Seed dormancy (i.e. delayed germination even when conditions arefavourable) is a key plant characteristic that occurs among manyspecies worldwide. But, what selective pressures led to seeddormancy? A recent study provides a major analysis of the factorsdriving this trait at the global scale (Zhanget al.,2022). Usingc.12 000 species and 10 million records across the globe, theyconclude that dormancy is a strategy for plants living under‘seasonal/unpredictable’ environments; and suggest that bet-hedg-ing could be the major mechanism behind the pattern. To reachtheir conclusions the authors relate the proportion of species withdormant seeds in a grid-cell global map against climate variablesrelated to annual precipitation, temperature and seasonality. Thenthey showed that the most significant variables were those related toclimate seasonality that they equate with unpredictable climates(although seasonal climates usually are highly predictable in theirseasonal cycles).

This research was performed under the framework of projects FIROTIC (PGC2018-096569-B-I00; Spanish government, MCIN/AEI/10.13039/501100011033 and FEDER) and FocScales (Promteo/2021/040, Generalitat Valenciana).

Peer reviewed