The effect of different nutrient concentrations on the growth rate and nitrogen storage of watercress (Nasturtium officinale R. Br.)

Abstract

The mechanisms that allow broadly distributed aquatic plants to inhabit variable resource environments are unclear, yet understanding these mechanisms is important because broad environmental tolerance is often linked to invasiveness in terrestrial and aquatic plants. In an experimental stream, we examined the effects of different nutrient concentrations on the growth rate, biomass, and foliar nutrient concentrations of a cosmopolitan and potentially invasive aquatic plant, Nasturtium officinale (R. Br.). Nasturtium seedlings were grown under six nutrient treatment levels ranging from 0.64 lm N:0.09 lm P to 1531 lm N:204.13 lm P, for 8 weeks. Absolute and relative growth rates, and biomass of seedlings increased along a gradient of increasing nutrient concentrations but the effect of nutrient concentration was dependent on growing time.Seedling biomass varied among nutrient treatments in weeks 4 through 8 of the experiment, but did not differ in week 2. By week 8, the two highest nutrient treatments had greater biomass than the two lowest nutrient treatments. Foliar nitrogen concentration increased, whereas carbon concentration and C:N ratios decreased in response to increasing nutrients. Nasturtium grows slowly in nutrient-poor conditions but rapidly increases its growth, biomass accrual, and nitrogen storage as conditions become nutrient-rich. The response of Nasturtium to enhanced nutrient conditions may indicate how aquatic nuisance species successfully invade and dominate plant communities in streams, where resources often vary both temporally and spatially.

Effects of Temperature and Nitrogen Application on Carbon and Nitrogen Accumulation and Bacterial Community Composition in Apple Rhizosphere Soil

“…Individual, healthy and uniform seedlings (when they had 7–8 true leaves) were selected for isotope labeling and low temperature treatment. The seedlings were watered once every 3 days during planting period as needed ( Nagakura et al, 2004 ; Fernandez-Going et al, 2013 ).…”

Nitrogen addition increases intraspecific competition in the invasive wetland plant Alternanthera philoxeroides, but not in its native congener Alternanthera sessilis

“…; Fernandez‐Going et al . ). Although effects of N addition on plant growth have been extensively documented, studies on N pulses have produced disparate results.…”

“…Both plant invasion and increasing atmospheric N deposition have profound effects on the structure and function of ecosystems (Galloway & Cowling 2002;Jia et al 2010;He et al 2011He et al , 2012. Comparing responses of invasive and non-invasive plants to N addition may help to predict the relative changes of invasive and noninvasive plants in facing the increased N input in future (Bilbrough & Caldwell 1997;Chang et al 2012;Fernandez-Going et al 2013). Although effects of N addition on plant growth have been extensively documented, studies on N pulses have produced disparate results.…”

The influence of agricultural land-use on plant and macroinvertebrate communities in springs

“…Watercress ( Nasturtium sp. ), a dominant vascular plant taxon in these springs, grows faster and larger under high nutrient conditions (Fernandez‐Going et al ) as well as needing high light conditions for growth (Going et al ). Rooted plants (like watercress) can draw nutrients from sediment, and nitrogen and phosphorus are often elevated in the sediment of spring‐fed agricultural streams (e.g., Mebane et al ).…”