Drought Tolerance Analysis Of A New Seashore Paspalum Germplasm 'T1'

Seashore paspalum is a warm-season perennial grass species,which can be irrigated with seawater.It was well used in golf,sport square,and city greenbelt construction in coastal areas from south latitude 30° to north latitude 30°.During the past several years,the seashore paspalum cultivars,including 'Seaspray','Salam','Adalayd' and 'SeaIsle 2000'were mostly used in China.In 2010,we found that the mutant species were not only shorter than the Paspalum 'Adalayd','Salam','Seaspray','SeaIsle 2000',but also in the morphological,biological and economic traits are relatively consistent,hereditary stability,can be identified as a new germplasm,temporarily named 'T1'.Drought and rewater treatments were conducted in a growth chamber with a new Seashore Paspalum germplasm'T1',and 'Seaspray','Salam','Adalayd','SeaIsle 2000','Tifway' and 'Common' as a control.We also evaluated the turfgrass quality,soil water content,chlorophyll content,plasma membrane stability,malondialdehyde content,and antioxidant enzymes activity between the 'T1' and the other six cultivars,and compared the drought tolerance between them,which made us between understand the drought tolerance of a new Seashore Paspalum germplasm 'T1'.The results are as follows:These results in our study showed that the soil relative water content(SWC)decreased continuously with the extension of drought treatment.The turf quality(TQ)and relative water content(RWC)of seven plant cultivars were significantly decreased.With the prolonging of drought time,soil water content(SWC)decreased from 14.8%to 1.6%,the'T1' turf quality(TQ)decreased from 8.7 to 2.3;leaf relative water content(RWC)of seven kinds of materials were decreased,the 'T1' is the smallest decline of 30.5%,Other materials of the relative water content of leaves(RWC)decreased from small to large were'Seaspray'(36.8%),'Salam'(40.7%),'Sealsle 2000'(44.7%),'Common'(47.1%),'Tifway'(47.9%).'Adalayd'(58.8%);After 30 days of drought treatment.the chlorophyll content of 'T1' decreased to 74.3%of the control.The EL of the seven cultivars increased significantly as the drought treatment,and the EL of the seven cultivars from high to low is'Seaspray'(50.8%),'Salam'(65.0%),'T1'(86.6%),'SeaIsle 2000'(87.2%)and 'Adalayd'(109.3%).The results showed that under the drought stress,the physiological indexes of'T1' could maintain the normal level for a long time,which indicated that 'T1' had strong resistance to drought.After rewatering treatment,the soil water content(SWC),turf quality(TQ),relative water content(RWC)and chlorophyll(Ch1)of seven kinds of materials showed a significant increased trend,and the conductivity(EL)showed a significant decreased trend.On the second day of rewatering,the soil water content(SWC)returned to the pre-treatment level.On the 7th day of rewatering,the chlorophyll content(Ch1)of 'T1'reached at 13.7 mg/g,which is the 96%of the pre-treatment level.After re watering,the conductivity of 'T1' is 32.7%.The results showed that most of the physiological indexes of'T1' returned to normal state after rewatering,and the growth condition was improved,indicating that the recovery ability of 'TI' was stronger after drought rewatering.Under drought treatment,the MDA content of the seven materials was significantly increased compared with control.The MDA content in the 'T1' reached at 355.8%of the control.After 7 days rewatering treatment,the MDA content of all materials decreased significantly,and the MDA content of 'T1' returned to the control level.At the 30th day of drought,the POD activities of the 'T1','Seaspray','Salam' and 'Sealsle 2000' increased significantly to 138.0%,156.0%,152.9%and 188.8%of the control,respectively.However,the POD activities of'Adalayd','Tifway' and 'Common' decreased significantly to 64.8%,35.7%and 51.0%of the control,respectively.After 7 days of rewatering,the POD activity of those five seashore paspalum cultivars returned to the control level.The POD activity of'Tifway' and 'Common' were also restored to 72.9%and 74.5%compared to untreated control,respectively,while there was still significant difference between treatment and control.The results showed that under the drought stress,'T1' could scavenge active oxygen free radicals by complex antioxidant enzymes,and recovered well after rewatering,and the increase duration of POD activity of 'T1' was longer than that of 'Adalayd','Tifway' and 'Common'.In summary,'T1' can withstand a long time of drought strss,and it has a strong drought resistance.'T1' is a kind of turfgrass with certain application value,and it is worth further study and utilization.