胡杨光合蒸腾与影响因子间关系的研究

对胡杨光合速率和蒸腾速率同各主要影响因子间相关关系进行了研究。结果表明:胡杨光合速率和气孔导度间呈对数关系,蒸腾速率与气孔导度间呈线性关系;两者与光合有效辐射均呈多项式关系;与空气温度均呈二项式关系。结果说明胡杨属气孔限制型植物,气孔导度和光合有效辐射共同决定胡杨的光合和蒸腾作用。气温和相对湿度通过影响胡杨的气孔导度进而影响胡杨的光合速率和蒸腾速率。适宜胡杨进行光合气体交换的环境条件是光合有效辐射保持在1700μmol.m-2.s-1左右,温度保持在35℃左右,相对湿度保持在20%-30%间。     

黑河下游胡杨林耗水规律研究

2003年5-10月,对黑河下游额济纳绿洲中一块25年生的胡杨林耗水进行了研究,结果表明通过标准木的标准比导率和树木胸径和边材面积的相关模型,可以比较准确地推算出林分的蒸腾耗水量。胡杨林的蒸腾耗水量具有明显的季节差异;胡杨幼林在生长季节耗水量为213.4mm。林分的生长状况主要受地下水位和土壤含水量的影响。     

黑河中游湿地胡杨蒸腾速率与叶性状的关联性分析

干旱区湿地植物叶片蒸腾作用与叶性状的关联性研究,对揭示植物叶片叶脉网络性状、叶片形态构建模式与植物体内水分平衡间的内在联系至关重要.以黑河中游湿地胡杨(Populus euphratica)为研究对象,按胡杨林距离水域的远近分别设置:I(离水域30～110 m,土壤含水量(SMC)58.23％)、II(离水域160～2...     

Retrieval of leaf biochemical properties by inversed PROSPECT model and hyperspectral indices: an application to Populus euphratica polymorphic leaves

Leaf biochemical properties have been widely assessed using hyperspectral reflectance information by inversion of PROSPECT model or by using hyperspectral indices,but few studies have focused on arid ecosystems.As a dominant species of riparian ecosystems in arid lands,Populus euphratica Oliv.is an unusual tree species with polymorphic leaves along the vertical profile of canopy corresponding to different growth stages.In this study,we evaluated both the inversed PROSPECT model and hyperspectral indices for estimating biochemical properties of P.euphratica leaves.Both the shapes and biochemical properties of P.euphratica leaves were found to change with the heights from ground surface.The results indicated that the model inversion calibrated for each leaf shape performed much better than the model calibrated for all leaf shapes,and also better than hyperspectral indices.Similar results were obtained for estimations of equivalent water thickness (EWT) and leaf mass per area (LMA).Hyperspectral indices identified in this study for estimating these leaf properties had root mean square error (RMSE) and R 2 values between those obtained with the two calibration strategies using the inversed PROSPECT model.Hence,the inversed PROSPECT model can be applied to estimate leaf biochemical properties in arid ecosystems,but the calibration to the model requires special attention.     

Physiological responses of Populus euphratica Oliv. to groundwater table variations in the lower reaches of Heihe River, Northwest China

Riparian vegetation in the lower reaches of Heihe River serves important ecological functions. However, the riparian ecosystems have been constantly deteriorating in the past 30 years simply due to water interception for oasis agricultural irrigation in the middle reaches of the river. This study pays a particular attention to Populus euphratica Oliv. forest because it is a dominant component of the riparian ecosystem in the lower reaches of Heihe River where the depth of groundwater table is the controlling factor in sustaining riparian ecosystems. To reveal leaf-related physiological responses of Populus euphratica Oliv. forest to groundwater table variations, we analyzed the relationships between the depth of groundwater table (DG) and three leaf-related parameters, i.e. leaf stomatal density (SD), specific leaf area (SLA), and stable carbon isotopic composition (δ 13 C). Our results show that the relationship between DG and leaf SD is a bi-mode one shaped by both salt stress and water stress. That is, salt stress appeared in shallow groundwater conditions and water stress happened in deep groundwater conditions, and the thin layer around 2.7 m of DG is a stress-free layer. Leaf SD fluctuated according to the DG variation, first decreased with increasing DG, then increased at depths ranging 2.7-3.7 m, and after a relatively stable plateau of SD at depths ranging 3.7-5.2 m, decreased again with increasing DG. Our results also show that SLA decreased exponentially with increasing DG and foliar δ 13 C values are also strongly dependent on DG, further demonstrating that these two parameters are sensitive indicators of water stress. The exponential curve suggests that SLA is more sensitive to DG when groundwater table is shallow and 3 m seems to be a threshold beyond which SLA becomes less sensitive to DG. Foliar δ 13 C becomes more sensitive when the groundwater table is deep and 7 m seems to be a threshold below which the δ 13 C signature becomes more sensitive to DG. These findings should be helpful in monitoring the growth and development of Populus euphratica Oliv. forests and also in providing protection measures (i.e. DG related) for Heihe River riparian forests.     

