Abstract:

In order to reveal the effect of exogenous methyl jasmonate (MeJA) and calcium and salicylic acid (SA) on the heat tolerance in Phalaenopsis Seedlings, these seedlings sprayed with 3 chemicals at the optimum concentration or distilled water (control) respectively were exposed to high temperature stress at 40℃ for 4 days, the variations of some physiological indexes in the leaves were measured. The results showed that, compared with the control treatment, the MeJA and Calcium treatments resulted in higher activities of SOD and POD and CAT. The SA treatment made the activity of CAT decreasing significantly, while it could increase the activities of SOD and POD. The 3 treatments could improve obviously the contents of prolin and soluble protein, and decrease significantly the relative electrical conductivity and MDA content under high temperature stress. According to these results, it indicated that the MeJA and Calcium and SA treatments could enhance effectively the heat tolerance in Phalaenopsis seedlings. On the basis of physiological and morphological indexes difference, the inducting intensity of the heat tolerance was in the following order: MeJA>Calcium>SA.