Patterns,magnitude,and controlling factors of hydraulic redistribution of soil water by Tamarix ramosissima roots

Tamarix spp. （Saltcedar） is a facultative phreatophyte that can tolerate drought when groundwater is not accessed. In addition to deep water uptake, hydraulic redistribution （HR） is another factor contributing to the drought tolerance of Tarnarix spp. In this study, data on soil volumetric moisture content （0）, lateral root sap flow, and relevant climate variables were used to investigate the patterns, magnitude, and controlling factors of HR of soil water by roots of Tamarix ramosissima Ledeb. in an extremely arid land in Northwest China. Results showed evident diurnal fluctuations in 0 at the depths of 30 and 50 cm, indicating ＂hydraulic lift＂ （HL）. 0 increased remarkably at 10 and 140 cm but decreased at 30 and 50 cm and slightly changed at 80 cm after rainfall, suggesting a possible ＂hydraulic descent＂ （HD）. However, no direct evidence was observed in the negative flow of lateral roots, supporting HR （including HL and HD） of T. ramosissima. The HR pathway unlikely occurred via lateral roots; instead, HR possibly occurred through adventitious roots with a diameter of 2-5 mm and a length of 60-100 cm. HR at depths of 20-60 cm ranged from 0.01-1.77 mm/d with an average of 0.43 mm/d, which accounted for an average of 22% of the estimated seasonal total water depletion at 0-160 cm during the growing season. The climate factors, particularly vapor pressure deficit and soil water potential gradient, accounted for at least 33% and 45% of HR variations with depths and years, respectively. In summary, T. ramosissima can be added to the wide list of existing species involved in HR. High levels of HR may represent a considerable fraction of daily soil water depletion and substantially improve plant water status. HR could vary tremendously in terms of years and depths, and this variation could be attributed to climate factors and soil water potential gradient.

Intra-annual stem diameter growth of Tamarix ramosissima and association with hydroclimatic factors in the lower reaches of China's Heihe River

High-resolution observations of cambial phenology and intra-annual growth dynamics are useful approaches for understanding the response of tree growth to climate and environmental change. During the past two decades, rapid socioeconomic development has increased the demand for water resources in the oases of the middle reaches of the Heihe River in northwestern China, and the lower reaches of the Heihe River have changed from a perennial river to an ephemeral stream with a decreased and degraded riparian zone. Tamarisk（Tamarix ramosissima） is the dominant shrub species of the desert riparian forest. In this study, the daily and seasonal patterns of tamarisk stem diameter growth, including the main period of tree ring formation, were examined. Observations concerning the driving forces of growth changes, along with implications for the ecology of the dendrohydrological area and management of desert riparian forests in similar arid regions, are also presented. The diurnal-seasonal activity of stem diameter and the dynamics of growth ring formation were studied using a point dendrometer and micro-coring methods during the 2012 growing season in shrub tamarisk in a desert riparian forest stand in the lower reaches of the Heihe River in Ejin Banner, Inner Mongolia of northwestern China. Generally, the variation in diurnal diameter of tamarisk was characterized by an unstable multi-peak pattern, with the cumulative stem diameter growth over the growing season following an S-shaped curve. The period from late May to early August was the main period of stem diameter growth and growth-ring formation. Among all of the hydroclimatic factors considered in this study, only groundwater depth was significantly correlated with stem diameter increment during this period. Therefore, for the dendrochronological study, the annual rings of the tamarisk can be used to reconstruct processes that determine the regional water regime, such as river runoff and fluctuations in groundwater depth. For the management of desert riparian forests, suitable groundwater depths must be maintained in the spring and summer to sustain tree health and a suitable stand structure.

