|Laroche, Francoise - S. FL WATER MGMT DISTRICT|
Submitted to: Florida Exotic Pest Plant Council
Publication Type: Proceedings
Publication Acceptance Date: March 23, 2005
Publication Date: May 11, 2005
Citation: Rayamajhi, M.B., Van, T.K., Laroche, F. 2005. Melaleuca quinquenervia seed dynamics in south florida: how long do they remain viable in south florida environment? Florida Exotic Pest Plant Council, Weed be Jamin. p.21. Interpretive Summary: Weevil feeding reduces both qualities and quantities of melaleuca seeds, however, the longevity of these seeds in the soil was not known. We buried melaleuca seeds at two soil depths under three different habitat types, and then harvested them periodically for viability testing until seed germination was completely exhausted. Seeds at permanently-wet sites lost viability within 18 months of burial, while seeds in dry and sandy soils remained viable for over 2 years. Overall, melaleuca seeds survived longer at dry sites and in deeper soils than at wet sites and on the soil surface. This shows that the dry sites should be monitored for seedling recruitment for at least 2-3 years after the seed source is eliminated.
Technical Abstract: We used burial and removal techniques with seed bags to examine Melaleuca quinquenervia (melaleuca) seed viability and longevity in the soil at four sites in south Florida. Seed viability was determined using combination of germination and 2,3,5-triphenyl-tetrazolium chloride (TTC) tests. Dry seeds stored in laboratory maintained ca. 15% viability over several years. In the field, seed viability decreased rapidly 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 2 years. Seed viability was prolonged in deeper soil at non-flooded sites only. Soil types also had a significant effect on seed viability. Loss of viability was faster in organic (muck) soils than in sandy soils. These results suggest that melaleuca soil seed bank may be severely depleted within 2 to 3 years of deposition on the forest floor under south Florida conditions