三种荒漠灌木根系的构形特征与叶性因子对干旱生境的适应性比较   总被引：22，自引：16，他引：6  

蒋礼学  李彦 《中国沙漠》2008,28(6):1118-1124

以古尔班通古特沙漠南缘原始荒漠的三种建群灌木多枝柽柳、梭梭和琵琶柴为研究对象,采用挖掘法调查其根系构性特征及其与土壤水分的关系,同时测定其比叶面积(SLA),比叶重（LMA）,单位重量叶氮含量(Nmass)及单位面积叶氮含量(Narea)。结果表明,三种荒漠灌木的根系分属不同的功能型,多枝柽柳是深根潜水性植物,琵琶柴是浅根性植物,而梭梭介于两者之间。而且,三种荒漠灌木随着根系分布的由深到浅,即随着土壤水分亏缺的加剧,在叶性因子方面做了一定的适应性调整。这些事实表明,在水分为主要限制因子的干旱生境中,根系构型特征在很大程度上决定了灌木的叶性策略。同时研究表明,荒漠灌木在抗旱和生长之间存在相对平衡的关系。  相似文献   

西鄂尔多斯地区强旱生小灌木水分参数的研究(Ⅰ)   总被引：19，自引：12，他引：7  

李骁  王迎春  征荣 《中国沙漠》2005,25(4):581-586

绵刺、红砂、四合木、霸王柴为东阿拉善-西鄂尔多斯地区的超旱生灌木。本文运用PV技术对绵刺、红砂、四合木、霸王柴的多种水分关系参数(ψ_π¹⁰⁰、ψ₀、F₀、RWC⁰等)进行了测定,并通过测得的各水分参数从水分生理角度对这四种超旱生小灌木的耐旱性进行了比较分析。研究表明:①绵刺、红砂、四合木、霸王柴具有不同的耐旱机理,红砂主要体现为增加细胞溶质浓度的渗透调节,而四合木表现为较小的细胞体积(低的F₀值)和较强的持水能力(较大的AWC值和V_a/V₀值)。②红砂具有非常低的ψ_π¹⁰⁰值(-3.1302MPa)与ψ₀值(-3.5074MPa),体现出其具有很强的保持最大膨压和维持低水势的能力。③四合木的F₀值(52.12%)很低,而AWC值(87.43%)和V_a/V₀值(7.8092)却很高,说明四合木具有较强的忍耐水分胁迫能力和抗脱水能力。④绵刺的根茎系统具有快速吸收和传导水分的能力,可能与其具有劈裂式生长的特征有关。⑤经过对数据的统计学检验分析,证明PV技术具有良好的重复性。  相似文献   

Modeling rainfall interception loss by two xerophytic shrubs in the Loess Plateau          下载免费PDF全文

Yu Zhang  Xiao‐Yan Li  Wei Li  Xiu‐Chen Wu  Fang‐Zhong Shi  Wei‐Wei Fang  Ting‐Ting Pei 《水文研究》2017,31(10):1926-1937

Rainfall interception loss plays an important role in ecohydrological processes in dryland shrub ecosystems, but its drivers still remain poorly understood. In this study, a statistical model was developed to simulate interception loss based on the mass balance measurements arising from the partitioning of rainfall in 2 dominant xerophytic shrub (Hippophae rhamnoides and Spiraea pubescens) communities in the Loess Plateau. We measured throughfall and stemflow in the field under natural rainfall, calculated the canopy storage capacity in the laboratory, and identified key factors controlling these components for the 2 shrubs. We quantified and scaled up the stemflow and the canopy storage capacity measurements from the branches and/or leaves to stand level. The average interception loss, throughfall, and stemflow fluxes account for 24.9%, 72.2%, and 2.9% of the gross rainfall for H. rhamnoides, and 19.2%, 70.7%, and 10.1% for S. pubescens, respectively. Throughfall increased with increasing rainfall for both shrubs; however, it was only correlated with the leaf area index for S. pubescens. For stemflow measured from individual branches, we found that the rainfall amount and basal diameter are the best predictors for H. rhamnoides, whereas rainfall amount and branch biomass appear to be the best predictors for S. pubescens. At the stand level, stemflow production is affected by the rainfall amount for H. rhamnoides, and it is affected by both the rainfall amount and the leaf area index for S. pubescens. The canopy storage capacity of H. rhamnoides (1.07–1.28 mm) was larger than S. pubescens (0.88–1.07 mm), and it is mainly determined by the branches and stems of H. rhamnoides and the leaves of S. pubescens. The differences in interception loss between the 2 shrub stands are mainly attributed to different canopy structures that induced differences in stemflow production and canopy storage. We evaluated the effects of canopy structure on rainfall interception loss, and our developed model provides a better understanding of the effects of the canopy structure on the water cycles in dryland shrub ecosystems.  相似文献   

