Seed germination temperatures of eight Mexican Agave species with economic importance Article uri icon

abstract

  • The genetic diversity of Agave plants is threatened by clonal commercial reproduction and climatic change. Sexual reproduction is uncommon and research on seed germination is scarce. The present study evaluated the seed germination of Agave lechuguilla, Agave striata, Agave americana var. marginata, Agave asperrima, Agave cupreata, Agave duranguesis, Agave angustifolia ssp. tequilana and Agave salmiana at constant temperatures (10, 15, 20, 25, 30, 35 and 40°C). Initial imbibition (after the first 12h) was significantly variable among species, positively correlated with seed weight (r=0.6560, P<0.001) and increased with temperature (from 35%25 at 10°C to 66%25 at 40°C). Temperature affected maximum imbibition (83-150%25) for A.asperrima, A.lechuguilla, A.salmiana and A.striata; other species averaged 110%25. Most germination kinetics best fitted a logistic model, whereas only a few treatments fit a Weibull model. The time to germination onset diminished (P<0.05) from 125-173h at 15°C to 68-84h at 25°C, and then ascended to 84-196h at 35°C. The mean germination rate and seed germination percentage after 312h peaked at 25°C (0.50-0.95%25 seeds/h and 85-99%25, respectively) and fell (P<0.05) to near zero at 10 and 40°C. Temperatures of 10, 35 and 40°C were partially lethal to A.asperrima, A.duranguensis and A.salmiana seeds. The time to germination onset, seed germination percentage after 312h and mean germination rate are best described by a Gaussian distribution, with its optimum at approximately 25°C. Thus, optimum temperatures are related to the ecological characteristics of each species area. © 2011 The Authors. Journal compilation © 2011 The Society for the Study of Species Biology.

publication date

  • 2012-01-01