Fertilizers and tube volumes in seminal propagation and cuttings of adult individuals of african mahogany
Name: CASSIA DOS SANTOS AZEVEDO
Publication date: 26/02/2024
Examining board:
Name |
Role |
|---|---|
| MARCOS VINICIUS WINCKLER CALDEIRA | Advisor |
Summary: The demand for high-quality timber has been growing significantly in recent years. In this sense, exotic species of high commercial value, such as African mahogany (Khaya spp.), emerge as promising alternatives for commercial plantations in Brazil. Considering the scarcity of studies addressing seedling production and vegetative propagation techniques in species of the genus Khaya, this dissertation was divided into two chapters, aiming to evaluate the use of different fertilizer doses and tube volumes in seedling propagation and to analyze the cutting technique in adult African mahogany individuals. Chapter I aimed to analyze the growth of seedlings from two species of the genus Khaya spp. with different doses of controlled-release fertilizer (CRF) and tube volumes. Khaya anthotheca and Khaya grandifoliola species were used for seedling production. The experiment was conducted in a factorial arrangement (2 × 5), evaluating the interaction of two tube volumes (180 and 280 cm³) and five concentrations of 15-9-12 CRF (0, 4, 8, 12, and 16 g L-1). After 180 days, the results indicated that different doses of CRF resulted in significant variations in the growth of K. anthotheca and K. grandifoliola seedlings, with the application of 10 g L-1 of CRF recommended for both species. Seedlings without CRF application (0 g L-1) showed the lowest values in all evaluated morphological characteristics. Tube volume did not show significant differences in the morphological growth characteristics analyzed in the species, ighlighting the Dickson Quality Index (DQI) as one of the most accurate measures, indicating the volume of 280 cm³ with higher quality seedlings. Chapter II aimed to analyze the potential of cutting as a method of vegetative propagation for K. grandifoliola, K. senegalensis, and K. ivorensis to investigate possible differences in tissue rejuvenation and/or revitalization. Cuttings were
collected from selected matrices of the genus Khaya spp. felled at ten years of age. Twelve matrices per species were selected and felled, totaling 36 trees to be used in the study. In order to verify the relationship of the adventitious rooting capacity of the
materials rescued by the vegetative propagation method via cuttings of the species, a study of tissue rejuvenation and revitalization was carried out. For this, the following leaf materials were compared: juvenile (six-month-old seedling), epicormic shoots (from branches of ten-year-old matrix trees at 5 m height from the base), adult (ten years old), and rescued material (basal shoots at 10 cm from the base). Based on the results, the cutting technique using tissues collected at the base of felled trees resulted in adventitious rooting in all species; however, the percentages of adventitious rooting did not exceed 30%. Basal cuttings with application of 0, 4,000, and 8,000 mg L-1 of IBA showed enzymatic activities of SOD, CAT, and APX similar to juvenile material originating from seed source. For studies aimed at investigating tissue rejuvenation/revitalization and its
successive metabolic activities, it is recommended to quantify the enzymes SOD and CAT for the K. grandifoliola species and only SOD for the K. senegalensis and K. ivorensis species.
