5种荒漠植物抗旱性及其与抗旱指标相关性的定量评价

通过测定苦豆子、苦马豆、骆驼蓬、钠猪毛菜和盐爪爪5种典型荒漠植物的相对含水量、叶绿素含量、电导率、比叶面积、根冠比和蒸腾速率6项抗旱指标,运用隶属函数值法对5种植物的综合抗旱适应性进行定量评价。评价结果表明,5种荒漠植物的综合抗旱性强弱顺序为:盐爪爪>钠猪毛菜>苦马豆>苦豆子>骆驼蓬。在此基础上运用灰色关联度分析方法,对5种植物的抗旱性和6项抗旱指标的相关性进行分析。关联度分析结果表明,各项抗旱指标与平均隶属函数值的关联顺序为:蒸腾速率>相对含水量>电导率>比叶面积>根冠比>叶绿素含量,即蒸腾速率、相对含水量和电导率是5种植物抗旱性评价的重要指标。     

四合木水分代谢特性的初步研究

四合木(Tetraena mongolica Maxim)为内蒙古特有的国家二级保护、内蒙古一级保护植物。本文首次报道了四合木的水分状况(总含水量、自由水含水量及束缚水含水量)和水分代谢(水势、蒸腾速率及抗脱水力),并且讨论了这些特性与忍受干旱的关系,为进一步保护这种植物提供科学依据。     

不同pH值缓冲液对玉米叶片蒸腾速率和相对含水量的影响

利用磷酸缓冲液和人造缓冲液(artificialsolution,AS)研究了玉米去根地上部分和离体叶片的蒸腾速率。结果表明,不同pH处理能够显著影响蒸腾速率,同一缓冲液不同pH值下的蒸腾速率差异较大;不同缓冲液影响下的蒸腾速率更是不同。不同pH值AS缓冲液对玉米离体叶片的相对含水量(RWC)有不同影响,pH7.5时的RWC较低。     

几种植物细胞膜的差别透性及其与抗旱性的关系

根据同时同地对４种旱生植物（白梭梭、梭梭柴、红果沙拐枣和多枝柽柳等）组织外渗液相对电导率和组织相对含水量的对比测定，我们发现组织相对含水量与细胞膜差别透性之间存在着反相关关系，即相对含水量越大细胞膜差别透性就越小。根据对不同土壤水分状况下４种植物组织外渗液相对电导率测定结果的对比分析，我们认为土壤水分含量过多或过少都会影响植物的正常生长而增大植物细胞膜的差别透性。     

浑善达克沙地植物蒸腾特征的研究

采用 L i-1 60 0型气孔仪测定了浑善达克沙地主要建群乡土植物种不同季节的蒸腾速率及其环境因子的日进程 ,结果表明 :浑善达克沙地中榆树、黄柳、圆叶桦、砂杞柳、羊草蒸腾速率的日变化均呈单峰曲线 ,而叉分蓼和楔叶茶子呈双峰曲线。同一种植物在不同样地土壤水分条件下 ,蒸腾速率不同。各植物种蒸腾速率的季节变化明显 ,7、8月份蒸腾速率高 ,6月份最低。各植物种中 ,黄柳为低蒸腾植物。回归分析表明 ,影响蒸腾速率最主要的因子为光照强度 ,其次为气温和空气相对湿度 ;蒸腾速率与各因子呈线性相关 ,其关系可用方程 Tr=a+b RH+c T+d Q表示。通过蒸腾速率的比较 ,提出了浑善达克沙地植被恢复应以建立“人工疏林草原”为主。     

降水对青杨蒸腾速率及其内部调节机制的影响

降水主要增加３０～８０ｃｍ土层含水量,使空气相对湿度在１３时以前有明显提高,此时气孔导度和叶片水势亦明显提高。雨前青杨蒸腾速率日进程曲线呈双峰型,日均值３８．８μｍｏｌ·ｍ－２·ｓ－１,蒸腾速率主由气孔导度和近叶面空气相对湿度进行调控。雨后蒸腾速率日进程曲线呈单峰型,日均值４９．９μｍｏｌ·ｍ－２·－１,植物蒸腾主受空气相对湿度和土壤水的影响,气孔调节不明显。一日内水分利用效率平均值雨前高于雨后。     

