Indian Journal of Plant Physiology

The aim of this experiment was to select suitable drought tolerant agroforestry tree species. The findings of this investigation indicated that summer drought from April to June for 25, 50 and 75 days during first and second year after transplanting adversely but differentially affected growth and physiological attributes of five tree species namely, Grewia optiva, Morus alba, Dalbergia sissoo, Acacia catechu and Populus deltoides. Plant height, collar diameter and leaf biomass were less in water stressed plants compared to unstressed plants within each tree species and within each drought level. In general, 75 days of drought exerted more pronounced effect on the performance of tree species. The minimum adverse effect of summer drought was seen on M. alba and D. sissoo, while the maximum on G. optiva and P. deltoides. Xylem water potential was significantly higher in unstressed plants compared to water stressed plants of all the five tree species. The water potential (ψ) in water stressed plants during second summer drought was higher compared to first summer drought. The lowest potential was recorded at 75^th day of drought. M. alba and D. sissoo maintained relatively high xylem water potential under water stress, whereas G. optiva and P. deltoides recorded the lowest values. Reduction in photosynthesis under drought over control was least in M. alba and D. sissoo, whereas maximum in stressed plants of P. deltoides up to 75^th day of drought. Drought injury index was minimum inM. alba (40.4%), followed by D. sissoo (52.1%) up to 75^th day.P. deltoides exhibited maximum injury index during the summer drought (83.8%).