Leaflet blade epidermis and its taxonomic significance in 13 species of Bignonieae (Bignoniaceae) from Pico do Jabre, Paraíba, Northeast of Brazil

Bignonieae is the largest tribe of Bignoniaceae, with 21 genera and 393 species of lianas and shrubs, 2–3-foliolate with the terminal leaflet modified as tendrils. We examined the micromorphologies of the leaflet blade epidermises of 13 species of Bignonieae belonging to Amphilophium, Anemopaegma, Bignonia, Cuspidaria, Dolichandra, Fridericia, Pyrostegia, Tanaecium, and Xylophragma, from Pico do Jabre, Paraíba, Brazil. These are lianas except for Tanaecium parviflorum (shrubby). We sought to identify epidermal leaflet parameters to support their taxonomy subject to great similarities between their vegetative characters, mainly in species of the same genus and related genera. Analyses were performed using light and scanning electron microscopy, and showed five types of epicuticular waxes, four cuticle types, three epidermal cell anticlinal wall types, and non-glandular and glandular trichomes. Hypostomatic leaves showed ten different types of stomata, with stomatal indices from 6.21% (Bignonia ramentacea) to 23.52% (Tanaecium parviflorum) and stomatal densities from 76 stomata/mm² (Pyrostegia venusta) to 752.9 (T. parviflorum). The presence of raphides in Amphilophium crucigerum and styloids in Fridericia pubescens constitute the first records for these genera. Epidermal micromorphology provided a set of distinctive characters to separate these species, representing an additional tool to support their taxonomies, as well as that of tribe Bignonieae.

Cryopreservation of Pyrostegia venusta (Ker Gawl.) Miers seeds

Seeds of Pyrostegia venusta (Ker Gawl.) Miers) were desiccated at 25 °C on silica gel for 0 h (T0), 7 h (T1) and 24 h (T2), reaching moisture contents of 6.5%, 4.4% and 3.8%, respectively. Seeds were frozen rapidly in liquid nitrogen (+LN) at -263 °C.min.-1 and after 72 h, they were thawed slowly at room temperature (25 ± 2 °C) at a speed of 5 °C.min.-1. Seed germinability evaluation before (-LN) and after freezing (+LN) was conducted at 25 °C, on paper roll substrate, and germinated at 16 hrs light/8 hrs dark, normal seedling counts for 38 days. The germinative percentages were 88% (T0-LN), 98% (T0+LN), 61% (T1-LN), 95% (T1+LN), 78% (T2-LN) and 89% (T2+LN). Mean days for seedling formation were 23 (T0-LN), 22 (T1-LN and T2-LN) and 30 days for seeds exposed to LN. Fast freezing, slow thawing, and the three tested moisture contents, were suitable for cryopreservation of Pyrostegia venusta seeds.