Response of the accumulation of proline in the bodies of<Emphasis Type="Italic">Populus euphratica</Emphasis> to the change of groundwater level at the lower reaches of Tarim River

The content of proline in the plant bodies is closely related to the converse-succession-resistant capability of plants. Under the drought stress, the proline accumulates rapidly in the plant bodies for maintaining a certain mois-ture content and an expanding-pressure momentum in cells through the osmoregulation, thus the drought-resis- tant capability and the converse-succession-resistant ca-pability of plants are increased[1,2]. Many researches on the relationship between the proline and the…     

黑河下游荒漠河岸林植物水分传输观测试验研究

荒漠河岸林是长期适应干旱区内陆河流域环境的产物,具有独特的水分利用和生存策略.对黑河下游胡杨、柽柳等主要荒漠河岸林植物液流、水势、木质部导水率、根系水分再分配以及植物水分来源等的测试分析表明,在降水稀少、蒸发强烈的黑河下游,胡杨、柽柳主要利用的是深层土壤水和地下水,其中成熟胡杨主要吸收地下175~325cm处土壤水和地下水供其蒸腾和生存所需;胡杨根系水力提升过程主要发生在10~70cm土层,蒸散导致的土壤耗水量中有10%来自根系提升的水量;植物根和枝条木质部的初始导水率(K_(s0))和最大导水率(K_(s,max))相对较高,其中柽柳木质部的潜在导水能力比胡杨强;胡杨、柽柳液流速度呈单峰型,在午后达到峰值,黎明前水势无显著变化,反映未受到严重水分胁迫;黑河下游河道附近的地下水埋深大多在4m以内,基本可以满足荒漠河岸林植物的生长发育,黑河下游荒漠河岸林生态系统处于稳定和发展状态.     

Photosynthesis of Populus euphratica and its response to elevated CO2 concentration in an arid environment

The photosynthetic characterization of Populus euphratica and its response to the elevated carbon dioxide concentration ([CO2]) were analyzed based on its net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), and water use efficiency (WUE) at different groundwater depths measured by a portable gas exchange system (LI-6400) in the lower reaches of the Tarim River. The results showed that the elevation of [CO2] decreased the gs, and increased the Pn, Ci and WUE of P. euphratica. However, the effects of the elevated [CO2] on gs, Pn, Ci and WUE varied considerably with groundwater depth. The response of photosynthesis to rising [CO2] was stronger at the greater groundwater depth (more than 6 m) than that at the shallower groundwater depth (less than 6 m). The critical groundwater depth required to maintain the normal survival of P. euphratica was less than 6 m. When the groundwater depth increased to more than 6 m, P. euphratica encountered moderate water stress, and the plant suffered severe water stress when the groundwater depth increased to more than 7 m.     

Analysis on water potential of Populus euphratica oliv and its meaning in the lower reaches of Tarim River,Xinjiang

Combined with materials measured on leaves water potential of Populus euphratica oliv in the process of ecological water delivery in the lower reaches of Tarim River, the influence of ground-water depths and soil salinity on leaves water potential of P. euphratica was analyzed. We found that there was evident negative correlation between the leaves water potential of P. euphratica and ground-water depths. The deeper the ground-water depths were, the lower the leaves water potential of P. euphratica was, the more serious drought stress P. euphratica suffered from. Besides, there was evident negative correlation between the soil salinity and the leaves water potential of P. euphratica. The bigger the soil salinity was, the lower the leaves water potential of P euphratica was, the more serious drought stress was indicated from which P. euphratica suffered. For sections rather distant for Daxihaizi Reservoir as well as for those places of wells rather distant from the river course, ground-water depths and the soil salinity were high; the leaves water potential of P. euphratica was low. The leaves water potential of P. euphratica can reflect the degree at which P. euphratica suffers from drought and salt stress, and has an important reference meaning in analyzing proper ground-water depths for the survival and growth of P. euphratic in the lower reaches of Tarim River.     

