Some sexual consequences of being a plant

Abstract

Plants have characteristic features that affect the expression of sexual function, notably the existence of a haploid organism in the life cycle, and in their development, which is modular, iterative and environmentally reactive. For instance, primary selection (the first filtering of the products of meiosis) is via gametes in diplontic animals, but via gametophyte organisms in plants. Intragametophytic selfing produces double haploid sporophytes which is in effect a form of clonal reproduction mediated by sexual mechanisms. In homosporous plants, the diploid sporophyte is sexless, sex being only expressed in the haploid gametophyte. However, in seed plants, the timing and location of gamete production is determined by the sporophyte, which therefore has a sexual role, and in dioecious plants has genetic sex, while the seed plant gametophyte has lost genetic sex. This evolutionary transition is one that E.J.H. Corner called ‘the transference of sexuality’. The iterative development characteristic of plants can lead to a wide variety of patterns in the distribution of sexual function, and in dioecious plants poor canalization of reproductive development can lead to intrasexual mating and the production of YY supermales or WW superfemales. Finally, plant modes of asexual reproduction (agamospermy/apogamy) are also distinctive by subverting gametophytic processes. This article is part of the theme issue ‘Sex determination and sex chromosome evolution in land plants’.

An insight into the roles of ubiquitin-specific proteases in plants: development and growth, morphogenesis, and stress response

“…Flowering plants constitute approximately 90% of all known plant species, with the majority of them reproducing sexually ( Amasino et al., 2017 ; Sauquet et al., 2017 ; Cronk, 2022 ). Plant sexual reproduction is a complex multistep process that involves cell fate specification and cell division, necessitating precise coordination of gene expression to respond to various signals ( Golicz et al., 2018 ).…”

Re-imagining Reproduction: The Queer Possibilities of Plants

“…In placing binary sex (male/female) and heterosexuality as key attributes of plants, sexual reproduction has loomed large in the plant sciences, and with it, a focus on angiosperms. It is worth remembering that while angiosperms are indeed a diverse group of organisms, only 5–6% of angiosperms are dioecious (defined as having separate male and female plants) and 7% are monoecious (defined as having separate male and female flowers in the same plant) ( Cronk 2022 ). The vast majority of angiosperms—over 85%—are “bisexual” (or hermaphroditic) with perfect flowers (defined as having both “male” and “female” parts or a complete set of all reproductive organs).…”

“…Plant reproductive biology poorly fits a model of binary sex, gender, and sexuality. Cronk (2022 ) provides an excellent summary and analysis of these differences. First, clonal plants challenge the idea that asexuality is an evolutionarily unsuccessful strategy.…”

“…However, this is very much not the case in angiosperms. In angiosperms, sporophytic development determines whether carpels, stamens, or both will develop into flowers ( Pannell 2017 ; Cronk 2022 ; Klein et al 2022 ). The identity of carpels vs. stamens determines what the products of meiosis will be and, in turn, what kind of gametes will be formed (retained vs. dispersed).…”

Does polyploidy inhibit sex chromosome evolution in angiosperms?

“…However, SLR regions of dioecious plants may be less subject to accumulation of deleterious mutations than in animals, because haploid gametophytes express up to 65% of genes (Joseph and Kirkpatrick, 2004;Gorelick, 2005;Cronk, 2022; 10.3389/fpls.2022.976765 Mank, 2022). Hence, haploid selection is probably much stronger in plants than in animals (Otto et al, 2015), and could prevent sex chromosome degeneration.…”