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| 荒漠河岸林植物木质部导水与栓塞特征及其对干旱胁迫的响应 | |
| 引用本文： | 周洪华,李卫红,木巴热克·,阿尤普,徐茜.荒漠河岸林植物木质部导水与栓塞特征及其对干旱胁迫的响应[J].植物生态学报,2012,36(1):19-29. |
| 作者姓名： | 周洪华 李卫红 木巴热克· 阿尤普 徐茜 |
| 作者单位： | 中国科学院新疆生态与地理研究所, 荒漠与绿洲生态国家重点实验室, 乌鲁木齐 830011; 新疆农业大学草业与环境科学学院, 乌鲁木齐 830052 |
| 摘 要： | 以同处于干旱区的塔里木河下游(铁干里克)和黑河下游(乌兰图格)断面为研究区, 比较了荒漠河岸林主要建群种胡杨(Populus euphratica)、柽柳(Tamarix spp.)、疏叶骆驼刺(Alhagi sparsifolia)和花花柴(Karelinia caspia)在长期遭受不同干旱胁迫下的根、枝条木质部导水力和栓塞化程度的变化特征, 并分析了木质部导水对干旱胁迫的响应及适应策略。结果表明: 1) 黑河下游荒漠河岸林植物的导水能力显著高于塔里木河下游, 其中柽柳、胡杨、疏叶骆驼刺和花花柴根木质部的初始比导率(Ks0)分别高11.97、6.74、7.10和3.73倍, 枝条的Ks0分别高9.48、3.65、2.07和1.88倍, 地下水埋深导致的干旱胁迫程度不同是诱发荒漠植物导水能力差异的根本原因; 2)柽柳耐干旱能力最强, 适应范围较宽, 而花花柴、疏叶骆驼刺的耐旱性相对较弱, 适生范围较窄, 这可能与植物的根系分布有关; 3)干旱胁迫较轻时, 枝条木质部是荒漠河岸林植物水分传输的主要阻力部位, 干旱胁迫严重时, 根木质部是限制植株水流的最大阻碍部位; 4)荒漠河岸林植物主要通过调节枝条木质部的水流阻力来适应干旱胁迫, 且其适应策略与干旱胁迫程度有关, 干旱胁迫轻时, 植物通过限制枝条木质部水流来协调整株植物的均匀生长; 干旱胁迫严重时, 植物通过牺牲劣势枝条、增强优势枝条水流来提高植株整体生存的机会。 |
| 关 键 词： | 干旱区内陆河流域 荒漠植物 栓塞 导水率 木质部 |
| 收稿时间： | 2011-08-31 |
| 修稿时间： | 2011-12-07 |
Xylem hydraulic conductivity and embolism properties of desert riparian forest plants and its response to drought stress |
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| ZHOU Hong-Hua,LI Wei-Hong,AYUP Mubarek,XU Qian.Xylem hydraulic conductivity and embolism properties of desert riparian forest plants and its response to drought stress[J].Acta Phytoecologica Sinica,2012,36(1):19-29. | |
| Authors: | ZHOU Hong-Hua LI Wei-Hong AYUP Mubarek XU Qian |
| Affiliation: | State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, 830011, China; College of Pratacultural and Environmental Sciences, Xinjiang Agricultural University, Ürümqi, 830052, China |
| Abstract: | Aims Xylem embolism is a physiological response of plant species to adverse environmental factors, such as water deficit. Desert riparian forest plays an important role in the inland river basin of China. Our objectives were to clarify how xylem embolism of desert plants responds to different drought stress and to understand their acclimation mechanism to drought environment. Methods Desert species, Populus euphratica, Tamarix spp., Alhagi sparsifolia and Karelinia caspia were chosen to study the response of xylem hydraulic conductivity and embolism of the root and shoot to different drought stress in two riparian areas: Tikanlik, which is located in the lower reaches of the Tarim River, and Ulan Tug, which is located in the lower reaches of the Heihe River. We used a xylem embolism meter. We also examined the effects of soil moisture, groundwater depth and climatic factors in the two areas on the root and shoot xylem hydraulic conductivity and embolism of the desert plants at the same time. Important findings Xylem hydraulic conductivities of the desert plants in Ulan Tug were significantly higher than those in Tikanlik. For example, the initial specific conductivity (Ks0) values in the root xylem of Tamarix spp., P. euphratica, A. sparsifolia and K. caspia increased 11.97, 6.74, 7.10 and 3.73 times, respectively, and the shoot xylem Ks0 values increased 9.48, 3.65, 2.07 and 1.88 times, respectively. The fundamental reason for the different xylem hydraulic conductivities of the plants was the difference in drought stress produced by different groundwater depths in the two regions. The drought resistance of Tamarix spp. was the strongest, meaning the genus could exist in a broad soil moisture environment, but A. sparsifolia and K. caspia only exist in a narrow soil moisture environment because of their weak drought resistance, which might be related to root distribution. The major resistance to water transportation of desert plants was shoot xylem when it encountered moderate drought stress, but it was root xylem when the plant encountered severe drought stress. Desert plants adapt to moderate drought stress through limiting shoot xylem hydraulic conductivity to coordinate the plant growth, but it adapted to severe drought stress through sacrificing inferior shoots and enhancing xylem hydraulic conductivity of the other shoots. |
| Keywords: | arid inland river basin desert plant embolism hydraulic conductivity xylem |
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