Effect of shade on the leaflet morphology of wild Pistachio sapling under drought stress

In this research, the effects of drought stress and shade on leaflet morphology of wild pistachio (Pistacia atlantica subsp. Mutica) saplings were evaluated in Albroz Research center (Karaj, Iran) in the summer of 2014. One-year pot wild pistachio saplings were treated by soil humidity (including 100%, 50% and 20% of field capacity) and artificial shading (including 0%, 30% and 50% of full sunlight) factors in a split plot experiment based on a randomized complete block design. After 5 months, terminal leaflet of the leaves was collected from different crown aspects and the morphological variables of leaflets were measured and calculated. Results showed that drought stress reduced the leaf area (LA), length, width, length to width ratio, perimeter, from factor and specific leaf area (SLA). Shade reduced the thickness and increased the LA and SLA of leaflets. The interaction of drought stress and shade on the SLA was significant which indicates that the response of the leaflet to shade depends on the amount of soil moisture, so that the addition of the shade reduced the effect of drought stress on this variable. In general, the results showed that the morphological characteristics of leaflets can be considered as feasible and important indicators of variation in soil moisture and light availability.