Heavier Seeds Research Articles

Einstein, tea leaves, meandering rivers, and the origin of supermassive black holes in ekpyrotic universe

Central supermassive black holes are found in most massive galaxies. However, their origin is still poorly understood. Observations of quasars show that many supermassive black holes existed less than 700 million years after the Big Bang. To explain the existence of such black holes with masses comparable to the stellar mass of the host galaxy, just 500 million years after the Big Bang, it is probably necessary to assume that they originated from heavy seeds. In an ekpyrotic universe, a hot Big Bang occurs as a result of the collision of two branes. Quantum fluctuations create ripples on the brane surfaces, leading to spatial variations in the timing of collisions, thereby creating density perturbations that can facilitate the formation of massive black hole seeds. I hypothesize that perhaps Rayleigh–Bénard–Marangoni-type convection in the extra dimension is a more efficient source of macroscopic density perturbations than quantum fluctuations.

INFLUENCE OF TARGET SEEDING RATES BASED ON THOUSAND KERNEL WEIGHT ON VEGETATIVE GROWTH TRAITS OF TRITICALE, VARIETY ADMIRAL- Part I.

A field experiment was conducted during two seasons 2019-2020 and 2020-2021 at the Grdarasha Research Station of the Agricultural Engineering Sciences College-Salahaddin University-Erbil. The experiment was designed as factorial within randomized complete block design (RCBD), with three replicates. The first factor included three target seeding rates of Triticale (×Triticosecale wittmack, variety Admiral (200,250,and300seeds.m-2), while the second factor was three grain size grades whole, thousand kernels weight (TKW) 47.32 g, heavy seeds, TKW 54.04 and light seeds TKW 40.18 g. The results revealed to no significant influence of seeds weight or seeding rates and their interaction on this trait excluding whole sample seed (ungraded) at the rate target of 300 seeds.m-2, which was significantly reduced flag leaf area. Leaf area index was significantly varied among seed weight and target seeding rates or by their interactions. The plant height of triticale although it was higher for heavy seeds and higher target seeding rates, but it was not reached significant level, either by seed grade or target seed rate and their interactions in both. Plant height ranges from 88.00 for heavy seeds at rate 300 seeds.m-2 to 83.00 for light seeds at rate 200 seeds.m-2 for the season 2019-2020. The highest tillers number was recorded for seed rate 300.m-2 with whole ungraded seeds (176.00).

Analysis of the role of the rice metallothionein gene OsMT2b in grain size regulation

Seed size is one of the three main characteristics determining rice yield. Clarification of the mechanisms regulating seed size in rice has implications for improving rice yield. Although several genes have been reported to regulate seed size, most of the reports are fragmentary. The role of metallothioneins (MTs) in regulating seed size remains unknown. Here, we found that OsMT2b was expressed in both spikelets and developing seeds. OsMT2b-overexpression lines had large and heavy seeds, and RNAi (RNA interference) lines had small and light seeds. Scanning electron microscopy (SEM) observations revealed that OsMT2b regulated spikelet hull size by affecting cell expansion in the outer epidermis. Histological analysis indicated that OsMT2b affected the number of cells in the cross-section of spikelet hulls, which affected seed size. The fresh weight of seeds was consistently higher in OsMT2b-overexpression lines than in seeds of the wild-type (WT) and RNAi lines from 6 DAP (days after pollination) until maturity, indicating that OsMT2b affected seed filling. Reverse transcription-quantitative PCR (RT-qPCR) analyses revealed that OsMT2b regulates the expression of reactive oxygen species scavenging-related genes involved in seed size regulation. In conclusion, our results indicated that OsMT2b positively regulates seed size, which provides a novel approach for regulating seed size with genetic engineering technology.

