分类： 生物学 >> 植物学 提交时间： 2023-03-13 合作期刊: 《干旱区研究》
摘要：叶片和根系能通过形态、生理和生物量累积的变化响应干旱胁迫。以策勒绿洲-沙漠过渡带的优势植物 疏叶骆驼刺(Alhagi sparsifolia Shap.)为研究对象，通过盆栽试验模拟3种水分条件（充分灌溉CK：土壤含水量占最大 田间持水量的70%~75%；轻度胁迫W1：田间持水量的50%~55%；重度胁迫W2：田间持水量的25%~30%），分析一年 生骆驼刺幼苗叶片和根系生长、生理的变化特征，揭示骆驼刺对干旱胁迫的适应策略。结果表明：（1）干旱显著抑 制骆驼刺地上和地下各器官生长，主要表现为：叶面积、根长、根表面积、根组织密度以及叶和根的可溶性糖含量显 著减小（P<0.05）；叶组织密度、叶干物质含量、比根长以及叶和根的脯氨酸、丙二醛含量增大。（2）生长前期，各处理 地上生物量均占比较大（CK、W1、W2下根冠比分别为0.43±0.14、0.59±0.1、0.83±0.83）；而生长后期各处理地下生物 量占比较大，其中重度胁迫下根冠比最大（3.12±0.32），表明骆驼刺在生长后期增强了地下部分的资源投入，且这种 资源分配特征在重度干旱胁迫下更明显。（3）Pearson相关性分析表明，骆驼刺叶形态与根生理相关的核心性状存 在显著的权衡关系（P<0.05），同时叶与根在生理代谢上能够协同变化。初步说明，骆驼刺幼苗在干旱下表现出干 物质储存和防御能力高、水分消耗低的适应特征，能够协调叶片和根系的资源分配关系，随胁迫时间的增加逐步形 成缓慢投资、保守生长的策略。该结果为该区域荒漠植被恢复和管理提供参考。
分类： 地球科学 >> 地理学 提交时间： 2021-12-03 合作期刊: 《干旱区科学》
SUN Lingxiao
YU Yang
GAO Yuting
ZHANG Haiyan
YU Xiang
HE Jing
WANG Dagang
Ireneusz MALIK
Malgorzata WISTUBA
YU Ruide
摘要：Net primary productivity (NPP) of the vegetation in an oasis can reflect the productivity capacity of a plant community under natural environmental conditions. Owing to the extreme arid climate conditions and scarce precipitation in the arid oasis regions, groundwater plays a key role in restricting the development of the vegetation. The Qira Oasis is located on the southern margin of the Taklimakan Desert (Tarim Basin, China) that is one of the most vulnerable regions regarding vegetation growth and water scarcity in the world. Based on remote sensing images of the Qira Oasis and daily meteorological data measured by the ground stations during the period 2006–2019, this study analyzed the temporal and spatial patterns of NPP in the oasis as well as its relation with the variation of groundwater depth using a modified Carnegie Ames Stanford Approach (CASA) model. At the spatial scale, NPP of the vegetation decreased from the interior of the Qira Oasis to the margin; at the temporal scale, NPP of the vegetation in the oasis fluctuated significantly (ranging from 29.80 to 50.07 g C/(m2•month)) but generally showed an increasing trend, with the average increase rate of 0.07 g C/(m2•month). The regions with decreasing NPP occupied 64% of the total area of the oasis. During the study period, NPP of both farmland and grassland showed an increasing trend, while that of forest showed a decreasing trend. The depth of groundwater was deep in the south of the oasis and shallow in the north, showing a gradual increasing trend from south to north. Groundwater, as one of the key factors in the surface change and evolution of the arid oasis, determines the succession direction of the vegetation in the Qira Oasis. With the increase of groundwater depth, grassland coverage and vegetation NPP decreased. During the period 2008–2015, with the recovery of groundwater level, NPP values of all types of vegetation with different coverages increased. This study will provide a scientific basis for the rational utilization and sustainable management of groundwater resources in the oasis.