Water use measurement by non-irrigated Tamarix ramosissima in arid regions of Northwest China

Tamarix ramosissima Ledeb. is a typical hardy desert plant growing in arid regions of Northwest China. Sap flow in stems of Z ramosissima plants were measured continuously to determine the diurnal and seasonal variations of sap flow and to understand the water requirements of this species and the response of sap flow to meteorological factors. This article compared the sap flow rate measured by the heat balance method with the transpiration rate measured by rapid weighing, and validated that heat balance sap flow gauges were reliable for monitoring transpiration. The influence of meteorological factors on stem sap flow during the growing season was： solar radiation 〉 vapor pressure deficit 〉 air temperature 〉 rela- tive humidity 〉 wind speed. Bidirectional sap flows occurred at night, and negative sap flow generally corresponded to high atmospheric humidity. The average error in predicted sap flow rate ranged from -0.78% to 14.00% from June to September and for transpiration the average error was 8.19%. Therefore, based on the functional equations between sap flow and meteorological factors as well as sapwood area, transpiration of an individual plant, and even the stand-level transpiration, can be estimated accurately through extrapolation.

不同土壤水盐条件下多枝柽柳(Tamarix ramosissima)对胡杨(Populus euphratica)幼苗的影响

目前胡杨更新困难,种群处于退化阶段,而与其生态位高度重叠的多枝柽柳却在扩张。为探讨多枝柽柳对胡杨生长的影响,本研究设置了3个水平的水分、盐分梯度,对胡杨进行了单种和混种的盆栽控制实验,通过测定胡杨幼苗的生长和存活状况,分析不同水、盐梯度下多枝柽柳如何影响胡杨生长。结果表明:(1)多枝柽柳伴生降低当年生胡杨幼苗的存活率,随着水分条件改善,胡杨存活率提高,而盐分对存活率没有显著的影响。(2)水分、盐分和伴生模式几个因子对胡杨的生长特征的影响存在显著的交互作用(P<0.05)。各水盐条件下,多枝柽柳会不同程度降低胡杨幼苗的株高、主根长和地上地下生物量,而根冠比增大。混种条件下,胡杨幼苗对水盐的响应更为敏感。(3)相对竞争强度对水盐环境有明显的响应(P<0.05),随水分条件改善,地上、地下相对竞争强度降低。多枝柽柳对胡杨的生长产生不良影响的机制是通过快速消耗土壤的水分,从而导致胡杨幼苗水分亏缺。土壤水分条件是胡杨和多枝柽柳幼苗共存的关键因素,在水分供给不足的情况下,对水分偏好的差异导致胡杨无法通过实生苗进行有效的更新从而加剧胡杨种群的衰退,而多枝柽柳更为耐旱的特性使其逐步占据河岸的生境。我们的研究结果强调了两个树种对环境因子的适应性差异决定了河岸带植被发育过程中植物-土壤的相互作用导致胡杨在演替过程中表现出的衰退现象。

NaCl处理对多枝柽柳(Tamarix ramosissima)生长及生理的影响

以1年生多枝柽柳(Tamarix ramosissima)幼株为材料,采用盆栽试验研究不同浓度(0、50、100、200、400mmol·L–1)NaCl处理对多枝柽柳生长状况及叶片过氧化氢(H2O2)、丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)活性,水势,可溶性糖和脯氨酸含量的影响。结果表明:低浓度(≤100mmol·L-1)的NaCl处理对多枝柽柳株高、冠幅面积、分枝数和叶、枝干重具有促进效应;高浓度(≥200mmol·L-1)的NaCl处理抑制了多枝柽柳生长,对侧根干重的抑制作用大于对冠幅面积、分枝数、叶干重、枝干重及株高的抑制。H2O2和MDA含量在低浓度(≤100mmol·L-1)NaCl处理下较对照未出现积累现象,随NaCl浓度升高(≥200mmol·L-1)二者含量较对照出现显著积累。低浓度(≤100mmol·L-1)NaCl处理下,多枝柽柳叶片SOD、POD、CAT和APX活性较对照均有所提高,高浓度的NaCl处理下SOD和POD活性开始降低。多枝柽柳叶片水势随NaCl处理浓度升高呈显著下降趋势。低浓度(≤100mmol·L-1)NaCl处理下脯氨酸和可溶性糖含量较对照呈上升趋势。