胡杨叶形变化与POD同工酶的关系研究

以5个不同发育阶段的胡杨植株为研究对象,调查各发育阶段胡杨植株树冠不同层次当年生枝同一节位叶片的叶形指数,同时测定其POD同工酶酶谱和酶活性,探讨不同发育阶段胡杨植株叶形的变化规律和POD同工酶酶谱及酶活性间的关系。结果表明:(1)不同发育阶段的胡杨植株都表现出叶形指数随冠层的升高而减小;(2)不同发育阶段的胡杨植株都表现出单株不同冠层叶片中POD同工酶表达具有高度的稳定性和相似性,酶谱带型基本一致,而不同发育阶段的胡杨植株间POD同工酶酶谱在质(酶带数目和迁移率)和量(酶的活性)上表现出不同程度的差异;(3)不同发育阶段的胡杨植株均表现为树冠不同层次当年生枝叶片的叶形指数与POD酶活性极显著正相关(r=0.668,p<0.01)。     

土地利用变化对塔里木河中游胡杨林的影响研究

本研究区位于塔里木河中游地区,本研究选取耕地变化、输水堤防的建设以及油气田开发三种土地利用方式,在大量野外调查的基础上,在3S技术和历史数据的支持下,分析了这些土地利用方式变化对胡杨林生态系统的影响。研究结果表明:研究区1992年之后内耕地大量增加,输水堤防对堤防内外侧胡杨生态系统具有不同影响,油气田开发会造成生态破坏和环境污染等问题。     

荒漠河岸林地区胡杨幼苗根系水力提升作用探究

植物水力提升作用是指低蒸腾条件下处于湿润区域根系吸水后运输到干燥区,并将水分释放到根际周围的干土中的现象。通过上下层分根试验法,研究生长季胡杨幼苗的根系提水作用。结果表明：① 与成年胡杨相似,胡杨幼苗根系存在水力提升作用;② 幼苗的水力提升作用发生在21:00 时至次日6:00时 ,生长季3株胡杨幼苗的总提水量分别为2.78 kg,2.31 kg和2.46 kg,日均提水量为0.022 6 kg,0.018 7 kg和0.02 0 kg;③ 3株胡杨幼苗的日均提水量占上层土壤蒸发量的13%~20%,在植物蒸腾作用明显的7~8月,日均提水量也较大;④ 下层土壤的根系生物量和提水量相关性显著。     

瓜州绿洲胡杨林下土壤水分空间特征研究

利用地统计学方法及ArcGIS中的Kriging空间插值法对瓜州绿洲胡杨林下土壤含水量的空间变化规律进行了研究.结果表明:在垂直方向上,QZ、SG和BL三个样地的土壤含水量随深度的增加而增加,TG样地,由于土壤板结,导致其含水量随深度的增加呈减少趋势.瓜州绿洲胡杨生长阶段与其林下土壤含水量呈负相关关系,且土壤含水量越向...     

