Regeneration Potential of the Canopy-Held Seeds of Melaleuca quinquenervia in South Florida

Abstract

Melaleuca quinquenervia produces and maintains extensive seed reservoirs in the forest canopy. We collected capsules from different infructescences (clusters; Cluster I is the youngest, located at the most distal position, and Cluster VII is the oldest, located at the most proximal position) on branches from dry, seasonally flooded, and permanently flooded habitats. Extracted seeds were soaked for 10 d in sterile deionized water and/or 2,3,5,-triphenol tetrazolium chloride (TTC) stain to assess viability. Microscopic inspections revealed that only 15% of the seeds were embryonic (filled), 50% of embryonic seeds were viable (stained red with TTC), and 73% of viable seeds were germinable after 10 d. The remaining 27% of viable seeds may have been dormant or, possibly, required special conditions for germination. A higher percentage of seeds were embryonic on trees at permanently flooded habitats (18%) when compared to dry (14%) or seasonally flooded (14%) habitats. Overall seed viabilities and germinabilities were comparable among the three habitat types. Proportions of filled seeds were constant among infructescence positions within each habitat. Both viability and germinability of seeds varied with infructescence age, both being highest in Clusters II-V and lowest in Cluster VII.