| The seedlings of four different Dianthus plants (Dianthus superbus L., Dianthus plumarius, Dianthus chinensis L.,and Dianthus barbatus L.) were used as test plants to evaluate their drought tolerance under natural drought stress.Morphological and physiological indexes related to the drought tolerance were measured, and the comprehensive evaluation method of drought tolerance capacity was evaluated using subordinate function value analysis on four different Dianthus plants.The results indicated that soil water content and relative water content of leaves of Dianthus plants were decreased with increasing severity of drought stress. Compared with the control, after drought stress of 12 d, the relative water content of leaves decreased by 64.14%、59.44%、80.84%、and 78.58%in all 4 studied plants,respectively.The content of malondialdehyde (MDA) increased 451.61%、353.44%、724.32%, and 647.95% after 10 d drought stress. The activity of superoxide dismutase (SOD) increased 77.58%、90.68%、29.05%,and 81.52% at day 8. The content of proline (Pro) increased while the content of chlorophyll (Chl) and the activity of superoxidedismutase (SOD) went up first and then decreased. At day 10, DtSOD and DtPOD genes showed rising trend in Dianthus plumarius and Dianthus superbus L. increased 2.5 and 2.25 times over that of control. The order of the drought tolerance of four Dianthus plants was Dianthus plumarius>Dianthus superbus>Dianthus barbatus>Dianthus chinensis. |