Comparison of heat tolerance of ten iris cultivars

An experiment was conducted to study the effect of 45°C high temperature stress on the antioxidant enzyme activity and non-enzyme substances in ten iris cultivars. Physiological and biochemical indexes, such as activities of peroxidase (POD), superoxide dismutase (SOD), and non-enzyme substances, soluble protein, malondialdehyde (MDA) and proline were investigated. The heat tolerance of different cultivars of iris was evaluated synthetically by principal component analysis and subordinate function. The results show that among the 10 cultivars, Iris ensata is the highest heat tolerance one while Iris germanica is the lowest one. The heat tolerance predicting regression equation established by activity of SOD and POD, contents of chlorophyll, soluble protein and MDA could be used to evaluate heat tolerance of other iris cultivars.