塔里木河上游胡杨(Populus euphratica、柽柳(Tamarix ramosissima)水分来源的稳定同位素示踪

通过分析塔里木河上游胡杨(Populus euphratica)、柽柳(Tamarix ramosissima)茎干水和各潜在水源(河水、土壤水、地下水)的δD、δ^(18)O同位素组成,应用多水源混合模型(IsoSource模型)研究了胡杨、柽柳的水分来源和对各潜在水源的利用比例。结果表明:0~100cm土壤水受蒸发影响大,土壤水δ^(18)O值偏大;100~300cm土壤水和地下水δ^(18)O值偏小且各点不存在显著差异。柽柳茎干水的δ^(18)O值小于胡杨,且均随河岸距离增加而减小;在河岸,胡杨最多能利用14.2%的河水,柽柳对河水的利用比例最大达到35.3%,二者对浅层0~100cm土壤水的利用比例较高;远离河岸,胡杨主要利用大于120cm的土壤水和地下水,对地下水的利用比例40%~50%,柽柳以地下水作为其主要水源,最大利用比例达到94.5%。胡杨生长需要适宜的地下水埋深条件(350~420cm),柽柳在浅地下水埋深和大于450cm的深地下水埋深条件下均能良好生长,对不同水分条件的适应能力优于胡杨。

绿洲沙漠过渡带柽柳(Tamarix ramosissima)灌丛沙堆-丘间地系统土壤盐分含量特征

以塔克拉玛干沙漠南缘策勒绿洲西部过渡带为研究区,选取植被盖度为30%、15%~20%、10%、<5%的4个典型样地,对各样地的柽柳(Tamarix ramosissima)灌丛沙堆-丘间地系统典型部位0~10cm和10~20cm土壤进行系统采样,测定土壤pH值及总盐、Cl^-、Na^+、K^+、SO_4^(2-)、Ca^(2+)、Mg^(2+)、CO_3^(2-)、HCO_3^-含量,从风沙地貌的角度探讨过渡带沙漠化进程中土壤盐分分异规律。结果表明:随着植被总盖度的降低,0~10cm层土壤pH值及总盐、Cl^-、K^+、Na+含量总体呈先升高后降低的趋势;土壤SO2-4和Ca^(2+)含量呈先降低后升高的变化趋势;Mg^(2+)含量随着植被盖度的变化没有明显的变化规律。灌丛下→沙堆边缘→丘间地→风影区,总盐、Cl^-、K^+、Na^+、SO_4^(2-)、Ga^(2+)、Mg^(2+)含量呈先减小后增大的变化规律,最大值均位于灌丛下,最小值位于丘间地;pH值和HCO_3^-含量大体呈先升高后降低的趋势,最小值位于灌丛下,最大值多位于丘间地,二者存在中度相关(r=0.644)。与0~10cm土层相比,10~20cm总盐、Cl^-、K^+、Na^+含量明显增加,SO_4^(2-)、HCO_3^-、Ga^(2+)含量降低,Mg^(2+)含量和pH值没有明显的变化。两土层各盐分含量随植被盖度的梯变呈相对一致的变化趋势。在不同的环境条件下,以蒸腾作用、泌盐作用和根系的选择性吸收作用等为主的生物积盐作用与地下水蒸发聚盐以及地表风蚀强度等非生物因素之间的平衡关系,应该是影响绿洲沙漠过渡带柽柳灌丛沙堆盐岛效应强弱的关键因素。

