AoB Plants最新文献

Ericaceous dwarf shrubs comprise a key component of the vegetation in several types of northern peatlands. Widespread draining of the peatlands is known to favour forest species (such as Vaccinium myrtillus and Vaccinium vitis-idaea) over mire species (such as Andromeda polifolia and Vaccinium oxycoccos), but it is unclear to what extent such assemblage shifts should form a target for ecological restoration. In this paper, we analyse the performance of eight co-occurring dwarf shrub species in a large-scale ecological restoration experiment in Scots pine-dominated wetlands that had been drained over 40 years ago in Estonia. We address two related questions: (1) how major ecosystem-change-related factors and within-assemblage interactions affect the 1-m² scale presence of each species in the drained landscape, and (2) to what extent their cover responses to ditch blocking and partial harvest over 6 years reveal a reversal of the drainage-caused succession. We explored those factors and the treatment effects using general linear mixed modelling of the species' presence and cover. At least four species were responding negatively to drainage, predominantly along with the stand successional stage. However, the results infer that most species were probably enhanced in the early post-drainage phase. The presence of each species was independently enhanced by the presence of other species; the only antagonistic relationship found was between V. myrtillus and V. uliginosum. Ditch blocking had a clear effect only on V. oxycoccos, which increased along with Sphagnum moss cover. In several species, we found a temporary decline in some treatments. Overall, the ericaceous shrub cover appeared rather resistant to the fundamental environmental changes investigated and it may serve as a relatively stable functional component both in natural and anthropogenic peatland transitions. In addition to clone longevity, the facilitative mechanisms suggested by co-occurrence patterns may play a role in this and deserve further study.

The pollination specialisation/generalisation continuum is a basic concept in pollination biology, usually defined as the number of species or functional groups of pollinators visiting a plant species. The level of specialisation can be affected by the relative abundance of pollinators on flowers, the among-pollinator variation in per-visit efficiency and the intra-population variation in floral traits. Here, we explore how these components influence the degree of generalisation of a Mediterranean herb, Moricandia arvensis (Brassicaceae). Moricandia arvensis shows a remarkable intra-individual floral polyphenism, with large cross-shaped lilac flowers during spring and small rounded white flowers during summer. We quantified the pollinator assemblages, grouped into functional groups, of six plant populations from SE Spain during spring and summer, experimentally tested their preference for spring and summer floral morphs, their per-visit efficiency, and their effectiveness during each flowering period, estimated as their contribution to plant's fitness. The level of generalisation differed between floral morphs: spring flowers are visited mainly by large long-tongued bees, while summer flowers are visited by a diverse set including small short-tongued bees, large long-tongued bees, large butterflies and beeflies. The functional groups of pollinators differed in their preferences for floral morphs, with large long-tongued bees, small short-tongued bees and beeflies preferring spring floral morphs, whereas flies and butterflies preferred summer floral morphs. Pollinator per-visit efficiency also varied among functional groups. Bees and butterflies produced many seeds per visit, while beetles, hoverflies and flies produced few or no seeds per visit. By combining floral visits with per-visit efficiency (effectiveness), the spring pollinator assemblage became significantly more specialised and the summer pollinator assemblage significantly more generalised. Our study suggests that, although traditionally neglected in pollination studies, examining pollinator effectiveness is crucial to accurately characterise generalisation-specialisation gradients, rigorously categorising pollination niches and correctly describing the architecture of plant-pollinator interactions.

The anatomical and cytological characteristics of the mucilage-secretory system have been widely studied in Malvaceae. However, conflicting information regarding the morphological nature of secretory structures exists, and some remain poorly understood. In this sense, some secretory structures in Malvaceae are not characterized as typical isolated idioblasts, canals, or cavities. Here, we describe a novel component of the mucilage-secretory apparatus in the Malvaceae family. Samples of the shoot apex, mature stem and fully expanded leaves were obtained from adult Peltaea polymorpha, which grow in the Cerrado (Brazilian savanna). The samples were processed using standard light and transmission electron microscopy methods. Mucilage cells occurred in the cortex and pith of petioles and stems, and in the midrib of leaves. These cells originate early in the stem apex from successive divisions of cells of the fundamental meristem, resulting in a row of interconnected secretory cells enveloped by a sheath of parenchyma cells devoid of secretory activity. Mucilage is stored in both protoplast and apoplast. In the same row, some cells filled with mucilage become very swollen and compress the neighbouring idioblasts that become flattened. This phenomenon results in a sandwich panel structure consisting of the swollen transversal walls of adjacent cells. As the differentiation progresses, the transversal walls of the rowed mucilage cells became very swollen, multilayered, and porous. Cytoplasmic strands cross such transversal walls connecting rowed cells. Mucilage-secreting cells in P. polymorpha are interconnected idioblasts and represent a novel component of the mucilage-secretory apparatus in Malvaceae. These findings open new avenues for understanding the structure and dynamics of mucilage-secreting cells from a functional perspective.

