In vitro propagation of Laelia albida (Orchidaceae) for conservation and ornamental purposes in Mexico

The orchid Laelia albida is an important cultural and religious plant resource of the Tehuacan-Cuicatlan Valley Biosphere Reserve in south-central Mexico. It is gradually becoming scarce due to overcollecting and habitat perturbation. For this reason, and for preservation purposes, the aim of the present work was to obtain the conditions to successfully propagate this species, through the use of mature seeds stored at 4 degrees C, and basal buds following in vitro techniques. Seeds with different storage periods (lot 1 and lot 2) were analyzed for seed viability as determined by the TTC method, germination percentage and germination index were analyzed on a monthly basis for 11 months on two Knudson C (K-4003, K-4128; Sigma). Seedlings were initially grown on the same culture media variants, but 30 days later they needed to be supplemented with potato starch (20 g.L(-1)). Basal buds were cultured on Knudson C containing nine BAP and NAA combinations two of which were also supplemented with potato starch (20 g.L(-1)) and coconut water (10%). Seed viability ranged from 78% to 98% throughout the 11 months and germination percentage was 70% to 90% without significant differences between the two lots. K-4003, either alone or supplemented with potato starch, was the best culture medium used to achieve all the development stages as well as seedlings with rhizoids. Bud proliferation was also successful on K-4003 added with BAP, NAA, potato starch and coconut water. The BAP (7.4 micromolar) and NAA (5.3 micromolar) combination promoted shoots and protocorm-like bodies (PLB). The results obtained with basal buds, make its preservation through in vitro culture possible and give the possibility to obtain available plantlets for its cultivation in regional nurseries. Storage conditions tested here may be useful for seed bank management for this species.