高光谱指数法用于确定多枝柽柳(Tamarix ramosissima)蒸腾速率

蒸腾速率(Tr)是植物生理生态学研究中表征蒸腾耗水的常用指标,研究植物的蒸腾耗水有助于了解当地生态系统稳定性和水资源的可持续利用,但在遥感应用尤其在干旱区遥感应用中很少被使用。本文以古尔班通古特沙漠南缘的主要建群种多枝柽柳(Tamarix ramosissima)作为研究对象,应用高光谱指数法对其Tr日变化过程进行研究,寻找和确定最佳的Tr光谱指数。选择的6个光谱指数判定系数R2介于0.06~0.73,其中简单比值(SR)光谱指数有最高的判定系数(R2=0.73)、较低的均方根误差(RMSE=0.24)和较为简单的形式,光谱范围处于近红外波段(1 645~1 655nm)/(1 775~1 785nm)。SR作为Tr最佳光谱指数,对植被水分关系变化敏感,能够较好地记录和监测Tr日变化过程,有益于揭示光谱指数物理和生理机制。

大理多花山矾扦插繁育技术研究

[目的]研究提高多花山矾(Symplocos ramosissima)插穗生根率和生根质量的方法。[方法]以大理多花山矾枝条为材料,探讨不同生长调节剂、育苗基质对扦插苗生根和移植生长的影响,并筛选出扦插苗苗期适宜基肥施用量,以提高扦插苗移植的成活率。[结果]扦插前将穗条在ABT 400 mg/L+IAA 200 mg/L的混合溶液中浸蘸30 s,可以获得较好的成活率和生根效果。选取66.7%园土+33.3%椰糠混合基质进行移植,可促进多花山矾扦插苗的成活以及生长。适合多花山矾扦插苗的基肥施用最佳方案为复合肥2 g/株+复合生物菌剂1 g/株。[结论]研究得出适宜多花山矾扦插苗成活及生长的生长调节剂、育苗基质及基肥,可为多花山矾苗木生产提供良好的技术支撑。

胡杨(Populus euphratica)与柽柳(Tamarix ramosissima)径向生长特征对比

基于对额济纳旗胡杨(Populus euphratica)和柽柳(Tamarix ramosissima)生长季树干的径向生长变化监测,以及气温、空气相对湿度和地下水位等环境因子的同步监测,利用突变检验和相关分析方法,对两树种日-季节尺度径向生长时间节点、阶段等特征及其环境因子响应模式进行了对比研究。结果显示:在两树种径向生长变化特征方面,日尺度上,胡杨每日径向生长最大值点出现和结束时间均比柽柳早3h左右;季节尺度上,胡杨进入快速生长阶段的时间迟于柽柳,并且比柽柳结束要早,持续时间短于柽柳。在环境响应机制方面,胡杨日收缩极值(eMDV)、日膨胀极值(iMDV)和日净生长量(ΔR)阶段变化平均值为柽柳的3倍以上,变化幅度也相对较大;两树种上述径向生长参数与气温和地下水埋深等因子日-季节尺度的响应模式基本一致,快速生长期的地下水位变化影响更为显著,尤其对于柽柳。研究结果对于荒漠河岸林可持续发展及内陆河流域水资源管理具有重要意义。

