In-vitro Micropropagation and Acclimatization of Selected Florida Native Orchids

Authors

Andrew MullinFollow

Document Type

Thesis

Degree

Master of Science (MS)

Major/Program

Environmental Studies

First Advisor's Name

Dr. Amir Khoddamzadeh

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Dr. Hing Liu

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Dr. Krish Jayachandran

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Dr. Jason Downing

Fourth Advisor's Committee Title

Committee member

Keywords

natural resources and conservation

Date of Defense

11-12-2021

Abstract

Florida is home to 106 native orchid species with the majority of them being endangered or critically imperiled, according to the International Union for Conservation of Nature (IUCN) and the Institute for Regional Conservation (IRC). In nature orchid germination rates are very low because they lack an endosperm, instead depending on an obligate relationship with a mycorrhizal fungus for nutrients. Most orchid seeds can be germinated in-vitro without the need for specific mycorrhizal fungi and therefore high rates of germination can be achieved. This study aims are a) to establish the fastest and most efficient in-vitro seed germination media and plant growth regulators (PGRs) combinations, and b) to optimize acclimatization methods.Two epiphytic and one terrestrial endangered and threatened native orchid species (Oncidium ensatum, Trichocentrum undulatum, and Encyclia tampensis) were selected in this study. To determine germination preferences, three different in-vitro seed germination media supplemented with PGRs were tested on an endangered epiphytic orchid Cyrtopodium punctatum: 1. MS, 2. MS+1.5mg/L BAP, 3. MS + 1 mg/L BAP+0.5 mg/L NAA with 12 replications per treatment, comparing the beginning stages of germination. Due to high seedling mortality during the introduction and reintroduction stages, two different acclimatization media were tested on plantlet growth (Coir, Sphagnum) with a fertilizer regimen of half strength 20N-20P-20K weekly for five months. To measure plantlet growth rates, phenotypic measurements (leaf number, leaf length, root length, plantlet height, light intensity, SPAD measurements, NDVI, pH, and EC) were conducted monthly for five months. The best media combinations for each orchid will be selected by the end of this experiment. The acclimatization portion of this study demonstrated that with Trichocentrum undulatum, coir outperformed sphagnum, resulting in longer leaf length and higher electric conductivity. In the case of Encyclia tampensis, neither media was significantly better than the other. Oncidium ensatum exhibited high mortality in both treatments, especially in sphagnum, possibly due to an unhealthy sample group of plants. As for in-vitro seed germination media supplemented with PGRs, there was no significant difference between media/PGR combinations pertaining to germination, growth stages, or seed mortality.

Identifier

FIDC010482

Comments

This is my final submission for my degree.

Recommended Citation

Mullin, Andrew, "In-vitro Micropropagation and Acclimatization of Selected Florida Native Orchids" (2021). FIU Electronic Theses and Dissertations. 4878.
https://digitalcommons.fiu.edu/etd/4878