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| 1 | 典型沙生灌木生态系统凝结水量估算显示文摘当前对干旱半干旱过渡带生态系统凝结水量的估算及其年际变化的认识仍十分有限。本研究以宁夏盐池沙生灌木生态系统为对象,运用微型蒸渗仪、涡度相关(eddy covariance,EC)法和Penman-Monteith公式对凝结水进行测定和估算,以求探索涡度相关法和Penman-Monteith公式估算凝结水的准确性,并且分析凝结水季节和年际变化、其对生态系统水量平衡的贡献及降雨对凝结水的影响。结果表明:1)以微型蒸渗仪观测结果为对照标准,涡度相关法因在夜间存在严重的能量不闭合会造成凝结水严重低估,而Penman-Monteith公式可以较准确地估算凝结水量(R2=0.94,P<0.05);2)采用Penman-Monteith公式估算2012—2014年凝结水,日平均凝结水量为0.14±0.08mm,年平均凝结水发生天数为259 d/a,估算2012—2014年凝结水年总量分别为46、33和29 mm。凝结水多发生在夏秋季。2012—2014年降雨年平均量为301 mm。凝结水年均总量是平均降雨总量的12%。3)降雨时与降雨后一天凝结水成显著正相关关系(R2=0.81,P<0.05)。2012—2014年≥20 mm的降雨次数占全年总降雨次数百分比分别为10%、5%和3%,≥20 mm的降雨能够为空气提供较多水分,增加凝结水量。因此≥20 mm降雨次数占全年总降雨次数的百分比将显著影响当年凝结水总量。结果证实,虽然凝结水总量年际差异较大且占降雨的百分比较小,凝结水是维持荒漠生态系统功能的重要稳定水源。 | 郭晓楠 查天山 贾昕 杨强 穆家伟 刘鹏 | 2016 | 北京林业大学学报2016,38,10: | 12 |
| 2 | 狭果鹤虱幼苗营养生长和生物量分配对凝结水梯度的响应显示文摘以新疆艾比湖湿地国家级自然保护区荒漠短命植物狭果鹤虱为研究对象,研究少凝结水、自然凝结水和倍增凝结水3个梯度下狭果鹤虱幼苗形态、生理响应对策及单株植物的干物质分配格局.结果表明:随凝结水量增加,狭果鹤虱幼苗与叶片吸收水分有关的性状叶绿素相对含量、叶片水势、株高、冠幅、茎质量和叶质比均显著增高,而与根吸收和运输水分有关的性状主茎径、根长和根径无显著变化;株高和叶绿素相对含量对凝结水量的响应最迅速;不同凝结水梯度下,狭果鹤虱幼苗对茎的生物量投入比例无显著差异,但随幼苗生长,3个梯度植物的根质比均逐渐下降,少凝结水处理植株降幅相对较小.狭果鹤虱幼苗主要通过改变地上部分性状响应凝结水量的变化,叶片光合潜力和干物质比重随凝结水量增加而显著增加. | 龚雪伟 吕光辉 冉启洋 杨晓东 | 2016 | 应用生态学报2016,27,7: | 11 |
| 3 | 凝结水对干旱胁迫下羊草和冰草生理生态特征及叶片形态的影响显示文摘为了探讨凝结水对植物生长的作用,该文研究了干旱处理下模拟凝结水对羊草(Leymus chinensis)和冰草(Agropyron cristatum)生理性状和叶片表面结构的影响。试验设计了干旱无凝结水、干旱每周发生3次和5次凝结水以及正常浇水不发生凝结水4个处理,通过超声波加湿器模拟凝结水的发生,研究凝结水对两种植物叶片相对含水量、水势、净光合速率、水分利用效率、生物量以及叶片表面结构等的影响。结果表明:凝结水显著增加了干旱胁迫下两种植物的叶片相对含水量和水势(p<0.05);凝结水显著提高了冰草的净光合速率、气孔导度与蒸腾速率(p<0.05);而羊草的气孔导度和蒸腾速率随凝结水的变化不明显。羊草和冰草的地上生物量和根系生物量随凝结水的发生有增加的趋势,但是各处理间差异不显著。凝结水降低了羊草和冰草黄叶数与总叶数的比值,这表明凝结水对干旱胁迫下植物叶片表面结构遭到的破损有一定的保护和修复作用。该研究证实羊草和冰草的叶片可以吸收凝结水,并对其光合作用、水分生理以及生长具有正效应。 | 岑宇 刘美珍 | 2017 | 植物生态学报2017,41,11: | 8 |
| 4 | 干旱半干旱区生态系统凝结水的影响因素及其作用研究进展显示文摘凝结水是干旱半干旱生态系统重要的水分补给来源,对于维持生态系统功能具有重要意义。综述了干旱半干旱生态系统气象条件、地形环境和植被属性等因素对凝结水形成的影响,以及气候和环境变化对凝结水产量的影响机制。在此基础上,进一步从植被生长、生物土壤结皮、小型动物、微生物和地表水热平衡过程等方面,探讨了凝结水产量变化对干旱半干旱生态系统组成和过程的重要作用。最后对未来相关研究提出以下建议:(1)增加长时间序列的凝结水观测数据分析,(2)系统探讨凝结水对干旱半干旱区生态系统功能的综合影响,并(3)完善气候变化背景下凝结水与生态系统关系的相关研究。本文旨在对该领域的未来研究提出综述、建议和展望。 | 冯天骄 张智起 张立旭 徐炜 贺金生 | 2021 | 生态学报2021,41,2: | 7 |
| 5 | 黄土丘陵半干旱区枣林露水量研究显示文摘利用2012年和2013年叶片湿度传感器(LWS)、温湿度仪、热扩散式探针(TDP)、中子仪实测的露水强度、冠层温湿度、树干径流、土壤水分及气象站监测的气象因子,分析了枣林生育期内露水量的变化规律,探讨了其与水资源输入、输出项的关系。研究结果表明,2012年和2013年枣林露水量随生育期变化呈现递增趋势,果实成熟期达到最大值。露水总量分别为31.31、37.87 mm,分别占同期降水量、蒸腾量和蒸发量的6.87%、10.00%、17.65%和7.90%、15.00%、17.90%,露水量日平均值分别达0.44、0.47 mm。此外,露水量具有发生频率高、稳定性强、重度露水量(大于0.20 mm)比重大的特点。在枣树全生育期内,露水量作为水资源输入项会引起蒸腾量在果实膨大和成熟期显著降低(P<0.05),但对蒸发量无显著影响。研究显示露水是该区枣林重要水源,是水量平衡中不可缺少的输入项。 | 高志永 汪有科 汪星 周玉红 赵英 郭旭新 | 2015 | 农业机械学报2015,46,10: | 5 |
