Nymphaea Odorata Research Articles

Foliar uptake of 137Cs from the water column by aquatic macrophytes

A transplant experiment was performed to determine the relative importances of root uptake from the sediments and foliar uptake from the water column in determining the accumulation of 137Cs by aquatic macrophytes. Uncontaminated individuals of three species, Brasenia schreberi, Nymphaea odorata and Nymphoides cordata, were transplanted into pots containing either contaminated sediments (i.e. 1.2 Bq 137Cs g −1 dry mass) or uncontaminated sediments (i.e. < 0.1 Bq g −1 dry mass) and immersed in Pond B, a former reactor cooling pond where 137Cs concentrations in surface waters range from 0.4 to 0.8 Bq liter −1. The plants in uncontaminated sediments rapidly accumulated 137Cs from the water column and after 35 days of immersion had 137Cs concentrations in leaves that were: (1) not statistically significantly different from those for plants in contaminated sediments; and (2) similar to those for the same species growing naturally in Pond B. The similarity in 137Cs concentrations between naturally-occurring plants and those in pots with uncontaminated sediments suggests that foliar uptake from the water column is the principal mode of Cs accumulation by these species in Pond B.

Mortality of Largemouth Bass (Micropterus salmoides) and Steelhead Trout (Oncorhynchus mykiss) in Densely Vegetated Littoral Areas Tested Usingin situBioassay

ABSTRACT Concentrations of dissolved oxygen (DO) in dense beds of aquatic macrophytes in two western Washington lakes were routinely measured below reported lethal limits (≤1 mg L−1) for largemouth bass (Micropterus salmoides) and steel head trout (Oncorhynchus mykiss). The impact of the observed low DO concentrations on resident fish was examined both by field observation and by conducting 72 hour in situ cage bioassays. Replicate cages were placed in two Western Washington lakes at the surface, 1 m, and 2 m deep, in dense patches of aquatic macrophytes and open water. No steelhead trout mortalities occurred over 72 hours in the open water or surface water in dense patches of Myriophyllum spicatumia Lake Washington where DO concentrations were consistently > 4.0 mg L−1. No significant mortality of steelhead trout occurred in the surface cages of the floating leaf Nymphaea odorata, but all fish were dead within 12 hr at 1 m, where concentrations of DO were consistently < 4 mg L−1. No significant mortaliti...

SPECIES COMPOSITION, BIOMASS, AND NUTRIENT CONTENT OF PERIPHYTON IN THE FLORIDA EVERGLADES1

ABSTRACT Periphyton biomass, nutrient dynamics in the biomass, and species composition were studied in two Florida Everglades sloughs from August 1991 to August 1992. Periphyton biomass on macrophytes was strongly season‐dependent. Maximum biomasses, 1180, 161, and 59 g dry mass.m−2 on Eleocharis vivipara, E. cellulosa, and Nymphaea odorata, respectively, occurred in summer and early autumn; winter and spring periphyton biomass was very low (practically not measurable). Periphyton was dominated by blue‐green algae (cyanobacteria) during the summer and autumn; diatoms dominated during the winter and spring. Green algae occurred mostly during the summer and autumn, but their growth was sparse and did not contribute significantly to periphyton biomass. Nitrogen‐to‐phosphorus ratios in the periphyton were very high (59–121:1), suggesting phosphorus limitation of periphyton growth. The periphyton contained large concentrations of calcium (up to 22.3% on dry mass basis) especially in late summer and autumn.

Aquatic Macrophyte Growth in a Turbid Windswept Lake

ABSTRACT High water turbidity developed in the 1970s in shallow windswept Rice Lake, Wisconsin, and created a depauperate macrophyte community that has persisted more than a decade later. In 1989, this flora was characterized by species with early spring growth, summer leaf canopies, and winter tubers or rhizomes. The community was dominated inshore by water lilies (Nymphaea tuberosa and Nuphar variegatum) and offshore by pondweeds (Potamogeton pectinatus and P. natans). Together with coontail (Ceratophyllum demersum), water crowfoot (Ranunculus longirostris), and elodea (Elodea canadensis), the submersed flora reached a summer dry-weight standing crop of only 28–31 g/m2.

