The rates of photosynthesis, chlorophyll content, dark respiration, proline and abscisic acid (ABA) in wheat (Triticum durum) under water deficit conditions

Abstract

A controlled environment pot experiment was conducetd to evaluate the effects of water stress on wheat crop. A number of parameters were estimated; two physiological functions; photosynthesis and dark respiration, two osmolytes (amino acid & free proline & Abscisic acid ABA) and the chlorophyll contents. Four cultivars of wheat used in this study were Al-gaimi, Sindy-1, Sindy-2 and Hab-ahmar. The plants were subjected to three water regimes (1) well-waterd plants at 80% of the field capacity of soil (FC) and two levels of water stress; (2) moderate stress at 50% FC and (3) severe stress at 30% FC. The water stress reduced the photosynthesis rates in Hab-ahmar and Sindy-2, but not in Al-gaimi and Sindy-1. The dark respiration was increased as a result of water stress in all cultivars, except Hab-ahmar. Chlorophyll content was reduced in all cultivars, except Al-gaimi. Both free proline and ABA showed generally an increase under water stress conditions. The differences between the wheat varieties in tolerance to water stress are discussed. © 2011 Friends Science Publishers