Mature-embryo culture in the cryopreservation of passion fruit (Passiflora edulis Sims) seeds

Abstract

Passion fruit seeds gradually lose their viability when preserved over long periods in cold chambers. Cryopreservation can overcome this problem, but there are two main obstacles: the initial water content in the seed and the regeneration of seedlings after the process. We aim to evaluate the cryopreservation of passion fruit (Passiflora edulis) seeds with different initial water contents and in vitro and ex vitro germination efficiency in seedling regeneration. The experiment was conducted as completely randomized design in a 4 × 2 factorial arrangement that consisted of four initial water contents (25, 15, 10, and 5%) in passion fruit seeds, with and without immersion in liquid nitrogen. After cryopreservation, the seeds from all treatments were divided into three groups: (1) underwent ex vitro germination on paper rolls, (2) the embryos were isolated and cultured in vitro, and (3) processed in permanent slides to study anatomy by light microscope. The cryopreserved seeds with a water content of 10% showed greater ex vitro (4%) and in vitro (100%) germination. Thus, for cryopreservation of passion fruit seeds, the water content of 10% and in vitro growth of isolated mature embryos is the most indicated combination to achieve higher germination rates quickly and uniformly, without anatomical damage to the cells and which provides a new alternative for safe long-term preservation of passion fruit seeds.