古尔班通古特沙漠西南缘多枝柽柳生理特性对沙堆不同堆积阶段的响应

多枝柽柳作为干旱荒漠区重要的防风固沙灌木,其长期与风沙作用过程中形成了柽柳灌丛沙堆,在维持区域生态环境稳定及遏制沙漠蔓延方面发挥着重要作用。以古尔班通古特沙漠西南缘地区不同发育阶段沙堆上生长的多枝柽柳(Tamarix ramosissima)为研究对象,以空间序列代替时间序列的方法模拟沙堆堆积发育过程,揭示多枝柽柳生理特征对沙堆不同堆积发育阶段的响应及适应机制。结果表明:(1)在沙堆堆积发育过程中,多枝柽柳叶片相对含水量(RWC)及自由水/束缚水(Vs/Va)均呈先上升后下降的变化,其中,在增长阶段沙堆上最高,衰退阶段沙堆上最低,水分饱和亏(WSD)则呈相反趋势;组织含水量(TWC)呈逐渐上升的变化,清晨水势(Ψ_(PD))及正午水势(Ψ_(MD))呈逐渐降低的变化。(2)在沙堆堆积发育过程中,多枝柽柳的光合有效辐射(PAR)、叶片温度(TL)、光合电子传递速率(ETR)以及调节性能量耗散[Y_((NPQ))]日变化均呈先上升后下降的变化,衰退阶段沙堆上多枝柽柳各参数的日均值最大;各发育阶段沙堆上多枝柽柳的非调节性能量耗散[Y_((NO))]日变化均呈先下降后上升的变化,实际光化学效率[Y_((II))]日变化均呈“N”型,且Y_((II))日均值大小依次为增长阶段沙堆(0.489)>稳定阶段沙堆(0.463)>雏形阶段沙堆(0.455)>衰退阶段沙堆(0.439)。(3)气温(TEMP)和PAR与叶片Y_((II))均呈显著负相关,与ETR均呈显著正相关;Y_((II))与ETR、Y_((NO))与Y_((NPQ))均呈现显著负相关;PAR、TEMP是影响不同堆积阶段沙堆上多枝柽柳生理特性的主要环境因子。综合分析表明,在沙堆堆积发育过程中,多枝柽柳可通过调节光合作用和水分利用之间的协同关系来响应微环境的变化,从而减少其脱水风险以实现最大程度资源利用。

Influence of moisture on the growth and biomass allocation in Haloxylon ammodendron and Tamarix ramosissima seedlings in the shelterbelt along the Tarim Desert Highway, Xinjiang, China

The authors studied the effects using three different levels of irrigation on the growth and biomass allocation in H. ammodendron and T. ramosissima seedlings in the shelterbelt along the Tarim Desert Highway. The three irrigation amounts were 35 (CK), 24.5 (treatment 1), and 14 (treatment 2) kg·ind. plant-1·once-1, respectively. The results show that (1) the vertical depth of the two seedlings’ root increased with lower levels of irrigation showing that the two species adapted to decreased irrigation by root elongation in the hinterland of the Taklimakan Desert, and the vertical root depth of H. ammodendron under treatment 2 was notably higher than CK. (2) Compared with CK, the belowground biomass of treatment 1 and 2 both showed a significant increase as follows: H. ammodendron seedlings in- creased by 14.51% and 37.03% under treatment 1 and 2, respectively, while T. ramosissima seedlings increased by 68.19% and 25.78% under treatment 1 and 2, respectively. This means that H. ammoden- dron seedlings were more adapted to the conditions in treatment 2 while T. ramosissima seedlings were better adapted to treatment 1 conditions. (3) When compared with CK, the fine root bomass of these two species all exhibited some increase under both treatments, and ANOVA analysis showed that the biomass of deep layer root of the two species under treatment 2 was notably higher than CK and treatment 1. This should help seedlings to more effectively absorb soil water from deep layers during dry conditions. (4) The root-shoot ratio was different for these two species. For H. ammodendron seed- lings, the root-shoot ratio was less than 1, while for T. ramosissim seedlings it was larger than 1. The root-shoot ratio of H. ammodendron seedlings increased with decreasing levels of irrigation, and that of T. ramosissim seedlings also increased under treatment 2. (5) With decreasing levels of irrigation, due to the difference of species, the growth variation of aboveground indexes was also different, while compared with CK, it was not significant.

Physiological response of Tamarix ramosissima under water stress along the lower reaches of Tarim River

Tamarix ramosissima is one of the con- structive species growing on both sides of Tarim River which is favorable to constituting a natural bar- rier containing local deserts and protecting the oasis. By analyzing characteristics of the main physiological indexes, such as chlorophyll, soluble sugar, proline (Pro), malondialdehyde (MDA), superoxide dismu- tase (SOD), peroxidase (POD), indole-3-acetic acid (IAA), C3-gibberellins (GA3) and abscisic acid (ABA), at different sections with different water tables in the lower reaches of Tarim River, it has been found that these physiological indexes have close correlations with water tables. In addition, the rational ecological, coercing and critical water tables of T. ramosissima are 2-4 m, 6 m and 10 m, respectively, which pro- vides an important theoretical basis for the ecological conservation of extremely arid regions.