浑善达克沙地土壤水热对黄柳蒸腾速率的影响研究

以浑善达克沙地典型植物黄柳为对象进行研究,测量其生育期蒸腾速率,并对黄柳生长区内的土壤水热进行测量,通过相关分析,确定土壤水热对黄柳蒸腾速率的影响.研究结果表明,黄柳生育期蒸腾速率与相应时间段的土壤含水率呈显著相关,土壤含水率大的时间段,黄柳的蒸腾速率明显增加;不同埋藏深度条件下的土壤温度与黄柳的蒸腾速率相关性较好,土壤含水率和土壤温度对黄柳的蒸腾速率均有影响.     

青海大通几种主要灌木适宜土壤水分条件研究

研究不同土壤水分梯度下盆栽苗木四翅滨藜(Atriplex canescens)、中宁枸杞(Lycium barbarum)、沙棘(Hippophae rhamnoides)的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、水分利用效率(WUE)与土壤含水量(SWC)的关系.结果表明:维持沙棘、四翅滨藜和中宁枸杞净光合速率为最高的土壤含水量分别是18.88%,17.41%和18.49%,三树种维持叶片水分利用效率最佳土壤含水量依次为10.58%,15.3%,12%;土壤水合补偿点分别为4.3%,4.4%,4.54%,最大蒸腾速率的土壤含水量分别为21.25%,22.49%,21.64%,沙棘最适宜的土壤含水量应在10.5%左右,四翅滨藜应在10%～12%,中宁枸杞应在10%～15.5%.     

水分与氮素营养对辽春10号小麦旗叶光合作用的影响

在盆栽条件下,研究不同水分条件下氮素营养对辽春10号春小麦籽粒灌浆期旗叶光合特性的影响.结果表明,随着土壤水分状况的改善,春小麦的光合作用不断增强.土壤相对合水量低于45%时,施氮处理春小麦旗叶气孔导度、蒸腾速率和WUEleaf降低,胞间二氧化碳浓度升高,光合速率受非气孔因素制约而降低.当土壤相对含水量在45%～75%时,随着氮肥施用量的增加和土壤相对含水量的提高,春小麦旗叶的光合效率、气孔导度、蒸腾速率和WUEleaf不断增加,胞间二氧化碳浓度逐渐减小,气孔因素制约了光合效率的提高.当土壤相对含水量高于75%时,氮素营养对春小麦旗叶光合的促进作用减弱.     

驼绒藜属植物蒸腾作用的某些特征

采用快速称重法测定了驼绒藜属 ( Ceratoides)植物 3个种 5个生态型蒸腾速率和失水率叶片离体 1 2分钟内的连续变化。结果发现 ,分段蒸腾速率 ( STR)和分段失水率 ( SDR)表现为无规则律动模式 ,其变幅和节奏具有不可预知性 ;平均蒸腾速率 ( ATR)表现为曲率较小的相对平滑的抛物线。ATR的线性分布较好地体现出植物间蒸腾速率调节能力的差异。华北驼绒藜的 2个生态型和驼绒藜宁夏生态型蒸腾作用的调节能力较强 ,而来自新疆的心叶驼绒藜和驼绒藜新疆生态型调节能力则较弱。不同植物 ATR的线性参数对温度、相对湿度和光照强度的敏感性差异很大。     

石羊河流域下游民勤荒漠植物光谱特征分析

选取石羊河流域下游民勤10种典型荒漠植物进行地面反射光谱测定,通过分析荒漠植物光谱特征、红边参数及对比荒漠植物与农作物光谱数据,提取荒漠植物识别的波段和所需波段光谱分辨率。结果表明:1)10种荒漠植物具有相似的光谱曲线形状,但是不同荒漠植物种由于叶子的组织结构、色素含量和含水量不同,使得反射率大小又具有各自的特点;5个波段区间光谱曲线差异显著,用于识别荒漠植物。2)荒漠植物红边位置都靠近长波方向;沙蒿的红边幅值最大,锦鸡儿最小;沙拐枣的红边面积最大,泡泡刺最小。3)荒漠植物光谱反射特征在680nm、970nm、1450nm和2190nm附近与农作物有较大差异,光谱分辨率在可见光和近红外波段需要30nm或更窄,在中红外波段需要50nm或更窄。     

