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|Title:||Allocation of biomass and carbohydrates in waterhyacinth (Eichhornia crassipes) : pond-scale verification|
|Authors:||Aquatic Plant Control Research Program (U.S.)|
Madsen, John Douglas.
Luu, Kien T.
Getsinger, Kurt D.
Aquatic plant control
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: Currently, little biologically based understanding exists for the optimum timing of control tactics, with respect to time of year and stage of growth of target plant. A better understanding of plant life cycles and carbohydrate allocation patterns may elucidate weak points in the life cycle of target plants and allow optimum application of control measures. The objectives of this study were to verify previous small-scale waterhyacinth carbohydrate allocation studies in a large pond environment, and to elucidate carbohydrate and biomass allocation patterns in waterhyacinth (Eichhornia crassipes (Mart.) Solms). Waterhyacinth was grown in a 0.3-ha pond near Lewisville, TX, from June 1989 to March 1990. Monthly plant samples were taken and sorted into component plant parts (i.e., leaf petioles, leaf laminae, stolons, stembases, roots, inflorescences, and dead material), which were then analyzed for free sugars, starch, and total nonstructural carbohydrates (TNC). Maximum plant biomass ranged from 991 to 1,146 g m⁻² during the period July through November 1989. Leaves and roots were the highest proportion of living plant mass, followed by stembases. Leaves were composed of 60 to 65 percent petioles and 35 to 40 percent laminae. A heavy frost in December killed above-water plant parts, mostly leaves. Carbohydrate concentrations were highest in stembases (up to 40 percent TNC), followed by stolons (15 percent); other plant parts were 10 percent or less. TNC mass per unit area was highest in leaf petioles before the frost, and in stembases after the frost. During the growing season, 60 percent of TNC was found in the leaf tissue on a per unit area or total plant weight basis, whereas only 20 percent was stored in the stembase. After frost, most of the plant's TNC was found in the stembase, since the TNC stored in the leaves was lost as dead material. The primary weak point in the life cycle of waterhyacinth, defined as the time of lowest whole-plant TNC stores, was observed in the early summer, before plants had built up sufficient carbohydrate reserves to provide for regrowth. A secondary period of potential low recovery would be in early fall, before a large proportion of total plant carbohydrates is stored as starch in the stembase. In general, control will be more effective when applied to small colonies not yet developed into mature stands, whether early in the year or early in the invasion or recovery cycle.
|Appears in Collections:||Technical Report|