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中国南方岩溶高原地区由于岩石孔隙裂隙发育,加上土层浅薄且不连续,地表持水能力差,漏失严重,加上降水时空分布不均,使得水分成为喀斯特地区植物生长的主要限制因子。喀斯特生境对植物种类具有较强的选择性,一般是易于生长,根系发达,能在岩溶环境中求得水分和养分的补充的植物,但植物水分具体来源一直是一个困扰的问题。针对植物根系吸收水分过程和水分在植物根部与茎干之间运输时,在水分到达如叶片或幼嫩未栓化的枝条之前不发生同位素分馏[1],因此,通过植物根系和茎干木质部水的同位素组成可得出植株所利用水的同位素组成状况[2]。对于喀斯特地区植物,传统方法很难确定植物具体吸收哪层土壤水分,并且根系的分布并不意味着水分或养分的吸收。喀斯特地区特殊的生境,植物根系分布与其他常态地貌下的根系模型有很大差异[3],再加上根系模型建立需耗费巨大人力物力,直接测定地下生态过程也十分困难,使得相关的根系分布数据极少[4]。运用稳定同位素技术,通过对比植物木质部水与各种水源的氘(D)和18O组成,可得出植物利用的水分如降水、土壤水、地下水或表层岩溶带水,并且可以确定植物对不同水源利用的程度[5-6]。在中国,环境同位素技术在喀斯特地貌区得到广泛应用[7-10],但主要集中在多属于峰丛洼地的广西[11]和贵州[12],而对以溶丘洼地为主[13]的云南喀斯特高原区研究较为薄弱。研究区属滇中高原岩溶地貌,位于石林地质公园,公园内部经过多年的退耕还林和保护等措施,植被出现了草丛、灌草地、灌丛、人工林、次生林、原生林等不同演替阶段的群落,不同树种、树龄在不同演替阶段水分利用来源存在较大差异[11-12]。其中原生林具备自然演化和自我更新的能力,是对某一地貌和气候的适应,在涵养水源、保持水土、调节气候和维持生态平衡等方面起着重要作用。因此本研究选取了滇中石林国家地质公园中保护较好的滇青冈原生林作为研究对象,通过分析滇青冈原生林中几种典型植被的木质部水及其各种潜在水源中的氧稳定同位素,得出植物水分利用来源季节变化,并结合IsoSource模型[13-14]分析潜在水源利用比例,初步阐明原生林植物水分利用机制及对岩溶干旱生境的适应策略,探讨如何在有限水资源下对喀斯特区植被进行有效恢复,为深入研究岩溶区脆弱生态环境植被保护和植被恢复提供实例,也为该区水源涵养林的选择提供参考。
Soil-water utilization levels in a Cyclobalanopsis glaucoides virgin forest on the Central Yunnan Karst Plateau
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摘要: 为阐明滇中岩溶高原滇青冈Cyclobalanopsis glaucoides原生林植物水分利用机理及其对岩溶干旱生境的适应策略, 运用氧稳定同位素技术, 分析了滇青冈, 云南木樨榄Olea yuennanensis, 清香木Pistacia weinmannifolia等3种不同年龄阶段常见优势木本植物小枝木质部水分及土壤水、表层岩溶带水氧同位素值的相关性, 确定植物水分来源, 并通过IsoSource模型计算不同潜在水源对滇青冈原生林的贡献。结果表明:滇青冈及其伴生的乔木水分利用层位及利用比例呈现时空差异, 并形成明显的水分竞争关系。旱季, 滇青冈、成熟云南木樨榄、幼龄清香木主要利用55~115 cm深层土壤水, 成熟的滇青冈和清香木对表层岩溶带水利用比例增加。雨季, 成熟的滇青冈、云南木樨榄、清香木和幼龄清香木因大气降水对浅表层土壤的补给主要利用20~55 cm土壤水, 利用比例分别为100%, 33.3%, 66.0%, 37.4%, 幼龄植株对表层岩溶带水的利用比例大于成熟植株。Abstract: To explain the water utilization mechanism of a Cyclobalanopsis glaucoides virgin forest on the Central Yunnan Karst Plateau in southwest China, and its adaptive strategies in an arid karst habitat, a stable isotope technique was featured to determine soil-water levels utilized by plants. Several dominant plant species (C. glaucoides, Olea yuennanensis, and Pistacia weinmannifolia) were selected and tested with oxygen isotopes of water on stems and soils from the virgin forest. Using IsoSource model calculations the contribution of different water samples was determined. Results revealed that water utilization positions and proportions for C. glaucoides in the primeval forest and its accompanying trees varied in time and space, and were competitors for water. During dry seasons, C. glaucoides, mature O. yuennanensis, and young P. weinmannifolia used soil water from depths of 55-115 cm with more groundwater used for mature C. glaucoides and mature P. weinmannifolia. In rainy seasons, because of the precipitation, 100% of the mature C. glaucoides, 33.3% of the O. yuennanensis, 66.0% of the P. weinmannifolia, and 37.4% of the young P. weinmannifolia used the 20-55 cm soil-water level.
