Germination of two Acacia species at elevated temperatures simulating climate change

Abstract

Temperature increase can affect germination in a positive or negative way. A temperature increment of 0.6 °C occurred during the last decades, and by 2099 an increment of 1.5 to 4.7 °C is expected. The aim in this study was to evaluate seed germination from certain provenances of Acacia farnesiana and A. schaffneri at different temperatures. The information generated thereby will make it possible to determine the ability of these two species to adapt to global warming. Fruits were collected from at least 10 mother plants per provenance per species; seeds were scarified and sown in soil in plastic trays, placed inside an incubator at actual soil temperature (Control (T0)), and subjected to 5 treatments with increased temperature: Control temperature +2 °C (T1), +5 °C (T2), +7 °C (T3), +10 °C (T4) and +15 °C (T5) for 15 days. A. farnesiana showed higher germination at T2 and T3, while A. schaffneri presented its higher germination at T2; there were not significant differences between the two species. A. farnesiana seeds had the fastest germination (t50) at T3, with significant differences between provenances (the fastest germination occurred at the School of Forest Sciences, UANL), and A. schaffneri seeds germinated fastest at T1, without significant differences between provenances. The results suggest that both species and their provenances can germinate if temperatures increase according to the current predictions.