Effect of low temperature stress on biochemical and physiological characteristics of some native genotypes of like-lime in the north of Iran

In this study, the vulnerability of six native genotypes of like-lime (1-6 number) with control tolerant variety of Unshiu and sensitive variety of Persian lime (to low temperature) were studied low temperature stress ( 3, 0, -3 and -6˚C), on physiological responses, in a completely randomized design with Tukey´s mean comparison. Analysis of variance showed that in the interaction between genotype and temperature, leaf water soaking, electrolyte leakage, lipid peroxidation, proline content and antioxidant capacity were significant. It was while in reaction of temperature and genotype, total carbohydrates, chlorophyll a, b, total and Carotenoids have not significant differences. Therefore, in comparison of data, the highest of leaf water soaking (91/628%), electrolyte leakage (99.3%) and lipid peroxidation (3.32 µgr/gr FW) were recorded in control sensitive plant (Persian lime) at temperature of -6˚C. Versus, the highest proline content (32.006 mg/gr leaf fresh Weight) and antioxidant capacity (73.36%) were observed in control tolerant plant (Unshiu) at temperature of -3˚C. It is noteworthy that total carbohydrate, chlorophyll a and total, were significantly different only under the influence of genotype factor. Accordingly, the maximum amount of chlorophyll a (2.359 mg/gr leaf fresh Weight), total chlorophyll (2.932 mg/gr leaf fresh Weight) and total carbohydrate (33.486 mg/gr leaf fresh Weight) were measured in in control tolerant plant (Unshiu). It should be noted that among the six native genotypes of like-lime studied, different reactions were recorded under low temperature. So that after control tolerant plant (Unshiu), native genotypes like-lime No. 6 showed better resistance against low temperature stress.