PJB-2017-501
PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES IN SOME ALMOND GENOTYPES (GRAFTED ON/GN15) SUBMITTED TO DROUGHT STRESS
HOSSEIN FATHI
Abstract
The concept of physiological and biochemical responses of plants to drought conditions is important for improving water-use efficiency (WUE). In this research some physiological characteristics including: relative water content (RWC), leaf water potential (?w), photosynthesis rate (PN), gas exchange (gs), leaf temperature (?T), electrolyte leakage (EL) of five almond genotypes grafted on/ GN15 rootstock, which submitted to drought stress were studied. Drought tolerance according to some parameters was distinguished in different genotypes. In all genotypes, as the level of water stress increased, relative water content (up to 32%), leaf water potential (up to -3.38Mpa), photosynthesis rate (up to 70%) and leaf stomatal conductance (up to 75% ) significantly decreased; whereas, electrolyte leakage (up to 53%), and leaf temperature increased. Water deficit significantly promoted water use efficiency (WUE) up to 7 folds in the drought tolerant genotypes. The differences of leaf temperature in the early morning and midday (?T) significantly decreased in drought tolerant genotypes. Significant correlation between ?T, PN and gs was found. We suggested that ?T could be used as a simple measurement for determining water stress in almond genotypes and monitoring water stress in the irrigation management of almond orchards. Finally, it can be concluded that in comparison, �Ferragness� cultivar, �Sahand� and H genotypes on GN15 rootstock could be acted more efficiency than other genotypes under severe drought stress, which is related to decrease in stomatal conductance and more ability to maintain RWC.
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