Vegetative dormancy in orchids incurs absolute and relative demographic costs in large but not in small plants

: Sonja Hurskainen, Kirsi Alahuhta, Hilde Hens, Anne Jäkäläniemi, Tiiu Kull, Richard P. Shefferson, Juha Tuomi

Publisher: OXFORD UNIV PRESS

: 2018

: Botanical Journal of the Linnean Society

: BOTANICAL JOURNAL OF THE LINNEAN SOCIETY

: BOT J LINN SOC

: 188

: 4

: 426

: 437

: 12

: 0024-4074

DOI: https://doi.org/10.1093/botlinnean/boy065

Terrestrial orchids do not always sprout every growing season and a significant proportion of the population may remain underground. Such vegetative dormancy may lead to absolute demographic costs or, alternatively, demographic benefits for dormant plants, as well as relative costs or benefits compared to the performance of plants that did emerge during the growing season. Using long-term data for three terrestrial orchids, we show that the effects of vegetative dormancy are size-and state-dependent. In large and mature individuals, vegetative dormancy appeared to incur absolute costs and to lead to more frequent decline in size and state compared to sprouting states. Instead, small plants tended to grow in size during vegetative dormancy, which sometimes even led to maturation in the young plants. However, this growth and maturation was just as common in young sprouting orchids, such that vegetative dormancy in small or young plants does not appear to offer either a pronounced relative benefit or cost for future performance.