Resumo

LALLANA, Víctor Hugo  e  GARCIA, Luz Fabiola. Pre-treatment effects on the viability test in Trichocentrum jonesianum (Orchidaceae) seeds. Investig. Agrar. [online]. 2013, vol.15, n.2, pp.129-132. ISSN 2305-0683.

Periodic determination of seed viability is an important evaluating information to know the conservation degree of samples. In some orchid species, an increase in precision of tetrazolium viability test has been reported when performing pre-treatments with sacarose solutions during seed imbibition. The objective was to evaluate the viability of Trichocentrum jonesianum seeds using the tetrazolium test with and without water and sacarose pre-treatment. It was used a solution of 1% 2,3,5-triphenyltetrazolium chloride (TTC), keeping seeds at 33 ºC in darkness for 24 h or 48 h: T1) Seeds immersed in TTC solution for 24 h, T2) Similar to T1–48 h, according to treatments: T3) Pre-treatment with 0.1% sodium hypochlo­rite plus 0.1% tween 20 (detergent) during 7 min with agitation and 8 min resting. Seeds were rinsed three times with distilled water and then immersed in TTC for 24 h, T4) 24 h of imbibition in 10% sacarose, being extracted and replaced by 2 mL TTC for 24 h and T5) 24 h of imbibition in distilled water, being then extracted and replaced by 2 mL TTC for 24 h. Each treatment was repeated three times recording as viable seeds those with pink to dark red color; as non-viable those colorless with visible embryo and embryoless seeds. The highest viability were obtained with T5 (90%) showing no significant differences with T4 (85%). T3 presented the lowest viability (68%), while T1 (78%) and T2 (77%) showed significant differen­ces with T4 and T5. Embryoless seeds ranged between 76% and 86% depending on the treatments. T4 (sacarose added) did not improve the conventional viability test performance.

Palavras-chave : Orchids; pretreatments; viability.

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