分类： 地球科学 >> 地理学 提交时间： 2021-11-10 合作期刊: 《干旱区科学》
摘要：Nitrogen (N) and phosphorus (P) are two essential nutrients that determine plant growth and many nutrient cycling processes. Increasing N and P deposition is an important driver of ecosystem changes. However, in contrast to numerous studies about the impacts of nutrient addition on forests and temperate grasslands, how plant foliar stoichiometry and nutrient resorption respond to N and P addition in alpine grasslands is poorly understood. Therefore, we conducted an N and P addition experiment (involving control, N addition, P addition, and N+P addition) in an alpine grassland on Kunlun Mountains (Xinjiang Uygur Autonomous Region, China) in 2016 and 2017 to investigate the changes in leaf nutrient concentrations (i.e., leaf N, Leaf P, and leaf N:P ratio) and nutrient resorption efficiency of Seriphidium rhodanthum and Stipa capillata, which are dominant species in this grassland. Results showed that N addition has significant effects on soil inorganic N (NO3–-N and NH4+-N) and leaf N of both species in the study periods. Compared with green leaves, leaf nutrient concentrations and nutrient resorption efficiency in senesced leaves of S. rhodanthum was more sensitive to N addition, whereas N addition influenced leaf N and leaf N:P ratio in green and senesced leaves of S. capillata. N addition did not influence N resorption efficiency of the two species. P addition and N+P addition significantly improved leaf P and had a negative effect on P resorption efficiency of the two species in the study period. These influences on plants can be explained by increasing P availability. The present results illustrated that the two species are more sensitive to P addition than N addition, which implies that P is the major limiting factor in the studied alpine grassland ecosystem. In addition, an interactive effect of N+P addition was only discernable with respect to soil availability, but did not affect plants. Therefore, exploring how nutrient characteristics and resorption response to N and P addition in the alpine grassland is important to understand nutrient use strategy of plants in terrestrial ecosystems.
分类： 地球科学 >> 地理学 提交时间： 2021-10-11 合作期刊: 《干旱区科学》
YU Yang
CHEN Xi
Ireneusz MALIK
Malgorzata WISTUBA
CAO Yiguo
HOU Dongde
TA Zhijie
HE Jing
ZHANG Lingyun
YU Ruide
ZHANG Haiyan
SUN Lingxiao
摘要：Central Asia is located in the hinterland of Eurasia, comprising Kazakhstan, Uzbekistan, Kyrgyzstan, Turkmenistan, and Tajikistan; over 93.00% of the total area is dryland. Temperature rise and human activities have severe impacts on the fragile ecosystems. Since the 1970s, nearly half the great lakes in Central Asia have shrunk and rivers are drying rapidly owing to climate changes and human activities. Water shortage and ecological crisis have attracted extensive international attention. In general, ecosystem services in Central Asia are declining, particularly with respect to biodiversity, water, and soil conservation. Furthermore, the annual average temperature and annual precipitation in Central Asia increased by 0.30°C/decade and 6.9 mm/decade in recent decades, respectively. Temperature rise significantly affected glacier retreat in the Tianshan Mountains and Pamir Mountains, which may intensify water shortage in the 21st century. The increase in precipitation cannot counterbalance the aggravation of water shortage caused by the temperature rise and human activities in Central Asia. The population of Central Asia is growing gradually, and its economy is increasing steadily. Moreover, the agricultural land has not been expended in the last two decades. Thus, water and ecological crises, such as the Aral Sea shrinkage in the 21st century, cannot be attributed to agriculture extension any longer. Unbalanced regional development and water interception/transfer have led to the irrational exploitation of water resources in some watersheds, inducing downstream water shortage and ecological degradation. In addition, accelerated industrialization and urbanization have intensified this process. Therefore, all Central Asian countries must urgently reach a consensus and adopt common measures for water and ecological protection.
