Studies On Drought Resistance Of Two Warm-season Turfgrasses

Based on two warm-season turfgrasses (Cynodon dactylon cv. Yundong,Cynodon dactylon cv. shanghai,Zoysia japonica cv. Lanyin3,Zoysia japonica cv. shanghaiJD-1,Zoysia japonica Steud.,Zoysia matrella (L.) Merr.), the physiological characteristics of the grasses under drought stress and rewatering was studied, the relations between the abilities of grasses tolerant to drought and Chl,Pn,Tr,Pro,SOD,POD,MDA,RPP were discussed in this paper. The main conclusions can be drawn as follows:(1) In response to the stress of drought, such indexes as leaf water potential,soil water potential and transpiration rate go down gradually,but there are differents between these varieties. Cynodon dactylon cv. Yundong showed the significant lower transpiration rate and higher soil water potential and leaf water potential, indicating the involvement of its drought avoidance mechanism.(2) With the intensity of drought increase, the content of Pro in six varieties goes up, but there are some differences in growth condition and Pro content between six varieties. It is shown in the experiment that Zoysia japonica cv. Lanyin3 and Cynodon dactylon cv. Yundong grow well under the stress of drought and the peak of Pro content in it comes latest and is lowest among six varieties, which indicates that Zoysia japonica cv. Lanyin3 and Cynodon dactylon cv. Yundong are more tolerant to drought. The ability of drought tolerant of Zoysia matrella (L.) Merr. is worst because the peak of Pro content in it comes earliest and is highest among six varieties. Based on above analysis, it can be safely inferred that the Pro content can be used as a physiological index to evaluating the ability of tolerance to drought.(3) The stress of drought could lead to increase of MDA and the permeability of the plasma member. There are some similarities but also some differences in results of six varieties:①The increase of MDA and RPP content in Cynodon dactylon cv. Yundong during a long period time is considerably slow, which indicates the strong tolerance to drought. The MDA and RPP content in Cynodon dactylon cv. shanghai,Zoysia japonica cv. Lanyin3 and Zoysia japonica Steud. go up slowly during the Pre-period time of drought stress, but with the further stress of drought, they increase sharply. Zoysia japonica cv. shanghaiJD-1 and Zoysia matrella (L.) Merr. increase sharply during the Pre-period time of drought stress.②The change range of RPP content in six cultivars is in inverse ratio to the ability of tolerance to drought and is in decreasing order of Cynodon dactylon cv. Yundong﹤Zoysia japonica cv. Lanyin3≈Cynodon dactylon cv. shanghai﹤Zoysia japonica Steud.﹤Zoysia japonica cv. shanghaiJD-1﹤Zoysia matrella (L.) Merr.. From the above results combined with some...