Sementes de orquídeas: conservação e avaliação de viabilidade

Abstract

In 2008, the Plant Tissue Culture Laboratory from the Agricultural Sciences College has partnered with Orchid Seed Stores for Sustainable Use (OSSSU) Project - Darwin Initiave - to create an orchid seed bank at Unoeste in Presidente Prudente, São Paulo. The aim of this project was to collaborate with the ex situ conservation of the largest plant family, that due to intense environmental degradation and unbridled exploitation, is also one of the most endangered. Seed storage in germplasm banks requires low conditions of humidity and temperature and has great advantages, as the numerous small seeds can last for years at very low costs. However, this strategy demands procedures such as viability tests for selecting lots to be stored, quality monitoring of stored seeds and eventually, germination tests to determine the potential for the production of individuals to be reintroduced into natural systems. Thus, the present work approaches the seed bank establishment at Unoeste and its importance for orchid biodiversity conservation. It also describes the results of preconditioning procedures, tested in order to improve the quality of tetrazolium test, one of the most used for the verification of seed vigor and viability. Finally were analyze the results of experiments to determine the germination cardinal temperatures - minimum, optimum and maximum - for some species of orchids.