不同配置城市防护绿地中胡杨构型特征

应用枝系构型理论,研究了胡杨在克拉玛依市防护林中的分枝构型的特征,并重点针对3种配置类型:胡杨(Populus euphratica Oliv.)×沙枣(Elaeagnus angustifolia L.)、胡杨×银白杨(Populus alba L.)和胡杨×白榆(Ulmus pumila L.),分析了胡杨分枝构型在不同配置中的变化。结果表明:防护绿地中胡杨不同部位(树冠)构型格局中,各级分枝长度数值和各级分枝角度数值从上到下均表现为逐渐变大的趋势;不同配置类型对胡杨构型特征(主要表现在分枝角度和分枝长度两个指标)的影响存在显著差异,影响力大小依次为胡杨×银白杨、胡杨×白榆、胡杨×沙枣。     

胡杨和灰叶胡杨锈菌夏孢子形态和侵染结构观察

 借助直接观察、显微和超微结构观测等手段,对胡杨和灰叶胡杨锈病显症叶片、锈菌夏孢子的形态、孢子萌发和侵染结构进行了观测。结果表明,胡杨和灰叶胡杨的锈菌夏孢子堆、夏孢子形态结构相似;夏孢子堆散生于叶片正反两面,近半球形或半椭球形,呈橙黄色或金黄色;夏孢子散落分布于叶片正反两面,圆形或卵圆形,透明、橙黄色,厚壁,单胞,表面密生刺瘤;胡杨和灰叶胡杨锈菌夏孢子的长轴和短轴长度、刺瘤高度及刺瘤间距四项指标均无显著性差异;夏孢子萌发产生芽管后形成菌丝,通过叶表气孔直接侵染叶片,以菌丝的形式在叶片组织内扩展。     

额济纳绿洲胡杨种群结构与分布格局研究

在内蒙古阿拉善盟额济纳旗一道桥、二道桥、三道桥、和四道桥的胡杨自然保护区内设置9个10m×10m样地,应用相邻格子法进行每木调查,并对胡杨(Populus euphratica)种群结构和分布格局进行了分析。结果表明:胡杨的种群结构为衰退型,幼苗、幼树和中龄树数量较小。额济纳胡杨种群整体分布格局为聚集分布,随着径级的增大其分布格局呈现规律性变化,幼小植群呈强聚集分布,大树倾向于随机分布,中龄树和成年树由聚集分布向随机分布过度。     

胡杨不同发育阶段叶片形态解剖学特征及其与胸径的关系

采用MSR-9600TFU2扫描仪和常规石蜡切片,分析胡杨不同发育阶段叶片形态解剖学特征及其与胸径的关系。结果表明:1叶片宽、叶面积、气孔密度、厚度均随胸径增加沿树冠基部向顶部方向逐渐增大,叶片长和叶形指数则随胸径增加沿树冠基部向顶部方向逐渐减小。2叶片上下表皮细胞数和表皮细胞长、栅栏组织厚度、栅栏组织细胞长和宽均随胸径增加沿树冠基部向顶部方向逐渐增大;海绵组织厚度随胸径的增加而逐渐减小,树冠基部向顶部方向则逐渐增大。3相关分析显示,叶片宽、叶面积和叶片厚度分别与胸径呈极显著/显著正相关,叶形指数与胸径呈极显著负相关;叶片栅栏组织厚度、表皮细胞数、表皮组织厚度、表皮细胞长分别与胸径呈极显著/显著正相关,海绵组织厚度与胸径呈极显著负相关;叶片形态指标与解剖结构指标间也存在正/负相关关系,表明胡杨叶形态结构变化与个体发育阶段密切相关。     

植物水分运转影响因子的研究进展

影响植物水分运转的主要因子有气象因子(包括太阳辐射、大气温度、大气湿度、风速、CO2浓度等)、土壤的水分状况、气孔导度、植物叶面积、水分在植物体内的传输阻力等。大量研究表明:植物蒸腾的日变化主要是由气象因子的日变化引起的,而蒸腾的年变化主要与土壤的水分状况、叶面积动态和气候条件有关。此外,组织贮存水和导管的空穴对植物的水分运转也有一定的影响。     

Response of stomatal conductance of two tree species to vapor pressure deficit in three climate zones

