Evaluation Of Salinity Tolerance And Salinity Tolerance Mechanism In Zoysiagrass (Zoysia Willd.)

Zoysiagrass is one of the most important warmgrasses which belongs to Chloridoideae in Gramineae total of11species. Zoysiagrass mainly distributed in Asia, Africa and Australia coastal areas. There were5species、2variety species and1variety species in China. The development for Zoysiagrass breeding in China was lagged to which in America and Korea. The main reason was the start late. It was important for Zoysiagrass breeding to research the evaluation of salinity tolerance in zoysiagrass germplasm. This research was evaluated on salinity tolerance for103Zoysia accessions through hydroponic culture method. And then we selected9accessions belonging to7species research to study on salinity mechanism. The result as follows:1Evaluation salinity tolerance in Zoysia turfgrass germplasmThere was large variation among103Zoysia accessions belonging to seven species in Salinity tolerance. Compared with the controls of material’manilagrass’ and Zoysia japonica’Lanyin3’, there were28and47accessions better than the controls in relative green leaf coverage, respectively; And there were11and26accessions better than the controls in relative dry shoot clipping weight, respectively. Across all materials, the best species for salt tolerance was Z. pacifica, the better were Z. matrella and Z. tenuifolia. Z. sinica, Z. japonica and Z. koreana were susceptible species.103Zoysia accessions were divided into three groups through clustering analysis with the relative green leaf coverage and relative dry shoot clipping weight. The group Ⅰ included Z5185and Z093with extreme salinity tolerance; the group II had the comparatively high relative green leaf coverage and relative dry shoot clipping weight (>70%), which could be divided into salinity tolerance and intermediate salinity tolerance; the group III had comparatively low relative green leaf coverage and relative dry shoot clipping weight, which could be divided into week salinity tolerance and sensitive at the Euclidean distance3.2Salinity tolerance mechanism of Zoysiagrass (1) ion controlThe9accessions belonging to7species were selected as the materials to research on salinity tolerance mechanism based on the result of evaluation salinity tolerance. The result showed that K+content reduce, but Na+content and Na+/K+increased in leaf and root. The K+contents in leaf and root of7species zoysiagrass were sharply reduced with treatment of10g/L NaCl, The change of Na+content and Na+/K+was opposite. The abilities of maintain Na+and K+content in leaf and root for the most salinity tolerant Z. pacifica、strong salinity tolerance Z. matrella, Z. tenuifolia were better than which of Z. sinica, Z. japonica and Z. koreana in the treatment of10g/L NaCl. The leaf water content reduced slowly and existed significant difference among Z. pacifica, Z. tenuifolia and Z. matrella, compared with Z. sinica、Z. japonica and Z. koreana. There was no significant difference among species in20g/L NaCl treatment. The value of SK+/Na+of Z.macrostachya was the smallest under the same NaCl concentrations treatment(2) Osmotic adjustmentThe proline content, glycine betaine (GB) content and leaf sap osmolality contribution of proline was increased progressively with NaCl concentrations increase while leaf sap osmolality decreased by degrees. Proline content, GB content, contribution rate of proline osmotic potentials and contribution rate of GB osmotic potentials in Z. pacifica, Z. te nuifolia and Z. matrella were higher than which in Z. japonica and Z. koreana with the significant difference(P<0.05). While for salt treatment, the trend was reverse.(3) PhotosynthesisChla content, Chlb content and Chl/Car of the most salinity tolerant Z. pacifica, strong salinity tolerance Z. tenuifolia and Z. matrella exceeded intermediate Z. sinica、 Z. japonica and sensitive Z. koreana. With salt concentrations increased, Pn of Z. sinica Z008、Z. japonica Z004and Z. koreana decreased while others increased first and then decreased. The values of Pn、Gs and Tr in the most salinity tolerant Z. pacifica、strong salinity tolerance Z matrella、Z. tenuifolia were higher than intermediate Z. sinica and Z. japonica in the same salt concentrations treatment.