Ontogenetic shift in biomass allocation and functional traits of leaves and seeds in a resprouting aridland shrub.

Abstract

Ontogeny-driven variation in plant functional traits is considered the core component of a plant's life-history strategy. However, how vegetative and reproductive traits covary to mediate growth and reproduction throughout the life history of resprouts is largely unknown. Here, the leaf and seed biomass allocation (SBA), nutrient contents and morphological and physiological traits of leaves and seeds were investigated during different life history stages of Caragana korshinskii Kom resprouts aged 1-13 years in a common garden. The findings indicated that with increasing age, leaf traits shifted from an acquisitive strategy-characterized by high photosynthesis (An), stomatal conductance (gs), leaf nitrogen content (LNC) and leaf phosphorus content (LPC), along with low leaf mass per area (LMA) and water-use efficiency (WUE)-to a conservative strategy characterized by low An, gs, LNC, LPC, high LMA and WUE, in combination with changes in leaf biomass allocation (LBA). Most notably, seed traits shifted from a K-strategy-characterized by high seed mass (SM), seed nitrogen content (SNC), seed phosphorus content (SPC) and seed germination rate (SGR), but low seed number (SN)-to an r-strategy with opposite traits, reflecting a trade-off with SBA. These ontogeny-driven strategies shift from an acquisitive strategy and K-strategy that favors faster growth and a quality-focused reproductive advantage in younger resprouts to a conservative strategy and r-strategy that improves vegetative adaptability and reproductive stability in older resprouts. Our results highlight that ontogeny-driven transitions in life history strategies and biomass allocation patterns jointly mediate vegetative and reproductive strategies in resprouts, providing new insights for understanding the dynamic balance between the growth and reproduction of resprouts.