策勒绿洲前沿两种植物的水分生理生态特征

20 0 3年夏季 ,在策勒绿洲前沿地区同一生境条件下 ,研究了骆驼刺 (Alhagisparsifolia)、多枝柽柳(Tamarixramosissima)水势和蒸腾作用的日变化及其与环境因子的关系。结果表明 :在相同土壤水分条件下 ,多枝柽柳的水势低于骆驼刺的水势。多枝柽柳的蒸腾作用与得到充分水分供应的植物一致 ,而骆驼刺则表现为中午限制供水的植物类型。多枝柽柳和骆驼刺气孔导度的变化是影响蒸腾速率最主要的因子 ,环境因子中气温、大气相对湿度与蒸腾速率的相关性最显著 ;有效光合辐射与水势的相关性最高。大气相对湿度与水势呈正相关 ,与蒸腾速率呈负相关。从两种植物表现出的水势和蒸腾作用的特点看 ,多枝柽柳较骆驼刺更适应所处的生境条件     

荒漠草地植物稳定性氮同位素对水分变化的响应

水分是影响荒漠地区植被分布的重要因素,近年来,我国西部地区的气候正向暖湿化发展,降水的变化势必会对植物N同位素的吸收、分配产生影响。利用¹⁵N标记法,通过不同的增水处理,研究古尔班通古特沙漠南缘标记样地和未标记样地植物N同位素吸收和分配对水分变化的响应,得出以下结论：① 增水处理增加了对土壤水分的补给,显著提高了土壤水分含量;② 未标记样地植物稳定性N同位素的[WTBX]Ndff[WTBZ]值的变化范围为0.39～0.59,其最大值出现在30%增水处理,最小值出现在20%增水处理;③ 氮素标记后,样地植物稳定性N同位素Ndff值明显上升,其变化范围为15.27～31.24。从植物不同部位来看,植物吸收的氮素在植物茎中的分配比例最大,而在根中的分配比例最小。     

大气CO2浓度增加对植物生长的影响

就大气CO2浓度增加对植物光合、呼吸、蒸腾和水分利用效率、植物体内养分含量、生物量、产量的影响,及对C3、C4植物影响的差异等最新研究进展进行了分析综评,并就高CO2浓度与光照、温度、氮素营养水平等环境因子相互作用后植物生长、耐旱性、地理分布等问题进行了讨论。     

Partitioning evapotranspiration of desert plants under different water regimes in the inland Heihe River Basin,Northwestern China

Plant transpiration (T), soil evaporation (E), and the proportion of evaporation in evapotranspiration (ET), and their patterns of change were analyzed in a desert habitat along the middle and lower reaches of the Heihe River Basin, Gansu Province, China. Typical desert plants with different life forms were selected and small lysimeter observations were conducted; various species were measured under two soil water regimes using 50% (FC 50%) and 20% (FC 20%) of field capacity in 2 years. Under the FC 50% treatment the observed ratio of T to ET of desert plants was less than one-third, making the ratio of E to ET greater than two-thirds; the proportion of T to ET of desert plants increased to above 40%, and that of E declined to below 60% under the FC 20% treatment. The lowest T of desert plants was 130–140 mm based on the plant crown projection area. The characteristic coefficient of ET of desert plants was twice that of the characteristic coefficient of transpiration. This study found that when ET was measured for the same desert plant species growing in different regions, the ET differed significantly (P < 0.05) under the same water regimes; when comparing different plant species in the same region no obvious differences in the transpiration water requirement and ET were observed. The proportion of T in ET increased significantly and E in ET decreased markedly (P < 0.05), if the soil moisture content declined to where the plants experienced water stress.     

