杯腺柳叶片枯落物浸提液对高寒灌丛草地6种草种子萌发的化感作用

Allelopathic effects of water extracts from Salix cerebralis on seed germination of six grassland plant species in alpine shrub grassland

摘要:

【目的】研究高寒灌丛草地优势植被杯腺柳(Salix cerebralis)叶片枯落物对优势草种子萌发的化感作用，为高寒灌丛草地的科学管理提供理论指导。【方法】使用不同浓度的杯腺柳叶片枯落物浸提液处理高寒灌丛草地中 6 种常见优势草种子，并进行发芽试验。【结果】杯腺柳叶片枯落物浸提液浓度在 50~75 g/L 间存在临界浓度，使浸提液对扁蓿豆、圆柱披碱草、垂穗披碱草种子萌发及幼苗生长从促进作用转变为抑制作用，呈现“低促高抑”的现象。各供试浓度(12. 5~100 g/L)的浸提液均抑制了甘肃马先蒿根的生长。浸提液对幼苗根的化感作用强于对芽的作用。化感综合效应表明，杯腺柳叶片枯落物浸提液对 6 种草地植物种子萌发的影响程度为：高山韭＞甘肃马先蒿＞草地早熟禾=垂穗披碱草＞扁蓿豆＞圆柱披碱草。【结论】退化高寒草甸的恢复措施应考虑通过合理放牧来调控草地枯落物的量和养分的循环，提高牧草质量以及维持草地健康。

Abstract:

【Objective】 This paper reports the study of the allelopathy of Salix cerebralis leaf litter on seed germi‐ nation of dominant grasses in alpine shrub grassland，and provide theoretical guidance for scientific management of al‐ pine shrub grassland.【Method】 Seeds of six common dominant grasses in alpine shrub grassland were treated with different concentrations of leaf litter extract of Salix cerebralis，and the germination rates were also measured. 【Result】 It was found that there was a critical concentration in the range of 50 to 75 g/L，which demonstrated the change from promoting to inhibiting the seed germination and seedling growth of Medicago ruthenica，Elymus cylin- dricus and Elymus nutans. The results suggested a phenomenon of "low promoting and high suppressing". At each concentration （12. 5~100 g/L），the leaf litter extracts inhibited the root growth of Pedicularis kansuensis. The allelo‐ pathic effect of the leaf litter extract on the root of seedlings was stronger than that on the bud. The comprehensive al‐ lelic effect showed that the influence of the litter extract of Salix cerebralis leaves on the seed germination of six grass‐ land plants was as follows：Allium Sikkimense>Pedicularis kansuensis>Poa pratensis=Elymus nutans>Medicago ruthenica>Elymus cylindricus.【Conclusion】 The restoration measures of degraded alpine meadow should be taken into consideration of the control of the litter amount. This could be achieved by the regulation of the accumulation of litter and nutrient cycle through rational grazing，and improvement of the quality of herbage and maintaining the health of grassland.