wheat or favor it in Iran. Therefore, this study was mainly aimed to determine the past trend in frequency of winter-kill events (Y) for wheat with -4 oC frost tolerance, u...

Freezing injury is an important limiting factor in the production of pomegranate in Iran.The aim of the present study was to evaluate the effect of paclobutrazol (PBZ) on cold hardiness of pomegranate (Punica granatum L.) cv. ‘Malas Saveh’. Different concentrations of PBZ including 0 (control), 31, 62, 125 or 250 mg L–1 were sprayed on one-year-old plants in August and the electrolyte leakage o...

Cold stress adversely affects plant growth and development and thus limits crop productivity. Diverse plant species tolerate cold stress to a varying degree, which depends on reprogramming gene expression to modify their physiology, metabolism, and growth. Cold signal in plants is transmitted to activate CBF-dependent (C-repeat/drought-responsive element binding factor-dependent) and CBF-indepe...

Changes in the activities of four enzymes involved in antioxidative plant defence against low temperature treatment were studied in winter wheat plants (Triticum aestivum L cv. Sadovo 1) grown on acid soil (pH 4.2, KCl) under controlled environmental conditions. To investigate the effect of molybdenum (Mo) deficiency on antioxidative defence of these plants, Mo was added to part of the plants a...

                The value of frost tolerance in wheat is increased with decreasing the temperature in late autumn and/or early winter (phase I, acclimation), then shows plateau state for a period with the coldest temperature (II), finally appears to decrease with warming the temperature (III, de-acclimation). This study was aimed to determine the threshold frost hardiness in wheat for avoiding ...

The CMSII mutant of Nicotiana sylvestris, which lacks a functional mitochondrial complex I, was used to investigate chloroplast-mitochondria interactions in light acclimation of photosynthetic carbon assimilation. CMSII and wild-type (WT) plants were grown at 80 micromol m(-2) s(-1) photosynthetic active radiation (PAR; 80) and 350 micromol m(-2) s(-1) PAR (350). Carbon assimilation at saturati...

Dehydrins (DHNs) are typically induced in response to abiotic stresses that impose cellular dehydration. As extracellular freezing results in cellular dehydration, accumulation of DHNs and development of desiccation tolerance are believed to be key components of the cold acclimation (CA) process. The present study shows that RcDhn5, one of the DHNs from Rhododendron catawbiense leaf tissues, en...

Research has shown that some plants respond to enhanced UV-B radiation by producing smaller and thicker leaves, by increasing the thickness of epidermis and concentration of UV-B absorbing compounds of their surface layers and activation of the antioxidant defence system. The response of high-altitude plants to UV-B radiation in controlled conditions is often less pronounced compared to low-alt...