Seasonal Changes in Biomass Allocation in Eight Winter Annuals of the Mojave Desert

Abstract

Seasonal changes in biomass allocation were determined for 8 spp. of winter annuals in the Mojave Desert: Astragalus sabulonum, Baileya pleniradiata, Oenothera deltoides and Schismus arabicus from a relatively moist sandy soil; and Camissonia brevipes, Chaenactis carphoclinia, Phacelia crenulata and Plantago insularis from a dry rocky soil. In all species, roots comprised 12-22% of total biomass until late in flowering, when root allocation declined. Maximum investment in reproductive structures varied among species from 16-50% of total biomass. The differences in allocation strategies were species-specific, not site-specific. No rapid changes in biomass allocation during the life cycle were observed.