| 6 | 毛乌素沙地两种典型灌木叶片凝结水吸收能力及吸水途径显示文摘凝结水是半干旱地区生态系统重要的水源,已有研究表明,一些沙生植物可以通过叶片吸收凝结水以改善其水分状况。该研究以毛乌素沙地典型沙生灌木黑沙蒿(又称油蒿)(Artemisia ordosica)和北沙柳(Salix psammophila)为研究对象,研究这两种植物的叶片是否具有吸收凝结水的能力,并探究叶片吸水的途径及运移的通道。分别将黑沙蒿与北沙柳失水和未失水离体枝条置入人工模拟加湿室中,使用高丰度氘水标记的凝结水进行浸润实验,比对浸润前后枝条质量、叶片水及茎水氢同位素丰度变化,确定黑沙蒿和北沙柳的叶片吸水能力;并将盆栽黑沙蒿和北沙柳整株置入人工模拟加湿室,使用荧光标记的凝结水进行浸润实验,比对浸润前后叶片、小枝荧光显像,确定黑沙蒿和北沙柳叶片吸收和运移凝结水的途径。结果显示:(1)黑沙蒿和北沙柳未失水枝条在浸润前后质量无显著差异,黑沙蒿和北沙柳失水离体枝条在凝结水浸润后质量显著提高了2.04%和6.74%,叶片水氘丰度提高了170.10‰和104.09‰,茎水氘丰度提高了10.52‰和12.72‰;(2)荧光标记凝结水浸润后,荧光示踪剂分布在黑沙蒿和北沙柳叶片的角质层、气孔、海绵组织、栅栏组织和维管束中,黑沙蒿叶片的厚角组织中也发现了荧光示踪剂,两种灌木小枝的表皮、韧皮部、木质部和髓中均观察到荧光。以上结果表明,毛乌素沙地两种典型灌木叶片均具有吸收凝结水的能力,水分亏缺植株的吸水能力更强;两种灌木叶片通过气孔或角质层吸收凝结水,并通过叶肉运移至维管束乃至小枝。黑沙蒿与北沙柳叶片具有的吸水功能可能是其适应干旱期水分亏缺的重要水分利用策略。 | 桂子洋 秦树高 胡朝 白凤 石慧书 张宇清 | 2021 | 植物生态学报2021,45,6: | 4 |
| 7 | 叶片吸收水分的研究进展显示文摘叶片吸收水分(foliar water uptake, FWU)是植物通过叶片'逆蒸腾作用'吸收和利用空气水分的现象。近年来, FWU一直是植物生理生态学领域的研究热点,几乎所有生态系统中的植物都存在FWU生理过程。FWU对植物个体、群落和生态系统的水分及碳平衡起到了不可忽视的作用,尤其是在全球气候变暖导致干旱加剧的背景下, FWU备受关注。为此,本文总结了国内外研究具有FWU现象的各科物种数量、FWU过程和影响因素:(1)降雨和云雾导致空气相对湿度上升或土壤水势降低等外界环境因素;(2)叶片表面结构对水分的渗透影响;(3)叶片内部结构和物质通过改变叶片吸水速率和通量进而影响FWU。同时,本文归纳了FWU的生理生态学意义:FWU可通过提高植物叶片水势,增加气孔导度和光合速率等,促进植物的生存和生长发育。此外,在极端情况下,叶片吸收的水分还可以通过植物的维管系统进入到根系及根周的土壤中,具有改善土壤水分平衡和保持水土等作用。 | 潘志立 郭雯 王婷 李永萍 杨石建 | 2021 | 植物生理学报2021,57,1: | 3 |
| 8 | 吸湿凝结水对荒漠地区生物土壤结皮生态功能的影响综述显示文摘生物土壤结皮可以作为一种模式系统来研究复杂的生态学问题,而吸湿凝结水是生物土壤结皮在干旱期维持功能活性的基础,吸湿凝结水输入期间生物土壤结皮的生理活动会影响土壤中的碳交换和许多生物地球化学过程,因此,在荒漠生态系统中,地表吸湿凝结水与生物土壤结皮的关系研究显得尤为重要。但由于吸湿凝结水的形成过程受下垫面特征以及诸多热力及气象环境要素的影响,需要基于土壤学、生物学、气象学、物理学和表面科学等学科的交叉集成研究。在综述国内外研究动态的基础上,根据吸湿凝结水形成的物理基础,对比分析了不同原理测量方法的优缺点及发展趋势,从吸湿凝结水对生物土壤结皮的作用机制和生物土壤结皮发育对吸湿凝结水形成的影响两方面总结和讨论了目前吸湿凝结水形成与生物土壤结皮关系研究的进展和不足,根据现有研究结果,阐述了在未来全球变化背景下,非降雨水输入特征的改变及对生物土壤结皮发育和荒漠生态系统功能的生态作用,并提出了当前研究中存在的问题及未来的研究重点,这些问题的解决将提高我们对荒漠生态系统稳定性和可持续性的科学认知水平。 | 潘颜霞 张亚峰 虎瑞 | 2022 | 地球科学进展2022,37,1: | 3 |
| 9 | Effects of shrub species and microhabitats on dew formation in a revegetation-stabilized desert ecosystem in Shapotou, northern China显示文摘Dew is an important supplement water source in arid and semi-arid areas. In order to determine the dew formation on different kinds of soils associated with various shrub species and microhabitats, we performed measurement of accumulated dew formation amount and duration in October 2009 in a revegetation-stabilized arid desert ecosystem in Shapotou area, northern China. The results indicated that the accumulated dew formation amount was four times larger at open spaces as compared to under the canopy, and it was nearly twice as much under living Artemisia ordosica plants(L.A.) as compared to under living Caragana korshinskii plants(L.C.). The opposite characteristics were found for