Wetland Restoration at a Former Nike Missile Base in the Great Lakes Basin

Restoration of an abandoned 16-ha Nike missile base site located on a former wetland in the lower Detroit River (Michigan, U.S.A.) was investigated with an emphasis on wetland restoration. The site included a 2.7-ha abandoned missile base, a 1.3-ha lake, 10.4 ha of emergent and submersed wetlands, and 1.8 ha of uplands. Aquatic beds in the shallow bay connected to the river supported floating leaved and submersed aquatics including Nymphaea tiiberosa, Vallisneria antericana, Elodea canadensis, and Heteranthera dubia, with mats of green, filamentous algae. A 10-ha diked wetland adjacent to the site was dominated by Typha spp., Salix spp., Nymphaea tuberosa, Myriophyllum spicatum, Elodea canadensis, Chara sp., and Juncus effusus. Restoration objectives included a nature preserve, an outdoor recreation area, an experimental wetland complex, and an environmental education center. Ten alternative designs were suggested, including four with wetlands open to the bay, three with diked wetlands, and the rest involving island construction, a reconstructed upland site, or a wetland research facility. Alternatives were evaluated for their contribution to local ecology, research, education and wildlife, ease of maintenance, and probability of success. Construction of a wetland resembling conditions before construction of the base was recommended for its low maintenance and opportunity for research on non diked wetland design and construction in protected bays in the Laurentian Great Lakes. Recreational and educational opportunities were also recommended as part of the site restoration.

Water Quality, Fishery, and Biologic Characteristics in a Shallow, Eutrophic Lake with Dense Macrophyte Populations

ABSTRACT Giffin Lake is a shallow, eutrophic lake in south central Washington and the sub ject of an intensive Phase I restoration diagnostic/feasibility study. Water quality problems in the lake have been manifested principally as excessive growth of the floating-leaved macrophyte, Nymphaea odorata, white water lily. Study results indicate that these macrophytes play a central role in chemical, physical, and biological functioning of the lake. The extensive macrophyte canopy prevents diffusion of oxygen to the sediments by inhibiting both gas exchange with the atmosphere and transfer of wind energy to the water column. Anaerobic conditions develop under the summer macrophyte canopy, as do steep nutrient gradients. Phytoplankton seasonal distribution appears to be strongly influenced by competition with macrophytes for nutrients and light. Zooplankton communities are dominated by rotifers which can tolerate low oxygen conditions and which feed on bacteria and detritus prevalent beneath the macrophytes. Fi...

The Effect of Nutritional Quality on Forage Preference by Beavers

We investigated the effect of nutritional parameters on preference by beavers (Castor canadensis) for five forage species. Cafeteria style experiments demonstrated that preferences ranked in the following descending order: trembling aspen (Populus tremuloides), white water lily (Nymphaea odorata), raspberry (Rubus idaeus), speckled alder (Alnus rugosa) and red maple (Acer rubrum). We assessed forage quality by determining dry matter, energy, crude protein, sodium, fibre and lignin contents as well as the digestibility of dry matter, energy and protein. Mean retention times of the diets in the gut of the beaver were estimated using a solid marker added to the forage. The mean retention times of aspen, raspberry and water lily were significantly shorter than those of alder and maple

Concentrations of zinc and chromium in aquatic macrophytes from the sudbury and muskoka regions of Ontario, Canada

Root and shoot samples of Eriocaulon septangulare, Nuphar variegatum, Nymphaea odorata and Pontederia cordata were collected from 15 lakes in central Ontario during the summer of 1988 to investigate possible relationships between zinc and chromium levels in aquatic macrophytes and water and sediment variables. Although concentrations of zinc and chromium differed greatly among the four species, both metals were consistently higher in Eriocaulon. Generally, root and rhizome tissue contained higher zinc and chromium than shoot tissues of the same species and site. Zinc concentrations (dry weight) ranged from 6·3 μg g −1 in Nuphar shoots to 87·7 μg g −1 in whole Eriocaulon. Chromium ranged from 0·23 μg g −1 in Pontederia shoots to 23·9 μg g −1 in whole Eriocaulon. No significant trends were detected throughout the growing season in macrophyte or sediment concentrations of either metal. Results of multiple linear regression analyses of several water quality and environmental variables on Eriocaulon indicated that sediment zinc was the best predictor of plant zinc, and sediment chromium and calcium were the best predictors of plant chromium.

New uses for calcium chloride solution as a mounting medium.

