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海三棱藨草及互花米草对模拟盐胁迫的响应及其耐盐阈值

李伟,袁琳*,张利权,赵志远,李蕙,朱晓泾,潘家琳,陈雅慧   

  1. (华东师范大学河口海岸学国家重点实验室, 崇明生态研究院, 上海 200062)
  • 出版日期:2018-09-10 发布日期:2018-09-10

Responses of Scirpus mariqueter andSpartina alterniflora tosimulated salt stress and salt-tolerance thresholds.

LI Wei, YUAN Lin*, ZHANG Li-quan, ZHAO Zhi-yuan, LI Hui, ZHU Xiao-jing, PAN Jia-lin, CHEN Ya-hui   

  1. (State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai 200062, China).
  • Online:2018-09-10 Published:2018-09-10

摘要: 盐度作为滨海湿地的关键环境因子之一,影响盐沼植物的存活、生长及分布。未来海平面上升引起的盐水入侵,将导致滨海湿地的盐沼植物面临高盐胁迫的挑战,进而影响滨海湿地生态系统的结构和功能。本研究选择长江口中低潮滩的主要先锋植物海三棱藨草(Scirpus mariqueter)和互花米草(Spartina alterniflora)为对象,通过人工控制实验,比较不同盐度处理下两种盐沼植物存活、营养生长及繁殖的响应,并确定两种盐沼植物存活的耐盐阈值,从而比较未来盐水入侵背景下,本地物种海三棱藨草及外来物种互花米草对盐胁迫的响应和适应性。结果表明:(1)海三棱藨草和互花米草的存活率随着盐度的增加均呈下降趋势,相同盐度处理下互花米草的存活率显著高于海三棱藨草的存活率(P<0.05);(2)盐胁迫明显影响了海三棱藨草和互花米草的生长,随着盐度的增加,海三棱藨草株高、地上生物量及地下生物量均呈逐渐下降的趋势,而互花米草株高、地上生物量及地下生物量呈先增加后下降的趋势,均在盐度为10‰时最高;(3)海三棱藨草和互花米草的分蘖数及结穗率均随着盐度增加呈下降趋势,盐胁迫在一定程度上抑制了两种植物的繁殖能力;(4)互花米草存活的耐盐阈值为43‰,高于海三棱藨草存活的耐盐阈值(21‰);(5)外来物种互花米草比本地物种海三棱藨草具有更强的耐盐性,未来海平面上升引起的盐水入侵将对本地物种海三棱藨草产生更加严重的影响。

关键词: 阈值, 石漠化, 适宜度, 人居环境, 布依族传统村落, 指标体系

Abstract: As one of the key environmental factors, salinity affects survival, growth, and distribution of salt marsh plants. Given the projected sea level rise and saltwater intrusion, coastal wetland ecosystems are subject to higher salt stress, thus shifting in structure and function. Here, we focused on two vascular plants, a native species Scirpus mariqueterand an invasive species Spartina alterniflora in the Yangtze Estuary, aiming to explore the survival, growth, and reproduction of these two dominant species under a series of salinity stress. The responses of S. mariqueterand S. alterniflorato salinity were compared, and the salinity thresholds for survival of both species were calculated. The results showed that: (1) Survival rate of both species decreased as salinity increased, whereas the survival rate of S. alterniflora surpassed that ofS. mariqueter under the same salinity (P<0.05). (2) Growth of both species was significantly curtailed by increasing salinity (P<0.05); plant height, aboveground and belowground biomass of S. mariqueterdecreased as salinity increased, but those of S. alterniflora increased first then decreased when salinity reached >10‰. (3) Number of tillers and percent seed setting of both species decreased as salinity increased, suggesting an inhibited reproductive potential as affected by salinity; (4) S. mariqueter (with a salinity threshold of 21‰) was more susceptible to salinity than S. alterniflora(a salinity threshold of 43‰); (5) Being more salt-tolerant, the invasive S. alterniflora would overwhelm the native S. mariqueter under scenarios of sea level rise and saltwater intrusion.

Key words: Buyei traditional village, suita-bility, human settlement environment, rocky desertification, threshold., index system