When can stress facilitate divergence by altering time to flowering?

Abstract

Stressors and heterogeneity are ubiquitous features of natural environments, and theory suggests that when environmental qualities alter flowering schedules through phenotypic plasticity, assortative mating can result that promotes evolutionary divergence. Therefore, it is important to determine whether common ecological stressors induce similar changes in flowering time. We review previous studies to determine whether two important stressors, water restriction and herbivory, induce consistent flowering time responses among species; for example, how often do water restriction and herbivory both delay flowering? We focus on the direction of change in flowering time, which affects the potential for divergence in heterogeneous environments. We also tested whether these stressors influenced time to flowering and nonphenology traits using Mimulus guttatus. The literature review suggests that water restriction has variable effects on flowering time, whereas herbivory delays flowering with exceptional consistency. In the Mimulus experiment, low water and herbivory advanced and delayed flowering, respectively. Overall, our results temper theoretical predictions for evolutionary divergence due to habitat‐induced changes in flowering time; in particular, we discuss how accounting for variation in the direction of change in flowering time can either increase or decrease the potential for divergence. In addition, we caution against adaptive interpretations of stress‐induced phenology shifts.

The soil microbial community alters patterns of selection on flowering time and fitness‐related traits in Ipomoea purpurea

“…Phenology plays an important role in plant evolutionary processes since the timing of flowering influences pollinator visitation and the potential for gene flow both within and among populations. The regulation of flowering time is primarily driven by abiotic factors, such as vernalization and photoperiod (Amasino, ), but stress, herbivory, genotype, and nutrient deficiencies can also influence phenology (Stanton et al., ; Franks et al., ; Jordan et al., ; Richardson et al., ). Here we add to the few available studies that consider the influence of the microbial community on plant flowering and show that the soil microbial community acts as a selective agent on flowering phenology and combinations of phenology and growth in the common morning glory.…”

Stable Epigenetic Variants Selected from an Induced Hypomethylated Fragaria vesca Population

“…This suggests the epialleles related to late flowering were reset through meiosis to cause a transient phenotypic change, as research indicated reversion of DNA methylation patterns affect the ability of epialleles to be subject to selection (Becker et al, 2011; Hirsch et al, 2012). Alternatively, no epialleles were present and the late flowering phenotype was induced by the toxic effect of 5-azaC or stress which disturbed the flowering time in the S0 generation (Jordan et al, 2015). In the S3, S4, and S5 generations, the early flowering trait was stably inherited.…”

Rapid growth and defence evolution following multiple introductions

“…One seedling per maternal line was allocated to either the control or simulated herbivory treatment. We simulated herbivory by vertically cutting off half of the newest fully formed leaf (wounding) and subsequently spraying the whole plant with 1 mM methyl jasmonate (MeJA) (Campos-Vargas & Saltveit, 2002;Heredia & Cisneros-Zevallos, 2009;Hodgins & Rieseberg, 2011;Jordan, Ally, & Hodgins, 2015). Control plants were not wounded and were sprayed with distilled water.…”