根系结构对湿地植物根系释氧能力的影响

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。

Effects of root structure on the ability of root oxygen release in constructed wetland

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.