Quiescence, growth and senescence of Egeria densa in Lake Marion

Getsinger, Kurt D.; Dillon, Christopher

doi:10.1016/0304-3770(84)90096-2

Cited by 41 publications

(18 citation statements)

References 8 publications

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“…Egeria densa did not exhibit distinct summer or winter senescence; both populations persisted as evergreen perennials, perhaps due to a lack of extreme seasonal changes (Greulich and Bornette 2003). Thus, rapid spring growth from a wintertype growth form (described by Getsinger and Dillon 1984) was not observed in the present study. Field evaluations should be conducted to determine whether these low points in TNC and N are substantial and consistent enough to use to target management of E. densa.…”

Section: Discussioncontrasting

confidence: 77%

Seasonal Changes in Carbohydrate and Nitrogen Concentrations in Oregon and California Populations of Brazilian Egeria (Egeria densa)

Pennington

Sytsma

2009

Invasive plant sci. manag.

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Total nonstructural carbohydrate (TNC) reserves support growth, formation of reproductive structures, and sprouting of plant tissues, and nitrogen (N) is essential for amino acid synthesis and photosynthetic enzyme production. Timing of weed management to periods when these critical resources are most limiting might improve efficacy. We examined seasonal changes in carbohydrate and nitrogen concentrations in Brazilian egeria (Egeria densa), a common submersed aquatic weed, from two locations in the United States. Plants were collected from a coastal Oregon reservoir and from California's Central Valley in the Sacramento–San Joaquin Delta. Starch comprised between 35 to 51% of the TNC in lower stems and root crowns. Seasonal changes in resource concentrations were not consistent between years within a population or for the same plant part between different populations. Lowest TNC concentrations were observed earlier in the growing season (March) in Disappointment Slough than in Big Creek (May to June). Conversely, highest concentrations were observed in October in Disappointment Sough and from August to March in Big Creek. Nitrogen concentrations were highest in stem tips in both populations, with more distinct seasonal changes in the California population. These data suggest western populations of E. densa might exhibit less-discernible low points in root crown and lower stem energy storage for targeting management activities to vulnerable phenological stages. Brazilian egeria has high phenological plasticity despite its low genetic diversity and lack of specialized reproductive and perennating structures, which allows the plant to invade and dominate submersed plant communities in areas with mild winters.

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Section: Discussioncontrasting

confidence: 77%

Seasonal Changes in Carbohydrate and Nitrogen Concentrations in Oregon and California Populations of Brazilian Egeria (Egeria densa)

Pennington

Sytsma

2009

Invasive plant sci. manag.

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“…Medidas em outros locais, geralmente em latitudes maiores, têm revelado biomassas apenas um pouco menores (Getsinger & Dillon, 1984;Feijoó et al, 1996;Wilcock et al, 1999). Atingido o limite de acumulação, a vegetação poderia restringir a produção de biomassa ao necessário para renovação das plantas mortas, das partes desprendidas ou predadas.…”

Section: Resultsunclassified

Capacidade de regeneração de Egeria densa nos reservatórios de Paulo Afonso, BA

Oliveira

Sampaio²,

Pereira³

et al. 2005

Planta daninha

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Para controlar a proliferação de Egeria densa e reduzir os prejuízos que vêm causando na geração de energia em Paulo Afonso, é necessário conhecer sua capacidade de regeneração. Para isso, foram marcados quadrados de 4 m², em diferentes épocas do ano e em três profundidades (0-2, 2-6 e 6-9 m), e retiradas as biomassas de E. densa iniciais e três meses depois. Na profundidade de 0-2 m, as retiradas de plantas foram repetidas por cinco vezes, em quatro dos mesmos quadrados. Nesta profundidade, as massas regeneradas (518 g m-2) foram semelhantes às iniciais (482 g m-2), independentemente da época do ano (estação seca, geral: 506 g m-2; chuvosa: 513 g m-2) e da repetição da retirada. Na de 2-6 m, as massas regeneradas foram apenas 66% das iniciais (150 e 229 g m-2) e na de 6-9 m, apenas 21% (11,6 e 54,9 g m-2). A rápida recolonização e o grande crescimento de E. densa tornam muito difícil erradicá-la dos reservatórios do São Francisco. Sugere-se que seja explorado esse grande potencial de produção de biomassa.

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“…Regardless of the good care taken with plants throughout the experiment, two separate sets (i.e., trials) of plants had to be considered, because individual plants experienced braking of branches and generalized tissue decay over time, making it difficult to continue with most of the quantifications for more than five months. The latter phenomenon, however, has been described as natural occurrence, in which E. densa undergoes a seasonal progression of senescence and quiescence [15,16]. A first set of 100 plants ( n = 5 per experimental tank) was included in the experiment of December 2005 and finally retrieved in May 2006.…”

Section: Methodsmentioning

confidence: 99%

Effect of prolonged exposition to pulp mill effluents on the invasive aquatic plant Egeria densa and other primary producers: A mesocosm approach

Palma

Silva

Muñoz

et al. 2008

Enviro Toxic and Chemistry

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The recent disappearance of the aquatic plant Egeria densa, a Brazilian native invasive species, from a wetland in southern Chile prompted several efforts to unveil the origin of this phenomenon. Because these changes occurred by the time a newly built pulp mill started its operations in the area, a reasonable doubt for a cause-effect relationship is plausible. We implemented a mesocosm approach to directly evaluate the effect of treated pulp mill effluents (PMEs) on several growth-related parameters of E. densa as well as other primary producers. We hypothesize that effluent, at a dilution similar to that detected in the zone of the wetland where the negative environmental impacts were evident, has a significant negative effect on this aquatic plant as well as on other primary producers inside a mesocosm system. After a prolonged (months) exposure to both 0% PME with pure river water and a 4 to 5% (v/v) dilution of treated PME, no effect on E. densa was measured. Furthermore, plants exposed to effluent exhibited a significantly greater general growth rate. Coincidently, chlorophyll a concentration in the water column and periphyton biomass also changed over time, but without any pattern attributable to the effluent. Values of the autotrophic index obtained from the periphyton growth pattern did not suggest enrichment of the system with organic matter. Our results only refer to the direct effect of mill effluents on several biotic responses, but they represent an important advance toward generation of the scientific knowledge necessary to understand how the ecosystem functions while receiving this and other unquantified sources of water.

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Quiescence, growth and senescence of Egeria densa in Lake Marion

Cited by 41 publications

References 8 publications

Seasonal Changes in Carbohydrate and Nitrogen Concentrations in Oregon and California Populations of Brazilian Egeria (Egeria densa)

Seasonal Changes in Carbohydrate and Nitrogen Concentrations in Oregon and California Populations of Brazilian Egeria (Egeria densa)

Capacidade de regeneração de Egeria densa nos reservatórios de Paulo Afonso, BA

Effect of prolonged exposition to pulp mill effluents on the invasive aquatic plant Egeria densa and other primary producers: A mesocosm approach

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