Biology subjects

Wadgymar, S. M.

Publications and source records attributed to Wadgymar, S. M..

2 recordsLinked to original sources

bioRxiv2023

Sex allocation plasticity in response to resource and pollination availability in the annual plant Brassica rapa (Brassicaceae)

Premise of researchHermaphroditic plants reproduce as females by maturing seeds from fertilized ovules and as males by fertilizing the ovules of other plants. Sex allocation theory predicts a trade-off between investment in male and female function. Thus, to maximize fitness, selection should favor plasticity in resource allocation among individuals or flowers of the same plant in response to environmental conditions. As female reproduction is typically more costly while male reproduction is mate-limited, we predict greater investment in female function when resources are plentiful and in male function when pollination is limited. MethodologyWe investigated plasticity in sex allocation in the rapid cycling lineage of the hermaphroditic mustard species, Brassica rapa, in response to resource availability (altered pot size) and the pollination environment (unpollinated or fully pollinated). We assess investment in male function (anther length) and female function (ovary length) in flower buds produced at the onset of reproduction and in buds produced approximately 15 days later. We also measured traits often correlated with increased allocation to female (plant size) and male (flower size) function. Pivotal ResultsLarger plants had longer anthers, longer ovaries, and larger flowers at the onset of reproduction, resulting in similar anther:ovary length ratios across plants of different sizes. Independent of plant-size, plants produced smaller anthers at the onset of reproduction in the low resource treatment and larger flowers over the course of reproduction in the pollen-absent treatment. Furthermore, larger plants produced increasingly longer ovaries over the course of reproduction compared to smaller plants. ConclusionsOur findings underscore the influence of condition on changes in sex allocation and correlated traits over time. Furthermore, we provide some additional supporting evidence that resource availability and the pollination environment can influence sex allocation and contribute cautionary advice on effective methods for experimentally eliciting and measuring sex allocation plasticity.

plant biology↗

bioRxiv2017

Phenological responses to multiple environmental drivers under climate change: insights from a long-term observational study and a manipulative field experiment

Climate change has induced pronounced shifts in the reproductive phenology of plants, with the timing of first flowering advancing in most species. Indeed, population persistence may be threatened by the inability to track climate change phenologically. Nevertheless, substantial variation exists in biological responses to climate change across taxa. Here, we explore the consequences of climate change for flowering phenology by integrating data from a long-term observational study and a manipulative experiment under contemporary conditions. Dissecting the environmental factors that influence phenological change will illuminate why interspecific variation exists in responses to climate change. We examine a 43-year record of first flowering for six species in subalpine meadows of Colorado in conjunction with a 3-year snow manipulation experiment on the perennial mustard Boechera stricta from the same site. We analyze shifts in the onset of flowering in relation to environmental drivers known to influence phenology: the timing of snowmelt, the accumulation of growing degree days, and photoperiod. At our study site, climate change is reducing snowpack and advancing the timing of spring snowmelt. We found that variation in phenological responses to climate change depended on the sequence in which species flowered, with early-flowering species flowering faster, at a lower heat sum, and under increasingly disparate photoperiods in comparison to species that flower later in the season. Furthermore, climate change is outpacing phenological change for all species. Early snow removal treatments confirm that the timing of snowmelt governs observed trends in flowering phenology of B. stricta and that climate change can reduce the probability of flowering, thereby depressing fitness. Shorter-term studies would not have captured the trends that we document in our observational and experimental datasets. Accurate predictions of the biological responses to climate change require a thorough understanding of the specific environmental factors driving shifts in phenology.

ecology↗