A aplicação do hormônio 24-Epibrassinolídeo promove o desenvolvimento e crescimento de mudas de Genipa Americana L. sob diferentes níveis de sombreamento

Abstract

One of the essential factors to start the restoration process of an area is the production of vigorous seedlings of adequate size for their survival, however, several challenges make large-scale production impossible, such as the unavailability of seeds and seedlings. The objective of this study is to analyze the effect of different concentrations of the hormone 24-epibrassinolide associated with different levels of shading on the development of genipap seedlings (Genipa americana L.). Genipap seedlings were used in three shading conditions: 50% shade, 35% shade and full sun. The seedlings were subjected to four concentrations of 10, 20, 30 and 40 nM of the hormone 24-epibrassinolide, maintaining a control treatment, in an experimental arrangement in randomized blocks, with four blocks and five treatments. Data were collected at 30, 60, 90, 120 and 150 days after application (DAA) of treatments, with measurements of plant length, stem diameter and number of leaves. To analyze growth parameters, R software was used, generating a Generalized Linear Model (GLM), and analysis of variance was performed on the results of biochemical parameters, with comparison of means by Tukey's test and to compare environmental and physiological data, a principal component analysis (PCA). Plants maintained at 35% shade showed positive effects on the parameters of height, diameter, number of leaves and lower concentrations of the hormone provided an increase in growth variables. The highest concentrations of biochemical variables were observed in conditions of lower hormone concentrations, under full sun and 50%. The environmental parameters were directly linked to the physiological responses of genipap seedlings. The accelerated development and growth of genipap seedlings is possible under certain shading conditions, and presents positive effects under the action of the hormone, which favors the development of robust plants.