温带荒漠珍稀濒危植物的引种栽培

我国荒漠大部分属温带荒漠,以干旱、风沙、盐碱、粗瘠和植被稀疏为主要特征。植物种类约有1000余种[1],其中不乏特有种和稀有植物种。与其它地区植物种类一样,随着自然生境的逆转和人类活动范围扩大,不少种濒临灭绝状态。改善自然生态环境,减少人为破坏,就地保护植物种质资源的流失,需通过建立自然保护区加以实现,而迁地保护濒危植物并开展必要的研究、种质保存和繁殖工作,协助自然界保存濒危稀有植物,并为栽培的濒危植物再转入自然生境提供科学依据、繁殖技术和苗木,则是植物园在植物多样性保护工作中的重要任务。     

防护林下草本植物层片物种多样性与环境因子的关系

沿塔里木沙漠公路防护林白北向南设置了10个调查样地,对草本植物的多度、盖度、丰富度进行调查,记录和测定各样地内地下水的埋深、电导率、矿化度,土壤电导率、灌木平均冠幅、灌木层郁闭度等环境因子.分析各样地物种多样性、样地间相似性的差异,以及草本植物层片物种多样性与环境因子的关系.结果表明:塔里木沙漠公路防护林下草本植物层片...     

Differences in response of desert plants of different ecotypes to climate warming:a case study in Minqin, Northwest China

Globally climates are warming.How do desert plants of different ecotypes respond to the climate change?This paper studied the differing responses to climate warming shown by desert plants of different ecotypes through analyzing the phenology and meteorological data of 22 desert plant species growing in Minqin Desert Botanical Garden in Northwest China during the period 1974–2009.The results indicate:(1)The temperature in the study area has risen quickly since 1974,and plants’growing periods became longer.The spring phenology of mesophytes advanced,and the autumn phenology of xerophytes was delayed;(2)The starting dates of spring phenophase of mesophytes and xerophytes differed significantly and both showed an advancing trend;(3)The spring phenology of mesophytes advanced by more days than that of xerophytes,whereas the autumn phenology of mesophytes was delayed by less days than that of the xerophytes;and(4)Mesophytes are more sensitive than xerophytes to rising temperature in spring and falling temperature in autumn.These findings are of value in plant management and regional introduction of different species.     

Combined effects of snow depth and nitrogen addition on ephemeral growth at the southern edge of the Gurbantunggut Desert, China

Water and nitrogen(N) inputs are considered as the two main limiting factors affecting plant growth.Changes in these inputs are expected to alter the structure and composition of the plant community,thereby influencing biodiversity and ecosystem function.Snowfall is a form of precipitation in winter,and snow melting can recharge soil water and result in a flourish of ephemerals during springtime in the Gurbantunggut Desert,ChinaA bi-factor experiment was designed and deployed during the snow-covering season from 2009 to 2010.The experiment aimed to explore the effects of different snow-covering depths and N addition levels on ephemerals.Findings indicated that deeper snow cover led to the increases in water content in topsoil as well as density and coverage of ephemeral plants in the same N treatment;by contrast,N addition sharply decreased the density of ephemerals in the same snow treatment.Meanwhile,N addition exhibited a different effect on the growth of ephemeral plants:in the 50% snow treatment,N addition limited the growth of ephemeral plants,showing that the height and the aboveground biomass of the ephemeral plants were lower than in those without N addition;while with the increases in snow depth(100% and 150% snow treatments),N addition benefited the growth of the dominant individual plants.Species richness was not significantly affected by snow in the same N treatment.However,N addition significantly decreased the species richness in the same snow-covering depth.The primary productivity of ephemerals in the N addition increased with the increase of snow depth.These variations indicated that the effect of N on the growth of ephemerals was restricted by water supply.With plenty of water(100% and 150% snow treatments),N addition contributed to the growth of ephemeral plants;while with less water(50% snow treatment),N addition restricted the growth of ephemeral plants.