dew duration between different microhabitats. Dew amounts at different vertical heights around the shrub stands were in the order of 50 cm above the canopy>the canopy edge>under the canopy. Dew amount continued to increase after dawn, and the proportion of average accumulated dew amount after dawn accounting for the average maximum amount increased from above the canopy to under the canopy. Dew formation duration after sunrise accounted for more than 50% of the total formation duration during the day time. Contrary to the distribution characteristics of dew amount, dew duration after dawn and total dew formation duration during the day time were both highest under the canopy, followed by at the canopy edge and then at 50 cm above the canopy. The portion of dew duration after dawn accounting for the total dew duration during the day time increased from above the canopy to under the canopy. From these results, we may conclude that dew availability as a supplemental water resource for improving the microhabitats in water-limited arid ecosystems is position dependent especially for the plant microhabitats at different stands layers. | YanXia PAN XinPing WANG | 2014 | Journal of Arid Land2014,6,4: | 3 |
| 10 | 毛乌素沙地4种典型植物叶片凝结水吸收能力及其水分生理响应显示文摘【目的】明确毛乌素沙地4种典型植物沙蓬、软毛虫实、刺藜和苦豆子的叶片凝结水吸收能力,阐明植物叶片对凝结水浸润的水分生理响应。【方法】将受试植物置于用高丰度氘水配置的人工标记凝结水环境中,进行凝结水浸润处理,通过比较处理组和对照组植物叶水、根水及根际土壤水的稳定氢同位素丰度变化,确定受试植物叶片是否具有吸水能力,示踪叶片吸收凝结水后,是否将水分转移到植物根系及根际土壤之中;使用露点水势仪、电子天平及气孔计,测定受试植物处理前后的叶水势、叶片含水量和气孔导度变化,了解受试植物对凝结水浸润的水分生理响应。【结果】(1)高丰度氘标记凝结水浸润后,处理组4种受试植物的叶水δ2H(20‰~100‰)均显著高于对照组(−25‰~−15‰),而根水(−45‰~−30‰)及根际土壤水(−50‰~−40‰)则与对照组无显著差异;(2)经过凝结水浸润试验处理,沙蓬的叶水势升高23.81%,叶含水量升高2.94%,气孔导度降低57.40%;软毛虫实的叶含水量升高了2.45%,叶水势和气孔导度无显著变化;刺藜的叶水势升高了21.95%,气孔导度和叶含水量无显著变化;苦豆子的叶水势、叶含水量和气孔导度均无显著变化。【结论】毛乌素沙地4种典型植物叶片均具有凝结水吸收能力,叶片吸收的水分未被发现转移至根部或根际土壤。沙蓬、软毛虫实、刺藜通过叶片吸水显著改善了自身水分生理状态,这可能是其适应沙地严酷水分条件的重要水分利用机制,有助于植物存活,而苦豆子叶片对凝结水浸润无明显响应,不能有效利用叶片吸水改变其水分生理状态。 | 李鹭辰 桂子洋 秦树高 张宇清 刘靓 杨凯捷 | 2021 | 北京林业大学学报2021,43,2: | 3 |
| 11 | The ecological role of dew in assisting seed germination of the annual desert plant species in a desert environment, northwestern China显示文摘It is important to understand the effects of dew events on non-mucilaginous seed germination of annual desert plant species during dry seasons, which is critical to maintaining long-term soil seed banks in a harsh desert environment. We hypothesize that dew deposition also assists in the non-mucilaginous seed germination of annual desert species. A common field dew treatment experiment was conducted in the Linze Inland River Basin Research Station to investigate the effects of dew deposition