中文摘要：

研究了水淹扰动包括不同的深度（0,10,60 cm）、持续时间（1周、2周）和发生频率（1次、2次）对扬子狐尾藻（Myriophyllum oguraense Miki subsp.yangtzense Wang）早期生长的影响。结果表明,湿生状态下未经过水淹处理的植株的总生物量最大、所产生的分枝数最多、株高最小;在经过水淹处理后,植株的总生物量、植株所产生的分枝数显著减少,而株高则显著增加。随着水淹深度的增大和持续时间的增加,植株的总生物量、分枝数显著减小,而株高则在浅水位处理下（10 cm）随着水淹持续时间的增加而增加,在深水位处理下（60 cm）随着水淹持续时间的增加而减小。总生物量在较长时间持续于浅水位下（2周,10 cm）和较短时间持续于深水位下（1周,60 cm）时随水淹发生频率的增高而增大,分枝数也呈增多趋势。随着水淹发生频率的增高,深水位（60 cm）显著促进株高的增加。此外,水淹处理后,茎生物量比增大,而根生物量比、叶生物量比、分枝生物量比则呈减小趋势。这些研究结果表明水淹扰动是影响扬子狐尾藻早期生长和克隆繁殖的重要因子之一,同时也说明扬子狐尾藻对不同的水淹扰动有不同的生长和克隆繁殖对策。

英文摘要：

In lakeshore areas,inundation events are relatively unpredictable and may vary greatly in timing and duration,affecting the growth of the majority of aquatic and wetland plants.Myriophyllum oguraense subsp.yangtzense Wang is a submerged macrophyte endemic in China and grows readily in lakeshore wetlands and shallow waters of the lower Yangtze River basin.To investigate how inundation affects the early growth of this endemic species,we manipulated plants in plastic pots of 16 cm in diameter and 12.5 cm in depth respectively,and subjected to varied inundation treatments of depth（0,10,and 60 cm）,duration（1 week and 2 weeks） and frequency（1 time and 2 times） in an outdoor experiment.Results showed that inundation significantly decreased plant biomass and the production of side branches,and greatly increased plant height.In contrast,plants which were never inundated had the highest plant biomass and side branch number,and had the shortest plant height.Plant biomass,branch number,and plant height significantly decreased with the increasing of water depth.On the other hand,as duration of inundation increased,plant biomass and side branch number decreased significantly.Plant height was affected by both water depth and duration.As the duration of inundation prolonged,plant height increased in shallow water treatments（10 cm） but decreased in deep water treatments（60 cm）.With increasing frequency of inundation,plant biomass increased in shallow water × long-lasting duration treatments（10 cm,2 weeks） and deep water × short-lasting duration treatments（60 cm,1 week）,and more side branches were produced.Additionally,plant height was affected by the interaction of water depth and frequency of inundation.Under high frequency of inundation,plant height decreased in shallow water treatments（10 cm） and increased in deep water treatments（60 cm）.Notably,root mass ratio,leaf mass ratio and branch mass ratio decreased while stem mass ratio increased under inundation treatments.Our data revealed that