Germination and morphological description of Oroceresus psudofussulatus (Cactaceae), a species endemic to the Xeric Inter-Andean Valleys of the Puna of northern Bolivia

Beatriz Mamani Sánchez, Naira Villegas Alvarado, Jorge Quezada Portugal, Máximo Nova Pinedo

Abstract

Cactaceae are emblematic plants, their trade, irrational exploitation, habitat destruction, and slow growth are causing many of them to be highly vulnerable. Oreocereus psudofossulatus, is an endemic cactus, distributed in the Xeric Inter-Andean Valleys of the Puna of northern Bolivia. The present research aims to evaluate the germination behavior and morphological description of the initial development of O. psudofossulatus under in vitro conditions. Likewise, to determine the germination percentage with pre-germination tests of soaking in water on paper substrates in Petri boxes. Also, to quantify the percentage of germination in substrates of sand, black soil and earthworm humus (ex situ). In addition, to compare the morphometric characteristics of sprouts from in vitro culture and Petri dishes. Seeds were sown in different techniques, one in MS/2 culture medium, in paper substrates in Petri boxes and in substrate of black soil, sand and earthworm humus, the latter in two treatments T1 (1:1:1) and T2 (1:1:2). The variables evaluated were percentage viability and gemination. O. psudofossulatus seeds showed 83 % germination in MS/2 medium; 72.7 % in paper substrate (petri boxes) and 95.6 % viability. The substrate treatment that presented the highest germination percentage (35 %) was T-2 (1:1:2).  In vitro, from radicle emergence through four phases until plant conversion (70 %) in 42 days, with this technique the cultivation time is reduced, which would not happen under natural conditions, since the seeds are exposed to arid climates with water deficit because they are in Xeric habitat.