Fresh cross sections of stems (Psilotum nudum, Coleus blumei, and Pelargonium peltatum) and roots (Setcreasea purpurea) 120 microns thick were fixed in FPA50 (formalin: propionic acid: 50% ethanol, 5:5:90, v/v) for 24 hr and stored in 70% ethanol. The sections were transferred to water and then to 1% phloroglucin in 20% calcium chloride solution plus either hydrochloric, nitric, or lactic acid in the following ratios of phloroglucin-CaCl2 solution:acid: 25:4, 20:2, or 15:5. The sections were mounted on slides either in one of the three mixtures or in fresh 20% calcium chloride solution. A rapid reaction of the acid-phloroglucin with lignin produced a deep red color in tracheary elements and an orange-red color in sclerenchyma. Fixed and stored leaf pieces from Nymphaea odorata were autoclaved in lactic acid, washed in two changes of 95% ethanol, transferred to water, and treated with the three acid-phloroglucin-calcium chloride mixtures. The abundant astrosclereids stained an orange-red color similar to that of sclerenchyma in the sections. In addition, a new method is reported for specifically staining lignified tissues. When sections or leaf pieces are stained in aqueous 0.05% toluidine blue O, then placed in 20% calcium chloride solution, all tissues destain except those with lignified or partially lignified cell walls. Thus, toluidine blue O applied as described becomes a reliable specific test for lignin comparable to the acid-phloroglucin test.

Gas transfer in floating-leaved plants

Pressurized gas transport with flow rates of 1.1 to 1.81 gas h-1 plant-1 have been detected in the floating-leaved aquatic macrophyte Euryale ferox on sunny days. The younger leaves gave the highest pressurization, but the gas flow was initiated mainly by the middle-aged leaves of the plants. The gas through-flow was shown to be highly beneficial for floating-leaved plants. It improved the oxygen level in the aerenchyma of the submerged organs of Nymphaea alba and Nymphoides peltata, and doubled the ATP level in the root tissues. On the other hand, the sulphur dioxide fumigation experiments on Nymphaea odorata indicated that the pressurized gas transport may adversely affect the floating-leaved plants, due to an increased contamination of the leaves leading to increased photo bleaching and impaired photosynthesis.

Physiological Studies of Two Fungi Isolated from Nymphaea odorata

Physiological studies of Dichotomophthoropsis nymphaearum and Sclerotium hydrophilum were undertaken to determine the growth parameters for these two fungi. Optimum or near-optimum growth of D. nymphaearum occurred at temperatures of 25 and 30 C. Optimum temperature for growth of S. hydrophilum was 30 C, although maximum sclerotial production occurred at 25 C. Both fungi were able to utilize all of the carbon sources tested. Dichotomophthoropsis nymphaearum gave lower mycelial yields on xylose, while S. hydrophilum grew poorly on maltose. Both fungi utilized inorganic and organic nitrogen sources, but mycelial yields were lower when ammonium sulphate served as the nitrogen source. Glycine was also a poor nitrogen source for S. hydrophilum. Thiamine was required by both isolates of D. nymphaearum studied and by one of the isolates of S. hydrophilum. Light was not found to be essential for conidium production by D. nymphaearum or for the initiation of sclerotia by S. hydrophilum, although it did affect maturation of these structures. Pairing of six isolates of each fungus in all possible combinations and on several media failed to give evidence of a sexual response or production of a sexual state.

Fungi Associated with Living Leaves ofNymphaea Odorata

Fungi Associated with Living Leaves of<i>Nymphaea Odorata</i>

Fungi Associated with Living Leaves of Nymphaea odorata

Fungi Associated with Living Leaves of Nymphaea odorata

Photosynthesis, Photorespiration, and Organic Carbon Release inNymphaea tuberosaPaine andNuphar variegatumEngelm

ABSTRACT Within two sympatric populations of Nymphaea tuberosa and Nuphar variegatum in a productive hardwater lake, both species exhibited similar seasonal patterns of photosynthesis, but the rates were much higher in Nymphaea than in Nuphar. Rates of photorespiration and organic carbon release were very low in both species during most of the growth season and were not a factor in the difference in photosynthetic rates. Both species were growing under optimal conditions, and the superior photosynthetic capacity of Nymphaea appeared to be associated with phenological differences permitting this species to compete successfully (i.e. coexist) with the earlier emerging, broader leaved Nuphar species.

