Effects of rest grazing periods on seed size and germination characteristics of Elymus nutans in alpine meadow
[Objective]The objective of this study was to determine the rest grazing period conducive to the seed size and germination characteristics of Elymus nutans.[Method]Five rest grazing periods were set up in Tianzhu al-pine meadow of east Qilian Mountain,including the critical period of soil thawing-grass withering period (RP1),the late period of soil thawing-grass withering period (RP2),the initial period of grass regreening-grass withering period (RP3),the late period of grass regreening—grass withering period(RP4) and the local traditional rest grazing(when the dominant plant height was 5 cm—grass withering period) (RP5). The effects of rest grazing in different periods on the seed size and germination characteristics of E. nutans and the relationship between them were studied.[Re-sult]The seed area,perimeter,length width ratio and length were the largest in RP1,and the area,perimeter and length were increased by 15.14％,10.22％ and 11.97％,respectively,compared with RP5. The thousand-grain weight of RP4 was significantly higher than that of RP1,RP2 and RP5.Compared with RP5,early rest grazing signifi-cantly improved the germination potential,germination index,germination percentage,bud length and vigor index. The germination percentages of RP1,RP2,RP3 and RP4 were 84.86％,121.23％,127.27％ and 127.27％ higher than RP5,respectively. Correlation analysis showed that thousand-grain weight was significantly positively corre-lated with germination potential and bud length.[Conclusion]RP1 rest grazing could improve the seed area,perim-eter,length width ratio and lengthof E. nutans,and the seeds have better germination characteristics,which is condu-cive to the protection and restoration of E. nutans vegetation.
万方数据
维普