Drought-induced changes in floral traits can disrupt plant-pollinator interactions, influencing pollination and reproductive success. These phenotypic changes likely also affect natural selection on floral traits, yet phenotypic selection studies manipulating drought remain rare. We studied how drought impacts selection to understand the potential evolutionary consequences of drought on floral traits. We used a factorial experiment with potted plants to manipulate both water availability (well-watered and drought) and pollination (open and supplemented). We examined the treatment effects on traits of Brassica rapa and estimated phenotypic selection and whether it was pollinator-mediated in these two abiotic conditions. Drought affected plant phenotypes, leading to plants with fewer flowers and ultimately lower seed production. Flowering time did not show variation with watering, but we found the strongest effect of drought on selection was for flowering time. There was a selection for flowering faster in drought but not well-watered conditions. Pollinators instead were the agents responsible for selection on flower size, but we did not find strong evidence that drought effected pollinator-mediated selection. There was a stronger selection for larger flowers in drought compared to well-watered plants, and it could be attributed to pollinators however, there was no significant difference between watering treatments. Our results show the effects of drought are not limited to phenotypic responses and may alter evolution in plants by changing phenotypic selection on traits. The connection between phenotypic plasticity and selection may be important to understand as we found the most variable trait (display size) was not under selection while the trait with different selection in drought (flowering time) did not change in response to drought. Our study highlights the importance of manipulating potential agents of selection, especially to understand fully the potential impacts of components of climate change such as drought.

New crop`s need to emerge to provide sustainable solutions to climate change and increasing abiotic and biotic constraints on agriculture. A large breadth of northern fruit trees and shrubs exhibit a high potential for domestication; however, obstacles to implementing traditional breeding methods have hampered or dissuaded efforts for improvement. This review article proposes a unique roadmap for de novo domestication of northern fruit crops, with a focus on biotechnological (e.g. genome editing, rapid cycle breeding, and in planta transformation) approaches that can boast rapid evolutionary gains. In addition, numerous biotechnological (e.g. virus-induced flowering and grafting-mediated flowering) and breeding strategies (e.g. adaptation of speed breeding to fruit trees) that can hasten the transition from juvenility to sexual maturity are described. A description of an accelerated genetic breeding strategy with insights for 16 underutilized species (e.g. shagbark hickory, running serviceberry, horse chestnut, and black walnut) is provided to support their enhancement. Deemed unrealistic only a decade ago, progress in the realm of bioengineering heralds a future for northern orphan crops through the implementation of fast-tracked crop improvement programs. As such, the roadmap presented in this article paves the way to integrating these novel biotechnological discoveries and propel the development of these forgotten crops in a sustainable and timely manner.

Phosphorus (P) and potassium (K) play important roles in plant metabolism and hydraulic balance, respectively, while calcium (Ca) and magnesium (Mg) are important components of cell walls. Although significant amounts of these nutrients are found in wood, relatively little is known on how the wood concentrations of these nutrients are related to other wood traits, or on the factors driving the resorption of these nutrients within stems. We measured wood nutrient (i.e. P, K, Ca, and Mg) concentrations, wood specific gravity (WSG), as well as wood fibre and parenchyma fractions, in both inner (i.e. close to the pith) and outer (i.e. close to the bark) wood, for 22 tree species from a rainforest of eastern Amazonia. We first examined the associations of wood nutrient concentrations with WSG, fibre fractions, and parenchyma fractions. Then, we assessed whether resorption rates (i.e. difference between heartwood and sapwood nutrient contents) differed among nutrients, and whether nutrient resorption rates were related to species ecological strategies. WSG was unrelated to wood Ca, positively related to wood P in outer wood, and negatively related to inner wood Mg, as well as to both inner and outer wood K. Overall, nutrients were unrelated or negatively related to fibre and parenchyma fractions, except for wood Ca and wood P, which were positively related to fibre and axial parenchyma fractions in outer wood, respectively. We found that resorption rates did not differ among nutrients, and that P resorption rates were higher in high WSG, while K, Ca, and Mg resorption rates were unrelated to WSG. This study illustrates that the relationships of wood nutrient concentration with WSG and cell type fractions can be nutrient-specific. Our results indicate that, excluding a positive association between wood Ca and fibre fractions, and between wood P and axial parenchyma fractions, wood nutrients were mostly unrelated to anatomical traits. Our findings also suggest that high-WSG (i.e. shade-tolerant) species store higher amounts of wood P, and are more efficient at resorbing wood P, than low-WSG (i.e. fast-growing) species. These insights are important to increase our understanding on wood nutrient allocation, nutrient resorption, and tree ecological strategies in lowland tropical forests.

