An alternative mechanism for shade adaptation: implication of allometric responses of three submersed macrophytes to water depth

Abstract

Allometric scaling models describing sizedependent biological relationships are important for understanding the adaptive responses of plants to environmental variation. In this study, allometric analysis was used to investigate the biomass allocation and morphology of three submerged macrophytes (Potamogeton maackianus, Potamogeton malaianus and Vallisneria natans) in response to water depth (1.0 and 2.5 m) in an in situ experiment. The three macrophytes exhibited different allometric strategies associated with distinct adjustments in morphology and biomass allocation in response to varying water depths. In deeper water, after accounting for the effects of plant size, P. maackianus and P. malaianus tended to enhance light harvesting by allocating more biomass to the stem, increasing shoot height and specific leaf area. V. natans tended to allocate more biomass to the leaf than to the basal stem (rosette), showing a higher leaf mass ratio and shoot height in deeper water. The three species decreased biomass allocation to roots as water depth increased. The main effect of water depth treatments was reduced light availability, which induced plastic shoot or leaf elongation. This shows that macrophytes have evolved responses to light limitation similar to those of terrestrial plants.

Effects of taxonomy, sediment, and water column on C:N:P stoichiometry of submerged macrophytes in Yangtze floodplain shallow lakes, China

“…3 Variance partitioning based on pRDA analysis for sediment, water column, and taxonomy on tissue C:N:P stoichiometric signatures Table 6 Percentage (100 %) of explained variance based on variance partitioning for C:N:P stoichiometric signatures and for C, N, P, C:N, C:P, and N:P, respectively, in response to sediment, water column, and taxonomy The p values which <0.001 were emphasized in boldface S sediment, W water column, T taxonomy consistent with previous study (Li et al 2015). Indeed, in deep water, most submerged macrophytes tend to allocate more biomass to stem for shoot elongation to alleviate low light availability (Fu et al 2012;Strand and Weisner 2001). Changes of this biomass allocation could lead to low tissue P and high C:P because the structural organs generally have higher C and lower P than leaves (Li et al 2013).…”

“…Light availability in water column can affect physiology, morphology, biomass allocation, community structure, or distribution of submersed macrophytes, causing great variation in the C, N, and P concentrations and C:N:P stoichiometry in plant (Cao et al 2011;Chambers and Kalff 1987;Cronin and Lodge 2003;Xing et al 2013). For instance, to alleviate low light availability in deep waters, Potamogeton maackianus and Potamogeton malaianus tend to enhance light harvesting by allocating more biomass to the stem, increasing shoot height and specific leaf area, whereas Vallisneria natans tend to allocate more biomass to the leaf than to the rosette (Fu et al 2012). Furthermore, the C:N:P stoichiometry in plant tissue is not always directly correlated with sediment or water column N and P availability (Güsewell and Koerselman 2002).…”

Size-dependent C, N and P stoichiometry of three submersed macrophytes along water depth gradients

“…Submersed macrophytes occupy littoral zone in lakes, where water level fluctuation affects growth and distribution of the plants (Strand and Weisner 2001;Fu et al 2012;Zhu et al 2012). Water level fluctuation alters light availability in water column, waves and water-air gas exchange, sediment texture and element composition, which affect physiology, morphology, biomass allocation, growth rate and distribution of submersed macrophytes (Strand and Weisner 2001;Fu et al 2012;Yuan et al 2013;Christia et al 2014).…”

“…Water level fluctuation alters light availability in water column, waves and water-air gas exchange, sediment texture and element composition, which affect physiology, morphology, biomass allocation, growth rate and distribution of submersed macrophytes (Strand and Weisner 2001;Fu et al 2012;Yuan et al 2013;Christia et al 2014). Growth of submersed macrophyte is reduced in deep water due to low light availability (Fu et al 2012;Zhu et al 2012;Li et al 2013). Most submersed macrophytes tend to allocate more biomass to stem and increase shoot height in deep water so as to alleviate low light stress (Strand and Weisner 2001;Fu et al 2012).…”

“…Growth of submersed macrophyte is reduced in deep water due to low light availability (Fu et al 2012;Zhu et al 2012;Li et al 2013). Most submersed macrophytes tend to allocate more biomass to stem and increase shoot height in deep water so as to alleviate low light stress (Strand and Weisner 2001;Fu et al 2012).…”