Allelopathic aquatic plants for aquatic weed management

This report presents, results of a feasibility study of use of allelopathic aquatic plants for aquatic weed management. In order to establish a list of potential allelopathic plants, we selected 16 aquatic plants native to the southeastern United States and subjected them to two bioassays — one involving lettuce seedlings and one involving the aquatic plantLemna minor as the target species. The lettuce seedling bioassay was selected because it is a widely used, experimentally simple assay to determine allelopathic activity. However, it uses lettuce, a terrestrial plant, as the target species, and thus may be less appropriate for use with aquatic plants. TheL. minor assay involves an aquatic plant as the target species and so is more appropriate for our goals, but it is experimentally much more complex and time-consuming. The plants selected for study wereBrasenia schreberi, Cabomba caroliniana, Ceratophyllum demersum, Eleocharis acicuiaris, Eleocharis obf usa, Hydrilla verticillata, Juncus repens, Limnobium spongia, Myriophyllum aquaticum, Myriophyllum spicatum, Najas guadalupensis, Nymphaea odorata, Nymphoides cordata, Potamogeton foliosus, Sparganium americanum, and Val/isneria americana.Nymphaea odorata (leaves and petioles) inhibited 78 % of lettuce seedling radicle growth and 98 % ofL. minor frond production. Brasenia schreberi inhibited 82 % of lettuce seedling radicle growth and 68 % of L. minor frond production. These results suggest thatN. odorata andB. schreberi are both highly inhibitory and are therefore candidates for use in aquatic weed management. Results also suggest that the simple lettuce seedling assay is a reasonable first “easy” one to use in an attempt to determine allelopathic potential of aquatic plants.

Distribution and biomass of aquatic macrophytes in an abandoned nuclear cooling reservoir

Pond B is an 87-ha abandoned reactor cooling reservoir on the Savannah River Plant, South Carolina. Since abandonment in 1964, the reservoir has reverted to a low conductivity and slightly acidic water chemistry, and has also been colonized by abundant macrophyte vegetation. To determine dominant species and their depth distributions, and to estimate seasonal changes in standing crop, above-sediment biomass of macrophyte vegetation was sampled at four water depths three times during the 1986 growing season. Three floating-leaved species, Nymphaea odorata Ait., Brasenia schreberi Gmel and Nymphoides cordata (Ell.) Fern., comprised 51.8% of biomass harvested, with greatest biomass at 1.5 m and in the October sampling. Free-floating Utricularia spp. (mostly U. floridana Nash) contributed 32% of harvest biomass, were abundant at all sampling depths and had greatest standing crop in May. Submersed rooted species comprised 15.4% of biomass harvest, dominated by Cobomba caroliniana var. pulcherrima Harper in deeper portions of the littoral zone. The species composition found in Pond B was similar to that of aquatic plant communities in other softwater Coastal Plain habitats (such as Carolina Bay ponds and rain-fed swamps), and differed from species composition reported for Par Pond, a neighboring reservoir with higher conductivity. These comparison suggested that differences in water chemistry may have been important in determining establishment of macrophytes species in these two reservoirs.

Marsh Seed Banks of the Okefenokee Swamp: Effects of Hydrologic Regime and Nutrients

Seedling germination from the seed banks of two marshes in the Okenfenokee Swamp, a deep macrophyte marsh and a shallow sedge marsh, was examined in the greenhouse under three hydrologic regimes and four nutrient conditions. Experimental hydrologic conditions of 3—mo duration, were constant exposure (no standing water), 1—mo exposure followed by reinundation, and constant inundation, repeated four times in 1 yr; nutrient conditions were amendments of N, P, N and P, and a control. The macrophyte marsh, whose water level fluctuates irregularly, has three guilds of species adapted to germination under different hydrologic conditions: drought—adapted, such as Rhyschospora inundata, which germinates in dry (exposed) conditions; inundation—adapted, such as Nymphaea odorata, which germinates only under water; and generalists, such as Eriocaulon compressum, which germinates in both exposed and inundated conditions. The relative abundances of these guilds fluctuate with the frequency and duration of drawdown in the habitat. Rhychospora inundata is a drought—adapted fugitive species in macrophyte marshes of the Okefenokee Swamp. It has a large population of seeds in the sediment, which germinate during a drought. Reinundation stimulates flowering and fruiting of adult plants. The sedge marsh, whose water level fluctuates regularly, has a single guild of species, dominated by Carex wateriana, which will not germinate in standing water. Nutrient content seedlings was parallel to the nutrients available. Nitrogen appears to limit marsh plant growth during drawdown, while phosphorus appears to limit a few species during inundation. As a result, most plants grow more rapidly in standing water, especially those that require drawdown for germination. The result is that this ombrotrophic, nutrient—poor wetland becomes more "lake—like," or P limited, during inundation, and more "land—like," or N limited, during low water levels.

