Curva de viabilidade, crescimento in vitro e potencial ornamental de Ionopsis utricularioides (Sw.) Lindl.

Abstract

The production of native orchids is one of the factors that can contribute to the reduction of extractivism. This study aimed to contribute to the appreciation and preservation of the native flora of the orchid Ionopsis utricularioides (Sw.) Lindl. by evaluating the storage period, predictive testing, the use of biostimulants as supplements in the culture medium, and the identification of the species' ornamental characteristics. To achieve the proposed objective, three independent experiments were conducted: I - Prediction curve for Ionopsis utricularioides (Sw.) Lindl. seeds via tetrazolium test: The aim was to improve the tetrazolium test method for I. utricularioides seeds and determine the longevity of these seeds by constructing a prediction curve. Eighteen seed samples from three different fruits were weighed and subsequently subjected to two distinct conditions: 1- without imbibition in distilled water: half of the tubes received 3 mL of an aqueous solution of 2,3,5-triphenyl chloride tetrazolium chloride (0.5%) for 24 h; 2- with imbibition in distilled water: the other half received 3 mL of distilled water for 24 h. After analysis in tetrazolium solution, the seed suspensions were kept in the dark for 24 h at room temperature and evaluated for the number of seeds with completely carmine-stained embryos (viable), partially stained, colorless, and devoid of embryos (nonviable). This evaluation was performed every 30 days for four months. For seeds of the species I. utricularioides, prior soaking in distilled water is recommended for the tetrazolium test, as this procedure facilitates the identification of viable seeds. II - Moringa extract on the in vitro growth and development of Ionopsis utricularioides (Sw.) Lindl.: This experiment was carried out to evaluate the effect of Moringa oleifera extract in the culture medium on the in vitro growth of I. utricularioides. The culture medium used was MS medium, supplemented with 30 g L-1 sucrose and gelled with 7.0 g L-1 bacteriological agar. This medium was used as a control, and for the other treatments, the media were supplemented as follows: 2) MS supplemented with 50 g L-1 moringa extract = 50; 3) DM with 100 g L-1 of moringa extract = 100; 4) DM with 150 g L-1 of moringa extract = 150; and 5) DM with 200 g L-1 of moringa extract = 200. Light conditions were provided by 3000K LED lamps under an irradiance of 43 µmol m-2s-1. At 180 days (in vitro), from the experimental period, survival, number of pseudobulbs, number of leaves, number of roots, plant height, length of the largest leaf, length of the largest root, and fresh weight were evaluated. The use of 50 g L⁻¹ of M. oleifera extract as a natural biostimulant in the culture medium showed promise for in vitro cultivation of Ionopsis utricularioides. These conditions favor plant survival and growth. III – Ornamental potential of Ionopsis utricularioides (Sw.) Lindl.: This study aimed to describe the vegetative and floral morphological characteristics of I. utricularioides, analyzing its ornamental potential. To achieve the proposed objective, eight individuals with flower buds were used. The evaluated characteristics were the following: plant length (mm), plant diameter (mm), number of pseudobulbs per plant, pseudobulb diameter (mm), leaf length (mm), number of inflorescences per plant, inflorescence length (mm), inflorescence diameter (mm), number of flowers per floral rush, floral rush length (mm), number of uncovered flowers per inflorescence per day, inflorescence durability (days), flower durability (days), and brightness. At the end of the experimental period, it was concluded that the species I. utricularioides has high ornamental potential for use in ornamental horticulture, due to its attributes, such as plant architecture, density period, coloration, size, and inflorescence durability. With the results obtained in the three experiments, obtained from the prediction of seeds over time, the supplementation of the culture medium with moringa extract, and the characterization of the ornamental potential of the species, can contribute to the valorization and conservation of the scientific native species.