Effects of different levels of glycine in the nutrient solution on the growth, nutrient composition, and antioxidant activity of coriander (Coriandrum sativum L.)

A nutrient solution experiment was performed using sand culture to evaluate the effects of different glycine levels on the growth and nutrient uptake of coriander ( Coriandrum sativum L.). Different glycine concentrations of 0, 5, 10, 20, or 40 mg L −1 were applied to plants via Hoagland’s nutrient solution in a completely randomized design with four replications and under greenhouse conditions. The results showed that leaf SPAD (soil and plant analysis development; an indicator of leaf greenness) value, stem diameter, and fresh and dry weights of shoots and roots were significantly increased by 10 mg L −1 glycine in comparison to the control plants. Application of glycine at 40 mg L −1 reduced many plant growth parameters, whereas leaf proline concentration was increased. All glycine levels except for 40 mg L −1 increased root fresh weight. Leaf protein content was increased by glycine applied at 10 or 20 mg L −1 , whereas leaf antioxidant activity was increased at all glycine levels. Application of glycine increased leaf concentrations of nitrogen and potassium (at 10 mg L −1 ), magnesium (at 5 mg L −1 ), and zinc (at all glycine levels) compared to the control plants. The results indicate that moderate level of glycine (10 mg L −1 ) in the nutrient solution can improve the growth and nutritional quality of coriander.