Physio-Biochemical Changes of Some Pistachio Rootstocks in Response to Drought and Recovery Periods

Abstract

The reduction of water resources in pistachio production areas of Iran has led to an increase in the frequency of irrigation, so the pistachio trees are continuously exposed to periods of drought and recovery after irrigation during the growing season. Choosing rootstocks that have the highest resistance to drought stress and the highest recovery speed can be considered as one of the basic strategies for facing such conditions. This experiment was carried out as factorial and in the form of a completely randomized design with three replications. The experimental factors were the type of rootstock in five levels and the sampling stage in three levels for destructive biochemical parameters and six levels for non-destructive chlorophyll fluoresce parameters. Drought stress was achieved by withholding irrigation for 15 days, and in the recovery phase, the pistachio seedlings were irrigated daily up to field capacity for 10 days. At the end of the experiment, shoot and root dry weights were measured. Evaluation of pistachio seedlings biomass showed that the periods of drought and recovery did not affect the dry weight of shoot and root and rootstock type was the only influencing factor. The highest amount of shoot and root dry weight was observed in lentisk (Pistacia lentiscus) and Bane-Baghi respectively, and the lowest amount was recorded in Bane and Sarakhs. Chlorophyll fluorescence indices were completely sensitive to drought stress and recovery. Dry period caused the measured biochemical parameters known as osmolytes to increase and the changes in these parameters were different in different rootstocks.

Keywords

• osmoregulation
• chlorophyll fluorescence
• chlorophyll pigments