Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 14, 2005
Publication Date: August 15, 2005
Citation: Van, T.K., Rayamajhi, M.B., Center, T.D. Seed longevity of Melaleuca quinquenervia: A burial experiment in South Florida. Journal of Aquatic Plant Management. 43:39-42. 2005. Interpretive Summary: Melaleuca, or paperbark tree, is an aggressive weed tree of Australian origin that has invaded the sensitive Everglades and surrounding areas in South Florida. The invasive behavior of Melaleuca seems attributable to its aggressive regeneration strategies associated with its massive seed production. A 21-m tall open-grown tree growing may bear 34 kg of mature capsules containing as many as 100 million seeds. We determined how long melaleuca seeds remain viable in the soil under different field conditions. We buried seeds at two depths in the top-soil of the melaleuca forests at four locations in South Florida and assessed seed viability at intervals over a 3-year period or until all viability was lost. Our results suggest that it may be possible to severely reduce soil seed populations of Melaleuca within 2 to 3 years in South Florida.
Technical Abstract: Burial and removal techniques with seed bags were used to examine the viability and longevity of Melaleuca quinquenervia seeds at four field sites representing different soil types and hydrological conditions in South Florida. Seed viability was determined over different burial durations in the soil through a combination of germination tests and 2, 3, 5-triphenyl-tetrazolium chloride (TTC) treatments. Control seeds kept dry at 25 C in the laboratory maintained same viability of ca. 15% over the 3-year study. In the field, seed viability decreased with increased burial duration. Most buried seeds lost viability by ca. 1.5 year at seasonally flooded and permanently flooded sites, whereas seeds buried at non-flooded sites survived over a period up to 2 to 2.3 years. Burial depth increased seed viability at the non-flooded sites (P<O.OOOI), but had little effect on viability at seasonally (P=0.3691) and permanently flooded sites (P=0.0735). Soil types also had significant effect on seed viability. Seeds buried in organic (muck) soils decreased viability significantly faster (P<O.OOOI) than those in sandy loam soils. Our results suggest that it may be possible to severely reduce soil seed populations of Melaleuca within 2 to 3 years in South Florida.