Impacts of cyanobacteria-dominated biological soil crusts on seedling emergence and fate: an in situ experiment

Abstract Background and aims Biological soil crusts (BSCs) co-occur with vascular plants in many ecosystems. Nevertheless, little is known regarding the interaction among BSCs and vascular plants, and no standard methods exist aiming to evaluate BSC–plant interactions. While some reports emphasized the inhibition effect of BSCs on germination, others reported the opposite or did not find any differences between germination under crusted and non-crusted conditions. Contradictory findings were also reported regarding the BSC effects on vascular plants after germination, with some reports claiming that BSCs promote growth, while others claim the opposite. Methods By a seed addition experiment (using light and heavy seeds of three species belonging to the Fabaceae family) in an early-successional system in Germany, we tested in situ the emergence of seedlings under variable surface conditions (cyanobacterial crust, disturbed and removed crust), and quantified crust-plant interactions (survival, flowering) during and following seedling emergence. Results In comparison to an average of 8% of the light Lotus corniculatus and 20% of the light Ornithopus sativus that emerged through the cyanobacterial BSC, 76% of the heavy Glycine max emerged. Once emerged, the crust did not significantly affect the survival, growth, biomass, or flowering of G. max, whereas many of the seedlings from lightweight seeds dried up soon after emergence. The thickness of the cyanobacterial biocrust had no influence on Fabaceae emergence. Conclusion The cyanobacterial BSC acted as a filter that hindered the emergence of the lightweight seeds.

Growth of high redshift supermassive black holes from heavy seeds in the BRAHMA cosmological simulations: Implications of overmassive black holes

Growth of high redshift supermassive black holes from heavy seeds in the <tt>BRAHMA</tt> cosmological simulations: Implications of overmassive black holes

Nanopriming with Zinc–Molybdenum in Jalapeño Pepper on Imbibition, Germination, and Early Growth

The jalapeño pepper is a vegetable of great economic importance worldwide. However, low germination efficiency, weak seedlings, and a high mortality rate during transplant compromise the viability and sustainability of the crop. An innovative solution is the nanopriming technique, an emerging and novel technology, which involves the imbibition of seeds for a specific period using mineral nanoparticles. The addition of micronutrients such as zinc and molybdenum has been used in seed germination and early seedling development due to their crucial roles. The aim of this study was to evaluate the effectiveness of using zinc–molybdenum nanopriming in jalapeño pepper on germination and early growth. The results showed that applying nanopriming (124–10 mg L−1 of zinc–molybdenum) promotes the effectiveness on the imbibition and germination of jalapeño pepper seeds, resulting in heavier seeds with a better initial absorption. This method not only improves germination rates and seedling vigor, but also points towards more sustainable and efficient agriculture. Building on these findings, the zinc–molybdenum nanopriming method could potentially transform jalapeño pepper cultivation by enhancing seed quality and resilience. Nanopriming could help increase crop yields and minimize reliance on chemical inputs, such as fertilizers and pesticides, which might reduce production costs and environmental impact.

Meso-scale environmental heterogeneity drives plant trait distributions in fragmented dry grasslands

Environmental heterogeneity shapes the patterns of resources and limiting factors and therefore can be an important driver of plant community composition through the selection of the most adaptive functional traits. In this study, we explored plant trait–environment relationships in environmentally heterogeneous microsite complexes at the meso-scale (few meters), and used ancient Bulgarian and Hungarian burial mounds covered by dry grasslands as a model habitat. We assessed within-site trait variability typical of certain microsites with different combinations of environmental parameters (mound slopes with different aspects, mound tops, and surrounding plain grasslands) using a dataset of 480 vegetation plots. For this we calculated community-weighted means (CWMs) and abundance models. We found that despite their small size, the vegetation on mounds was characterized by different sets of functional traits (higher canopy, higher level of clonality, and heavier seeds) compared to the plain grasslands. North-facing slopes with mild environmental conditions were characterized by perennial species with light seeds, short flowering period, and a high proportion of dwarf shrubs sharply contrasted from the plain grasslands and from the south-facing slopes and mound tops with harsh environmental conditions. Patterns predicted by CWMs and abundance models differed in the case of certain traits (perenniality, canopy height, and leaf dry matter content), suggesting that environmental factors do not necessarily affect trait optima directly, but influence them indirectly through correlating traits. Due to the large relative differences in environmental parameters, contrasts in trait composition among microsites were mostly consistent and independent from the macroclimate. Mounds with high environmental heterogeneity can considerably increase variability in plant functional traits and ecological strategies at the site and landscape levels. The large trait variation on topographically heterogeneous landscape features can increase community resilience against climate change or stochastic disturbances, which underlines their conservation importance.

