The effect of irrigation regime on biomass and resin production in Grindelia chiloensis

ZAVALA, J; RAVETTA, D.A.

FIELD CROPS RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2001 vol. 69 p. 227 - 236

0378-4290

Grindelia chiloensis (Corn.) Cabr. is a shrub native to Patagonia, Argentina and can accumulate as much as 25% resin in itsleaves, with net primary productivity between 90 and 170 g per year per plant when growing in native stands. Undercultivation, 67.4 g of resin per plant have been produced (about 2.24 Mg haÿ1). The objective of this study was to assess theeffect of irrigation regime on biomass and resin production on G. chiloensis. In order to achieve this objective, four irrigationtreatments were performed during 1996±1997 and 1997±1998: (i) weekly irrigation (7d), (ii) irrigation at 20-day intervals(20d), (iii) irrigation at 40-day intervals (40d), (iv) non-irrigated (N-I). It was found that the intermittent water supply at 40dwas suf®cient to promote canopy development, and increase water use ef®ciency (WUE) and resin production per plant (RP)with highest resin production (approximately 5.12 Mg haÿ1 in 1997). In order to achieve high levels of RP, above groundbiomass was maximized at the expense of a reduction in WUE. A concomitant increase in WUE (at the leaf level; WUEL) andleaf resin content with water stress and time was found. This result supports the hypothesis that epicuticular resin couldin¯uence water transpiration (E), as it represents an additional barrier to gas diffusion from the epidermis and through thestomatal pores. # 2001 Published by Elsevier Science B.V.Keywords: Biomass; Terpenes; Transpiration; Water supply; Water use ef®cienc