Growth and defense trade-offs in dioecious Salix myrtillacea exposed to drought and low temperature stress

Abstract

Extensive studies have shown that plants can develop stress memories to improve their tolerance to subsequent abiotic stresses. However, the comprehensive understanding of sex-related stress memory in response to drought, low temperature, and their cross conditions remains an ongoing pursuit. In this study, we investigated plant growth, photosynthetic physiology, and the leaf metabolome in female and male Salix myrtillacea exposed to drought, low temperature, and their cross. Our results underscored the profound detrimental impact of different stresses on growth performance and the photosynthetic apparatus in both sexes. Furthermore, female willows showed greater tolerance to drought, low-temperature and cross-stress, as evidenced by their improved growth performance and higher abundance of amino acids (e.g., proline, histidine, glutamine and methionine) and sugar alcohols (e.g., melibiose, sorbitol and mannitol). Conversely, male plants displayed a richer diversity and abundance of flavonoids in comparison to females. In the key metabolic pathways, flavonoids (e.g., syringetin, laricitrin and isoquercitrin) were more abundant under cross-stressed conditions, suggesting that the generation of stress memory significantly enhanced the resistance of male willows at the metabolic level. Taken together, these results suggest that the enhanced resistance of female and male plants is associated with a trade-off between growth and defense. The formation of stress memory in females and males may be associated with greater plasticity in growth performance and accumulation of defensive metabolites, contributing to sex-specific patterns of adversity resistance and niche segregation.