EFFECTS OF WATER DEFICIT AND SALT STRESS ON SOME PHOTOSYNTHESIS PARAMETERS IN WHEAT AND AEGILOPS COMOSA LINES

Abstract

Photosynthetic responses of Aegilops comosa genotypes were compared to those of wheat Mv9kr1 and Chinese spring in order to verify whether Ae. comosa TA2760 and MvGB1039 genotypes are potentially suitable gene sources for improving the drought and salt tolerance of bread wheat. Although there are some differences between the non-stressed plants and the measure of the decrease of the net-photosynthesis (P N ), it was strongly inhibited by water deficit. Salt stress had similar effect on P N but at the highest (300 mM) NaCl concentration P N of the genotypes showed some activity. Severe drought induced a strong decrease in the effective quantum yield of PS II (ɸ PSII ) in the genotypes, while it was moderate in the case of salt treatment. Moreover, ɸ PSII was unaffected by the increase of NaCl concentration in wheat lines. Parallel with the decrease in ɸ PSII , the photoprotective mechanisms were enhanced in the wheat and wild wheat genotypes during water deficit. These results suggest that the Ae. comosa genotypes seem to respond to these stress factors with similar photosynthetic activity to the wheat lines. Thus, based on the above-mentioned facts, the examined Ae. comosa lines are not particularly good candidates for improving drought tolerance of wheat.