Micropropagation and polyploidization of Tacca integrifolia

Bc. Pavla Bryxová

Master's thesis

Abstract:

Tacca integrifolia is a tropical ornamental plant with possibility of using in gardens and interiors as well. The objectives of this thesis were to develop a suitable protocol for micropropagation and mitotic polyploidization protocol using two antimitotic agents oryzalin and trifluralin. To carry out the multiplication experiment, shoots were cultivated on MS (Murashige & Skoog, 1962) culture medium supplemented with cytokinins BAP and zeatin at concentrations 0.3-2.0 mg. l-1 alone or in combination with NAA at concentration 0.1 mg. l-1. Optimal treatment proved to be 1.0 mg. l-1 BAP producing the highest number of adventitious shoots (10.38±1.19 shoots per explant). Rooting of shoots was tested on MS medium supplemented by auxin NAA at concentrations 0.1 and 0.3 mg. l-1. Higher number of roots was obtained from treatment 0.1 mg. l-1 NAA (3.18±0.45 roots per explant). A total of 29 well-rooted plants were transferred ex vitro, to the greenhouse conditions; a survival rate of 86.2% was obtained after eight weeks of evaluation. Genetic stability was verified through ISSR markers and flow cytometry. Three ISSR primers showed no polymorphism among plants tested. Similarly, no changes in ploidy level during the micropropagation process was detected via flow cytometry. To induce polyploidy, 160 plants were treated with oryzalin and trifluralin at concentration 25 and 35 µM in 24 and 48 h of exposure time. Ploidy level of all regenerated explants was measured using flow cytometry. The highest efficiency in ploidy induction was achieved in treatment 25 µM oryzalin applied for 48 h, where 20% of tetraploid plants were obtained and survival rate reached 95%. Total production of artificial induced tetraploids was 13.75%. Tetraploid plants displayed lower growth and leaf morphological changes. In this study, micropropagation protocol was optimized. This technique can serve as an efficient tool for commercial production of genetically identical plant. Morhoplogical changes in tetraploids can be beneficial in breeding of Tacca integrifolia. However, thorough morphological study of tetraploid plants is further needed.

Keywords

flow cytometry, micropropagation, molecular markers, polyploidy, Tacca integrifolia

Language used: English

Date on which the thesis was submitted / produced: 20. 4. 2018

Thesis defence

• Supervisor: Ing. Iva Viehmannová, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme / field:
Tropical Agriculture / Tropical Crop Management and Ecology