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林业科学 ›› 2021, Vol. 57 ›› Issue (7): 32-42.doi: 10.11707/j.1001-7488.20210704

• 论文与研究报告 • 上一篇    下一篇

科尔沁沙地刺榆水力结构特征对土壤水分环境的响应

曹宇1,3,4,巢林2,安宇宁1,4,吴德东1,3,4,张学利1,3,4,李红1,4,刘艳艳2,*   

  1. 1. 辽宁省沙地治理与利用研究所 阜新 123000
    2. 南宁师范大学地理与海洋研究院 北部湾环境演变与资源利用教育部重点实验室 广西地表过程与智慧模拟重点实验室 南宁 530001
    3. 辽宁章古台科尔沁沙地生态系统国家定位观测研究站 彰武 123203
    4. 辽宁省固沙造林研究所 阜新 123000
  • 收稿日期:2020-02-22 出版日期:2021-07-25 发布日期:2021-09-02
  • 通讯作者: 刘艳艳
  • 基金资助:
    国家自然科学基金项目(31800333);辽宁省公益研究基金项目(2020JH4/10100047);辽宁省自然科学基金项目(2019-MS-201)

Response of Hydraulic Architecture of Hemiptelea davidii to Soil Water Conditions in Horqin Sandy Land

Yu Cao1,3,4,Lin Chao2,Yuning An1,4,Dedong Wu1,3,4,Xueli Zhang1,3,4,Hong Li1,4,Yanyan Liu2,*   

  1. 1. Liaoning Institute of Sandy Land Control and Utilization Fuxin 123000
    2. Key Laboratory of Environment Change and Resources Use in Beibu Gulf of Ministry of Education Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation, Institute of Geography and Oceanography, Nanning Normal University Nanning 530001
    3. Department of Horqin Sandy Land Ecosystem National Positioning Observatory, Zhanggutai, Liaoning Province Zhangwu 123203
    4. Institute of Sand-Fixation and Afforestation Research of Liaoning Province Fuxin 123000
  • Received:2020-02-22 Online:2021-07-25 Published:2021-09-02
  • Contact: Yanyan Liu

摘要:

目的: 比较科尔沁沙地典型生境上生长的刺榆木质部水力结构特征、叶片水分关系与光合气体交换特征,探讨刺榆适应不同土壤水分环境的内在生理机制,为科尔沁沙地防风固沙造林和植被修复的适地适树提供理论依据。方法: 以生长在科尔沁沙地丘间低地和沙丘上部2种土壤水分环境中的刺榆为研究对象,从树木水力结构角度,分析不同生境刺榆枝条水分传输效率与安全性的差异,结合叶片水分关系、光合生理特性以及木质部解剖结构等进行对比研究。结果: 与沙丘上部相比,丘间低地土壤水分条件较好,刺榆枝条木质部导管直径较大、水分传输效率(Ks)更高(P<0.05),叶片和枝条水势均更高(P<0.05)。尽管2种生境上生长的刺榆叶片光合碳同化速率无明显差异,但气孔导度(gs)和水分利用效率(WUEi)明显不同,沙丘上部刺榆的gs更低(P<0.05),WUEi更高(P<0.05)。丘间低地刺榆枝条末端叶面积和边材面积的比值(LA/SA)显著高于沙丘上部(P<0.05),地径、树高和地上生物量等指标也显著高于沙丘上部(P<0.05);但沙丘上部刺榆木材密度更高,抗气穴化栓塞能力更强,水力安全边界(HSM)也较宽(ΨS-md-P50ΨS-md-P80较大)。结论: 在土壤水分条件较好的丘间低地生长的刺榆,导管直径较大,水分传输效率更高,可保证较高的生长速率和竞争力;而在土壤水分条件较差的沙丘上部生长的刺榆,木质部导管直径变小,虽然水分传输效率降低,但有助于获得更强的木质部抗气穴化栓塞能力,从而保证植株能在水分胁迫较严重的生境中长期存活。刺榆水力结构特征随水分生境变化而调整的策略,反映出其较强的抗旱性和适应性。

关键词: 刺榆, 水分传输, 抗气穴化栓塞, 脆弱性, 水力安全边界, 水分利用效率

Abstract:

Objective: The aim of this study was to investigate the internal physiological mechanisms of Hemiptelea davidii adapting to different soil water environments by comparing the effect of microenvironments(interdune and upperdune) with different soil water conditions on the characteristics of xylem hydraulic architecture, leaf water relations and photosynthetic gas exchange of H.davidii, in order to provide a theoretical basis for windproof and sand fixation afforestation and vegetation restoration in Horqin sandy land. Method: In this study, the H.davidii inhabiting in the interdune and upperdune with different soil water conditionsin Horqin sandy land was targeted. The differences in water transport efficiency and safety of H. davidii in the two habitats were analyzed from the perspective of trees hydraulic architecture, and a comparative study on leaf water relation, photosynthetic gas exchange and xylem anatomical structure was conducted. Result: Soil water status in interdune was much better than that in upperdune, thus H. davidii growing in interdune presented the larger conduits, and significantly higher stem water transport efficiency(Ks) and leaf and stem water potential(P < 0.05). Although, there was no significant difference in leaf photosynthetic carbon assimilation rate between the two habitats, the stomatal conductance(gs) and intrinsic water use efficiency(WUEi) showed significantly different. gs of the upperdune was significantly lower(P < 0.05), and its WUEi was significantly higher(P < 0.05).Different soil water content in habitats also had significant impacts on the ratio of leaf area to sapwood area(LA/SA) of H. davidii, the value of LA/SA was significantly higher ininterdune than that of upperdune habitat(P < 0.05). Growth indicators such as basal diameter, tree height and aboveground biomass were also significantly higher in interdune than those of the upperdune habitat(P < 0.05). H. davidii in the upperdune showed higher wood density and stronger resistance to cavitation, and the hydraulic safety margin(HSM) was also wider(larger values of ΨS-md-P50 and ΨS-md-P80). Conclusion: Growing in the interdune habitat with less water-limited environment, H. davidii tends to have larger conduits which facilitate higher water transport efficiency and ensure higher growth rate and competitiveness. On the contrary, in the upperdune habitat with more water-limited environment, it tends to have smaller conduits. Although this strategy reduces the water transport efficiency of xylem, it helps to obtain stronger resistance to cavitation, thereby ensuring the long-term survival of plants undersevere water stress. The strategy of adjusting hydraulic architecture traits of H. davidii with different water conditions reflects its stronger drought resistance and adaptability.

Key words: Hemiptelea davidii, water transport, resistance to cavitation/embolism, vulnerability, hydraulic safety margin, water use efficiency

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