Production of Phenols and Spines in Response to Shoot Damage in Prosopis caldenia and Prosopis flexuosa

Abstract

Shoot damage affects the chemical and physical defenses of woody plants. We studied how branch defoliation and intensive shoot damage affected leaf phenol concentration and spinescence in Prosopis caldenia and P. flexuosa. Individuals of both species were branch defoliated, heavily pruned, or naturally burnt. At the end of the growing season, stump (from pruned plants) and burnt sprouts, defoliated branches, and branches from intact control plants were harvested for assessment of phenols and spinescence. In both species, foliar phenol content in stump or burnt sprouts and defoliated branches were similar or below that of intact control branches. The biomass invested in spines was similar, spine length lower, and spine density higher in stump or burnt sprouts than in control branches in both species. These findings are discussed in relation to the juvenile-reversion hypothesis and the carbon/nutrient balance hypothesis.