Allocation of photoassimilates to biomass, resin and carbohydrates in Grindelia chiloensis as affected by light intensity

ZAVALA, J; RAVETTA, D.A.

FIELD CROPS RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2001 vol. 69 p. 143 - 149

0378-4290

Grindelia chiloensis (Asteraceae) is a shrub native to Patagonia, Argentina, and can accumulate as much as 25% resin (on adry weight basis) in leaves. The resin can be used in applications similar to those of pine resins. Reductions in availableradiation are thought to decrease both the plant C:N ratio and resin production. The objective of this study was to assess theeffect of light availability on the allocation of photoassimilates to biomass, resin (terpenes) and carbohydrates in G. chiloensis.To examine this, three radiation treatments were applied to ®eld grown plants: (i) 100% radiation (full-sun), (ii) 50% radiationand (iii) 25% photon ¯ux density radiation. Changes in available radiation resulted in signi®cant changes in above groundbiomass accumulation, carbon based secondary metabolites (resin), non-structural carbohydrate (TNC) content, and relativegrowth rate (RGR). At low radiation levels, above ground biomass accumulation, RGR, resin, TNC content and CO2assimilation rate were highly reduced (from 150 to 80 g per plant, from 16 to 7%, and from 30.2 to 8.6 g per plant, forbiomass, resin content, and resin production, respectively). The responses to low radiation found in G. chiloensis would limitproductivity and the distribution of this species when grown under cultivation. # 2001 Elsevier Science B.V. All rightsreserved.Keywords: Biomass production; C:N ratio; Terpenes; Radiation availability