Male Fertility under Environmental Stress: Do Polyamines Act as Pollen Tube Growth Protectants?

Abstract

Although pollen structure and morphology evolved toward the optimization of stability and fertilization efficiency, its performance is affected by harsh environmental conditions, e.g., heat, cold, drought, pollutants, and other stressors. These phenomena are expected to increase in the coming years in relation to predicted environmental scenarios, contributing to a rapid increase in the interest of the scientific community in understanding the molecular and physiological responses implemented by male gametophyte to accomplish reproduction. Here, after a brief introduction summarizing the main events underlying pollen physiology with a focus on polyamine involvement in its development and germination, we review the main effects that environmental stresses can cause on pollen. We report the most relevant evidence in the literature underlying morphological, cytoskeletal, metabolic and signaling alterations involved in stress perception and response, focusing on the final stage of pollen life, i.e., from when it hydrates, to pollen tube growth and sperm cell transport, with these being the most sensitive to environmental changes. Finally, we hypothesize the molecular mechanisms through which polyamines, well-known molecules involved in plant development, stress response and adaptation, can exert a protective action against environmental stresses in pollen by decoding the essential steps and the intersection between polyamines and pollen tube growth mechanisms.

Green Synthesis of Hyperbranched Spermine-Coated Fe3O4 Nanoparticles and Their Effect on Corn Seedlings under Copper Oxide Stress

“…This could be due to enhanced seed coat permeability, allowing more water to enter the cells, and increasing metabolism and germination . A similar observation has been reported in several works. ,,, …”

“…In addition to the important function of micronutrients in enhancing plant germination and growth, under abiotic stress conditions, polyamines (PAs) have a significant effect on enhancing tolerance to abiotic stresses . PAs are small organic polycations that are commonly prevalent in living organisms and are now regarded as a new class of growth substances that include spermidine, spermine, and their obligate precursor putrescine, which play a key role in regulating plant developmental and physiological processes . Polyamine levels as well as various abiotic factors influence polyamine biosynthesis and metabolic pathways.…”

“…14 PAs are small organic polycations that are commonly prevalent in living organisms and are now regarded as a new class of growth substances that include spermidine, spermine, and their obligate precursor putrescine, which play a key role in regulating plant developmental and physiological processes. 15 Polyamine levels as well as various abiotic factors influence polyamine biosynthesis and metabolic pathways. Consequently, polyamines could be great targets for future genetic engineering techniques to improve plant abiotic stress tolerance.…”

Pollen performance of pomegranate under high-temperature stress

“…Tip-localized ROS is requise to ensure PT elongation (Swanson and Gilroy, 2010). Due to the tip-localized ROS is over accumulate under abiotic stress cases, alterations in tip-localized ROS accumulation can be utilized as a mark to measure the harmfull effects in PP under stress conditions (Aloisi et al, 2022). Wang et al (2016) and Parrotta et al (2019) noticed that cold stress improved the ROS signal in the PT apex of Camellia sinensis (L.) Kuntze and Nicotiana tabacum L., respectively.…”

Pollen-Pistil Interaction

“…The effects of environmental stresses on pollen-pistil interactions were presented in a review article and in an original research article on cotton. In the review article, the authors described the main effects that environmental stresses can cause on pollen, such as thermal stress induced by high and low temperatures, heavy metals, UV-B radiation, osmotic stress, and nutrient deficiency [ 12 ]. The most relevant evidence underlying the morphological, cytoskeletal, metabolic, and signaling alterations involved in the perception and response to stress were illustrated, focusing on the final stage of pollen life, i.e., from hydration, pollen tube growth, and transport of sperm cells, these being the phases most sensitive to environmental climatic changes.…”