Investigation of 5-aminolevolinic acid (ALA) effects on seed germination and seedling growth of Silybum marianum under salinity stress

Abstract

Salinity is a major environmental stress which adversely affects germination and seedling establishment in a wide variety of crops. However, studying of seeds with different plant growth regulators may helpful to alleviate the deleterious effects of salinity and enhance germination and seedling growth in salt stress environment. In present experiment we investigated the effects of 5-Aminolevolinic Acid (ALA) on germination and seedling growth parameters of milk thistle grown at different salinity levels. The experiment was arranged in factorial experiment in randomized complete block design with three replications. Results revealed that all parameters were significantly affected by salinity conditions and concentrations of ALA. In general, all parameters decreased with increasing NaCl concentrations, however the amount of these parameters increased with increasing ALA concentration. In addition, different between 0.25 and 0.50mM was not significant for germination percentage, shoot length, seedling fresh weight, seedling dry weight and leaf length. Interaction effects showed that highest value of root length and leaf length were produced from the 0.25 and 0.50mM ALA under the control treatment of salinity level. In contrast, the highest amount of seedling fresh weight were obtained from 0.25 and 0.50mM concentrations of ALA under control treatment of salinity. In general, our results suggest that ALA at low concentrations (0.25-1mM) has the potential to improve salt tolerance in milk thistle seedlings through concentrations treatment. We hope ALA may be useful in helping to solve serious problems occurring on a global scale, such as the desertification of green lands and salt damage to farm lands.