水盐梯度下湿地柽柳(Tamarix ramosissima)光合响应特征和水分利用效率

光合响应特征与水分利用效率研究对深入理解柽柳(Tamarix ramosissima)对水盐胁迫的适应性机制十分必要,可为荒漠绿洲湿地盐渍化的改善和治理提供科学指导。以荒漠绿洲湿地柽柳为研究对象,利用Li-6400光合仪测定水盐梯度下柽柳的光合参数及其对光强的响应,探讨水盐梯度对荒漠绿洲湿地植物光合作用和水分利用效率的影响机制。结果表明:荒漠绿洲湿地柽柳的净光合速率(P_n)呈不对称双峰型日变化趋势,河岸灌木、盐沼和绿洲草地湿地的次峰较主峰分别下降19%、8.5%和11.2%;蒸腾速率(T_r)表现为单峰型。在同一水盐环境下,柽柳的Pn和水分利用效率(WUE)随光合有效辐射(PAR)的增强先快速升高后渐趋平缓。Tr对PAR的增强表现均不敏感。盐沼湿地柽柳的最大净光合速率、光饱和点与表观量子效率均最大,光补偿点最小。柽柳光饱和点512.67~1 790μmol·m^(-2)·s^(-1),光补偿点16.28~19.23μmol·m^(-2)·s^(-1)。适度的水盐含量会促进光合作用,水盐含量过高或过低均会抑制光合速率。盐分含量越低,荒漠绿洲湿地柽柳适应光强的范围越广。适度的水分含量下降可促进水分利用效率的提高。

Impacts of predictor variables and species models on simulating Tamarix ramosissima distribution in Tarim Basin, northwestern China

Aims Preserving and restoring Tamarix ramosissima is urgently required in the Tarim Basin,Northwest China.Using species distribution models to predict the biogeographical distribution of species is regularly used in conservation and other management activities.However,the uncertainty in the data and models inevitably reduces their prediction power.The major purpose of this study is to assess the impacts of predictor variables and species distribution models on simulating T.ramosissima distribution,to explore the relationships between predictor variables and species distribution models and to model the potential distribution of T.ramosissima in this basin.Methods Three models—the generalized linear model(GLM),classification and regression tree(CART)and Random Forests—were selected and were processed on the BIOMOD platform.The presence/absence data of T.ramosissima in the Tarim Basin,which were calculated from vegetation maps,were used as response variables.Climate,soil and digital elevation model(DEM)data variables were divided into four datasets and then used as predictors.The four datasets were(i)climate variables,(ii)soil,climate and DEM variables,(iii)principal component analysis(PCA)-based climate variables and(iv)PCA-based soil,climate and DEM variables.Important Findings The results indicate that predictive variables for species distribution models should be chosen carefully,because too many predictors can reduce the prediction power.The effectiveness of using PCA to reduce the correlation among predictors and enhance the modelling power depends on the chosen predictor variables and models.Our results implied that it is better to reduce the correlating predictors before model processing.The Random Forests model was more precise than the GLM and CART models.The best model for T.ramosissima was the Random Forests model with climate predictors alone.Soil variables considered in this study could not significantly improve the model’s prediction accuracy for T.ramosissima.The potential distribution area of T.ramosissima in the Tarim Basin is;3.57310^(4) km^(2),which has the potential to mitigate global warming and produce bioenergy through restoring T.ramosissima in the Tarim Basin.

