In vitro germination and morphogenesis of Melanoxylon brauna Schott
Name: ELISA REGINA DA SILVA
Publication date: 28/02/2019
Advisor:
Name |
Role |
|---|---|
| RODRIGO SOBREIRA ALEXANDRE | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| EDILSON ROMAIS SCHMILDT | External Examiner * |
| JOSÉ CARLOS LOPES | Co advisor * |
| RODRIGO SOBREIRA ALEXANDRE | Advisor * |
Summary: Melanoxylon brauna, a Fabaceae native to Brazil threatened with extinction, is commonly propagated sexually, a low seed production is a problem in seedling production. Plant tissue culture is an alternative to the maintenance of braúna germplasm banks. However, there are few studies aimed at an in vitro propagation of braúna. The objective of this study was to evaluate the in vitro germination and morphogenesis of Melanoxylon brauna by means of the organogenesis of juvenile explants. Chapter I. Experiments I and II: Seeds were treated with sodium hypochlorite (NaClO) and Captan® 2% p.a. with and without residue, by different immersion rates, respectively. The following were analyzed: contamination; germination and normal and abnormal seedlings. Experiment III: Biotest of phytotoxicity of captana in lettuce. Lettuce seeds were exposed in Petri dishes with 2.5 mL Captan® at 0.5; 1; 2; 4 and 8% wt. an.; 0.01% glyphosate and distilled water. Germination; length of seedlings; cell cycle; nuclear and chromosomal alterations of the cells of the meristem root. The use of NaClO is not efficient in disinfestation of braúna seeds. Captan® for 10 minutes with residue, being efficient in disinfestation, allowed the seeds to express superior results of germination and vigor, however, showed toxicity and its mechanism of action in the lettuce cell cycle is clastogenic and aneugenic, which suggests the formation of abnormal seedlings in braúna. Chapter II. Three experiments were carried out: I. Proliferation of axillary buds with explants apex caulinar; nodal segment with axillary bud; nodal segment with two axillary buds and cotyledonary node in BAP (0; 4.44; 8.88; 17.76 and 26.64 μM). It was analyzed: number and length of shoots; percentage of budding explants; percentage of calogenesis and percentage of shoots by direct and indirect organogenesis. II. In vitro rhizogenesis of shoots with IBA, ANA and 2,4-D (0; 1; 2 and 3 mg L-1); III. In vitro rhizogenesis of shoots with temporary immersion in AIB (0; 1000; 2000; 3000 and 4000 mg L-1). The percentage of calogenesis and rhizogenesis was analyzed; number, length and dry mass of the roots. The nodal segment with two axillary buds was more responsive in BAP cauligenesis (8.88 μM). The auxin concentrations of IBA, ANA and 2,4-D were not favorable for rhizogenesis. The IBA at concentrations of 2544.81 and 2607.52 mg L-1 promoted superior results in rhizogenesis.
Keywords: braúna, plant tissue culture, disinfestation, cytokinin, auxins.
