>> Wave effects on seedling establishment of three pioneer marsh species: survival, morphology and biomechanics
题名：Wave effects on seedling establishment of three pioneer marsh species: survival, morphology and biomechanics
来源：Annals of botany
发表年代：2019年
作者：Haobing Cao, Zhenchang Zhu, Rebecca James, Peter M.J. Herman, Liquan Zhang, Lin Yuan*, Tjeerd J. Bouma*
Abstract BACKGROUND AND AIMS: It is important to have an in-depth mechanistic understanding of tidal marshestablishment and dynamics to ensure the long-term persistence of these valuable ecosystems. As wave forcing may be expected to impact seedlingestablishment, we studied the effect of water-imposed drag forces on seedlingsurvival, morphology and biomechanical properties of threemarshpioneerspecies that are dominant along the salinity gradient in many areas around the world: Spartina anglica (salt to brackish), Scirpus maritimus (brackish) and Phragmites australis (brackish to fresh). METHODS: Using a newly developed plant-shaking mesocosm (PSM) that mimicked water-imposed wave drag forces, the effect of wave stress on seedlingsurvival was examined, together with impacts on morphology and biomechanical properties. KEY RESULTS: After 7 weeks of exposure to wave stress, lowered seedlingsurvival and growth for all species was revealed. Wave treatments increased the root/shoot biomass ratio to enhance anchorage and made seedlings more flexible (i.e. reduced flexural rigidity), which might be regarded as a mixed outcome between a stress avoidance and stress tolerance strategy. CONCLUSIONS: The different biomechanical responses between the three dominant marshpioneerspecies, overall, make them less resistant to external stress. Therefore, our results indicate that the likelihood of marshes becoming established is reduced if wave energy increases. Despite the different biomechanical response of these threepioneerspecies to waves, the seedlings of all species were found to have low resistance to external stresses. © The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