Stomatal behavior is a central topic of plant ecophysiological research under global environmental change. However, the physiological mechanism controlling the response of stomata to vapor pressure deficit(VPD) or relative humidity(RH) has been inadequately understood till now. In this study, responses of stomatal conductance(gs) to VPD in two species of trees(Fraxinus chinensis Roxb., Populus alba L. var. pyramidalis Bge.) in three different climate zones(Jinan with typical warm humid/semi-humid climate, Urumqi with temperate continental arid climate and Turpan with extreme arid desert climate) were measured. Levels of two phytohormones(abscisic acid, ABA; indole-3-acetic acid, IAA) in the leaves of the two tree species at these three sites were also measured by high performance liquid chromatography. The results showed that the responses of gs to an increasing VPD in these two tree species at the three sites had peak curves which could be fitted with a Log Normal Model(gs=a·exp(–0.5(ln(D/c)/b)2). The VPD/RH values corresponding to the maximum gs can be calculated using the fitting models for the two tree species in the three sites. We found that the calculated gs-max-VPD correlated negatively with relative air humidity in the three sites during the plant growth period(April to October 2010), which showed the values of gs-max-VPD were related to the climate conditions. The prevailing empirical stomatal model(Leuning model) and optimal stomatal behavior model could not properly simulate our measured data. The water use efficiency in the two tree species did not show obvious differences under three very different climatic conditions, but the highest gs, photosynthetic and transpiration rates occurred in P. alba var. of Turpan. The sensitivity in response of gs to VPD in leaves of the two trees showed positive correlations with the concentration of ABA, which implied that ABA level could be used as an indicator of the sensitivity of stomatal response to VPD. Our results confirmed that the prediction of the response of gs to VPD might be incomplete in the two current popular models. Therefore, an improved gs model which is able to integrate the results is needed. Also, the stomatal response mechanism of single peak curves of gs to VPD should be considered.     

The influence of Verticillium dahliae and drought on potato crop growth. 1. effects on gas exchange and stomatal behaviour of individual leaves and crop canopies

Potato (Solanum tuberosum L.) plants cv.Saturna were subjected to infection withVerticillium dahliae and drought stress. At the early stages of growth, stomatal conductance, transpiration and net photosynthesis were measured at light saturation (PAR>300 m^–2) on individual leaves and with mobile field equipment with the aid of field enclosures. No significant changes in stomatal conductance and gas exchange characteristics occurred as a result ofV. dahliae instomatal conductance, transpiration and and photosynthetic rates, especially on older leaves and on plants exposed to direct sunlight for a longer period of time. In combination with drought,V. dahliae only occasionally showed interaction; their effects being less than additive. High values of coefficients of variatoon necessitated a high number of measurements per treatment; the more so in the inoculated plants which shows thatV. dahliae seems to affect certain leaves while not affecting others early in growth. Crop photosynthesis was less reduced byV. dahliae than individual leaf photosynthesis due to the levelling effect of integration over the whole canopy and possibly through a stimulation of the top leaves. The upper non-affected leaves are responsible for the bulk of photosynthetic crop activity. The results indicate that following an infection withV. dahliae photosynthesis is reduced early in growth as a result of drought stress in the leaves.Samenvatting Aardappelplanten (Solanum tuberosum L.) cv.Saturna werden onderworpen aan stress als gevolg vanVerticillium dahliae en droogte. In vroege stadia van de groei werden stomataire geleiding, transpiratie en netto fotosynthese bij lichtverzadiging (PAR>300 W m^–2) gemeten aan individuele bladeren en met een mobiel instrumentarium met behulp van gewaskappen. Er werden geen significante verschillen gevonden in de waarden van de stomataire geleiding en de gasuitwisslingskarakteristieken als gevolg vanV. dahliae-besmetting tot een maand na opkomst. Daarna leidde infectie metV. dahliae tot een afname van de stomataire geleiding, transpiratie en netto fotosynthese, speciaal bij oudere bladeren en bij planten die meer aan zonlicht waren blootgesteld. Soms vertoondeV. dahliae interactie met droogte en bleken beide effecten minder dan optelbaar. De hoge waarden van de variatiecoëfficiënten maakten een groot aantal metingen per behandeling noodzakelijk; dit was vooral het geval bij metV. dahliae geïnfecteerde planten hetgeen aantoont datV. dahliae vooral in het begin van de groei niet alle bladeren in gelijke mate aantast. Door de matigende invloed van de integratie van alle bladlagen en mogelijk doordat de bovenste bladeren werden gestimuleerd, werd de totale gewasfotosynthese in mindere mate beïnvloed doorV. dahliae dan de individuele bladfotosynthese. De bovenste niet geïnfecteerde bladeren bleken verantwoordelijk voor het grootste gedeelte van de gewas-fotosynthese. De resultaten tonen aan, dat volgend op een infectie metV. dahliae, de fotosynthese reeds in een vroeg stadium van de groei wordt verminderd als een gevolg van droogtestress in de bladeren.     