The shift from outcrossing to predominantly selfing is one of the most common transitions in plant evolution. This evolutionary shift has received considerable attention from biologists; however, this work has almost exclusively been focused on animal-pollinated systems. Despite the seminal ecological and economic importance of wind-pollinated species, the mechanisms controlling the degree of outcrossing in wind-pollinated taxa remain poorly understood. As a first step toward addressing this issue, we have conducted a comparative study of floral biology between two recently diverged sister species, Oryza rufipogon and Oryza nivara (Poaceae), that are wind-pollinated and possess distinct mating systems with O. rufipogon being outcrossing and O. nivara highly self-fertilized Therefore, these species present an ideal system for exploring mating system evolution in wind-pollinated taxa. We have identified key floral traits that differ between populations of these species and that are associated with mating system divergence including anther length, anther basal pore size, stigma papillae density, panicle shape, panicle exsertion, pollen viability, and early anther dehiscence. Of these traits, large anther basal pore size and early anther dehiscence are hypothesized to confer reliable autogamous selfing in O. nivara. Manipulations of floret number were conducted to partition the role of geitonogamy and autogamy in conferring self-fertilization. This experiment revealed that selfing in O. nivara is consistent with autogamous selfing, whereas O. rufipogon achieves selfing through geitonogamy. This study serves as a model for understanding the floral mechanisms controlling the outcrossing rate in other wind-pollinated systems, most notably other grasses.

Functional-structural plant (FSP) models are useful tools for understanding plant functioning and how plants react to their environment. Developing tree FSP models is data-intensive and measuring tree architecture using conventional measurement tools is a laborious process. Light detection and ranging (LiDAR) could be an alternative nondestructive method to obtain structural information about tree architecture. This research investigated how terrestrial LiDAR (TLS)-derived tree traits could be used in the design and parameterization of tree FSP models. A systematic literature search was performed to create an overview of tree parameters needed for FSP model development. The resulting structural parameters were compared to LiDAR literature to get an overview of the possibilities and limitations. Furthermore, a tropical tree and Scots pine FSP model were selected and parametrized with TLS-derived parameters. Quantitative structural models were used to derive the parameters and a total of 37 TLS-scanned tropical trees and 10 Scots pines were included in the analysis. Ninety papers on FSP tree models were screened and eight papers fulfilled all the selection criteria. From these papers, 50 structural parameters used for FSP model development were identified, from which 28 parameters were found to be derivable from LiDAR. The TLS-derived parameters were compared to measurements, and the accuracy was variable. It was found that branch angle could be used as model input, but internode length was unsuitable. Outputs of the FSP models with TLS-derived branch angle differed from the FSP model outcomes with default branch angle. Results showed that it is possible to use TLS for FSP model inputs, although with caution as this has implications for the model variable outputs. In the future, LiDAR could help improve efficiency in building new FSP models, increase the accuracy of existing models, add metrics for optimization, and open new possibilities to explore previously unobtainable plant traits.

Perennial grasses' reproductive phenology profoundly impacts plant morphogenesis, biomass production, and perenniality in natural ecosystems and cultivated grasslands. Complex interactions between vegetative and reproductive development complicate grass phenology prediction for various environments and genotypes. This work aims to analyse genetic × environment interactions effects on tiller growth and reproductive development in Lolium perenne. Three perennial ryegrass cultivars, Bronsyn, Carvalis, and Tryskal, were grown from seedling to heading under four inductive conditions. T0 plants were continuously exposed to high temperatures and long days (HT-LD). T1, T2, and T3, plants were initially exposed to low temperatures and short days (LT-SD) for 9 weeks. Then, T1 plants were immediately transferred to high temperatures and long days (HT-LD). Before their exposure to HT-LD, T2, and T3 plants were first transferred to high temperatures and short days (HT-SD) for 3 and 6 weeks, respectively. Leaf length, leaf emergence, and heading were regularly monitored. Floral transition and heading only occurred in T1, T2, and T3, i.e. after successive exposure to low temperature and long photoperiod. Bronsyn had higher heading earliness and proportion of reproductive tillers than Carvalis and Tryskal. The duration of HT-SD exposure affected the final number of leaves and spikelets. The rate of leaf and spikelet production significantly increased once plants were exposed to LD. Our results suggest an additive effect of the photoperiod and floral transition on leaf elongation rate. These findings enhance our understanding of the genetic × environment interactions on the vegetative and reproductive development in perennial ryegrass.

[This corrects the article DOI: 10.1093/aobpla/plae055.].