Differential Strategies to Tolerate Flooding in Polygonum hydropiper Plants Originating From Low- and High-Elevation Habitats.

Xin-Sheng Chen,Yun-He Cai,Feng Li,Zheng-Miao Deng,Ya-Fang Li,Zhi-Yong Hou,Yong-Hong Xie

doi:10.3389/fpls.2018.01970

Abstract

In species that occur over a wide range of flooding conditions, plant populations may have evolved divergent strategies as a consequence of long-term adaptation to local flooding conditions. In the present study, we investigated the effects of a flooding gradient on the growth and carbohydrate reserves of Polygonum hydropiper plants originating from low- and high-elevation habitats in the Dongting Lake wetlands. The results indicated that shoot length did not differ, whereas the total biomass and carbohydrate reserves were reduced under flooded compared to well-drained conditions for plants originating from both habitat types. However, shoot length, shoot mass, rhizome mass, and total biomass were lower in plants from low-elevation habitats than in those from high-elevation habitats in the flooded condition. Soluble sugar and starch contents in belowground biomass were higher in plants from low-elevation habitats than in those from high-elevation habitats independently of the water level. Therefore, P. hydropiper plants from low-elevation habitats exhibit a lower growth rate and more conservative energy strategy to cope with flooding in comparison with plants from high-elevation habitats. Differential strategies to cope with flooding among P. hydropiper populations are most likely a response to the flooding pressures of the habitat of origin and may potentially drive ecotype differentiation within species along flooding gradients.

Highlights

Flooding is considered to be a major determining factor in plant growth and species distribution in riparian and lacustrine wetlands
We investigated the effect of flooding gradients on the growth and carbohydrate reserves of Polygonum hydropiper (L.) Delarbre plants originating from two habitats with contrasting flooding conditions in the Dongting Lake wetlands
Shoot mass, and rhizome mass produced by P. hydropiper were significantly affected by habitat type and water level (Table 1).The total biomass and rhizome mass of P. hydropiper plants were significantly lower in the flooding treatments (15- and 30-cm water levels) than in the welldrained treatment (−15-cm water level) (Figures 1A,D)

Summary

Introduction

Flooding is considered to be a major determining factor in plant growth and species distribution in riparian and lacustrine wetlands (van Eck et al, 2004; Dwire et al, 2006; Luo et al, 2008). The strategies of plants to cope with flooding-induced low oxygen can be categorized as the escape strategy and the quiescence strategy (Bailey-Serres and Voesenek, 2008, 2010; Striker et al, 2012). The plant grows and/or elongates its shoot to reach the surface and restore contact with the atmosphere (Bailey-Serres and Voesenek, 2008; Manzur et al, 2009). The process of shoot elongation is costly under low-oxygen conditions, i.e., the energy required for growing tissues would lead to faster carbohydrate depletion by anaerobic metabolism (Bailey-Serres and Voesenek, 2008, 2010). The quiescence strategy is characterized by stable functional traits, such as minimum growth and conservation of carbohydrate reserves (Setter and Laureles, 1996; Sauter, 2000; Bailey-Serres and Voesenek, 2008)

Methods

Results

Conclusion