اثر تنش یخ زدگی بر نشت الکترولیتها در شش رقم گلرنگ

Abstract

Accepted: 3-10-2009 Abstract Freezing stress affected some vital processes of plant, and causing the disturbance on plant growth. In order to study the effect of freezing stress on electrolyte leakage (EL) of safflower (Carthamus tinctorius) a factorial experiment carried out using six safflower genotypes (k.w.16, k.w.6, k.w.3, line 295, zarghan 295 and IL-111) and six freezing temperatures (0,-4,-8,-12,-16,-20 0C) on the base of completely randomized design with three replications in Fall 2006. For acclimation, potted plants were grown in natural conditions till 5-7 leaf stage and then, the plants were frozen according to the freezing temperature (FT) regimes. Cell membrane integrity was evaluated through EL and also lethal temperature 50 (LT50) according to the EL percentage of samples were determined. The effects of FT and genotypes on EL and LT50 were significant (P<0.05). EL increased on the all genotypes with decreasing the temperature lower than -40C. Line 295 and k.w.6 had the highest and the lowest EL, respectively. The greatest curve slops of EL were observed on the line 295 and zarghan 279 and they had the most EL at the -120C, on the other hand, the peak of EL for the other genotypes were started at -160C. According to the LT50, the k.w.6 and zarghan 279 were the most and the least freezing tolerant genotypes, respectively. There was a strong correlation (r = 76**) between EL and LT50, so using of this index for evaluation of freezing injury on safflower may be possible. Keywords: Electrolyte leakage, Freezing, LT50, Safflower