, Volume 88, Issue 1, pp 138–140

Developmental responses of portulaca seedlings to conflicting spectral signals

  • Ariel Novoplansky
Original Papers

DOI: 10.1007/BF00328414

Cite this article as:
Novoplansky, A. Oecologia (1991) 88: 138. doi:10.1007/BF00328414


Portulaca oleracea seedlings avoid growing in the direction of neighbouring plants even when they are very small or remote. The present study was designed to determine the relative effect on the development of Portulaca seedlings of light availability (i.e. the resource level) as compared with spectral composition (i.e. the signal of future competition for the resource). The plants were subjected to various intensities of photosynthetic light and red/far-red (R/FR) ratios from opposite directions. The seedlings became recumbent preferentially towards the direction with the lower FR light, even when this meant growing towards plastic that absorbed 20 times more photosynthetic light. A preference for the direction with higher photosynthetic light over lower FR was also found, though only under extreme light differences. The response of the seedlings was not absolute: the orientation chosen depended on the light received from other alternative directions.

Key words

Developmental plasticityEnvironmental signalsRed/far-red ratiosPlant competitionPortulaca oleracea L.

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Ariel Novoplansky
    • 1
  1. 1.Department of BotanyThe Hebrew UniversityJerusalemIsrael