Arbuscular mycorrhizal fungi infection in desert riparian forest and its environmental implications: A case study in the lower reach of Tarim River

This study was conducted on the desert riparian forest along the lower reach of the inland Tarim River, which is located in the arid region of Northwest China. Fifteen plant species in 10 families were collected from five monitoring sections, and examined for the infection ofarbuscular mycorrhizal fungi （AMF）. The impact of different soil factors on AMF infection rate and intensity was compared using the principal component analysis （PCA） method. The results indicate that 11 species are AM and only 4 are non-AM plants. The estimated capacity of AMF infection depends on families of plants and also the parameters （infection rate, infection intensity, fungal spore density） used. The density of fungal spores was relatively higher in Phragmites communis and Populus euphratica in Graminaceae and Salicaceae families, respectively. The infection rate was above 50% in all the AM plants, except Calligonumjunceum. The highest infection rate appeared in Alhagi sparsifolia （97%） and Glycyrrhizainflata （92%）. However, when compared by AMF infection intensity, Tamarix spp. became the top one, followed by Alhagi sparsifolia, and Glycyrrhiza inflata was in the middle range of all the species. The PCA has identified that soil total salt, moisture, organic matter, total nitrogen, total P, available K and pH were closely associated with the AMF infection.     

Analysis on water potential of Populus euphratica oliv and its meaning in the lower reaches of Tarim River, Xinjiang

Combined with materials measured on leaves water potential of Populus euphratica ofiv in the process of ecological water delivery in the lower reaches of Tarim River, the influence of ground-water depths and soil salinity on leaves water potential of P. euphratica was analyzed. We found that there was evident negative correlation between the leaves water potential of P. euphratica and ground-water depths. The deeper the ground-water depths were, the lower the leaves water potential of P. euphratica was, the more serious drought stress P. euphratica suffered from. Besides, there was evident negative correlation between the soil salinity and the leaves water potential of P. euphratica. The bigger the soil salinity was, the lower the leaves water potential of P. euphratica was, the more serious drought stress was indicated from which P. euphratica suffered. For sections rather distant for Daxihaizi Reservoir as well as for those places of wells rather distant from the river course, ground-water depths and the soil salinity were high; the leaves water potential of P. euphratica was low. The leaves water potential of P. euphratica can reflect the degree at which P. euphratica suffers from drought and salt stress, and has an important reference meaning in analyzing proper ground-water depths for the survival and growth of P. euphratic in the lower reaches of Tarim River.     

Natural diet and food habitat use of the Tarim red deer,Cervus elaphus yarkandensis

In order to determine the natural diet and food habitat use of Tarim red deer (Cervus elaphus yarkandensis), a study was carried out in Qiemo, Xinjiang , China from October 2000 to June 2001. Direct observation combined with faecal analysis method was used to determine the natural diet of red deer. 15 different species of plant were identified as food items. Among them, 13 species of plants were identified in winter diet and 9 species in summer. Red deer consumed a wider range of species in winter because of their nutrient requirement as well as the shortage of food and the scarcity of high-quality forage in the study area. Phragmites communis, Glycyrrhiza inflata and populus diversifo-lia were frequently present in the deer's diet whenever in winter and summer. Among them, Phragmites communis was the most abundant plant in the area and was included in the deer's diet. Observation on food selection frequency of captive Tarim red deer showed that Populus diversifolia was the first preferred species. However, this food was limited in the study area. Five food habitat types were found in the study area according to plant association: (1) Phragmites communis-Tamarix ramosissima association, (2) Tamarix ramosissima-Halostachys cas-pica association, (3) Tamarix ramosissima-Phragmites communis association, (4) Populus diversifolia-Phragmites communis association, (5) Burned area. Among them, Phragmites communis-Tamarix ramosissima association (reed meadow and reed marsh) was preferred to other types within the study area whenever in summer and winter. Dense reed cover could reduce the chance of detection from predator and obstruct attack from predator. Furthermore, under the cover of the reed, Tarim red deer was protected from direct solar radiation during the hours of hot day in summer. The reed meadow and marsh was preferred, presumably because the red deer could minimize their movements while searching for food, water and cover.     

