Differential effects of water depth and sediment type on clonal growth of the submersed macrophyte Vallisneria natans

Abstract

The response of clonal growth and ramet morphology to water depth (from 60 to 260 cm) and sediment type (sand versus organic clay) was investigated for the stoloniferous submersed macrophyte Vallisneria natans in an outdoor pond experiment. Results showed that water depth significantly affected clonal growth of V. natans in terms of clone weight, number of ramets, number of generations, clonal radius and stolon length. V. natans showed an optimal clonal growth at water depths of 110-160 cm, but at greater depths clonal growth was severely retarded. A high allometric effect was exhibited in ramet morphology. Along the sequentially produced ramet generations, ramet weight and plant height decreased while stolon length and the root:leaf weight ratio increased. When using ramet generations as covariate, sediment type rather than water depth more strongly affected the ramet characteristics. For plants grown in clay, ramet weight, ramet height and stolon length were greater, and plants exhibited lower root:leaf weight ratio. These data suggest that water depth and sediment type have differential effects on clonal growth of V. natans: Water depth appears primarily to affect numerical increase in ramets and spatial spread, whereas sediment type mainly affects biomass accumulation and biomass allocation.

Impact of water depth and sediment type on root morphology of the submerged plantVallisneria natans

“…The results obtained here also indicate that V. natans has wide ecological amplitude to nutrient availability in sediment. Xiao et al (2007) has indicated that water depth and sediment type have differential effects on the growth of V. natans. Water depth affects its clonal growth significantly except for clonal weight, which is significantly affected by sediment type.…”

“…Research indicates that, for many submerged plants, the achievement of maximum summer biomass is impacted by both water depth and sediment composition (Chambers & Kalff 1987). The clonal growth of submerged plants is also impacted by both water depth and sediment type (Xiao et al 2007).…”

“…Studies on the interactions between growth and sediment nutrient level have suggested that submerged plants can adapt to sediment by altering root growth patterns; a high root/ leaf mass ratio is characteristically associated with plants growing in low-nutrient or infertile sediment (Barko et al 1991;Gross et al 1993). Another study has also indicated that root/leaf mass ratio can be regulated by both water depth and sediment type (Xiao et al 2007). However, efficient nutrient acquisition depends not only on biomass allocation but also on root morphology (Chapin 1980;Linkohr et al 2002).…”

Responses of chlorophyll and MDA ofVallisneria natansto nitrogen and phosphorus availability and epiphytic algae

“…Thus MDA is often used as stress resistance indicators for environmental stresses (Li 2000). To understand the mechanisms that lead to the loss of macrophytes, we used the submerged macrophyte V. natans, an ecologically important species widely used in nutrient removal in eutrophic waters, because rapid decline of V. natans is observed with eutrophication of lakes (Xiao et al 2007). We investigated the responses of chlorophyll content and MDA levels, as indicators of physiological responses, to common environmental stressors.…”

Time-Dependent Oxidative Stress Responses of Submerged Macrophyte Vallisneria natans Seedlings Exposed to Ammonia in Combination with Microcystin Under Laboratory Conditions

“…Here, we focused on the combined effects of the two main toxins, dissolved ammonia and dissolved MC-LR that arise as a result of cyanobacterial bloom decay, a process that seriously impact fresh waters. In the experiments, therefore, we used submerged macrophyte Vallisnerria natans, an ecologically important species widely used in nutrient removal in eutrophic waters (Xiao et al 2007), as a test aquatic plant to determine the antioxidant responses to the combined toxicity of microcystin and ammonia. We hypothesized that:…”