基于网络药理学和分子对接技术初探红柳治疗酒精性肝损伤的作用机制及实验验证

目的 基于网络药理学和分子对接技术,研究天然植物红柳治疗小鼠酒精性肝损伤(ALI)的作用机制。方法 使用TCMSP平台,以口服利用度≥30%和类药性≥0.18分别作为预设条件,对红柳活性化学成分进行筛选;使用GeneCards、DrugBank等数据库,筛选ALI相关靶点;通过VennDiagram软件获得交集靶点(红柳和ALI);根据疾病-活性成分-交集靶点网络数据,最终遴选出主要活性成分和致病的关键靶点进行分子对接。动物实验采用慢性酒精喂养加急性灌胃法建立C57BL/6J小鼠ALI模型。通过丙二醛(MDA)、谷草转氨酶(AST)、谷丙转氨酶(ALT)、肝脏指数、HE染色、NF-κB p65蛋白表达水平等指标验证红柳对ALI的作用机制。结果 通过网络药理学从红柳中筛选获得活性成分12个,与ALI交集靶点共151个。推测红柳的主要活性成分为槲皮素、山柰酚、异鼠李素等,通过RELA/NF-κB p65、JUN、MAPK1、AKT1等关键靶点调节脂质-动脉粥样硬化、糖尿病并发症AGE-RAGE以及流体剪切应力-动脉粥样硬化等信号通路来发挥抗ALI作用。分子对接显示红柳主要活性成分与通路关键靶点蛋白结合能量均≤-28.8696 kJ·mol^(-1)。动物实验结果显示,与模型组相比,红柳组肝脏指数、MDA、ALT、AST和NF-κB p65水平均有所下降,HE染色显示肝组织变性情况减轻。结论 本研究初步揭示了红柳可通过多化学成分、多靶点、多通路对ALI起一定的保护作用,为天然药用植物的开发和利用提供了理论参考。

Effect of Vigna radiata, Tamarix ramosissima and Carthamus lanatus extracts on Leishmania major and Leishmania tropica: An in vitro study

Objective:Current therapy strategies of leishmaniasis have some problems such as high cost,toxicity and side effects.Plant extracts can be a source of drugs to control leishmaniasis.In this study,the effect of hydroalcoholic and chloroformic extracts of Vigna radiata,Tamarix ramosissima,and Carthamus lanatus on Leishmania major and L.tropica was studied.Methods:The plant samples were collected from west of Iran and their extracts were prepared.Antipromastigote activity assay of all extracts was done using tetrazolium-dye assay.Results:Only high concentrations of V.radiata and C.lanatus were able to inhibit Leishmania,while both high and low concentrations of T.ramosissima had antileishmanial effect.No difference was observed between hydroalcoholic with chloroformic extract of each plant.Conclusion:Altogether,the results revealed the antileishmanial activity of T.ramosissima extracts against L.major and L.tropica,indicating its potential as an antileishmanial agent.

极端干旱区多枝柽柳叶片功能性状及其与土壤理化因子的关系

叶片是植物获取资源的重要器官,研究其功能性状与环境因子的关系,有助于更好地了解植物对环境要素变化的生态适应性。以塔里木盆地北缘不同生境下(绿洲、过渡带、荒漠)典型荒漠植物多枝柽柳(Tamarix ramosissima)为研究对象,分析其叶片结构和生理性状在不同生境间的差异,建立叶片性状与土壤理化因子的相关关系,解析荒漠植物的生态适应性并揭示影响荒漠植物叶片功能性状的关键环境因子。结果表明:(1)多枝柽柳叶片功能性状具有不同程度的变异,其中叶片面积变异幅度最大(40%),比叶面积、可溶性蛋白含量等变异幅度最小(均为15%)。(2)多枝柽柳叶片厚度和叶片面积等结构性状以及叶片可溶性蛋白、脯氨酸、淀粉含量等生理性状在不同生境中均具有显著差异(P<0.05),其中可溶性蛋白、脯氨酸含量均在荒漠生境中达到最高。(3)多枝柽柳叶片部分功能性状之间存在显著的相关关系,其中叶片厚度、淀粉含量等与叶组织密度呈显著负相关关系(P<0.05),而叶片厚度与淀粉含量之间、可溶性糖含量与非结构性碳水化合物含量之间均呈极显著正相关关系(P<0.01)。(4)通过RDA排序分析发现,土壤速效磷含量、土壤含水量、pH、容重等土壤环境因子影响较大,对多枝柽柳叶片功能性状有较好的解释。研究表明多枝柽柳通过叶片功能性状变化以及性状之间协同-权衡的生态对策来适应极端干旱环境,土壤水分和速效磷含量是影响其叶片功能性状最关键的土壤环境因子,研究可为极端干旱区荒漠植被的科学管理、保护和恢复提供理论依据。

