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泥沙掩埋和干旱对三峡库区消落带双穗稗草生长的影响

李强*,王书敏,丁武泉,朱启红   

  1. (环境材料与修复技术重庆市重点实验室, 重庆文理学院, 重庆 402160)
  • 出版日期:2017-03-10 发布日期:2017-03-10

Influence of sand burial and drought on the growth of Paspalum distichum in waterlevelfluctuating zone of the Three Gorges Reservoir.

LI Qiang*, WANG Shu-min, DING Wu-quan, ZHU Qi-hong   

  1. (Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing 402160, China).
  • Online:2017-03-10 Published:2017-03-10

摘要: 三峡库区消落带植物恢复不仅面临长期淹水逆境,还面临泥沙掩埋、干旱等环境因素的胁迫。蓄水期后引种三峡库区消落带双穗稗草,掩埋于不同粒径和埋深的沉降泥沙,探讨泥沙掩埋、干旱对反季节淹水后双穗稗草出苗和生长的影响。结果表明:在埋深≥8 cm和粒径≤2 mm条件下消落带双穗稗草萌发苗不能穿透覆盖层出苗,且随着泥沙粒径减小出苗率迅速下降。在埋深4 cm条件下处理组植株叶片形成和发育显著被促进,且随着泥沙粒径增大叶片数、叶长、叶宽呈显著增加趋势。但干旱和泥沙掩埋复合胁迫显著抑制双穗稗草幼苗的生长发育,处理组株高、叶片数、叶长和叶宽显著被抑制,随着泥沙粒径减小幼苗电子传递速率和热耗散能力显著降低,死亡率显著增大。因此,在泥沙掩埋及干旱复合胁迫下消落带双穗稗草的生长能力随粒径减小和埋深增加呈显著降低趋势,导致库区消落带双穗稗草种群衰退演替加快。

Abstract: In the waterlevelfluctuating zone (WLFZ) of the Three Gorges Reservoir, vegetation restoration is challenged not only by submersion for long periods, but also by sand deposition, drought, and other factors. To study the influence of sand burial and drought on the germination and growth of Paspalum distichum in the WLFZ of the Three Gorges Reservoir, P. distichum was transplanted and buried in sand of several particle sizes at various depths after antiseasonal flooding. Results showed that germinating seedlings of P. distichum in the WLFZ could not penetrate sand layers deeper than 8 cm with a particle size of less than 2 mm. As particle size decreased, the emergence rate dropped sharply. Under the condition of 4 cm depth, the leaf formation and development were significantly promoted, and leaf number, leaf length and leaf width were significantly accelerated with the increase of particle size. However, combined stress of sand burial and drought significantly inhibited the growth and development of seedlings, and plant height, leaf number, leaf length and leaf width were significantly restrained. The photosynthetic electron transport rate and the heat dissipation ability of the seedlings declined significantly with the decrease of particle size, and their death rate increased significantly. Thus, the ability of P. distichum for growth was significantly reduced with the decrease of particle size and the increase of burial depth under combined stress of sand burial and drought, which would lead to more rapid decline of P. distichum population in the WLFZs of the Three Gorges Reservoir.