What drives the shift between sexual and clonal reproduction of Caragana stenophylla along a climatic aridity gradient?

Abstract

BackgroundThe reasons that clonal plants shift between sexual and clonal reproduction have persisted as a knowledge gap in ecological literature. We hypothesized that clonal plants’ shifts between sexual and clonal reproduction in different environments are driven by the relative costs of sexual and clonal reproduction. Moreover, we hypothesized plants prioritize sexual reproduction over clonal reproduction. To test these hypotheses, we determined the costs of sexual and clonal reproduction, and proportions of sexual and clonal reproduction of Caragana stenophylla along a climatic aridity gradient (semi-arid, arid, very arid and intensively arid zones) in the Inner Mongolia Steppe using several complementary field experiments.ResultsThe cost of sexual reproduction increased while the cost of clonal reproduction decreased as climatic drought stress increased from the semi-arid to the intensively arid zones. The changes in the costs of these reproductive modes drove a shift in the reproductive mode of C. stenophylla from more sexual reproduction in the semi-arid zone to more clonal propagation in the intensively arid zone. However, because of the evolutionary advantages of sexual reproduction, sexual reproduction still held priority over clonal production in C. stenophylla, with the priority of sexual reproduction gradually increasing from the semi-arid to the intensively arid zones.ConclusionsOur study suggested that sexual reproduction has relatively high priority in propagation of C. stenophylla. However, if the costs of sexual reproduction are too high, C. stenophylla likely chooses clonal reproduction, and the ratio between sexual and clonal reproduction could be mediated by reproductive cost. These reproductive strategies reflect optimal resource utilization, and allow the persistence of both reproductive modes across stressful conditions depending on their evolutionary advantages.

Genotypic Males Play an Important Role in the Creation of Genetic Diversity in Gynogenetic Gibel Carp

“…Although unisexual reproduction can avoid the mating costs and achieve high fecundity, its disadvantages are obvious that deleterious mutations cannot be purged and new genotypes cannot be created without meiosis (Muller, 1964;Wang et al, 2018;Warren et al, 2018). As clearance of deleterious mutations and creation of genetic diversity are essential for adaptation to changing environment, the unisexual vertebrates are predicted to be an evolutionary dead-end (Van Valen, 1973;Strotz et al, 2018;Warren et al, 2018).…”

“…First, occasional sexual reproduction can allow recombination and purge deleterious mutations. And these individuals with facultative reproductive strategies (where individuals can switch between unisexual and sexual reproductions) can possess the advantages of both reproduction modes (Burke and Bonduriansky, 2017;Wang et al, 2018). Second, introgression of DNA into the unisexual lineage can compensate for deleterious mutations, which has been used to partially explain a substantial polymorphism and high heterozygosity in gynogenetic Amazon molly (Warren et al, 2018).…”

Clonal architectures and diversity spatial pattern of different ploidies for Clintonia udensis in the Hualongshan Mountains

“…Different species have been found to possess different clonal architecture patterns. Furthermore, the clonal architectures of species might represent malleable changes under different habitat conditions (Kartzinel et al, 2015;Wang et al, 2018b;Huang et al, 2018). Within heterogeneous environments, clonal plants can adjust their strategies to secure resources through the pliable changes in their clonal architectures, which ultimately result in changes of the properties of its ramets (Kartzinel et al, 2015;Wang et al, 2018a).…”

“…Nevertheless, the spatial structures and diversity of clonal plants may be affected by biological and abiotic factors such as habitat heterogeneity, growth strategies, and seedling recruitment patterns (Kartzinel et al, 2015;Sandén et al, 2020). So, analyzing spatial genetic structures and clarifying the genetic patterns of different patches of clonal plants might be of great significance for exploring the formation, maintenance, and decline mechanisms of clonal plant populations (Kartzinel et al, 2015;Wang et al, 2018b;Mandel et al, 2019).…”

Pre‐adaptation to climate change through topography‐driven phenotypic plasticity

“…For example, plants with less, or smaller stomata (Dittberner et al, 2018;Fraser, Greenall, Carlyle, Turkington, & Friedman, 2008) and with reduced specific leaf area (SLA; Bansal, Harrington, Gould, & St.Clair, 2015;Kooyers, Greenlee, Colicchio, Oh, & Blackman, 2015;Ramírez-Valiente et al, 2009) have been found to be capable of controlling transpiration rates and increasing photosynthetic water-use efficiency under drought stress. For clonal species, drought stress is also expected to increase the magnitude of vegetative reproduction (Wang et al, 2018;Xie et al, 2012). In Northern hemisphere environments, south-oriented slopes in particular receive more light and facilitate transpiration, and are therefore expected to be dominated by drought-resistant phenotypes, especially where strong inclinations facilitate water run-off.…”