Seasonal Growth, Biomass Allocation, and Invasive Attributes Manifested by Dioscorea bulbifera L. (Air-Potato) Plants Generated from Bulbils in Florida

Abstract

Dioscorea bulbifera is a serious invader of various ecosystems in Florida, where plants generated by its two morphotypes climb aggressively and smother supporting vegetation. There is a dearth of published research on its invasive biological attributes including vine growth and biomass production by plants generated from bulbils. Herein, we assessed these parameters in common garden studies by planting bulbils from four biomass categories (PBBCs I–IV) of both morphotypes. Vine lengths, longevity-based growth rates (VLGR), biomass, and quantities of leaves and daughter bulbils in both morphotypes showed positive correlation with the biomass of planted parental bulbils. This indicated similarity between corresponding attributes in two morphotypes. Total vine length showed strong positive correlation with VLGR, biomass, and quantities of leaves and bulbils. Overall vine longevity among plants from PBBCs I–IV did not significantly differ whereas the total vine lengths, VLGRs, number of branches, and quantities of leaves and bulbils increased with the biomass of the parental bulbils. Plants recruited by smaller bulbils allocated more biomass to leaves and tubers compared to stems and bulbils, whereas the plants recruited by larger bulbils allocated more biomass to leaves and bulbils compared to tubers and stems. Higher proportion of biomass allocation to leaves and bulbils presumably ensures immediate faster growth, longer vines, and a greater number of daughter bulbils for future recruitment of new plants. Vine length (associated with faster growth rate, capable of blanketing supporting structures and producing large quantities of bulbils) has been noted as the primary invasive biological attribute that facilitates D. bulbifera's status as a noxious exotic weed in Florida. Control measure that can reduce vine length should reduce or eliminate the invasive behavior of D. bulbifera in Florida.