蒙古沙冬青功能性状对土壤水分的响应

Response of Functional Traits of Ammopiptanthus mongolicus to Soil Moisture

植物功能性状是资源分配和生存繁殖的重要量化指标,反映了其对环境变化的响应与适应机制。本文通过测定固定沙地、砾质沙地两种生境下蒙古沙冬青(Ammopiptanthus mongolicus)个体形态特征、叶片功能性状以及花数量和花部结构特征,探究其生长发育与繁殖过程中资源分配对不同土壤水分的响应规律。结果显示:(1)由于土壤水分含量的差异,砾质沙地上蒙古沙冬青的基径、冠幅、地上生物量显著大于固定沙地(P<0.05)。(2)不同土壤水分条件下,蒙古沙冬青叶面积、叶体积、叶组织密度具有显著差异性(P<0.05);比叶面积、叶鲜重、叶干重具有极显著差异性(P<0.01)。(3)土壤水分含量低的生境下,植株比叶面积与叶面积、叶体积显著正相关(P<0.05),与叶组织密度极显著负相关(P<0.001);土壤水分充足条件下,叶形指数与叶面积显著负相关(P<0.01)。异质生境下,叶干物质含量均与叶片含水量显著负相关(P<0.05),而与水分饱和亏、叶面积极显著正相关(P<0.001)。(4)土壤水分含量低的生境下,蒙古沙冬青花数量、花瓣长度与花萼大小均减小;异质生境下,花数量均与冠幅、地上生物量极显著正相关(P<0.001)。综上所述,蒙古沙冬青通过降低个体大小,减小叶面积和增加比叶面积、叶组织密度以及减少花数量适应干旱环境,功能性状与植物对资源的获取和利用密切相关,反映了其在异质生境下的生活史适应策略。

Plant functional traits are important quantitative indicators of resource allocation and survival and reproduction,reflecting their response and adaptation mechanisms to environmental changes.In this paper,we investigated the response of resource allocation to different soil moisture during growth,development and reproduction of Ammopiptanthus mongolicus in two habitats:fixed sand and gravelly sand,by determining the individual morphology,functional traits of leaf blades,and the number of flowers and floral structure of A.mongolicus.The results showed that(1) the basal diameter,crown width and above-ground biomass of A.mongolicus on gravelly sand were significantly larger than those on fixed sand(P<0.05) due to the differences in soil moisture content.(2) Leaf area,leaf volume,and leaf tissue density of A.mongolicus were significantly different under different soil moisture conditions(P<0.05);specific leaf area,leaf fresh weight,and leaf dry weight were highly significant(P<0.01).(3) Under the habitat with low soil moisture content,plant specific leaf area was significantly and positively correlated with leaf area and leaf volume(P<0.05),and highly significantly and negatively correlated with leaf tissue density(P<0.001);under the condition of sufficient soil moisture,leaf shape index was significantly and negatively correlated with leaf area(P<0.01).Under heterogeneous habitats,leaf dry matter content was all significantly negatively correlated with leaf water content(P<0.05),while it was significantly positively correlated with water saturation deficit and leaf surface(P<0.001).(4) The number of flowers,petal length and calyx size of A.mongolicus decreased in habitats with low soil moisture content,and the number of flowers were all highly significantly positively correlated with crown width and above-ground biomass in heterogeneous habitats(P<0.001).In conclusion,A.mongolicus adapted to the arid environment by decreasing individual size,decreasing leaf area and increasing specific leaf area,leaf tissue density,and decreasing flower number,and the functional traits were closely related to the plant utilization of resources,which reflected its life-history adaptive strategy in heterogeneous habitats.