Decontaminant solution on in vitro growth of Byrsonima intermedia seedlingsby Luciano Coutinho Silva, Renato Paiva, Daiane Peixoto Vargas, Diogo Pedrosa Corrêa da Silva, Sandro Barbosa, Raírys Cravo Herrera

Cienc. Rural

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Year
2015
DOI
10.1590/0103-8478cr20120078
Subject
Veterinary (all) / Agronomy and Crop Science / Animal Science and Zoology

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674 Silva et al.

Ciência Rural, v.45, n.4, abr, 2015.

Decontaminant solution on in vitro growth of Byrsonima intermedia seedlings

Solução desinfestante no crescimento in vitro de plântulas de Byrsonima intermedia

Luciano Coutinho SilvaI Renato PaivaII Daiane Peixoto VargasIII Diogo Pedrosa Corrêa da SilvaII

Sandro BarbosaIV Raírys Cravo HerreraV

ISSN 0103-8478

Ciência Rural, Santa Maria, v.45, n.4, p.674-679, abr, 2015

Received 04.30.12 Approved 08.27.14 Returned by the author 12.08.14

CR-2012-0078.R3 http://dx.doi.org/10.1590/0103-8478cr20120078

ABSTRACT

Byrsonima intermedia A. Juss., is a medicinal and fruit plant of the Cerrado in which the conventional propagation is difficult due to the presence of extremely lignified endocarps.

Although sodium hypochlorite (NaOCl) is widely used in the surface decontamination, there are few reports of its effects on explant growth. The aim of this work was to study the effect of different pH and exposure periods of B. intermedia seeds to a

NaOCl solution. Seeds were subjected to different exposure periods (1, 5 and 10 minutes) to a NaOCl solution at different pH (5, 7, 10 and 12) and after treatment with NaOCl, embryos were inoculated in a WPM medium with 50% concentration of salts without sucrose, 0.5% agar and pH 5.8 and after 75 days of culture the growth of seedlings was evaluated. The use of NaOCl is effective in the decontamination of B. intermedia seeds, independent of pH variation and exposure periods and the parameters such as percentage of normal seedlings, shoot length, and number of leaves are positively affected by the use of NaOCl solution at pH 8.5-8.9 and by increasing the exposure period, however, the number of roots is affected only by increasing the exposure period in the NaOCl solution.

Key words: micropropagation, native plant, tissue culture, pH,

NaOCl.

RESUMO

Byrsonima intermedia A. Juss. é uma planta medicinal e frutífera do Cerrado, cuja propagação convencional é difícil, devido à presença do endocarpo extremamente lignificado.

Embora o hipoclorito de sódio (NaOCl) seja amplamente utilizado para a desinfestação superficial, existem poucos relatos de seus efeitos sobre o crescimento do explante. Neste trabalho, o objetivo foi estudar o efeito de diferentes pHs e períodos de exposição de sementes de B. intermedia em uma solução de NaOCl. As sementes foram submetidas a diferentes tempos de exposição (1, 5 e 10 minutos) numa solução de NaOCl com diferentes pHs (5, 7, 10 e 12) e, após o tratamento com hipoclorito de sódio, os embriões foram inoculados em meio WPM com a concentração de 50% de sais sem sacarose, ágar a 0,5% e pH 5,8 e, depois de 75 dias de cultivo, o crescimento das plântulas foi avaliado. A utilização de

NaOCl é eficaz na desinfestação de sementes de B. intermedia, independente da variação do pH ou dos períodos de exposição. A porcentagem de plântulas normais, o comprimento da parte aérea e o número de folhas são positivamente afetados pela utilização de solução de NaOCl a pH de 8,5-8,9 ou pelo aumento do período de exposição, enquanto o número de raízes é afetado apenas pelo aumento do período de exposição na solução NaOCl.

Palavras-chave: micropropagação, planta nativa, cultura de tecidos, pH, NaOCl.

INTRODUCTION

Byrsonima intermedia A. Juss. is a native and medicinal and fruit plant of the Cerrado (HERRERA et al., 2011) that presents difficulties for the propagation by seeds (LORENZI, 2002) due to the presence of extremely lignified endocarps (SOUTO & OLIVEIRA, 2005). As growth rooms and culture media, in vitro culture environments present ideal conditions for the growth of fungi and bacteria, thus, the explant decontamination is a critical factor to any

IDepartamento de Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal da Paraíba (UFPB), Campus I, 58051-900, João Pessoa, PB, Brasil. E-mail: lucoutsilva@yahoo.com.br. Correspondent author.

IISetor de Fisiologia Vegetal, Departamento de Biologia, Universidade Federal de Lavras (UFLA), Lavras, MG, Brasil.

IIIEmbrapa Clima Temperado, Pelotas, RS, Brasil.

IVUniversidade Federal de Alfenas (UNIFAL), Alfenas, MG, Brasil.

VUniversidade Federal do Pará (UFPA), Altamira, PA, Brasil.

BIOLOGY

Decontaminant solution on in vitro growth of Byrsonima intermedia seedlings.

Ciência Rural, v.45, n.4, abr, 2015. 675 tissue culture assay that uses plant material from ex vitro sources. When this treatment is not successful, the progress of in vitro culture studies becomes nonviable (GEORGE et al., 2008).

A decontaminant agent should eliminate microorganisms and, at the same time, not negatively affect the development of the explant and a variety of decontaminants can be used, such as ethanol, hydrogen peroxide, mercuric chloride, silver nitrate and even antibiotics (YILDIZ & ER, 2002;

RIBEIRO & TEIXEIRA, 2008). However, sodium hypochlorite (NaOCl) has been widely used in plant surface decontamination, showing high efficiency in combating bacteria and fungi (EMMANUEL et al., 2004), for example: node segments of Annona sp (SANTANA et al., 2011); young nodal stems segments of Maclura tinctoria L. (GOMES et al., 2010); nodule segments of Annona glabra L. (OLIVEIRA et al., 2010); Rhodiola rosea L. seeds (TASHEVA & KOSTURKOVA, 2010); flower-stalk sections of Limonium sinuatum L. Mill. (LIU et al., 2005); and seeds of Syngonanthus elegantulus

Ruhland (PÊGO et al., 2013).

The antimicrobial activity of NaOCl is mainly attributed to hypochlorous acid (HOCl) which presents low molecular weight allowing penetration the cell wall of the microorganism (LEN et al., 2002) and its concentration is increased by the addition of NaOCl or by lowering the solution pH. However, HOCl reversibly dissociates into H+ and OCl-, which presents less pronounced biocidal action, and the pH of the solution influences the final balance of these elements (CHUN et al., 1997;

EMMANUEL et al., 2004).