Grass florets bet-hedge against unpredictable rainfall in arid landscapes

Seed germination in the arid zone is a high-risk event. For grasses specifically, the ancillary bracts of the floret surrounding the seed have been associated with innate dormancy mechanisms, resulting in infrequent recruitment even under favourable rainfall.

Arid grassland

Lewandrowski et al. investigate the effects of environmental cues such as temperature, water stress and smoke, on seed germination in six dominant Triodia species from the arid zone of Australia. Florets consistently display limited germination, with increased germination under temperature and water stress only when seed dormancy was alleviated, and a smoke-derived chemical stimulant, karrikinolide, was applied. They infer that any climate change driven shifts in rainfall patterns in the arid zone are likely to impact on Triodia recruitment.

Reference List

Lewandrowski, W., Erickson, T. E., Dalziell, E. L., & Stevens, J. C. (2017). Ecological niche and bet-hedging strategies for Triodia (R.Br.) seed germination. Annals of Botany, 121(2), 367–375. https://doi.org/10.1093/aob/mcx158