Sobrevivência e desenvolvimento in vitro de Cattleya (Orchidaceae) submetida a tratamentos com colchicina

Abstract

ResumoNas orquidáceas, a poliploidia produz características desejáveis, que se traduzem em aumento das peças florais, grau de suculência, intensificação do colorido, durabilidade e maior resistência das flores. A colchicina como agente indutor de poliploidia em cultura de plantas in vitro tem suas limitações, pois em elevadas concentrações ou tratamentos muito prolongados, torna-se tóxica. O objetivo do trabalho foi avaliar a influência da concentração e do tempo de exposição à colchicina, na sobrevivência e no desenvolvimento in vitro de Cattleya tigrina. Protocormos foram tratados com colchicina em concentrações de 0,5 e 1g.L -1 durante 24, 48 e 72 horas. Foram avaliados taxa de sobrevivência dos protocormos (%), porcentagem de plântulas com múltiplas brotações e altura após três e sete meses. Com o aumento da concentração e do tempo de exposição à colchicina houve maior mortalidade e aumento do número de plântulas com múltiplas brotações e altura reduzida. Palavras-chave: Cattleya tigrina, poliploidia, protocormos AbstractPolyploidy produces desirable characteristicsin orchids that are represented by increase of the floral pieces, succulency degree, intensification of color, durability and larger resistance of flowers. The colchicine as polyploidy inductor agent in in vitro culture of plants has limitations, because when in high concentrations or very long treatments, it becomes poisonous for the vegetal tissues. The objective of this research work was to evaluate the influence of concentrations and times of exposition to the colchicine, on the survival and on the in vitro development of Cattleya tigrina. Protocorms were treated with colchicine in the concentrations of 0.5 and 1g.L -1 during 24, 48 and 72 hours. There were evaluated the tax of survival of the protocorms (%), percentage of plantlings with multiple buds and plant height after three and seven months. The increase of the concentration and of the time of exposition to colchicine caused a larger plant mortality and an increase of plantlings with reduced height.

In Vitro Induction of Polyploidy by Colchicine in the Protocorm of the Orchid Dendrobium wardianum Warner

“…The identified tetraploids recovered normal growth in subsequent culture. A similar result was found for Cattleya (Orchidaceae); the optimal concentration of the colchicine solution ranged from 125 to 250 mM, but the durations might be different for each species (de Mello e Silva et al 2000;Huy et al 2019;Lone et al 2010;Wu et al 2020). Although the solid medium with colchicine treatment showed higher lethality, it is possible to obtain tetraploids in lower concentrations, thus reducing the amount of expensive and toxic colchicine necessary.…”

Inducing and identifying artificially-induced polyploidy in bananas

“…High concentrations or long periods of exposure to these substances are usually observed to cause phytotoxic effects -generating high mortality among treated seedlings-and tolerance to colchicine and oryzalin varies among species and varieties, depending upon their genetic make up (Vakili, 1962;Ganga and Chezhyan, 2002). Colchicine toxicity at high dosages was reported by Lone et al (2010), who found lower survival rates of the protocorms of Cattleya tigrina (32%) that had been treated with 1 g.L -1 colchicine for 72 h. Regeneration rates of 27.26 % after colchicine exposure were observed in Tagetes erecta (Sajjad et al, 2013). Regeneration rates of 37 and 67% were observed in explants of Aframomum corrorima treated for 7 days with colchicine and oryzalin respectively (Wannakrairoj and Wondyifraw, 2013).…”

In Vitro Polyploidization of Brassolaeliocattleya Hybrid Orchid

“…Lone et al [ 26 ] observed a reduction in the survival rate of protocorms of Cattleya tigrina at the highest concentration of colchicine (1%), showing survival rates of 100%, 96% and 84%, with 24, 48 and 72 h of exposure, respectively, and compared to the control (100%). Similar results were reported for Vanda (Orchidaceae) protocorms treated with colchicine, aiming to induce polyploidy.…”