Effect of rootstocks on leaf water potential, water relations, antioxidant activities and drought tolerance in flemish beauty pear under water stress conditions

A study was conducted to investigate the effect of two Pyrus seedling rootstocks [Kainth (Pyrus pashia Buck and Ham.), Shiara (Pyrus serotina Redh.) and three clonal quince (Cydonia oblonga Mill) rootstocks [BA 29, Quince A and Quince C] on growth, water relations and antioxidant activities of one-year-old Flemish Beauty pears at −0.5 bars and −10.0 bars (water-stress) of soil moisture levels. Plant height, shoot and root dry weights of plants on different rootstocks decreased markedly by water stress. Plants on Kainth and BA 29 rootstocks were less affected under water stress than those on other rootstocks. Plants on Kainth and BA 29 rootstocks maintained higher leaf water potential and showed less reduction in stomatal conductance and photosynthetic rate. These plant accumulated more soluble sugar, ascorbic acid and proline content in their leaves in comparison to plants on other rootstocks under water stress conditions. The antioxidant enzymes (catalases, peroxidases and superoxide dismutase) activities increased significantly under water stress and increase was higher in plants on Kainth and BA 29 rootstocks than those on other rootstocks. The results suggest that plants on Kainth and BA 29 rootstocks exhibit better protection mechanism against oxidative damage under water stress conditions than those on other rootstocks.