Plant Polyamines in Reproductive Activity and Response to Abiotic Stress*

TLDR

Polyamines are essential internal regulators of flower initiation, floral organ development, fruit growth, and ripening, and are up‑regulated by osmotic stress to support photosynthetic activity during senescence. The review aims to clarify the physiological significance of stress‑induced polyamine metabolism changes and their role in reproductive activity through transgenic plant studies and advanced molecular probes. The authors review evidence for polyamines’ critical roles in reproductive activity and abiotic stress response.

Abstract

Abstract: In this review we will focus on two areas in which the accumulated evidence for a critical physiological role of polyamines is becoming compelling, i.e. reproductive activity and response to abiotic stress. Regarding reproductive behavior, it seems clear that polyamines are members of the array of internal compounds required for flower initiation, normal floral organ morphogenesis, fruit growth and fruit ripening in particular plant species. Abiotic stresses such as osmotic stress can “turn on” arginine decarboxylase (ADC) genes, resulting in a rapid increase in their mRNA levels. Localization of ADC enzyme in the chloroplast suggests a role of PAs in the maintenance of photosynthetic activity during senescence responses induced by osmotic stress. We envisage that the use of transgenic plants and improved molecular probes will resolve in the near future the physiological significance of stress‐induced changes in PA metabolism as well as the role of these compounds in reproductive activity.