DRy MATTER ESTIMATION AND PARTITIONING OF ASSIMILATES IN DOMINANT SHRuBS wITH TwO DIFFERENT MORPHOLOGIES FROM THE HIGH CENTRAL ANDES OF SAN JuAN, ARGENTINA

Background and aims: High mountain shrubs play a key role in the maintenance and functioning of ecosystem processes. Nevertheless, studies to understand their morphology and dry matter partitioning are scarce. The goal of this study is to quantify dry matter partitioning and study the morphology for Senecio oreophyton and Baccharis tola ssp. tola in the Central Andes, Argentina. Additionally, allometric equations are proposed. M&M: The work was done in the Austral Puna, province of San Juan. A total of 60 S. oreophyton and B. tola plants were selected. Biometric variables were measured in each specimen to estimate dry matter. The lateral and top view of each specimen were photographed to determine shrub morphology. Each specimen was harvested and differentiated in stem, leaves and roots. Results: The geometric shape of S. oreophyton was similar to an inverted cone and B. tola was similar to a hemisphere shape. In both shrubs, aboveground dry matter was higher than the belowground dry matter. In B. tola, similar proportions of dry matter assigned to the stem and leaves were found. Allometric equations were established for each component from direct field measurements. Conclusions: The dry matter partitioning found for both shrubs would indicate that it is strongly associated with the morphology of the plant, and its strategy for surviving under harsh conditions. This is a contribution to improve the knowledge about morphological characteristics of woody shrubs and their environmental interactions for conservation and management in highlands.