Study On Salt-resistance Comparision Of Bermudagrass Under Salt Stress Of Na₂SO₄

Bermudagrass was a turfgrass which was used widely, studied deeply among warm-season turfgrasses. But due to the colder climate and saline soil spreading widely in northwest China, the utilization of Bermudagrass was greatly limited. New varieties "Xinnong No.1 Bermudagrass" and "Kashi Bermudagrass", which were cultivated by the researchers of Xinjiang Agricultural University through ten years' study, were one of the highest cold-resistant warm-season turfgrasses, furthermore they could grow well in heavy saltnized soil which mainly contains of Na2SO4 (total salinity:3.86mS/cm).Study on the salt-resistant capacity and physiological changes process of Xinnong No.1 Bermudagrass, Kashi Bermudagrass, Tuokexun Bermudagrass(Bermudagrass line), Tifdwarf and common Bermudagrass under salt stress of Na2SO4 was made through the physiological and biochemical indexes ,which were generally used in crop and herbage appraisal. The results were:1 Seed germination experiment shown, under salt stress of Na2SO4, seed germination rate of Bermudagrass was reduced significantly, and the concentration of salt solution was negative correlation with seed germination rate. Seed germination rate could be increased significantly by the condition of changed temperature, and the order of salt-resistance was Common Bermudagrass＞Tuokexun Bermudagrass＞Kashi Bermudagrass＞Xinnong No.1 Bermudagrass.2 Membrane injury rate was one of physiological indexes that could effectively measure salt-resistant ability of Bermudagrass. Under salt stress of Na2SO4, the extent of membrane injury rate was greater in Tifdwarf than in others, so it had lower salt-resistance.3 The MDA content in Bermudagrass was increased with the salt stress, and it had certain positive correlation with over-oxidation degree of cytoplasm membrane. The more MDA content was, the more critical degree of cytoplasm membrane was oxidized, the worse salt-resistant ability of Bermudagrass was.4 Under salt stress of Na2SO4, Pro content of Bermudagrass was increased ,and was positive correlation with membrane injury rate. The more accumulation of Pro content was, the lower salt-resistance of Bermudagrass was. So the salt-resistant capacity of Tifdwarf was lowest among the Bermudagrass.5 NRA was negative correlation significantly with membrane injury rate. NRA in all Bermudagrass emerged the descending trend, and high-speed falling of NRA in Xinnong No.1 Bermudagrass was helpful to prevent accumulation of toxic nitrogenous compounds, so it possessed higher salt-resistance.6 Chl content was reduced with the increasing salt concentration, but Chla/b was increased, as show Bermudagrass could decrease the restraint of growth by raising Chla/b. Chla/b can be used as a referential index to measure salt-resistance of Bermudagrass.7 K+/Na+ had some correlation with salt-resistance of Bermudagrass. K+/Na+ indicated the declining tendency due to the decreasing of salt concentration, and Xinnong No.1Bermudagrass,Kashi Bermudagrass,Tuokexun Bermudagrass had low-speed falling, so they had higher salt-resistance.8 Under salt stress of Na2SO4, Xinnong No.1 Bermudagrass,Kashi Bermudagrass,Tuokexun Bermudagrass possessed higher capacity of absorption selectivity of K+ and Na+ from the soil, so they had rather salt-resistance.9 The capacity of absorption selectivity of K+ and Na+ from the soil was one of reasons they could grow well in heavy saline-alkali habitat.10 By summarizing all indexes, membrane injury rate, MDA, Pro, NRA and SK+,Na+absorption could be utilized as important indexes to measure the salt-resistance of Bermudagrass.