分类： 地球科学 >> 地理学 提交时间： 2020-01-06 合作期刊: 《干旱区地理》
摘要：新疆荒漠地区植被覆盖度遥感估算模型十分缺乏，给荒漠化监测等相关工作带来很大不便，开展植被覆盖度遥感估算经验模型研究，对于促进和完善相关地区的生态监测及研究工作具有积极的现实意义。通过对阜康市北部沙漠南缘和克拉玛依市中部平原荒漠进行无人机航拍，利用无人机遥感提取（光合）植被信息，并将无人机航拍影像的植被覆盖度统计单元与高分辨率卫星影像像元在空间上直接相对应，获取在高分辨率卫星影像像元尺度上的植被盖度，然后通过植被覆盖度和空间上与其相对应的源自高分辨率卫星影像的NDVI数据的拟合关系，建立基于源自高分二号影像的NDVI的阜康北部沙漠植被覆盖度遥感估算线性模型以及基于源自ZY1-02C影像的NDVI的克拉玛依平原荒漠植被覆盖度遥感估算二次多项式模型。研究中所采用的无人机遥感与卫星遥感相结合、植被覆盖度统计单元与卫星像元在空间上直接对应的方法，可避免以往相关工作中常以点位测量数据代表卫星像元数据所带来的不确定性。由于所用卫星影像的NDVI数据稳定性相对不足等原因，所建立的遥感估算模型的估算精度尚相对偏低，有待于今后进一步的工作加以改进。
分类： 地球科学 >> 地理学 提交时间： 2020-01-06 合作期刊: 《干旱区地理》
摘要：雅丹形态特征吸引人们的长期关注，对其形态的定量描述至今仍讨论热烈且众说纷纭。通过对罗布泊地区风蚀地貌的野外调查和无人机测量，发现普遍存在雅丹共基座现象。分布在同一个基座体上的风蚀残丘称之为共基座雅丹，属于雅丹与基座体的复合。对共基座雅丹和基座体开展雅丹形态参数的测量及分析，结果表明：共基座雅丹长宽比比值集中分布于3∶1~5∶1区间，与鲸背状等流线型雅丹形态表现相似，显示单一风向侵蚀残留特征；雅丹共基座现象是风蚀切穿深一层抗风蚀相对较强的地层形成的风蚀垄岗现象，厚度不等的不同抗风蚀强度地层在垂向上交替出现和受单一风向的风蚀作用是形成该现象的重要因素；通过对雅丹共基座现象的阐释和定量分析，对完善雅丹形态测量、深化雅丹形态变化的理解以及认识差异性风蚀过程具有重要意义。
分类： 农、林、牧、渔 >> 农业基础学科 提交时间： 2017-11-10 合作期刊: 《中国生态农业学报》
摘要：为探究古尔班通古特沙漠南缘莫索湾地区33 年来人工梭梭林群落(依靠天然降水)的生态特征, 本文对两种造林技术(积雪-客沙造林和秋灌造林)人工梭梭林地梭梭的长势、草本植物、土壤水分进行了调查和监测。结果表明: ①积雪-客沙造林和秋灌造林梭梭至今生长良好, 目前植株高度和冠幅均大于2 m 和2 m2, 当年新生枝条长度均大于20 cm; 初始造林梭梭存活率较高, 分别为40%和63%; 经过自然更新, 现有密度均有所提高, 人工林形成异龄复层混交林, 林下生长有不同优势种的草本植物; 土壤含水量均>2.00%, 能够满足梭梭生长。②由于两种造林技术的土地处理方式和初期水分供给量不同, 导致两种林地梭梭生长、林下草本植物盖度和多样性以及天然更新梭梭植株数量均有很大差异, 整体秋灌造林地的状况优于积雪-客沙造林地。③两种造林技术对于当地生态条件均有很好的适应性, 虽然积雪客沙造林密度相对较低, 但优于自然植被状况, 且造林成本低;秋灌造林密度较大, 天然更新植株数量较多, 但造林成本高, 后期生长较缓慢, 需要采取一定的人工措施调整密度。综上可知, 积雪-客沙造林和秋灌造林梭梭目前生长均较稳定, 后者对该区生态条件适应性更强。
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