Abstract:

The effects of drought stress on the physical index and the dry leaf yield in the different Stevia rebaudina Bertoni germplasms of IS-1, QF-1, Qingtianza4, JD-1 and AL-4 was studied with the pot method in greenhouse. The results indicated that the content of soluble protein, the relative electric conductivity, the content of malondiadehyde (MDA), the activities of peroxidase(POD) and superoxide dismutase (SOD) and the dry leaf yield of the stevia germplasms were different and showed different degree changes with the continuing of drought-stress time. The content of soluble protein of the stevia germplasm showed decreasing trend, but that in IS-1 rose in the T3 (without irrigation for 15 days). The relative electric conductivity showed stable and significant increase. The MAD content in the IS-1 and in the AL-4 decreased firstly and then increased, but that in the QF-1, Qingtianza4 and JD-1 increased continually. The dry leaf yield of this stevia germplasm showed decrease in different degree. The different change degree of the diverse stevia dermplasm in the same treatment indicated that drought resistance of the stevia germplasm is different：the drought resistance of the IS-1 is the strongest，the drought resistance of the QF-1 is the weakest，the order of the drought resistance in other stevia germplasm are AL-4>Qingtianza4>JD-1.