The effect of gamma-aminobutyric acid on leaf physiological and biochemical indices of two grape (Vitis vinifera L.) cultivars under cold stress

In this research, the effect of foliar application of gamma-amino-butyric acid (GABA; ۰, ۱.۵ and ۳ mM) on abscisic acid, soluble sugars, polyamines, the activity of some antioxidant enzymes, and membrane stability index of two grape cultivars (Khalili and Perlette) was investigated under greenhouse condition with two temperature treatments (۲ºC and ۲۴ºC) factorially (۲×۳) based on a completely randomized design with three replications. The vines were sprayed with different concentrations of GABA at the ۱۵-leaf stage. After ۲۴ hours, half of the vines treated with GABA along with the control plants were exposed to ۲ºC (cold stress condition) for ۱۲ hours and the rest vines (treated with GABA and control) were kept at ۲۴ºC (non-stress condition) and sampled after ۱۲ hours. The application of GABA under cold stress conditions caused a preservation of chlorophyll and a decrease of ion leakage, malondialdehyde and hydrogen peroxide and increase of protein, proline and abscisic acid content compared to control plants in both cultivars. The amount of sucrose, fructose and glucose in the leaves was higher in the treated Khalili cultivar compared to the Perlette cultivar under cold stress. Also, under cold stress, GABA spray led to an increase in the amount of polyamines of putrescin, spermine and spermidine. Under cold stress, the activities of superoxide dismutase and catalase enzymes at a concentration of ۳ mM and ascorbate-peroxidase at a concentration of ۱.۵ mM of GABA showed the highest value compared to the control plants. GABA treatment maintained membrane stability and increased cold tolerance of vines by increasing in abscisic acid content, soluble sugars and antioxidant system, The effect of GABA on the cold tolerance of Khalili cultivar was greater than that of Perlette cultivar.

کلیدواژه ها:

Abscisic acid ، Polyamines ، Glucose ، Catalase ، Ion leakage ، آبسیزیک اسید ، پلی آمین ها ، گلوکز ، کاتالاز ، نشت یونی