Anatomy and micromorphometric analysis of leaf Catasetum x apolloi Benelli & Grade with addition of potassium silicate under different light sources

Abstract

The aim of this study was to compare vitroplants Catasetum x apolloi grown under natural light and artificial light and different concentrations of potassium silicate, providing data on the anatomical differentiation that aids the acclimatization process of this species. Plants from in vitro seeding were used; 5 protocorms of approximately 0.5 cm were inoculated into vials with a capacity of 500 mL containing 100 mL of alternative culture medium plus potassium silicate (0.0, 0.5; 1.0 mL L -1 ), pH adjusted to 5.5 ± 0.5 and gelated with 4GL -1 agar before the autoclaving process. Cultures were maintained under natural light (TNE) and artificial light (TAE) for 90 days, and micromorphometric analysis was performed for polar and equatorial diameter, density and stomatal index, blade thickness in the central rib, and secondary veins. Applications in K 2 SiO 4 alternative medium provided the following: elongation of the hypodermis, thicker mesophyll, and more prominent midrib; elipptical guard cells; formation of epistomatal chamber; and lower stomatal density and stomatal with lower equatorial and polar diameters. The conditions that favored the acclimatization were lower light intensities and lower potassium silicate doses.Keywords: leaf anatomy, light, orchids, plants vitro. Anatomia e análise micromorfométrica foliar de Catasetum x apolloi Benelli & Grade com adição de silicato de potássio em diferentes fontes de luzResumo O objetivo desse trabalho foi comparar vitroplantas de Catasetum x apolloi cultivadas sob luz natural e luz artificial e diferentes concentrações de silicato de potássio, fornecendo dados sobre diferenciação anatômica que auxiliem no processo de aclimatação dessa espécie. Utilizou-se plantas provenientes da semeadura in vitro, 5 protocormos de aproximadamente 0,5 cm foram inoculados em frascos com capacidade para 500 mL contendo 100 mL de meio de cultura alternativo, acrescido de silicato de potássio (0,0; 0,5; 1,0 mL L -1 ), pH ajustado para 5,5 ±0,5 e gelificado com 4gL -1 de ágar antes do processo de autoclavagem. As culturas foram mantidas sob luz natural (TAA) e luz artificial (TAN) por 90 dias, e feitas análises micromorfométricas (diâmetro polar e equatorial, densidade e índice estomático, espessura do limbo na nervura central e nervuras secundárias). As aplicações de K 2 SiO 4 em meio alternativo, propiciaram: alongamento da hipoderme; mesofilo mais espesso e nervura central mais proeminente; células guardas elípticas; formação de câmaras supraestomáticas; menor densidade estomática e estômatos com menores diâmetros equatorial e polar. As condições que podem favorecer a aclimatação são menores intensidades de luz e menores doses de silicato de potássio.Palavras-chave: anatomia foliar, luminosidade, orquídeas, vitroplantas.

Morphophysiological responses of Billbergia zebrina Lindl. (Bromeliaceae) in function of types and concentrations of carbohydrates during conventional in vitro culture

“…The carbohydrates used during in vitro culture may affect both the morphology/anatomy and physiology of bromeliads (Martins et al, 2015c;Martins et al, 2016aMartins et al, , 2016b. Anatomical analysis of micropropagated plants is an excellent tool to ascertain how the in vitro conditions can affect the success of all the micropropagation stages, including transfer to ex vitro conditions (Martins et al, 2015c;Eburneo et al, 2017). Studies have also measured the chlorophyll a fluorescence to determine the performance of the photosynthetic apparatus of plants grown in vitro (Dobránszki and Drienyovszki, 2014;Matysiak and Gabryszewska, 2016;Rosa et al, 2018).…”

Light sources on the germination and initial in vitro establishment of Schomburgkia crispa Lindl., a species of the Brazilian Cerrado

“…Plants grown in the first condition showed higher epidermal thickness, leaf mesophyll thickness, root velamen thickness, and stomatal density. Moreover, EBURNEO et al (2017) reported that Catasetum x apolloi Benelli & Grade stomata responded better to water stress when the orchid grew in a natural light environment.…”