水热因子对塔里木河下游胡杨年轮指数和植被指数的影响

【目的】探索塔里木河流域树木年轮与植被遥感间的关系。【方法】借助树木年轮学的方法和技术手段,利用塔里木河下游10个采样点的胡杨样芯数据和长时间序列中国植被指数(GIMMS NDVI)数据及水热因子数据,在分析该区胡杨年轮指数和植被指数变化特征基础上,重点探讨水热因子、胡杨年轮指数及归一化植被指数(NDVI)三者间的相关性。【结果】胡杨年轮指数和年际NDVI变化在1980—2001年间均呈下降趋势,区内植被在该时间段内退化较为严重。年内NDVI变化呈单峰状,5—8月为植被生长季,1—4月和9—12月为植被非生长季。【结论】该区胡杨年轮生长受5月(P<0.01, 显著负相关)地下水埋深和6月(P<0.01,显著负相关)温度影响显著,而NDVI主要与5—7月(P<0.01, 显著负相关)和10月(P<0.01, 显著负相关)的地下水埋深及7月(P<0.01, 显著负相关)温度有关,且影响NDVI和胡杨年轮指数的主要因子是水热因子中的地下水埋深因子。胡杨年轮指数与NDVI间的相关性差,未能通过0.05水平检验。     

柽柳根系构型对干旱的适应策略

本文分析了塔里木河下游2个不同林龄柽柳(Tamarix spp)根系的构型参数,以了解柽柳对干旱的适应策略.结果表明:1)柽柳的根系拓扑结构受生境和林龄的不同而存在差异,表现为四年生柽柳的根系分支模式接近叉状分支,一年生柽柳根系的分支更趋于鱼尾形分支,且远离积水区一年生柽柳根系的拓扑指数较近积水区一年生柽柳大,根系分枝更简单,表明一年生柽柳在受到水分胁迫时会通过降低根系分支来适应干旱.2)不同生境、林龄的柽柳均表现出长的根系连接长度,但远离积水区较近积水区的一年生柽柳根系连接长度有增加趋势,表明干旱可以促使一年生柽柳根系伸长生长.3)较小的总分支率是柽柳根系的分支特点.一年生柽柳和四年生柽柳根系的分支率存在差异,一年生柽柳较小的主根分支和较大的逐级分支率有助于资源的获取速率和促进主根的向下生长.四年生柽柳主根分支较丰富,逐级分支率由主根向低级根逐级减小,一方面可以满足柽柳对资源的需要,同时通过长的连接长度可以避免根系的重叠和根系间资源的竞争.     

干旱区内陆河流域荒漠河岸林变化研究

新疆塔里木河流域以胡杨为建群种的荒漠河岸林是我国及世界上胡杨分布最为集中的地区之一。通过分析该地区土壤含水率、地下水埋深、地形地貌类型与胡杨空间分布、龄级结构、郁闭度的关系,探讨其生长状况。同时,采用１９８３年、１９９２年及１９９６年遥感信息源编制植被专题图件,在ＧＩＳ支持下处理图件,并应用制图数据及相关自然及人文数据,分析胡杨面积变化及演替规律,强调了系统重建设及恢复的重要作用。     

Assessment of waterrecharging based on ecological features of riparian forest in the lower reaches of Tarim River

