Tropentag, September 17 - 19, 2014 in Prague, Czech Republic "Bridging the gap between increasing knowledge and decreasing resources"

Chlorophyll Fluorescence as a Tool for Evaluation of Drought Stress Tolerance in Iranian Pistachio Cultivars

¹Iran Pistachio Research Institute, Iran
²University of Ghent, Dept. of Plant Production, Belgium
³University of Antwerp, Dept. of Bioscience Engineering, Belgium

Abstract

Pistachio (Pistacia vera L., Anacardiaceae) is one of the major horticulture crops in Iran with high plantation surface areas, production and export rates. However, water deficiency has been becoming a main limiting factor for growth and development, and especially for maintaining yield quality and volume of this crop. In this study, the responses of chlorophyll fluorescence, carbohydrate content and a number of growth parameters of three Iranian pistachio cultivars (P. vera cv. Akbari, Kaleghochi and Ohadi) to different osmotic drought stress levels (-0.1, -0.75 and -1.5 MPa) and subsequent recovery were investigated in a greenhouse experiment held in Ghent, Belgium.
With increasing drought stress intensity, desired parameters were monitored during both drought stress build–up and subsequent recovery. Maximum quantum efficiency of PSII photochemistry (Fv/Fm), effective quantum yield (ΦPSII) and photochemical quenching (qP) decreased in drought-stressed plants in both drought and recovery stages. Non-photochemical quenching (NPQ) was not significant influenced after two weeks of drought stress. When comparing the different cultivars of pistachio, our results show that decreasing the solution's osmotic potential lowered Fv/Fm and NPQ in Akbari while no effect was observed for the other cultivars. There were no significant differences between ΦPSII and qP during drought stress build-up among the three cultivars.
For the drought treatments, we evidenced a significant accumulation of fructose, sucrose and starch in all cultivars during drought stress stage, whereas there was no significant accumulation of glucose compared to control. Total fresh and dry plant weights and leaf dry weight decreased significantly at all drought stress levels compared to control. The ratio of root/shoot and leaf dry weight increased in drought-stressed treatments. Stem elongation had a significantly higher value in control compared to drought stress treatments. Seedling main stem diameter did not vary significantly between drought stress treatments and control.
As overall conclusion, most of chlorophyll florescence parameters decreased in drought stress condition. Therefore, these parameters could be used as a tool to recognise the resistant or susceptible pistachio cultivars.

Keywords: Carbohydrate content, growth parameters, water deficiency

Contact Address: Ali Esmaeilpour, Iran Pistachio Research Institute
current address: University of Ghent, Dept. of Plant Production, Ghent, Belgium, e-mail: ali.esmaeilpourugent.be