on the seed germination of four annual species, including Agriophyllum squarrosum, Corispermum mongolicum, Bassia dasyphylla and Halogeton arachnoideus. The results showed that the presence of dew significantly increased seed germination percentages and decreased the nonviable seed percentages of B. dasyphylla and H. arachnoideus, whereas there was no such trend for the seeds of C. mongolicum and A. squarrosum. The ecological effects of dew on the seed germination and viability of the annual desert plants were species specific. Although dew wetting is insufficient to cause seed germination, it may help in priming the seeds. | ZHUANG Yanli ZHAO Wenzhi | 2016 | Journal of Arid Land2016,8,2: | 3 |
| 12 | An ultrasonic humidification fluorescent tracing method for detecting unsaturated atmospheric water absorption by the aerial parts of desert plants显示文摘Atmospheric water absorption by plants has been explored for more than two centuries, and the aerial parts of plants, particularly the leaves of certain species, have been demonstrated to have an ability to absorb and utilize saturated atmospheric water such as fog, dew and condensed water. So far, however, there have been few studies on the aerial parts of desert plants in their absorption of unsaturated water from the atmosphere. This study presents an ultrasonic humidification fluorescent tracing method of detecting unsaturated atmospheric water absorption by the aerial parts of desert plants. We constructed an organic glass room based on the sizes of field plants. Then, the aboveground parts of the plants were humidified in the sealed glasshouse using an ultrasonic humidifier containing fluorescent reagents. The humidity and wetting time were controlled by turning on or off the humidifier according to the reading of a thermo-hygrometer suspended in the glasshouse. Fluorescence microscopy was employed to observe these plant samples. This method can generate unsaturated atmospheric water vapor and incorporate other fluorescent reagents or water-soluble chemical reagents for gasified humidification. In addition, it can identify plant parts that absorb unsaturated atmospheric water from the air, detect water absorption sites on the surface of leaves or tender stems, and determine the ability of tissues or microstructure of aerial parts to absorb water. This method provides a direct visual evidence for the inspection of leaf or tender stem microstructure in response to unsaturated atmospheric water absorption. Moreover, this method shows that aqueous pores in the cuticles of leaves or tender stems of desert plants are large enough to allow the passage of ionic fluorescent brightener with a molecular weight of up to 917 g/mol. Thus, this paper provides an important approach that explores the mechanism by which desert plants utilize unsaturated atmospheric water. | WANG Xiaohua XIAO Honglang REN Juan CHENG Yiben YANG Qiu | 2016 | Journal of Arid Land2016,8,2: | 3 |