The occurrence and development of riparian forests which are mainly dominated by mesophytes species relate closely with surface water. Since there is no water discharge to the lower reaches of Tarim River in past 5 decade years, the riparian forests degrade severely. Based on the analyses of the monitored data of Yingsu, Argan and Luobuzhuang in 2002 and 2003, the effect of water-recharging is discussed. The water-recharging project neglects the fact that that it is flooding that controls the process of Populus euphratica colonizing on the bare surface, but focuses on groundwater influence on vegetation. The flooding control deviates Inherent laws of riparian forests development, so the natural regeneration of riparian forests is checked. The response scope of riparian plants on groundwater uplift is extremely narrow, and most riparian communities have not been optimized. No seedlings of dominant species are found in flooding areas because their physio-ecological characteristics are ignored. The vegetation changes in vicinities of stream only reflect the demand of mesophytes species on the shallow groundwater, however, the water-recharging fails to provide suitable habitats for the seedlings establishment of riparian plants. The present water-recharging scheme is difficult to realize vegetation restoration.     

Assessment of water-recharging based on ecological features of riparian forest in the lower reaches of Tarim River

The occurrence and development of riparian forests which are mainly dominated by mesophytes species relate closely with surface water. Since there is no water discharge to the lower reaches of Tarim River in past 5 decade years, the riparian forests degrade severely. Based on the analyses of the monitored data of Yingsu, Argan and Luobuzhuang in 2002 and 2003, the effect of water-recharging is discussed. The water-recharging project neglects the fact that that it is flooding that controls the process of Populus euphratica colonizing on the bare surface, but focuses on groundwater influence on vegetation. The flooding control deviates Inherent laws of riparian forests development, so the natural regeneration of riparian forests is checked. The response scope of riparian plants on groundwater uplift is extremely narrow, and most riparian communities have not been optimized. No seedlings of dominant species are found in flooding areas because their physio-ecological characteristics are ignored. The vegetation changes in vicinities of stream only reflect the demand of mesophytes species on the shallow groundwater, however, the water-recharging fails to provide suitable habitats for the seedlings establishment of riparian plants. The present water-recharging scheme is difficult to realize vegetation restoration.     

Analysis on water potential of Populus euphratica oliv and its meaning in the lower reaches of Tarim River,Xinjiang

Science Bulletin - Combined with materials measured on leaves water potential of Populus euphratica oliv in the process of ecological water delivery in the lower reaches of Tarim River, the...     

Assessment of water-recharging based on ecological features of riparian forest in the lower reaches of Tarim River

The occurrence and development of riparian forests which are mainly dominated by mesophytes species relate closely with surface water. Since there is no water discharge to the lower reaches of Tarim River in past 5 decade years, the riparian forests degrade severely. Based on the analyses of the monitored data of Yingsu, Argan and Luobuzhuang in 2002 and 2003, the effect of water-recharging is discussed. The water-recharging project neglects the fact that that it is flooding that controls the process of Populus euphratica colonizing on the bare surface, but focuses on groundwater influence on vegetation. The flooding control deviates inherent laws of riparian forests development, so the natural regeneration of riparian forests is checked. The response scope of riparian plants on groundwater uplift is extremely narrow, and most riparian communities have not been optimized. No seedlings of dominant species are found in flooding areas because their physio-ecological characteristics are ignored. The vegetation changes in vicinities of stream only reflect the demand of mesophytes species on the shallow groundwater, however, the water-recharging fails to provide suitable habitats for the seedlings establishment of riparian plants. The present water-recharging scheme is difficult to realize vegetation restoration.

     

汾河河岸植被类型及其利用与保护

汾河发源于山西宁武县境内的管涔山,是黄河水系的干流之一。主要河岸植被类型有旱柳群落、沙棘群落、赖草群落、柽柳群落、芦苇群落、香蒲群落、狭叶香蒲群落、小香蒲群落、草群落、稗草群落、假苇拂子茅群落、苔草群落、鹅绒委陵菜群落、眼子菜群落、蓼群落、狐尾藻群落、水田芥群落、莲群落、蒿群落。最后,提出了对汾河河岸植被保护利用改造的对策。     