The positive impact of honeybee activity on fennel crop production and sustainability

This study investigates the ecological interaction between honeybees (Apis mellifera) and fennel (Foeniculum vulgare) plants, examining the mutual benefits of this relationship. Field experiments conducted in Egypt from December 2022 to May 2023 recorded diverse insect pollinators attracted to fennel flowers, especially honeybees. Assessing honeybee colonies near fennel fields showed improvements in sealed brood (357.5–772.5 cells), unsealed brood (176.3–343.8 cells), pollen collection (53.25–257.5 units), honey accumulation (257.5–877.5 units), and colony strength (7.75–10) over three weeks. Fennel exposure explained 88–99% of variability in foraging metrics. Comparing open versus self-pollinated fennel revealed enhanced attributes with bee pollination, including higher flower age (25.67 vs 19.67 days), more seeds per umbel (121.3 vs 95.33), bigger seeds (6.533 vs 4.400 mm), heavier seeds (0.510 vs 0.237 g/100 seeds), and increased fruit weight per umbel (0.619 vs 0.226 g). Natural variation in seed color and shape also occurred. The outcomes demonstrate the integral role of honeybees in fennel agroecosystems through efficient pollination services that improve crop productivity and quality. Fennel provides abundant nutritional resources that bolster honeybee colony health. This research elucidates the symbiotic bee-fennel relationship, underscoring mutualistic benefits and the importance of ecological conservation for sustainable agriculture.

Geographic variation in reproductive traits and germination-niche dynamics in conservation-dependent Banksia arborea populations restricted to banded ironstone formations

The temperature and moisture requirements for reproduction (i.e. seed production and germination) underpin the biogeographical relationships between climate, distribution and population dynamics of plants, particularly narrow range endemic species. We aimed to investigate reproductive outputs and the responses of seeds to temperature and moisture availability across three Banksia arborea populations that are distributed over a narrow range (< 200 km2) of semi-arid habitat on banded ironstone formations of Western Australia. We conducted reproductive trait assessments by quantifying follicles per cone, proportion of viable seed and associated seed mass followed by hydrothermal germination assessments for each population to characterise temperature and water stress tolerance. We found the southern-most population, that receives marginally higher rainfall, had heavier seeds (10 ± 0.02 mg), a cooler optimum temperature (16.1 °C) and wider germination capacity under water stress at 10 °C and 15 °C (Ψb50 = -0.66 to -0.87 MPa) compared to the two northern populations (Ψb50 = -0.60 to -0.65 MPa). By contrast, both northern populations had slightly warmer optimum temperatures for germination (16.9–17.5 °C) and a higher capacity to germinate under water stress at warmer temperatures of 22.5 °C (Ψb50 = -0.43 to -0.56 MPa, compared to -0.29 MPa). Our work highlights that, even within the specific requirements of a narrow range endemic, different populations adapt to marginally different temperature and water stress tolerances. Warming of the southern populations could impact on future recruitment, and conservation action to promote resilient ecosystems are suggested.