| 13 | 采矿废弃地自然定居植物的群落特征——以新疆维吾尔自治区青河县阿苇戈壁矿区为例显示文摘在干旱且无灌溉条件的矿区,演替初期自然定居的植物是植被修复乃至生态修复的基础。文章通过野外实地踏查和植物群落样方调查,对新疆青河县阿苇戈壁砂铁矿废弃地自然定居的植物及原生植被进行了研究分析。结果表明:(1)停产7年来,该采矿废弃地自然定居植物的群落总盖度约为1%,自然定居植物共有56种,菊科和藜科植物最多,占27%.从生活型来看,一年生和两年生草本植物占比最高,为41.1%,多年生草本植物和灌木分别占39.3%和16.1%.其中,对植被覆盖贡献最大的有雾冰藜、盐生草、大籽蒿等一年生和两年生植物,充当了废弃地自然修复的先锋植物;(2)这些植物发生的微生境为高大排土堆的平坦顶部、可集雪集雨的小排土包背风面和低洼处以及复垦推平地。文章分析了自然定居植物群落特性对干旱冷凉矿区植被恢复的启示。 | 赵晓英 朱成林 海鹰 成鹏 王伍 帕如扎·哈力木拉提 | 2022 | 新疆师范大学学报(自然科学版)2022,41,4: | 2 |
| 14 | 云南小额信贷扶贫的实践与思考显示文摘 | 王学仁 | 2000 | 理论前沿2000,,4: | 2 |
| 15 | Dew measurement and estimation of rain-fed jujube (Zizyphus jujube Mill) in a semi-arid loess hilly region of China显示文摘Dew is an important water source for plants in arid and semi-arid regions. However, information on dew is scarce in such regions. In this study, we explored dew formation, amount, and duration of rain-fed jujube(Zizyphus jujube Mill) trees in a semi-arid loess hilly region of China(i.e., Mizhi County). The data included dew intensity and duration, relative humidity, temperature, and wind speed measured from 26 July to 23 October, 2012 and from 24 June to 17 October, 2013 using a micro-climate system(including dielectric leaf wetness sensors, VP-3 Relative Humidity/Temperature Sensor, High Resolution Rain Gauge, and Davis Cup Anemometer). The results show that atmospheric conditions of relative humidity of >78% and dew point temperature of 1°C–3°C are significantly favorable to dew formation. Compared with the rainfall, dew was characterized by high frequency, strong stability, and long duration. Furthermore, heavy dew accounted for a large proportion of the total amount. The empirical models(i.e., relative humidity model(RH model) and dew point depression model(DPD model)) for daily dew duration estimation performed well at 15-min intervals, with low errors ranging between 1.29 and 1.60 h, respectively. But it should be noted that the models should be calibrated firstly by determining the optimal thresholds of relatively humidity for RH model and dew point depression for DPD model. For rain-fed jujube trees in the semi-arid loess hilly regions of China, the optimal threshold of relative humidity was 78%, and the optimal upper and lower thresholds of dew point depression were 1°C and 5°C, respectively. The study further demonstrates that dew is an important water resource that cannot be ignored for rain-fed jujube trees and may affect water balance at regional scales. | WANG Xing GAO Zhiyong WANG Youke Wang Zhi JIN Shanshan | 2017 | Journal of Arid Land2017,9,4: | 1 |
