春季不同时期休牧对高寒草甸珠芽蓼繁殖策略的影响

Effects of rest grazing in different periods of springon the reproductive strategy of Polygonumviviparum in alpine meadow

摘要:

【目的】 研究春季不同时期休牧对珠芽蓼（Polygonum viviparum）繁殖的影响，确定最佳休牧期，为高寒草甸春季更合理的休牧提供科学依据。【方法】 设置了分别从土壤解冻临界期、土壤解冻后期、牧草返青初期、牧草返青后期、当地传统休牧期到牧草枯黄期5 个不同休牧时期的样地（T1、T2、T3、T4、T5），测定不同样地中珠芽蓼生长与繁殖的相关指标。【结果】 T1 珠芽蓼株高、叶面积、比叶面积、地上生物量高于T5，其中株高与叶面积对繁殖特性的影响大于其他生长指标。随着休牧时间的推迟，珠芽蓼植株对繁殖器官的投入越少。花序轴长占比、花数量占比、花大小、花生物量占比随休牧推迟也呈下降趋势。不同样地内珠芽蓼的珠芽轴长占比大于花序轴长占比、珠芽数量占比大于花数量占比、珠芽生物量占比大于花生物量占比。【结论】 珠芽蓼以营养繁殖为主要繁殖方式，在土壤解冻临界期休牧可促进其有性繁殖。

Abstract:

【Objective】 To study the effects of rest grazing at different periods in spring on the propagation of Po-lygonum viviparum，determine the optimalrest grazing period，and provide a scientific basis for more effectiverestgrazingmanagementof alpine meadow in spring.【Method】 Five different rest grazing periods （T1，T2，T3，T4，T5）were established，corresponding tothe critical period of soil thawing，the late stage of soil thawing，the early stage ofgrass regreening，the late stage of grass regreening，the local traditional grazing rest period until the yellowing stageof grass. The growth and reproductive characteristics of P. viviparum in different plots were assessed.【Result】 Theresults showed that plant height，leaf area，specific leaf area and aboveground biomass in T1 were higher than those of T5. Plant height and leaf area had a greater impact on reproductive characteristics compared to other growth indices.Asthe rest grazing period was delayed，P. viviparum allocated less energy to reproductive organs The proportion of inflorescencelength，flower number，flower biomass，and flower size also showed a downward trend. Conversely，theproportion of bulbil length was greater than that of inflorescence length，the proportion of bulbil number was greaterthan that of flower number，and the proportion of bulbil biomass was greater than that of flower biomass across thedifferentplots.【Conclusion】 The primaryreproductive mode of P. viviparum is vegetative reproduction. Grazing restduring the critical period of soil thawing can promote its sexual reproduction.