Changes in polyamine pattern mediates sex differentiation and unisexual flower development in monoecious cucumber (Cucumis sativus L.)

Abstract

Changes in the levels of polyamines are associated with fundamental physiological processes such as embryogenesis, induction of flowering, fruit development and ripening, senescence, and responses to environmental stresses, but the role of polyamines in sex differentiation and unisexual flower development has not been deeply studied. To extend the knowledge on the regulatory mechanisms of flowering in monoecious plant (producing unisexual flowers), we investigated the morphogenesis and free polyamine levels in Cucumis sativus during sex differentiation and unisexual flower development in vitro using histocytological and biochemical methods. As shown in our study, floral development in vitro was undisturbed and flowers of both sexes were produced. Sex differentiation relied on preventing the development of generative organs of the opposite sex, as we observed carpel repression in male flowers and stamen repression in female flowers. Pollen viability was negatively correlated with female flower development on the same node. Biochemical analysis revealed increased accumulation of aliphatic amines (tri, tetra-amines) in generative (flower buds and flowers) compare to vegetative (axillary buds and leaves) organs. Undifferentiated floral buds contained elevated levels of agmatine, cadaverine, spermidine and spermine. Sex differentiation was associated with significantly decreased levels of agmatine and cadaverine. Our results showed that female flowers contained higher levels of total polyamine than male flowers. The increased level of cadaverine was associated with macrogametogenesis and female flower maturation. Putrescine was important for male flower development. Such results support the hypothesis that aliphatic amines are involved in unisexual flower development.

Exogenously Applied Polyamines Reduce Reactive Oxygen Species, Enhancing Cell Division and the Shoot Regeneration from Brassica oleracea L. var. capitata Protoplasts

“…Free PAs can also covalently bind to acidic proteins, membrane phospholipids, and nucleic acid proteins or nucleic acids [14,15]. These PAs are associated with the regulation of enzyme activity, the stability of nucleic acids, DNA replication, gene transcription, cell division, and membrane stability [17,18], and have an effect on the regulation of developmental and physiological processes, e.g., root growth, flower initiation, and fruit development [19][20][21].…”

Role of metabolites in flower development and discovery of compounds controlling flowering time

“…Polyamines are also involved in floral bud differentiation. Free and conjugated forms of putrescine, spermine, and spermidine increased rapidly during early stages of floral bud differentiation as well as the entire period of flower development in Cucumis sativus and Rosa damascena, and Rosa bourboniana (Kiełkowska andDziurka, 2021, Sood andNagar (2004, Fig. 2A).…”

History and Current Status of Haploidization in Carrot (Daucus carota L.)

“…Polyamines are biogenic amines found in animals, plants, as well as fungi and bacteria. Polyamines are involved in many physiological processes, such as flowering, fruit development, senescence and stress response [39]. Hoverer, exogenous polyamines can regulate growth and development, including embryogenesis and organogenesis in vitro [40].…”