RESPONSES OF GROWTH, WATER RELATIONS AND COMPATIBLE SOLUTES CONTENTS TO REPEATED DROUGHT STRESS IN CEDRUS LIBANI


Deligoz A. , Bayar E. , Yazici N.

FRESENIUS ENVIRONMENTAL BULLETIN, cilt.25, ss.3760-3767, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 25 Konu: 9
  • Basım Tarihi: 2016
  • Dergi Adı: FRESENIUS ENVIRONMENTAL BULLETIN
  • Sayfa Sayıları: ss.3760-3767

Özet

In this study, to investigate the responses of Cedrus libani A. Rich seedlings to repeated drought cycles, morpho-physiological parameters of the seedlings were determined. The seedlings were conditioned by drought cycles which consisted in withholding irrigation until the predawn water potential (Psi(pd)) fell to -0.8 MPa (mild drought conditioning) or -2.1 MPa (severe drought conditioning). At the end of each drought cycle (once the target Psi(pd) level was reached), the seedlings were watered to field capacity. These drought cycles were continued for 13 weeks. The control (well-watered) seedlings were watered every 2 to 3 days throughout the experiment. Repeated drought stress caused a significant reduction in growth parameters such as height and dry weights (root, shoot and needle). Root collar diameter also reduced significantly in the severe drought-stressed seedlings compared to well-watered and mild drought stress. However, severe drought stress increased the root:shoot ratio. Repeated drought stress had no effect on water relation parameters such as osmotic potential at full turgor and at turgor loss point. In under severe and mild drought conditions, proline significantly increased. Cedrus libani seedlings showed the less growth, higher root/shoot ratio and proline accumulation as an adaptation mechanism against repeated drought stress.