| 16 | Characteristics of dew events in an arid artificial oasis cropland and a sub-humid cropland in China显示文摘Dew is an important source of water which significantly influences the physiological status of vegetation and the microclimate environment. For quantifying the characteristics of dew events and analyzing the underlying mechanism of dew formation in different ecosystems, we measured, based on the flux-profile method, the amount, frequency and duration of dew events in two croplands, an arid artificial oasis cropland in Zhangye, Gansu province and a sub-humid cropland in Luancheng, Hebei province in China. The results showed that dew events were observed in a total of 69 days in Zhangye, which accounted for 59% of the growing season(from 28 May to 21 September, 2012), while 128 days in Luancheng, which accounted for 79% of the growing season(from 5 April to 13 September, 2008). The frequencies of dew events were 2.8 and 2.4 times of those of precipitation in Zhangye and Luancheng, respectively. In addition, the dew amount reached up to 9.9 and 20.2 mm in Zhangye and Luancheng, which accounted for 9.5% and 4.1% of precipitation, respectively. The average amount of dew was 0.14 and 0.16 mm/night in Zhangye and Luancheng, respectively and the duration of dew events ranged from 0.5 to 12.0 h in the two study sites. Dew amounts were associated with the gradient of atmospheric water vapor concentration and dew duration(P<0.001) in both the two sites. The result implies that dew events play a more important role in crop growth in arid areas in comparison to sub-humid areas considering the dew occurrence frequency and the amount per night. | MENG Yao WEN Xuefa | 2016 | Journal of Arid Land2016,8,3: | 1 |
| 17 | 凝结水输入差异下狭果鹤虱幼苗的水分和光合生理显示文摘凝结水作为荒漠生态系统一种重要的补充水源,其输入量的增加或者减少都将对荒漠短命植物的生态过程产生重要影响。选择艾比湖湿地国家级自然保护区为研究区,研究模拟少凝结水(W_0)、自然凝结水(W_1)和倍增凝结水(W_2)3种不同凝结水量输入下短命植物狭果鹤虱(Lappula semiglabra)幼苗的水分和光合生理适应对策。结果表明:倍增凝结水会明显改善狭果鹤虱幼苗的水分状况,而少凝结水导致狭果鹤虱幼苗叶片的水势和含水量不同程度的降低;少凝结水致使狭果鹤虱幼苗蒸腾速率和净光合速率显著降低(P<0.05),且净光合速率日走势由双峰曲线转变为单峰曲线;凝结水倍增可以延缓狭果鹤虱幼苗气孔导度的降低过程,少凝结水降低狭果鹤虱幼苗叶片气孔导度;凝结水输入差异对狭果鹤虱幼苗叶片胞间CO_2浓度无显著影响(P>0.05);狭果鹤虱幼苗叶片的水分利用效率在不同凝结水量输入下无显著差异(P>0.05),体现了荒漠短命植物稳定的水分利用策略。 | 龚雪伟 吕光辉 Martin Welp Siegmund Missall 玉米提.哈力克 牟宗江 | 2017 | 生态学杂志2017,36,8: | 1 |
