Revista Chilena de Historia Natural 79 (3): 309-319, 2006
RESEARCH ARTICLE
Abiotic factors effects influencing the germination of six herbaceous species of Chilean arid
zone
The arid zone of northern Chile has a dry climate that prevents the massive emergency of
plant species. The exception to this general trend arises when scarce and irregular rainfall events occur, modify the environmental
humidity, and stimulate the germination of seeds. The main external factors that modify the internal nature of the seeds are the
hydration time, light, temperature and scarification. In this work two questions were addressed: (a) is the germination of seeds of arid
zones regulated by independent external factors or by a combined array of stimuli? and (b) do exist correspondence between
laboratory and in situ germinative conditions?. Seeds of six native and endemic herbaceous species of the north of Chile
(Cistanthe salsoloides, Leucocoryne purpurea, Pasithea coerulea, Placea amoena, Schizanthus
litoralis y Trichopetalum plumosum) were subjected to two germination experiments, with factorial
combinations of hydration time, temperature, light, dehydration and scarification. Schizanthus litoralis, was subjected to an
additional scarification-dehydration experiment (experiment 3). Results showed a common response of all the species in study to
certain external factors. Maximum germination percentages were reached when exceeding a threshold of 96 h of hydration and at
temperatures of 10 to 25 ºC. Light response was species-dependent. Agreement was found between the germinative conditions
determined in laboratory and natural conditions of germination. Therefore, the seeds of plant species of arid zones display similar
germinative thresholds and the techniques of germination in laboratory must be determined by the environmental characteristics of the
place of origin and the time of natural germination.
Key words:
germination, hydration,
temperature, light, arid zones
