An Unexplored Side of Regeneration Niche: Seed Quantity and Quality Are Determined by the Effect of Temperature on Pollen Performance

Abstract

In 1977, Peter Grubb introduced the regeneration niche concept, which assumes that a plant species cannot persist if the environmental conditions are only suitable for adult plant growth and survival, but not for seed production, dispersal, germination, and seedling establishment. During the last decade, this concept has received considerable research attention as it helps to better understand community assembly, population dynamics, and plant responses to environmental changes. Yet, in its present form, it focuses too much on the post-fertilization stages of plant sexual reproduction, neglecting the fact that the environment can operate as a constraint at many points in the chain of processes necessary for successful regeneration. In this review, we draw the attention of the plant ecology research community to the pre-fertilization stages of plant sexual reproduction, an almost ignored but important aspect of the regeneration niche, and their potential consequences for successful seed production. Particularly, we focus on how temperature affects pollen performance and determines plant reproduction success by playing an important role in the temporal and spatial variations in seed quality and quantity. We also review the pollen adaptations to temperature stresses at different levels of plant organization and discuss the plasticity of the performance of pollen under changing temperature conditions. The reviewed literature demonstrates that pre-fertilization stages of seed production, particularly the extreme sensitivity of male gametophyte performance to temperature, are the key determinants of a species’ regeneration niche. Thus, we suggest that previous views stating that the regeneration niche begins with the production of seeds should be modified to include the preceding stages. Lastly, we identify several gaps in pollen-related studies revealing a framework of opportunities for future research, particularly how these findings could be used in the field of plant biology and ecology.

Ready for change: Seed traits contribute to the high adaptability of mudflat species to their unpredictable habitat

“…During the last two decades, there has been an increasing trend to use regeneration traits to investigate patterns and mechanisms of species distribution, abundance and community composition, due to their high environmental sensitivity (Bykova, Chuine, Morin, & Higgins, ; Jiménez‐Alfaro, Silveira, Fidelis, Poschlod, & Commander, ; Poschlod et al, ; Poschlod, Tackenberg, & Bonn, ; Rosbakh, Pacini, Nepi, & Poschlod, ). According to Grubb's regeneration niche concept (Grubb, ), a plant species can neither remain part of an established community for a long time nor can it take part in a newly established community without optimising regenerative functional traits or trait values, closely matched to the environmental filter that governs the local community assembly process.…”

The thermal ecology of flowers

“…Körner, 1998). A suite of pre- and post-fertilization processes also require an optimal temperature (reviewed by Rosbakh et al , 2018). As with most relationships between temperature and developmental rates, pollen germination and tube growth generally display a unimodal response to temperature, declining in extreme thermal environments (Steinacher and Wagner, 2012; Peng et al , 2015; Distefano et al , 2018).…”

Intraspecific Functional Trait Response to Advanced Snowmelt Suggests Increase of Growth Potential but Decrease of Seed Production in Snowbed Plant Species

“…Therefore, the temperature difference of more than 1°C in almost all of the early snowmelt areas (Forcella Travenanzes = 1.33°, Pale di San Martino = 1.35°, Val Martello = 2.01°, and Passo Gavia = 0.5°), could induce pollen limitation by reduced pollen tube growth and/or constrained pollen germination which will eventually result in lower fertilization success ( Totland, 2001 ). A recent review confirms the importance of temperature on pollen performance and thus on seed quantity ( Rosbakh et al, 2018 ). Reduced seed production by snowbed species under advanced snowmelt points toward negative effects on the seed rain.…”