A chronosequence of aquatic macrophyte communities in dune ponds

Differences in macrophyte community composition in a chronosequence of spatially separated dune ponds near the south shore of Lake Michigan were examined and related to environmental variables. Five ponds from each of five pond rows were sampled. In each pond, the cover of each plant species and water and sediment depth were sampled using a stratified random design. Radiocarbon dates were obtained from selected ponds. Ordination of the vegetation data by detrended correspondence analysis revealed similarities in the plant communities of ponds in the same row and community differences between ponds in different rows. Younger ponds (<300 years) were dominated by Chara spp. and Najas flexilis, middle-age ponds (2100 years) by Myriophyllum spp. and Nymphaea tuberosa, and older ponds (3000 years) by Typha angustifolia. Distribution of macrophyte communities was most closely correlated with water depth, which generally decreased with increasing age of the pond row. Some sediment chemistry differences were found between pond rows, but there were no significant differences in water chemistry. Although a linear succession pattern is suggested, we think that anthropogenic disturbance played a major role in determining the vegetation differences observed. Thus, a chronosequence of spatially separated ponds can provide valuable information on hydrarch succession, but it may be misleading and actually represent succession affected by disturbance history.

Mechanism and Adaptive Significance of Substrate Selection by a Sessile Rotifer

We examined the nature and adaptive significance of substrate selection by larvae of the sessile rotifer Collotheca gracilipes. In a small artificial pond the preferred substrate was the anatomical undersurfaces (abaxial) of Elodea canadensis leaves, although four other macrophytes were present (Ceratophyllum demersum, Lemna minor, Myriophyllum spicatum, and Nymphaea odorata). Density of adults on Elodea at times reached &gt;6 individuals/mm2, with &gt;98% attached to abaxial surfaces. However, larvae offered plants in pairwise combinations selected substrates in the following order; Lemma &gt; Elodea &gt; Myriophyllum &gt; Nymphaea. No larval loyalty to parental substrate was exhibited. Larvae preferentially selected abaxial over adaxial surfaces of Elodea leaves (91% on abaxial) in continuous illumination experiments, but the larvae did not discriminate between the two surfaces in total darkness (48% on abaxial). In the absence of a plant substrate, cell debris from any one of four aquatic and two terrestrial plant species induced larval settlement on the bottom of plastic well—depressions. Activity could not be attributed to carbohydrate, lipid, nucleic acid, or protein moieties within these extracts. However, alpha—amylase induced rapid larval settlement in the depressions. In the presence of this calcium chelator, larvae did not distinguish between ad— and abaxial leaf surfaces to the same degree as without the enzyme. Phospholipase—C and EDTA induced similar effects. Larval preference for abaxial surfaces could be reduced slightly when PH was stabilized at &lt;7.0. Because living Elodea in neutral—to—alkaline water can remove Ca+2 from beneath its leaves and release it from adaxial surfaces while photosynthesizing, we hypothesized that larvae initiate substrate selection activities on any surface when they are in microhabitats having ambient Ca+2 concentrations below a threshold concentration. Short—term, in vitro growth experiments showed that rotifers attached to abaxial surfaces of Elodea leaves grew significantly taller and produced more eggs per female than those which had been induced to settle on adaxial surfaces.

Aquatic plants of acid lakes in Kejimkujik National Park, Nova Scotia; floristic composition and relation to water chemistry

To document the aquatic flora of acid lakes in Kejimkujik National Park, N.S., the presence and abundance of aquatic macrophytes growing in water deeper than 3 dm were recorded in 20 lakes. Of the 45 species found, the most important were Sphagnum macrophyllum, Eriocaulon septangulare, Utricularia purpurea, Scirpus subterminalis, Pontederia cordata, Nuphar variegatum, Nymphaea odorata, Eleocharis acicularis, Sparganium angustifolium, Potamogeton confervoides, Lobelia dortmanna, Potamogeton epihydrus, and Utricularia vulgaris. To explore the relationship between floristic composition and water chemistry, information on 12 chemical variables and colour was related to species presence–absence using a nonparametric test based on relative neighbourhood graphs. Analyses of variance (ANOVAs) using chemical data and six groups suggested by a conditional clustering of the species presence–absence data demonstrated significant heterogeneity in Ca, pH, and HCO3. Furthermore, these three proved to be highly correlated. A canonical variate analysis of the six groups revealed one significant axis and separated the lakes into two major groups, characterized by relative acidity. An ANOVA of these two groups established that colour was also significant. There were fewer species in the more acidic (range 8–20, average 15) than in the less acidic lakes (range 15–32, average 22).