聚丙烯酰胺和CO2浓度变化对胡杨叶片光合和水分利用效率的影响

采用盆栽实验研究了不同聚丙烯酰胺用量下较短时间内CO2浓度升高对1年生胡杨叶片光合和水分和用效率的影响。结果表明：（1）随着聚丙烯酰胺用量的减少,土壤水吸力上升,干旱胁迫加重。叶片水势、净光合速率（Pn）、水分利用效率（WUE）、气孔导度（Gs）、蒸腾速率（Tr）随着干旱胁迫的加重而降低,胞间CO2浓度（Ci）则呈上升趋势。（2）随着CO2浓度的升高,各处理的胡杨叶片Pn、WUE、Ci上升,Tr、Gs下降。由此说明：CO2浓度升高对胡杨叶片Pn和WUE的促进作用在一定程度上能缓解干旱胁迫作用;聚丙烯酰胺用量大时,CO2浓度升高对胡杨Pn的促进作用较好;随着外界CO2浓度的升高,气孔关闭,蒸腾速率降低,从而增加了胡杨WUE,这将加强胡杨的耐旱能力。     

塔里木河下游公益林植物群落分类及其群落特征研究

对塔里木河下游公益林30个样地的实际调查资料,运用二元指示种分析（TWINSPAN）对该区植物群落进行了分类,采用物种多样性指数、丰富度和均匀度指数对塔里木河下游的天然植被的物种多样性进行了分析。结果表明,研究区内的植物区系组成贫乏,群落结构简单,多样性指数和丰富度指数均较低,TWINSPAN程序将30个样地划分为9个群落类型。     

崇明东滩芦苇的生态特征及其演替过程的分析

2002年12月~2003年12月,分别在春夏秋冬四个季节对上海市崇明东滩98堤外及堤内湿地恢复生态示范区的芦苇群落的生态特征进行了调查.结果表明,芦苇是本湿地恢复生态示范区中的主要组成种,其盖度达到70％,密度最大为211.83支/m²,最高生物量为1 783.8g/m²,是初级生产力的主要组成部分.在2003年6月以后由于湿地生态示范区内鱼塘水被放干,碱篷和结缕草侵入,群落进入陆生演替阶段.并对湿地恢复和重建工程中人为干扰所造成植物群落的陆生演替进行了主成分分析,证明本地的湿地环境一旦陆化以后植物群落的演替十分迅速,据此我们为生态示范区的植物群落管理措施提出技术性的建议.     

基于多源遥感的和田河流域生态补水对流域植被变化影响研究

利用Landsat遥感影像和MODIS数据集,得到和田河流域沙漠段河流水面面积和植被覆盖面积的时空分布特征．进一步分析归一化植被指数（NDVI）的季节变化特征与景观格局指数,得到和田河流域沙漠段生态环境的空间变化特征．结果表明:生态补水措施增加了流域的水体和植被面积,缓解了生态环境;并且生态补水后河流曲折系数下降,平均水面宽度增加,河流逐步朝平流化方向发展;NDVI的空间分布呈现河流两端植被覆盖量高,中间覆盖量低的特点．分析景观格局指数得到,生态应急补水使和田河流域沙漠段水体景观和植被景观分布呈现聚集分布,有效地缓解了生态环境．      

塔克拉玛干沙漠南缘地下水在脆弱生态环境中的作用

塔克拉玛干沙漠南缘属典型的干旱区内陆盆地生态环境弱带,在绿洲与沙漠相交错分布的干旱生态系统中,地下水显示出重要的生态调控作用。土壤环境（水分、土壤含盐量）受地下水环境状况（地下水位、水质）的制约,从而决定了植被生长情况,地下水埋深地４ｍ时,土壤含水量一般在１１．７％～３３．９％之间变化,茺膜河岸林,柽柳灌丛和多数草木植物均能正常生长,当地下水位埋深大于４ｍ时,天然植物生长明显受到制约,土壤含盐量与