اثر تنش اسمزی بر برخی خصوصیات فیزیولوژیکی ارقام گندم

This study was conducted to evaluate the effect of osmotic stress on physiological characters of wheat cultivars as a factorial experiment based on completely randomized design with three replications in 2012 at the Mohaghegh Ardabili University. Twenty wheat cultivars studied in three stress levels (control, -6 and -12 Bars). Analysis of variance showed that the stress had significant effect on all traits, except of carotenoids, chlorophyll b and quantum yield. Comparisons of means by Duncan method at one percent probability level showed that increasing of osmotic stress increased averages of soluble sugar, proline and chlorophyll a in most cultivars. But, the average of chlorophyll fluorescence, maximum fluorescence (Fm), variable fluorescence (Fv) and carotenoids were decreased in more varieties such as Tajan, Gascogen, Mihan, Rasool, Gaspard and ­Roshan (­winter type back­ cross) in compared with control level. Also, mean of quantum yield and chlorophyll b were greate in most varieties such as Arta and ­Roshan in -6 bar osmotic stress level. According to cluster analysis results based on physiological traits in control level, the varieties of Zarrin, Inia, Arta, Moghan1, Tajan and Shiroodi had high deviation from total mean for most of traits. In -6 bar osmotic stress, the varieties of Mihan, Shiroodi, Arg, Tous, Orum, Kavir, Moghan3 and ­Roshan (­winter type back­ cross) and in -12 bar osmotic stress, the varieties of Mihan, Gascogen, Mihan, Moghan2 and Rasool categorized in tolerant varieties groups.