Allocation of resources to floral traits often declines distally within inflorescences in flowering plants. Architecture and resource competition have been proposed as underlying mechanisms. The aim of the present study is to assess the relative importance of resource competition and architectural effects in pollen and ovule production on racemes of Hosta ventricosa, an apomictic perennial herb. Combinations of two defoliation treatments (intact and defoliated) and two fruit-set treatments (no-fruit and fruit) were created, and the roles of architecture and resource competition at each resource level were assessed. Pollen and ovule number per flower increased after defoliation, but pollen to ovule ratio per flower did not change. Pollen, ovules and the pollen to ovule ratio per flower declined distally on racemes at each resource level. In the intact treatment, fruit development of early flowers did not affect either pollen or ovule number of late flowers. In the defoliated treatment, fruit development of early flowers reduced both pollen and ovule numbers of late flowers due to over-compensation caused by defoliation. Late flowers on defoliated fruit racemes produced less pollen than intact fruit racemes but the same number of ovules; therefore, the reduction in pollen number was not caused by over-compensation. In addition, the fruit-set rate of early flowers during flowering was higher in intact racemes than in defoliated racemes. In flowering plants, the relative importance of architecture and resource competition in allocation to pollen and ovules may vary with the resource pools or the overall resource availability of maternal plants.

Akebia trifoliata is a newly domesticated perennial fruit tree, and the lack of molecular research on stress resistance seriously affects its genetic improvement and commercial value development. Superoxide dismutase (SOD) can effectively eliminate the accumulation of reactive oxygen species (ROS) during the rapid growth of plant organs under biotic and abiotic stresses, maintaining a steady state of physiological metabolism. In this study, 13 SODs consisting of two FeSODs (FSDs), four MnSODs (MSDs) and seven Cu/ZnSODs (CSDs) were identified in the A. trifoliata genome. Structurally, the phylogeny, intron–exon pattern and motif sequences within these three subfamilies show high conservation. Evolutionarily, segmental/wide genome duplication (WGD) and dispersed duplication form the current SOD profile of A. trifoliata. Weighted gene coexpression network analysis (WGCNA) revealed the metabolic pathways of nine (69.2%) SODs involved in fruit development, among which AktMSD4 regulates fruit development and AktCSD4 participates in the stress response. In addition, under the stress of multiple pathogens, six (46.6%) SODs were continuously upregulated in the rinds of resistant lines; of these, three SODs (AktMSD1, AktMSD2 and AktMSD3) were weakly or not expressed in susceptible lines. The results pave the way for theoretical research on SODs and afford the opportunity for genetic improvement of A. trifoliata.

Cercis chinensis Bunge (C. chinensis), well known as an ornamental plant widely distributed in China, and its flowers, bark, fruit, etc., have multiple bioactivities. However, reports on the changes in mineral elements, nutrient composition and antioxidant activity in C. chinensis flower at different development stages are rare. In this study, the flower samples were collected every 20 days from March 2023 to May 2023. The changes in carbon (C), nitrogen (N), phosphorous (P), soluble protein (SP), amino acid (AA), non-structural carbohydrate (NSC), total phenol (TP) and total flavonoids (TF) content as well as antioxidant activity in C. chinensis flower at different development stages were investigated. The results suggested that C, N, and P content, the C:N:P stoichiometric ratio, NSC contents, SP, AA, TP, TF and antioxidant activity of flower showed large variations at three development stages. This study found that C and P contents showed a significant decrease with the development and opening of flowers, while N content showed an opposite trend. The soluble protein content first decreased and then increased. The amino acid content, total polyphenol content, and total flavonoid content all showed a significant downward trend, while the content of NSC increased. Both ABTS and ferric-reducing antioxidant power (FRAP) showed significant decreases at various developmental stages, but DPPH was completely opposite. The highest NSC content and DPPH activity were observed at stage III, but the highest AA, TP, TF, as well ABTS and FRAP activity wereobserved at stage I. These findings will improve understanding of the requirements and dynamic balance among C, N, and P, NSC and nutrient contents as well as antioxidant activity of C. chinensis flowers in response to development stages.

Light availability may have direct effects on reproduction through resource availability, and indirect effects on female reproduction by influencing plant-pollinator interactions. Floral display size, pollinator visitation per flower, resource and pollen limitation of fruit and seed production were quantified in a forested patch and an adjacent open patch of two populations of the perennial herb Hosta ventricosa. Plants in the open patch produced significantly larger floral displays than those in the forested patch in both populations. Floral display size had a positive effect on pollinator visitation rate per flower in one population, but no effect in the other. Plants in the open patch received approximately 8–11 times more visitation rates and produced significantly more fruit and seeds per flower than those in the forested patch. However, supplemental pollination resulted in significantly more fruit and seed production per flower compared to natural pollination in the forested patch but not in the open patch in one population, and did not enhance fruit and seed production in either the forested or the open patch in the other. In both populations, supplementally pollinated plants in the open patch produced significantly more fruit and seeds per flower than supplementally pollinated plants in the forested patch. In H. ventricosa, local variation in light conditions could affect pollinator activity and influence female reproduction through resource availability; however differences in the degree of pollen limitation between local habitats were found to be population-specific.