Donghu Experimental Station of Lake Ecosystem, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China.
College of Fisheries, Henan Normal University, Xinxiang, 453007, People's Republic of China.
Environ Sci Pollut Res Int. 2018 Dec;25(34):34027-34045. doi: 10.1007/s11356-018-3047-2. Epub 2018 Oct 2.
Few studies have focused on the biomechanical responses of submerged, rosette-forming macrophytes to wave action, water depth, or their co-occurrence in naturally eutrophic systems. The plant architecture, root anchorage strength-related traits, leaf morphology, and biomechanics of Vallisneria natans inhabiting a range of water depths were examined along three transects (T1, T2, and T3) in a eutrophic lake, Lake Erhai, in Yunnan Province, China. These transects were exposed to weak wave action and hyper-eutrophication (T1), moderate wave action and eutrophication (T2), or strong wave action and eutrophication (T3). The results showed that V. natans was mainly distributed at intermediate depths, with the widest colonization depth in T1. The values of plant architecture, root anchorage strength-related traits, leaf morphology, and biomechanics were generally highest in T3 and smallest in T2. Along the depth gradient, these values were generally highest at 3.5, 2.5, and 2.5 m for the plants growing in T1, T2, and T3, respectively. These findings suggest that V. natans adopts a "tolerance" strategy to cope with the effects of strong wave action in eutrophic habitats and an "avoidance" strategy when exposed to moderate wave action in eutrophic areas. Since the absence of an avoidance strategy increases the resistance to low-light stress at the expense of increased drag forces, there is a limit to the wave action that V. natans can withstand. This study indicates that biomechanics could be important when determining the distribution pattern of V. natans in Lake Erhai.
很少有研究关注水下、呈玫瑰花状的大型水生植物对波浪作用、水深或它们在自然富营养系统中共存的生物力学响应。本研究在云南省洱海的三个断面（T1、T2 和 T3）中，检查了不同水深下的苦草（Vallisneria natans）的植物结构、根系锚固强度相关特征、叶片形态和生物力学特性。这些断面分别受到弱波浪作用和富营养化（T1）、中波浪作用和富营养化（T2）或强波浪作用和富营养化（T3）的影响。结果表明，苦草主要分布在中等水深，在 T1 中分布最广。植物结构、根系锚固强度相关特征、叶片形态和生物力学特性的值在 T3 中通常最高，在 T2 中最小。沿水深梯度，在 T1、T2 和 T3 中，分别在 3.5、2.5 和 2.5 m 处生长的植物的这些值通常最高。这些发现表明，苦草在富营养栖息地中采用“耐受”策略来应对强波浪作用的影响，而在富营养区中受到中波浪作用时则采用“回避”策略。由于回避策略的缺失会以增加阻力为代价增加对低光胁迫的抵抗力，因此苦草能够承受的波浪作用是有限的。本研究表明，生物力学在确定洱海苦草的分布模式时可能很重要。
