泥沙埋深对苦草和微齿眼子菜及两物种混合分解的影响  

DECOMPOSITION OF TWO SUBMERGED MACROPHYTES AND THEIR MIXTURE:EFFECT OF SEDIMENT BURIAL

作　　者：曹丹丹[1] 王东[1] 杨雪[1] 郭璇[1] 牛红玉[1] 

机构地区：[1]华中师范大学生命科学学院地理过程分析与模拟湖北省重点实验室,武汉430079

出　　处：《水生生物学报》2016年第2期327-336,共10页Acta Hydrobiologica Sinica

基　　金：国家自然科学基金项目(31270378);"荆江航道整治工程对水生生物相互关系的影响及其生态效应研究"项目;国家标本平台教学标本子平台(http://mnh.scu.edu.cn/)资助~~

摘　　要：为探讨泥沙淤积对水生植物分解的影响,研究了沉水植物苦草(Vallisneria natans)、微齿眼子菜(Potamogeton maackianus)及两物种混合在底泥中不同埋深(0和5 cm)的分解速率和养分动态,实验周期为117d。结果显示:(1)在0和5 cm埋深处理下,苦草、微齿眼子菜及两物种混合的分解速率均表现为苦草最快,微齿眼子菜最慢,物种混合介于两单种之间。与0 cm处理相比,在5 om埋深处理下苦草、微齿眼子菜及两物种混合的分解速率显著降低(P<0.05)。苦草在0和5 cm埋深处理下分解35天后干重剩余率分别为0和43.51%、在5 cm处理下分解82d后干重剩余率为0。微齿眼子菜和两物种混合在5 cm埋深处理下分解117d后的干重剩余率分别提高了31.09%和37.44%。(2)与0 cm处理相比,5 cm埋深处理显著抑制苦草、微齿眼子菜及两物种混合的N、P释放。苦草在0和5 cm埋深处理下分解35天后N剩余率分别为0和31.28%、P剩余率分别为0和24.45%。在5 cm埋深处理下分解117天后微齿眼子菜N和P剩余率分别提高了19.45%和14.73%、两物种混合N、P剩余率分别提高了41.57%和22.82%。(3)两物种混合在0和5 cm埋深处理下,其分解速率均表现为加和效应,但N、P元素释放在0 cm处理下分别表现为协同效应和加和效应,在5 cm埋深处理下均表现为拮抗效应。(4)随着分解的进行,5 cm埋深处理下的苦草和微齿眼子菜的微生物呼吸速率均显著降低,物种混合的微生物生物量始终低于0 cm处理。这些结果表明泥沙埋深显著降低了苦草、微齿眼子菜及两物种混合的分解速率和N、P元素释放,物种混合的N、P元素释放在分解后期均因沉积作用而产生了拮抗效应。此外,泥沙埋深对分解的抑制作用与微生物呼吸及生物量降低有密切的关系。研究结果可为认识水生植物分解对沉积作用的响应机制提供资料,并为了解水生植物分解对底质营养动态的影响提供参考。Decomposition of aquatic macrophytes makes the nutrients stocked in biomass release to the surroundings, and thereby can considerably affect nutrient cycling and energy flow in aquatic ecosystem. In most case, aquatic macrophytes may readily produce a considerable amount of stem and/or leaf fragments due to both natural and anthropogenic disturbances. The detached fragments will be deposited within the sediment. To date, the breakdown of aquatic macrophytes associated with sedimentation remains largely unexplored. Vallisneria natans and Potamogeton maackianus are two dominant submerged plants in shallow lakes of the Yangtze River basin of China. In the field, a substantial amount of the detached plant parts may be produced and deposited separately or coupled with each other at the substrate sur- face or buried within the sediment, contributing to the formation of an organic slime in the lakeshore areas. To investi- gate the effect of sediment burial on the decomposition of V. natans, P. maackianus and their mixture, three types of plant materials confined in litterbags were incubated and subjected to 0 cm and 5 cm buried treatments for 117 days. There were 5 g materials used for each species and mixture （2.52.5 of V. natans： P. maackianus, w/w basis） in the litterbags. The decomposition rates, nitrogen and phosphorus content of the remaining materials, and microbial respiration and biomass were measured at days 7, 19, 35, 56, 82 and 117 respectively. Decomposition rates of both V. natans and P. maackianus were significantly and positively correlated with initial N contents （P 〈 0.05, r = 0.896）, and negatively correlated with C/N ratio （P 〈 0.05, r = -0.963）. The decomposition rate was the highest for V. natans, the lowest for P. maackianus, and intermediate for their mixture. The decomposition rate and nutrient release of V. natans, P. maackianus and their mixture were greatly reduced in 5 cm burial treatments compared to 0 cm treatments. After 35 days experiment, the dry mass remaining percent

关 键 词：水生植物 泥沙埋深 分解速率 

分 类 号：Q948.8[生物学—植物学]