Effect of Gibberellic Acid (GA) on Carrot (Daucus carota L.) under Cadmium Chloride Stress

Abstract

Carrot (Daucus carota L.) is a very essential and highly nutritive vegetable of the world. It is extensively used all over the world due to its nutritional composition. Cadmium is the metal that affects various vegetables and gibberellic acid is a useful hormone against a variety of stress. In old botanical garden pot experiment was performed to check the effect of gibberellic acid under cadmium chloride stress at University of Agriculture Faisalabad. In plastic pots that contain sand the seeds of carrot T29 and red gold were sown. The experiment comprising of 3 levels of cadmium chloride (0, 200μM and 400μM) that were applied to the sand and as foliar spray two levels of gibberellic acid (0 and 0.1M) applied to plant exogenously. Under completely randomized design (CRD) the data for growth, activities of antioxidants, gas exchange, photosynthetic pigments and mineral nutrients was analysed. It was recorded that morphological parameters and photosynthetic pigments like chlorophyll a, chlorophyll b, chlorophyll ab and carotenoids decrease by the stress of cadmium chloride. The Cd stress (400μM) shows negative effect alongside the ionic attributes like N, P, and K ions reduced by level of 400μM application of cadmium chloride and spray of GAs (0.1M) shows positive effect on carrot using standard procedures. physiological parameters like Phenolics, Proline, Hydrogen peroxide and soluble sugars reduce by the stress of cadmium chloride (200μM). antioxidant attributes like SOD, POD, and CAT reduced by 400μM level of cadmium chloride. Overall Result showed that Cd effect all the way in plant life cycle hence it is concluded that by using 0.1M gibberellic acid provide best
result to overcome stress condition.