胡杨、灰叶胡杨蒸腾耗水规律初步研究

以塔里木盆地3年生胡杨、灰叶胡杨幼苗为试验材料,采用盆栽方法模拟不同土壤干旱条件,研究胡杨、灰叶胡杨的蒸腾耗水规律。结果表明:生长期胡杨、灰叶胡杨的蒸腾耗水量表现出适宜水分>轻度胁迫>中度胁迫>重度胁迫,月蒸腾耗水量呈单峰变化,最高值出现在7月。不同土壤水分条件下,两树种月耗水量差异均较明显,说明土壤水分含量是决定树木蒸腾耗水量的主要因素;天气状况也影响苗木耗水量,耗水峰值多出现在晴天,峰谷多是阴天。不同土壤水分条件下灰叶胡杨单株耗水量均高于胡杨,水分条件较好时灰叶胡杨的生长较胡杨好,水分利用效率高,但随水分的减少胡杨的水分利用效率提高,表明胡杨对干旱环境的适应性较灰叶胡杨强,能有效地利用有限的水资源在荒漠生境中生存。     

新疆南疆地区绿洲外围混交林中胡杨和新疆杨光合特性比较

利用Licor-6400便携式光合仪对新疆南疆绿洲外围人工营造的混交林中的胡杨和新疆杨的净光合速率（Pn）、蒸腾速率（Tr）、水分利用效率（WUE）、气孔导度（Gs）和胞间CO2浓度（Ci）等光合生理指标进行了测定。结果表明：1）胡杨的净光合速率日变化曲线呈＂单峰型＂曲线,新疆杨的净光合速率日变化曲线呈＂双峰型＂曲线,...     

胡杨种子萌发和胚根生长对环境因子变化的响应

通过温度、水分、PEG和NaCl溶液对荒漠河岸树种胡杨（Populus euphratica Olivier.）种子萌发和胚根生长的影响研究,结果表明：胡杨种子在10～40℃时萌发率均超过50％;其种子能够在完全水分浸泡情况下萌发生长;在NaCl和PEG-6000溶液胁迫下,萌发率与水势呈显著线性负相关（R^2〉0．89）,并受到温度的微弱影响;水势对种子萌发和胚根生长的抑制作用,在高水势时,NaCl比PEG-6000溶液明显,而在低水势时后者超过了前者;在各种胁迫下,胚根生长都比种子萌发受到的抑制明显。实验结果显示,早期的低盐和充分的水分条件是胡杨幼苗存活的关键。     

不同灌溉量梯度下胡杨和新疆杨苗期的抗旱性比较

在新疆和田地区墨玉县选取两年生的胡杨和新疆杨实生苗,栽植于苗圃进行不同灌溉水量的处理。不同处理下土壤的含水量分别为田间持水量的85%,70%,47%和24%。测定不同处理水平下胡杨和新疆杨在不同时刻的叶片水势,结果表明:胡杨和新疆杨的水势在一天中的变化趋势呈"V"字型,胡杨的水势日平均值高于新疆杨。利用Licor-6400便携式光合仪对两种杨树的净光合速率和蒸腾速率进行了测定,结果显示相同处理下胡杨的净光合速率和蒸腾速率的日平均值大于新疆杨,胡杨的瞬时水分利用效率高于新疆杨。此外,还测量了两种杨树的叶片的稳定碳同位素比率,结果显示胡杨的δ13C值显著大于新疆杨(p<0.05),表明它的长期水分利用效率较高。运用隶属函数综合各个指标的比较结果来看,胡杨的抗旱性强于新疆杨。