西藏拉萨亏组山4种常见植物的比叶面积与叶片含水率:围封和海拔效应

Specific LeafArea and Leaf Moisture Content of Four Common Plants in Mount Kuizu,Lhasa,Tibet:Enclosure and Altitude Effects

目的 比叶面积和叶片含水率作为衡量植物适应策略的关键生理指标,能够揭示植物对海拔变化和放牧压力的响应机制。该研究以拉萨亏组山四种常见植物—钉柱委陵菜(Potentilla saundersiana)、弱小火绒草(Leontopodium pusillum)、圆穗蓼(Bistorta macrophylla)和缘毛紫菀(Aster souliei)为研究对象,对比分析植物的比叶面积和叶片含水率,旨在探究四种植物在不同海拔和围封生境下的生理生态适应策略。方法 在不同海拔梯度、草地类型(高寒草原、高寒灌丛草甸、高寒草甸)和放牧模式(围封与自然放牧)下对四种植物比叶面积和叶片含水率进行测定和分析。结果 围封样地中,钉柱委陵菜和圆穗蓼的比叶面积随海拔升高无显著变化;自由放牧样地中,钉柱委陵菜和弱小火绒草比叶面积与海拔呈相反趋势。围封样地中,弱小火绒草和圆穗蓼叶片含水率随海拔升高而降低;自由放牧样地中,钉柱委陵菜、弱小火绒草和圆穗蓼叶片含水率均随海拔升高而降低。缘毛紫菀叶片含水率在两种放牧样地中均随海拔升高而降低。不同海拔下,四种植物比叶面积和叶片含水率存在显著差异。自由放牧和围封处理对两种性状有显著影响,围封样地植物比叶面积和叶片含水率普遍高于自由放牧样地。不同草地类型植物的比叶面积和叶片含水率变化具有一定规律性。四种植物比叶面积与海拔总体呈现负相关性,其中圆穗蓼负相关性显著;叶片含水率与海拔之间同样呈现负相关性,其中缘毛紫菀负相关性显著。结论 四种植物通过调整其比叶面积和叶片含水率来适应不同海拔的生态环境,尤其在围封和自由放牧两种不同放牧模式下,这种适应性特征表现得更为突出。这些发现为理解植物如何响应和适应环境变化提供了重要的科学依据。

Objective Specific leaf area and leaf moisture content are key physiological indicators to measure plant adaptation strategies,which can reveal the responses mechanism of plants to altitude change and grazing pressure.In this study,four common plants in Mount Kuizu,Lhasa,namely Potentilla saundersiana,Leontopodium pusillum,Bis-torta macrophylla,and Aster souliei were selected as research objects to compare and analyze the specific leaf area and leaf moisture content of the plants.The aim of this studywas to explore the physiological and ecological adapta-tion strategies of these four plants at different altitudes and enclosed habitats.Methods The specific leaf area and leaf moisture content of the four plants were measured and analyzed under different altitude gradients,grassland types(alpine steppe,alpine shrub meadow,alpine meadow),and grazing patterns(enclosure and natural grazing).Results In the enclosed plots,there was no significant change in the specific leaf area of Potentilla saundersiana and Bistorta macrophylla with altitude.In the free-grazing plots,the specific leaf area of Potentilla saundersiana and Leon-topodium pusillum showed an opposite trend with altitude.In enclosed plots,the leaf moisture content of Leontopodi-um pusillum and Bistorta macrophylla decreased with the increase of altitude,while the in free grazing plots,the leaf moisture content of Potentilla saundersiana,Leontopodium pusillum,and Bistorta macrophylla all decreased with the increase of altitude.The leaf moisture content of Aster souliei decreased with the increase of altitude in both grazing plots.There were significant differences in specific leaf area and leaf moisture content among the four plants at differ-ent altitudes.Free grazing and enclosure treatments had significant effects on the two traits,which were found as that the specific leaf area and leaf moisture content of the four plants in the enclosure plots were generally higher than those in the free-grazing plots.The specific leaf area and leaf moisture content of plants of different grassland types changed regularly.There was a negative correlation between the specific leaf area and altitude of the four plants,while Bistorta macrophylla showed a significant negative correlation.There was also a negative correlation between the leaf mosture content and altitude,while Aster souliei showed a significant negative correlation.Conclusion The four plants adapted to the ecological environment at different altitudes by adjusting their specific leaf area and leaf moisture content,especially in the two different grazing modes of enclosure and free grazing.These findings provide important an important scientific basis for understanding how plants respond to and adapt to environmental changes.