Drought stress responses of seedlings of two oak species ( Quercus cerris and Quercus robur )

Authors : Ayşe DELİGÖZ, Esra BAYAR

Pages : 114-123

View : 14 | Download : 7

Publication Date : 2018-04-01

Article Type : Research Paper

Abstract :Effects of drought stress on growth, predawn xylem water potential insert ignore into journalissuearticles values(ψ pd );, osmotic solutes insert ignore into journalissuearticles values(soluble sugar and proline);, and stomatal conductance were assessed in two oak insert ignore into journalissuearticles values( Quercus cerris L. and Quercus robur L.); seedlings. Seedlings of both species were subjected to three drought treatments with the following irrigation intervals: well-watered insert ignore into journalissuearticles values(control: irrigation every 2-3 days);, moderate drought stress insert ignore into journalissuearticles values(irrigation every 15 days);, and severe drought stress insert ignore into journalissuearticles values(irrigation every 30 days);. Drought-stressed seedlings of Q. cerris and Q. robur had more negative predawn xylem water potential than their well-watered seedlings. In Q. cerris , root collar diameter and root dry weights were negatively influenced by drought, while height, shoot dry weight, and root:shoot ratios were unaffected. Height and shoot dry weight of drought-stressed Q. robur were decreased, while root:shoot ratio increased. Drought caused significant decreases in stomatal conductance of both species. Q. cerris seedlings sustained higher stomatal conductance compared with Q. robur . Proline and soluble sugar increased in response to drought stress. Q. robur had a higher proline accumulation than Q. cerris . These findings suggested that the Q. cerris and Q. robur seedlings showed a drought stress adaptive mechanism either by restricting their growth or increasing root:shoot ratio or by decreasing water loss insert ignore into journalissuearticles values(reduced stomatal conductance); and accumulating of osmotic solutes.
Keywords : Growth, osmotic adjustment, proline, Quercus, stomatal conductance, water potential