Floral display and habitat quality affect cost of reproduction in Primula farinosa

Early Life History Divergence Mediates Elevational Adaptation in a Perennial Alpine Plant

Spatially divergent natural selection can drive adaptation to contrasting environments and thus the evolution of ecotypes. In perennial plants, selection shapes life history traits by acting on subsequent life stages, each contributing to fitness. While evidence of adaptation in perennial plants is common, the expression of life history traits is rarely characterized, limiting our understanding of their role in adaptive evolution. We conducted a multi-year reciprocal transplant experiment with seedlings from low and high elevation populations of the alpine carnation Dianthus carthusianorum to test for adaptation linked to contrasting climates and inferred specific contributions of early life stages to fitness. We assessed genotype by environment interactions in single fitness components, applied matrix population models to achieve an integrated estimate of fitness through population growth rates, and performed trade-off analyses to investigate the advantage of alternate life history traits across environments. We found evidence of genotype by environment interactions consistent with elevational adaptation at multiple stages of the early life cycle. Estimates of population growth rates corroborated a strong advantage of the local genotype. Early reproduction and survival are alternate major contributors to adaptation at low and high elevation, respectively, and are linked by trade-offs that underlie the evolution of divergent life history traits across environments. While these traits have a strong genetic basis, foreign populations express co-gradient plasticity, reflecting the adaptive strategy of the local populations. Our study reveals that selection associated to climate has driven the evolution of divergent life histories and the formation of elevational ecotypes. While the high energy environment and strong competition favor investment in early reproduction at low elevation, limiting resources favor a more conservative strategy relying on self-maintenance at high elevation. The co-gradient plasticity expressed by high-elevation populations may facilitate their persistence under warming climatic conditions.

Growing or reproducing? Assessing the existence of a trade-off in the globose cactus Gymnocalycium monvillei

Resource allocation in plants is a fundamental aspect of life history theory. In Cactaceae, the specific trade-off between sexual reproduction and vegetative growth has still not been studied. The aim of this work was to assess if there is a trade-off between growth and reproduction, and to analyse whether both growth and allocation to reproduction depend on size of the individual. In this study, we used Gymnocalycium monvillei, a globose cactus endemic to the mountains of central Argentina, as a model species. Specifically, we analysed the relationship of growth (percentage increase in diameter) and size of individuals (diameter) to seed production, seed mass, germination, and mean germination time. To relativize the effect of size on seed production, two variables were calculated: the ratio of seed production to plant size (RSPS), and the ratio of total seed mass to plant size (RSMS). We found that both seed production and total seed mass were significantly related to cactus size. However, growth was not related to seed mass or to seed production, even when they were relativized. Germination and mean germination time were not related to plant size or growth. In the studied species, a slow-growing globose cactus, we did not find a trade-off between growth and reproduction.

Costs of reproduction under experimental climate change across elevations in the perennial forb Boechera stricta

Investment in current reproduction can reduce future fitness by depleting resources needed for maintenance, particularly under environmental stress. These trade-offs influence life-history evolution. We tested whether climate change alters the future-fitness costs of current reproduction in a large-scale field experiment of Boechera stricta (Brassicaceae). Over 6 years, we simulated climate change along an elevational gradient in the Rocky Mountains through snow removal, which accelerates snowmelt and reduces soil water availability. Costs of reproduction were greatest in arid, lower elevations, where high initial reproductive effort depressed future fitness. At mid-elevations, initial reproduction augmented subsequent fitness in benign conditions, but pronounced costs emerged under snow removal. At high elevation, snow removal dampened costs of reproduction by prolonging the growing season. In most scenarios, failed reproduction in response to resource limitation depressed lifetime fecundity. Indeed, fruit abortion only benefited high-fitness individuals under benign conditions. We propose that climate change could shift life-history trade-offs in an environment-dependent fashion, possibly favouring early reproduction and short lifespans in stressful conditions.

Natural variation of life-history traits, water use, and drought responses in Arabidopsis

The ability of plants to acquire and use water is critical in determining life-history traits such as growth, flowering, and allocation of biomass into reproduction. In this context, a combination of functionally linked traits is essential for plants to respond to environmental changes in a coordinated fashion to maximize resource use efficiency. We analyzed different water-use traits in Arabidopsis ecotypes to identify functionally linked traits that determine water use and plant growth performance. Water-use traits measured were (i) leaf-level water-use efficiency (WUE i ) to evaluate the amount of CO 2 fixed relative to water loss per leaf area and (ii) short-term plant water use at the vegetative stage (VWU) as a measure of whole-plant transpiration. Previously observed phenotypic variance in VWU, WUE i and life-history parameters, highlighted C24 as a valuable ecotype that combined drought tolerance, preferential reproductive biomass allocation, high WUE i , and reduced water use. We therefore screened 35 Arabidopsis ecotypes for these parameters, in order to assess whether the phenotypic combinations observed in C24 existed more widely within Arabidopsis ecotypes. All parameters were measured on a short dehydration cycle. A segmented regression analysis was carried out to evaluate the plasticity of the drought response and identified the breakpoint as a reliable measure of drought sensitivity. VWU was largely dependent on rosette area, but importantly the drought sensitivity and plasticity measures were independent of the transpiring leaf surface. A breakpoint at high rSWC indicated a more drought-sensitive plant that closed stomata early during the dehydration cycle and consequently showed stronger plasticity in leaf-level WUE i parameters. None of the sensitivity, plasticity, or water-use measurements were able to predict the overall growth performance; however, there was a general trade-off between vegetative and reproductive biomass. PCA and hierarchical clustering revealed that C24 was unique among the 35 ecotypes in uniting all the beneficial water use and stress tolerance traits, while also maintaining above average plant growth. We propose that a short dehydration cycle, measuring drought sensitivity and VWU is a fast and reliable screen for plant water use and drought response strategies.

Large size and high light do not lower the cost of reproduction for the Neotropical herb Goeppertia marantifolia

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PREMISE OF THE STUDY

Sexual reproduction is often associated with a cost in terms of reduced survival, growth, or future reproduction. It has been proposed that plant size and the environment (availability of key resources) can sometimes lower or even nullify the cost of reproduction.•

METHODS

We address this issue experimentally with the Neotropical herb Goeppertia marantifolia, by manipulating sexual reproductive effort and measuring the demographic performance of plants and of their clonal offspring, in the context of natural variation in light availability.•

KEY RESULTS

Plants in the high-reproductive-effort treatment grew less between seasons but did not differ in their probability of flowering the second season or in inflorescence size compared with plants in the low-effort treatment. Reproductive effort of parent plants influenced the leaf area of their clonal offspring. Plants that invested less in sexual reproduction produced clonal offspring that were initially larger than those produced by plants that invested more in reproduction. The magnitude of this effect was greater in parent plants that received two seasons of the manipulated reproductive effort than in those that received a single season. The trade-off between reproductive modes dampened with time, leading to smaller differences in clonal offspring leaf area between treatments over time.•

CONCLUSIONS

We found evidence of a cost of reproduction and trade-offs between reproductive modes, although the magnitude of these costs was small. However, we found no evidence of lower costs of reproduction for larger plants or for plants in higher-light environments over our 2-yr study period.