| 18 | 荒漠植物凝结水形成机制研究进展显示文摘系统综述了国内外对凝结水的最新研究进展,包括凝结水形成机制、生态作用以及冠层凝结水吸收利用.结合荒漠植物的特点及研究现状,指出加强对荒漠植物吸收冠层凝结水的内在机理研究有助于理解荒漠植物对干旱胁迫的适应,可为全球变暖背景下的荒漠植物响应对策的阐述提供理论依据. | 刘涛 徐华君 张永福 | 2017 | 安徽农业科学2017,45,35: | 1 |
| 19 | 塔里木河下游典型胡杨群落大气凝结水的形成规律与数量评估显示文摘在极端干旱的塔克拉玛干沙漠边缘地区,凝结水可能是一种重要的水源。然而,目前对该地区凝结水的形成、数量等特征所知甚少。借助于涡动协方差观测系统于2013年6-12月对沙漠边缘胡杨林群落的水汽通量、气象要素等进行观测,目的是揭示凝结水的形成特征及其在区域水量平衡中的作用,初步探讨凝结水定量评估方法。研究结果表明:胡杨林群落具有明显水汽凝结现象,在整个182 d的观测期内,凝结水出现的天数达到了148 d,占整个观测期总日数的81%,累积凝结水量为19.78 mm;凝结水出现时,夜间平均持续时间为3-4 h左右,平均日凝结水量为0.13 mm。单一冠层凝结出现天数为47 d,凝结总量8.5 mm,明显大于单一的地面凝结(44 d,6.65 mm),生长季冠层凝结是主要的。基于观测数据,构建了凝结水出现天数、日持续时间与凝结速率的评估方程,模拟结果在长时间尺度上(月、季)可较好的反映实测结果(R2〉0.9)。观测结果显示,凝结水总量超过同期降水量0.48 mm,并达到当年年降水量的84%,凝结水对水分收支的作用与年降水相当,在区域水量平衡中扮演了重要的角色。 | 郝兴明 美尔汗.黑扎特 朱成刚 | 2016 | 干旱区地理2016,39,4: | 0 |
| 20 | Study of variegated and white flower petals of Capparis spinosa expanded at dusk in arid landscapes显示文摘In this study,we provide the first evidence of two pairs of petals of the rapidly expanded and short-lived nocturnal flowers of Capparis spinosa L.(caper)during the prolonged drought period in Eastern Mediterranean region.The corolla of the winter-deciduous,perennial C.spinosa consists of two pairs of petals:a pair of white distinct petals and a pair of connate variegated petals with green basal parts.The results indicated the presence of substantially different amounts of chlorophyll in the two pairs of petals,while their carbohydrates’content is comparable with that of the green sepals.High resolution imaging of petal surfaces of short-lived flowers of C.spinosa, obtained by using scanning electron microscopy,revealed stomata on the adaxial epidermis on both the white and the green parts of the variegated petals;while dense hairs were found on the surface of the abaxial green parts of the variegated petals.Adaxial,epidermal cells of the variegated petals,viewed using atomic force microscopy,possess a submicron,cuticular microfolding that differs between the white and the green parts of the petals.It appears that microridges on the adaxial,white parts of petals of C.spinosa compensate for an increase in cell surface area of the short lived petals,while the roughness of the green parts of petals was found to be higher than that of the white parts.Thus,the micromorphology of surfaces of epidermal cells is expected to affect optical properties and wettability of the floral tissues.These findings may be particularly important for understanding the performance of the short-lived petals of C.spinosa,which are exposed to dryland environments. | Chrysanthi CHIMONA Avra STAMELLOU Apostolos ARGIROPOULOS Sophia RHIZOPOULOU | 2012 | Journal of Arid Land2012,4,2: | 0 |