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[1] ALESSIO G A, de LILLIS M, BRUGNOLI E, et al. Water sources and water-use efficiency in mediterranean coastaldune vegetation[J]. Plant Biol, 2004, 6(3):350-357. [2] 赵良菊, 肖洪浪, 程国栋, 等.黑河下游河岸林植物水分来源初步研究, 地球学报, 2008, 29(6):709-718. ZHAO Liangju, XIAO Honglang, CHENG Guodong, et al. A preliminary study of water sources of riparian plants in the lower reaches of the Heihe Basin[J]. Acta Geosci Sin, 2008, 29(6):709-718. [3] 容丽, 王世杰, 俞国松.荔波喀斯特森林4种木本植物水分来源的稳定同位素分析[J].林业科学, 2012, 48(7):14-22. RONG Li, WANG Shijie, YU Guosong, et al. Stable isotope analysis of water sources of four woody species in the Libo karst forest[J]. Sci Silv Sin, 2012, 48(7):14-22. [4] SCHENK H J, JACKSON R B. Mapping the global distribution of deep roots in relation to climate and soil characteristics[J]. Geoderma, 2005, 126(1):129-140. [5] EGGEMEYER K D, AWADA T, HARVEY F E, et al. Seasonal changes in depth of water uptake for encroaching trees Juniperus virginiana and Pinus ponderosa and two dominant C4 grasses in a semiarid grassland[J]. Tree Physiol, 2009, 29(2):157-169. [6] YANG Hao, AUERSWALD K, BAI Yongfei, et al. Complementarity in water sources among dominant species in typical steppe ecosystems of Inner Mongolia, China[J]. Plant Soil, 2010, 340(1/2):303-313. [7] McCOLE A A, STERN L A. Seasonal water use patterns of Juniperus ashei on the Edwards Plateau, Texas, based on stable isotopes in water[J]. J Hydrol, 2007, 342(3/4):238-248. [8] SCHWINNING S. The water relations of two evergreen tree species in a karst savanna[J]. Oecologia, 2008, 158(3):373-383. [9] REN H. A review of the studies of desertification process and restoration mechanism of karst rocky ecosystem[J]. Trop Geogr, 2005, 25(3):195-200. [10] QUEREJETA J I, ESTRADA-MEDINA H, ALLEN M F, et al. Water source partitioning among trees growing on shallow karst soils in a seasonally dry tropical climate[J]. Oecologia, 2007, 152(1):26-36. [11] 聂云鹏, 陈洪松, 王克林.石灰岩地区连片出露石丛生境植物水分来源的季节性差异[J].植物生态学报, 2011, 35(10):1029-1037. NIE Yunpeng, CHEN Hongsong, WANG Kelin. Seasonal variation of water sources for plants growing on continuous rock outcrops in limestone area of southwest China[J]. Chin J Plant Ecol, 2011, 35(10):1029-1037. [12] 石林研究组.中国路南石林喀斯特研究[M].昆明:云南科技出版社, 2011. [13] PHILLIPS D L, GREGG J W. Source partitioning using stable isotopes:coping with too many sources[J]. Oecologia, 2003, 136(2):261-269. [14] PHILLIPS D L, NEWSOME S D, GREGG J W. Combining sources in stable isotope mixing models:alternative methods[J]. Oecologia, 2005, 144(4):520-527. [15] 吴毅, 刘文耀, 沈有信, 等.滇石林地质公园喀斯特山地天然林和人工林凋落物与死地被物的动态特征[J].山地学报, 2007, 25(3):317-325. WU Yi, LIU Wenyao, SHEN Youxin, et al. Dynamics of litterfall and litter on forest floor of natural forest and plantations in Stone Forest World Geological Park[J]. J Mount Sci, 2007, 25(3):317-325. [16] 金振洲.云南常绿阔叶林的类型和特征[J].云南植物研究, 1979, 1(1):90-105. JIN Zhenzhou, The types and characteristics of evergreen broad-leaf-forest in Yunnan[J]. Acta Bot Yunnan, 1979, 1(1):90-105. [17] 邓晓琪, 王世杰, 容丽.喀斯特区专属植物水分来源研究[J].地球与环境, 2012, 40(2):154-160. DENG Xiaoqi, WANG Shijie, RONG Li. Study on water sources of proper plant species in Karst areas[J]. Earth Environ, 2012, 40(2):154-160. [18] SCHENK H J, JACKSON R B. The global biogeography of roots[J]. Ecol Monogr, 2002, 72(3):311-328. [19] 郝艳茹, 彭少麟.根系及其主要影响因子在森林演替过程中的变化[J].生态环境, 2005, 14(5):762-767. HAO Yanru, PENG Shaolin, Variation of roots and its impact factors in succession[J]. Ecol Environ, 2005, 14(5):762-767. [20] 边俊景, 孙自永, 周爱国, 等.干旱区植物水分来源的D, 18O同位素示踪研究进展[J].地质科技情报, 2009, 28(4):117-120. BIAN Junjing, SUN Ziyong, ZHOU Aiguo, et al, Advances in the D and 18O isotopes of water source of plants in arid areas[J]. Geol Sci Technol Inf, 2009, 28(4):117-120. [21] ROSE K L, GRAHAM R C, PARKER D R. Water source utilization by Pinus jeffreyi and Arctostaphylos patula on thin soils over bedrock[J]. Oecologia, 2003, 134(1):46-54. [22] POOT P, LAMBERS H. Shallow-soil endemics:Adaptive advantages and constraints of a specialized root-system morphology[J]. New Phytol, 2008, 178(2):371-381. [23] 李鹏菊, 刘文杰, 王平元, 等.西双版纳石灰山热带季节性湿润林内几种植物的水分利用策略[J].云南植物研究, 2008, 30(4):496-504. LI Pengju, LIU Wenjie, WANG Pingyuan, et al, Plant water use strategies in a limestone tropical seasonal moist rainforest in Xishuangbanna, SW China[J]. Acta Bot Yunnan, 2008, 30(4):496-504. -
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https://zlxb.zafu.edu.cn/article/doi/10.11833/j.issn.2095-0756.2014.05.005