长身高原鳅(Triplophysa tenuis)对维持木扎提河的水生态系统物质和能量流动具有重要作用。文章基于脂肪酸生物标记法和碳、氮稳定同位素(δ^(13)C、δ^(15)N)技术研究了长身高原鳅的食性和营养生态位特征。结果显示,其肌肉中共检测出22种脂肪酸,其中有8种饱和脂肪酸、6种单不饱和脂肪酸、8种多不饱和脂肪酸;由特征脂肪酸组成情况推测,长身高原鳅对浮游动物、硅藻、陆地植物或喜摄食硅藻的鱼虾均有摄食,表现为杂食性。长身高原鳅的δ^(13)C和δ^(15)N分别介于-27.09‰~-20.98‰和5.71‰~8.45‰,营养级介于2.68~3.48。雌雄样本间的δ^(13)C、δ^(15)N和营养级均不存在显著性差异(P>0.05);雄性样本核心生态位(Standard ellipse area,SEAc)和总生态位(Total area of convex hull,TA)均高于雌性。δ^(13)C与体长间表现为极显著正相关性(P<0.01),δ^(15)N和营养级与体长间不具有显著相关性。70~80 mm体长组与90 mm以上体长组SEAc面积不存在重叠且在聚类分析中被分为不同组。综上,长身高原鳅的食性为杂食性且食物组成随体长变化而不同,作为营养级偏高的捕食者,长身高原鳅能延长食物链长度,增加食物网复杂性,有利于维持水域生态系统的稳定性。
叶片结构性状是植物适应环境和维持生命活动的基础。为探究荒漠建群种灰杨(Populus pruinosa Schrenk)叶片结构性状的空间变异及其与环境因子的关系,以新疆11个天然灰杨居群为研究对象,对灰杨叶片的形态、解剖性状进行研究,用Pearson相关性分析、植物性状网络(PTN)、冗余分析(RDA)等方法对灰杨叶片结构性状的空间变异与气候、土壤因子的关系进行分析。结果表明:1) 灰杨叶片的解剖性状比形态性状的变异性更高,出叶强度(LIM)和主脉维管束面积(MVBA)具有较高的变异系数。2) 形态性状和解剖性状间存在显著的协同与权衡关系,在性状网络中,MVBA为中心性状,可能起着影响灰杨叶片结构的中心调控作用。3) 年均温、年降水量和土壤全钾含量对灰杨叶片结构性状的影响较大,在较干旱生境下灰杨表现出小比叶面积和大叶组织密度的资源保守型策略,相对湿润时则采取高比叶面积和低叶组织密度的资源获取型策略。Leaf structural traits are fundamental to plant adaptation and the maintenance of life processes. To investigate the spatial variation in leaf structural traits of the desert tree species Populus pruinosa Schrenk and its association with environmental factors, 11 natural P. pruinosa populations in Xinjiang were selected as the research objects to study the morphology and anatomical traits of P. pruinosa leaves. Pearson correlation analysis, plant trait network, redundancy analysis and other methods were performed to analyze the spatial variation in leaf traits and their relationship with climatic and soil factors. The results showed that: 1) The leaf anatomical traits of P. pruinosa exhibited greater variability than their morphological traits, and leafing intensity and main vein vascular bundle area showed particularly high coefficients of variation. 2) A significant synergistic and trade-off relationship was identified between morphological and anatomical traits, with main vein vascular bundle area emerged as a central trait within the structural trait network. This suggested a pivotal regulatory role in shaping the leaf structure of P. pruinosa. 3) The annual average temperature, annual precipitation, and soil total potassium content significantly influenced the leaf structural traits of P. pruinosa. In drier habitats, P. pruinosa exhibited a resource conservation strategy of small SLA and large LTD, whereas in relatively humid environments, an opposite resource acquisition strategy was adopted.
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