Abstract

Laretia acaulis (Cav.) Gill. et Hook (APIACEAE) is a cushion species inhabiting in fragmented populations in the Andes from 2400-3000 m, between Huasco (28 ° 46'S) and Talca (35 ° 25'S) in the north-central Chile. Despite its wide latitudinal distribution and harsh environmental conditions that must tolerate in their habitat, their conservation status is Vulnerable caused primarily by human disturbance. However, these habitats are also identified to be susceptible to increased temperatures due to the current global change. Probably this could be affecting the germination process, key natural regeneration. The objective was to evaluate the effect of time of cold stratification at 4 °C on the percentage and speed of germination Laretia acaulis. For this, seeds were collected in Riecillos sector (33 ° 0 '40' S, 70 º 21 '09'' W, 2,555 m) and transferred to Bank Base Seed INIA. The seeds ware subjected to a stratification in dark at 4 °C for different times of exposure to cold (0, 15, 30, 45, 60, 90, 135, 180, 225 days). Each treatment used 500 seeds, spread over 10 replicates of 50 seeds and germination was recorded every 3 ± 1 days. Germination started after 40 days and occurred at temperatures between 4 ° C -10 ° C (P <0.05), achieving a maximum of 46% of seeds germinated to 135 days of cold stratification. Seeds exposed to a temperature higher than 20 ° C failed to germinate (P> 0.05). These results could be due to condition of immaturity of the embryo that when occurs seed dispersal. Acaulis Laretia seeds may possess morpho-physiological dormancy that can be overcome by low temperatures (4-10 ° C) in their natural habitat, however, this could also be difficult if there is a likely increase in global change temperatures.