四翅滨藜和多枝柽柳对土壤干旱的响应差异

在干旱区防护林建设中,选择抗逆性和适应力强的植物树种是关键。通过模拟不同干旱梯度的盆栽控水试验来比较塔里木盆地引种植物四翅滨藜和乡土植物多枝柽柳对干旱胁迫生态适应性差异。结果表明:(1)随着干旱程度增加,四翅滨藜和多枝柽柳叶片含水量均逐渐降低,保水力、脯氨酸含量、相对电导率逐渐增大。四翅滨藜和多枝柽柳的可溶性糖含量、丙二醛含量分别在轻度、重度干旱下达最大值,多枝柽柳的增幅更大。(2)四翅滨藜和多枝柽柳POD活性逐渐增大,重度干旱下,多枝柽柳较对照增加的百分比约为四翅滨藜的3倍;在中度干旱下SOD活性最大,多枝柽柳较对照增加的百分比约为四翅滨藜的5倍。多枝柽柳2种酶活性变化均大于四翅滨藜。(3)四翅滨藜和多枝柽柳叶绿素含量均为:轻度干旱>对照>中度干旱>重度干旱,多枝柽柳的净光合速率、蒸腾速率、气孔导度和胞间二氧化碳浓度均逐渐降低,轻度干旱对四翅滨藜叶绿素和光合能力有略微促进作用。(4)相关性和主成分分析结果显示,干旱胁迫下多枝柽柳各性状间的联系更紧密,四翅滨藜不易改变性状和性状之间的联系,相对保守。四翅滨藜受到干旱胁迫的影响较小,其干旱适应性略强于多枝柽柳。

额济纳绿洲不同土壤水盐条件多枝柽柳对胡杨种群分布的影响

【目的】生态输水工程实施后,胡杨种群得到了一定的恢复,但恢复效果远不如与其生态位高度重叠的多枝柽柳显著。本研究拟探讨不同土壤水盐环境下,胡杨种群的适应优势是否受到多枝柽柳伴生的影响,以期为胡杨林的保护管理和绿洲生态输水方案制定提供科学参考。【方法】本研究以西北干旱区河岸林群落的关键建群种胡杨和多枝柽柳为研究对象,选取目前野外常见的两种土壤水盐生境(相对高水高盐和水盐适中),分析两个物种种群空间分布及其与水盐的相互关系。【结果】(1)在相对高水高盐的环境中,胡杨种群呈现衰退趋势,幼龄木极少且更新受限,而多枝柽柳则表现稳定状态。水盐适中的环境中,胡杨种群结构稳定,各龄级相差不大,多枝柽柳种群则表现为增长趋势。(2)不同土壤水盐条件下,两个物种主要以聚集分布为主以抵抗不良环境的胁迫,胡杨幼苗的生长还会受多枝柽柳伴生抑制。(3)不同的土壤水盐条件会造成两物种多度的差异。多枝柽柳与胡杨种群个体数的比值均与盐分呈正相关,但在盐分含量不高时,随水分的增加,多枝柽柳种群个体数量减少,胡杨种群个体数量则增多。【结论】本研究结果进一步验证:除环境过滤作用外,多枝柽柳的竞争也是目前胡杨在演替过程中表现出衰退现象的一个重要因素。在高盐环境中多枝柽柳会逐渐取代胡杨,水分条件的改善可以减缓这种趋势的发生。