Carbon acquisition strategies uncoupled from predictions derivedfrom species life-cycle

GONZÁLEZ-PALEO, L.; RAVETTA, D.A.

FLORA

ELSEVIER GMBH

Año: 2015 p. 1 - 9

0367-2530

tWe compare carbon use strategies of congeneric annual (P. gracilis and P. angustifolia) and perennial(P. mendocina and P. pinetorum) Physaria (Brassicaceae), to evaluate the relevance of eco-physiologicaltraits as determinants of differences in growth and to add information on the current debate on theagro-ecological suitability of perennial species for grain production in low resource ecosystems. Becauseof differences in growth and in seed-output previously found within this genus, we hypothesized thatC acquisition strategies would not be fully coupled with predictions derived from a species life-cycle.Further, we expected to find different suites of traits related to C-acquisition among perennial species ofPhysaria. We found species with high (P. gracilis and P. pinetorum) and low (P. mendocina and P. angustifolia)relative growth rate (RGR) and biomass. The variation in RGR was linked to differences in specific leafarea (SLA) and allocation to leaves (leaf mass ratio, LMR) and roots (root mass ratio, RMR), but not tothe species life-cycle. Physaria gracilis had high allocation to leaf area (leaf area ratio, LAR), LMR, highSLA, and low RMR and carbohydrates reserves. The slow-growth strategy found in P. mendocina waslinked to low LAR, low SLA and large below-ground allocation. The other species showed intermediatestrategies between these two. The sets of traits present in P. gracilis and in P. mendocina are extremes inthe C acquisition?conservation trade-off, and may allow them to cope with low resource environmentsin different ways. SLA, LMR and RMR were the main determinants of RGR, while total non-structuralcarbohydrates (TNC) and leaf longevity were linked to the life-cycle. Taken together these charactersdefine the intermediate growth strategies of P. angustifolia and P. pinetorum. These intermediate strategieswere not dependent on the species life cycle and support the hypothesis of uncoupled relationshipsbetween growth, C acquisition strategies and life-cycle