University of Florida

Micropropagation protocol development for ornamental aquatic plants

Many ornamental aquatic plants sold in the aquarium and water garden trade are imported into the United States. Given Florida's mild climate, some of these species have become naturalized and weedy, and are prohibited from further importation and sale in Florida. Currently, however, there are no reliable methods to assess the weed potential of imported aquatic plants prior to their becoming a problem.

Certain aquatic plant species have a greater capacity to rapidly colonize water bodies and become problematic. The competitive success of these plants has been attributed, in part, to their diverse and effective means for rapid vegetative growth and regeneration. Of the 12 most weedy aquatic plants, eleven species expand within their range through effective vegetative reproduction from propagules including shoot fragments and specialized hibernacula (tubers or turions).

Vegetative production of aquatic plants can occur in several ways. Many aquatic macrophytes can regenerate rapidly from stem fragments possessing a single axillary or modified bud. In several taxonomically diverse aquatic plant genera, including Utricularia, Rorippa, Ceratopteris, Hygrophila, Myriophyllum, and Podostemum, production of adventitious plantlets on detached and/or injured leaves is also an effective method of regeneration in situ. It is not known, however, what role, if any, adventitious shoot formation from fragmented tissues may play in aquatic plant dispersal. Comparative studies of in vitro growth and regeneration of designated prohibited (know weedy) and non-prohibited (putative non-weedy) exotic species could provide valuable baseline information with which to assess aquatic plant growth potential.

Specific Objectives

  1. Develop standardized in vitro culture procedures for rapid screening of aquatic plant growth potential.
  2. Determine the growth potential of prohibited and non-prohibited aquatic plant species in vitro.

Baseline data of the in vitro growth and regeneration rate of 20 prohibited aquatic plant species has revealed that extremely high capacities for rapid shoot production from stem and leaf tissues, and that regeneration can be precisely controlled and assessed in vitro. There was a high correlation between "weediness" in nature and regeneration by lateral shoot production in vitro. The capacity for adventitious shoot formation appeared to be limited to specific genera.

Aquatic Species Screened:

Crassula helmsii

Limnophila sessliiflora

Egeria densa

Limnocharis flava

Eichhornia azurea

Limnophila idica

Hydrilla verticillata (dioecious biotype)

Myriophyllum spicatum

Hydrilla verticillata (moneocious biotype)

Myriophyllum laxum

Hygrophila polysperma

Pontederia rotundifolia

Lagarosiphon spp.

Pista stratiotes

Trapa natans

Solanum tampinsce

Crassula helmsii Limnophila sessliiflora Egeria densa Limnocharis flava Eichhornia azurea Limnophila idica Hydrilla verticillata (dioecious biotype) Myriophyllum spicatum Hydrilla verticillata (moneocious biotype) Myriophyllum laxum Hygrophila polysperma Pontederia rotundifolia Lagarosiphon spp. Pista stratiotes Trapa natans Solanum tampinsce

To explore specific information concerning this project, proceed to Michael Kane's personal web page.