科尔沁沙地2种优势固沙灌木的相容性生物量模型     

黑维高  詹瑾  韩丹  杨红玲  李玉霖 《中国沙漠》2019,39(5):193-199

基于现有的灌木生物量模型存在各组分与总量不相容问题，以半干旱区科尔沁沙地2种优势固沙灌木小叶锦鸡儿（Caragana microphylla）和黄柳（Salix gordejevii）为对象，通过对大样本的相关形态指标及生物量实测数据进行非线性回归和非线性误差变量联立方程组的计算，建立了2种灌木叶片、新枝、老枝和地上生物量的独立模型及与各组分相容的生物量模型，并通过决定系数R²、估计值的标准差SEE、总相对误差TRE、平均系统误差MSE（ASE）、平均预估误差MPE和平均百分标准误差MPSE对模型进行评价。结果表明：非线性加权回归使得两种灌木各组分的独立模型拟合效果优化，而生物量相容模型与独立模型相比，由于抽样误差的存在拟合效果不佳，相关评价指标较低。  相似文献   

科尔沁沙地优势固沙灌木叶片凋落物分解的主场效应   总被引：1，自引：1，他引：1  

杨红玲  李玉霖  宁志英  张子谦 《中国沙漠》2019,39(5):62-70

在气候变化和人类活动的影响下，科尔沁沙质草地中灌木植物种增加，导致沙质草地逐渐向灌木地转变。选取该地区优势固沙灌木差不嘎蒿（Artemisia halodendron）和小叶锦鸡儿叶（Caragana microphylla）凋落物及其混合凋落物开展交互移置培养试验，分析了培养过程中CO₂释放和干物质损失量以及混合凋落物CO₂释放量实测值与预测值的差异，辨析主场效应产生的原因及其驱动机制，以期为将主场效应纳入到凋落物分解模型提供理论基础。结果表明：与高质量的小叶锦鸡儿叶凋落物相比，质量较低的差不嘎蒿叶凋落物分解具有更强的主场效应；其次，引起叶凋落物分解的主场效应归因于土壤微生物的特化作用，而不是土壤动物的搬运或贮藏行为。此外，混合凋落物主场效应与其分解生境中长期输入的凋落物的质量相似性紧密相关，质量相似性越大，主场效应越强，这也是本研究中混合凋落物分解在差不嘎蒿灌丛土壤下具有较强主场效应的原因。  相似文献   

The influence of Caragana korshinskii shrub on soil and hydrological properties in a revegetation-stabilized desert ecosystem     

Yan-Xia Pan  Xin-Ping Wang  Xin-Rong Li  Ya-Feng Zhang  Rui Hu  Hao Zhang 《水文科学杂志》2013,58(10):1925-1934

Abstract

Shrub-induced spatial heterogeneity of soil and hydrological properties are common in arid and semi-arid ecosystems. To examine the influence of shrubs on spatial patterns of soil physical, chemical and hydrological properties, the typical sand-fixation species, Caragana korshinskii, was studied in the Shapotou area of the Tengger Desert, China. Miniature cylinder infiltrometers were used to quantify the spatial variations of infiltration rate in the soils, and were installed at 20-cm intervals around the shrubs. Meanwhile, soil samples were collected at 0–5 cm depth every 10 cm to analyse their physical and chemical properties and soil moisture content. The results indicate that the various measured parameters showed a gradational change from sub-canopy to open space. The establishment of shrubs formed obvious “fertile islands” where more soil nutrients collected. The total nitrogen (TN), soil organic matter (SOM), electrical conductivity (EC) and surface soil moisture content decreased gradually from around shrub stems to the interspace. The sand content around shrub stems was significantly higher (p < 0.05), and decreased gradually from the centre towards the outside microsites. The silt and clay contents showed opposite variability characteristics. The variation of soil bulk density was less within 140 cm distance from the stem, and no abrupt change was found at the shrub’s drip line. No significant tendency was found for the soil pH values. The steady infiltration rates declined with increasing stem distance and then tended to be stable, and no abrupt change occurred at the position of the overhead canopy margin. The increase of infiltration rate was rapid nearer to the stem; the variability trend can be fitted by a log-log (power function) model. This study indicated the gradational change in soil and hydrological properties, which was not consistent with the binary division of shrubs into “canopy” and “interspace” zones.