根系结构对湿地植物根系释氧能力的影响.docVIP

根系结构对湿地植物根系释氧能力的影响 　　摘要：为了研究湿地植物的根系结构对根系释氧能力（以根系释氧速率和释氧速率对水位变化的敏感性来表征）的影响。采用柠檬酸钛法测定菖蒲、再力花、香蒲、芦苇4 种湿地植物在5种不同水位条件下的根系释氧速率，并采用标准差分析法分析不同湿地植物根系释氧速率对水位变化的敏感性。同时，采用比重瓶法测量湿地植物根系孔隙度，并对植物根部结构进行显微观察。结果表明：4种湿地植物的根系释氧速率从大到小总体上依次表现为香蒲芦苇再力花菖蒲，对水位变化的敏感性从大到小依次表现为香蒲芦苇菖蒲再力花。此外，湿地植物根系释氧能力与植物根系结构关系密切，主要表现为：湿地植物根系通气组织越发达、释氧屏障越不明显，则根系释氧速率越大、对水位变化越敏感。 　　关键词：人工湿地；根系结构；根系释氧速率；水位；敏感性 　　中图分类号：Q945 文献标志码：A 文章编号：1672-1683（2016）04-0112-05 　　Abstract：To study the effects of root structure on the ability of oxygen release from the root systems of plants（expressed by root oxygen release rate and sensibility of root oxygen release rate to dynamic water level），four different wetland plants were used（Acorus calamus Linn，Thalia dealbata，Typha orientalis Presl，Phragmites australis）.The root oxygen release rates in five different water levels were measured using titanium citrate buffer.Standard deviation was also used to illustrate the sensibility to dynamic water level of different wetland plants.In addition，root porosity was measured by pycnometer method and root structure was observed by microscope.The results showed that the root oxygen release rate of these wetland plants decreased in the following order as a whole：Typha Phragmites Thalia Acorus.The sensibility of root oxygen release rate to dynamic water level decreased in the following order：Typha Phragmites Acorus Thalia.Moreover，it was found that more developed Aerenchyma and less oxygen barrier may have positive relationship with the ability of root oxygen release.The more sensitive to the release rate of the plant root system，the more sensitive to the change of water level. 　　Key words：constructed wetland；root structure；root oxygen release rate；water level；sensibility 　　目前，人工湿地技术被广泛用于处理多种类型的废水，如污水厂尾水[1]、市政污水、分散型农村生活污水[2]等。一些研究表明，供氧条件是影响人工湿地净化能力特别是脱氮能力的关键因素[3-4]。Stein[5]通过研究人工湿[HJ1.96mm]地对于不同浓度COD去除的影响后发现植物具有很高的传输氧的能力，植物根系释氧是湿地土壤中氧的主要来源。另外，由于“根区理论”已被人们广泛接受[6-7]，湿地植物的根系释氧（ROL）能够使湿地植物根际溶解氧及其微生物分布发生变化。Justin等[8]提出植物根系结构如通气组织、皮层细胞排列方式等会影响