Influence of Exogenous Glycinebetaine Application on Improving Chilling Tolerance in Corn Seedlings (Zea mays L.)

Glycinebetaine (GB) as an osmoprotectant plays an important role in improving plant resistance to abiotic stresses. In order to assess the effect of GB spray on enhancing chilling tolerance in corn plants, an experiment with 7 concentration treatments (0, 2.5, 5, 10, 25, 50 and 100 mM) of glycinebetaine was carried out as randomized complete block design with three replications. Corn plants were sprayed by corresponding GB concentrations at 2 to 3- leaf stage and then were exposed to low temperature of 4ºC for 3 days. Following the chilling stress period, plants were located in the room temperature (25 ± 5ºC). Results showed that seedlings sprayed with GB concentrations of 10-100 mM were visually in a better status and more tolerant to chilling injuries. Moreover, chlorophyll content and root and shoot dry weight of seedlings sprayed with this range of GB were significantly higher than those sprayed with distilled water. In addition, electrolyte leakage was effectively declined by spraying the seedlings with GB in the range of 10-50 and further increase in GB concentration significantly enhanced electrolyte leakage. In total, the foliar application of GB resulted in relative improvement of chilling tolerance in corn seedlings.