A Candidate Supermassive Black Hole in a Gravitationally Lensed Galaxy at Z ≈ 10

While supermassive black holes (SMBHs) are widely observed in the nearby and distant Universe, their origin remains debated with two viable formation scenarios with light and heavy seeds. In the light seeding model, the seed of the first SMBHs form from the collapse of massive stars with masses of 10–100 M ⊙, while the heavy seeding model posits the formation of 104–5 M ⊙ seeds from direct collapse. The detection of SMBHs at redshifts z ≳ 10, edging closer to their formation epoch, provides critical observational discrimination between these scenarios. Here, we focus on the JWST-detected galaxy, GHZ 9, at z ≈ 10 that is lensed by the foreground cluster, A2744. Based on 2.1 Ms deep Chandra observations, we detect a candidate X-ray active galactic nucleus (AGN), which is spatially coincident with the high-redshift galaxy, GHZ 9. The SMBH candidate is inferred to have a bolometric luminosity of (1.0−0.4+0.5)×1046ergs−1 , which corresponds to a black hole (BH) mass of (8.0−3.2+3.7)×107M⊙ assuming Eddington-limited accretion. This extreme mass at such an early cosmic epoch suggests the heavy seed origin for this BH candidate. Based on the Chandra and JWST discoveries of extremely high-redshift quasars, we have constructed the first simple AGN luminosity function extending to z ≈ 10. Comparison of this luminosity function with theoretical models indicates an overabundant z ≈ 10 SMBH population, consistent with a higher-than-expected seed formation efficiency.

INFLUENCED OF SEED WEIGHT ON EARLY GROWTH OF Acacia senegal (Linn) Willd (Gum Arabic) SEEDLINGS

Seed weight has enormous influence on the germination rate and growth performance of many species which necessary is for productivity and sustainability. Study was carried out to examine the effects of seed weight on germination and early growth of Acacia senegal (Linn) Willd (Gum Arabic) seedlings. The work was conducted in the Forestry nursery of Department of Forestry and Wildlife, Federal University Dutse, Jigawa state. Complete Randomized Design (CRD) was employed with three (3) treatments of twenty replications (20) making sixty samplings. The seed weights used were classified into three groups: Heavy seeds (1g and above), Medium seeds (0.5-0.9 g) and Light seeds (0.1- 0.4g). Germination counts and early growth parameters were assessed. Data were subjected to Analysis of Variance (ANOVA) at 0.05 probability level and descriptive statistics such as bar chart was used. It is interesting to note that the study found that heavy seeds (1g) had an earlier germination rate and better early growth performance compared to intermediate-weight (0.5 - 0.9g) and light-weight (0.4 - 0.1g) seeds. The heavy seeds showed the best overall performance, according to the results. Heavy seeds showed the best performance. Therefore, heavy weight seeds were recommended for planting, plantation establishment and nursery studies.

Transgenerational plasticity to drought: contrasting patterns of non-genetic inheritance in two semiarid Mediterraneanshrubs.

Intra- and transgenerational plasticity may provide substantial phenotypic variation to cope with environmental change. Since assessing the unique contribution of the maternal environment to the offspring phenotype is challenging in perennial, outcrossing plants, little is known about the evolutionary and ecological implications of transgenerational plasticity and its persistence over the life cycle in these species. We evaluated how intra- and transgenerational plasticity interplay to shape the adaptive responses to drought in two perennial Mediterranean shrubs. We used a novel common garden approach that reduced within-family genetic variation in both the maternal and offspring generations by growing the same maternal individual in two contrasting watering environments, well-watered and drought, in consecutive years. We then assessed phenotypic differences at the reproductive stage between offspring reciprocally-grown in the same environments. Maternal drought had an effect on offspring performance only in Helianthemum squamatum. Offspring of drought-stressed plants showed more inflorescences, less sclerophyllous leaves and higher growth rates in both watering conditions, and heavier seeds under drought, than offspring of well-watered maternal plants. Maternal drought also induced similar plasticity patterns across maternal families, showing a general increase in seed mass in response to offspring drought, a pattern not observed in the offspring of well-watered plants. In contrast, both species expressed immediate adaptive plasticity, and the magnitude of intragenerational plasticity was larger than the transgenerational plastic responses. Our results highlight that adaptive effects associated with maternal drought can persist beyond the seedling stage and provide evidence of species-level variation in the expression of transgenerational plasticity. Such differences between co-occurring Mediterranean species in the prevalence of this form of non-genetic inheritance may result in differential vulnerability toclimatechange.

A small and vigorous black hole in the early Universe

Several theories have been proposed to describe the formation of black hole seeds in the early Universe and to explain the emergence of very massive black holes observed in the first thousand million years after the Big Bang1–3. Models consider different seeding and accretion scenarios4–7, which require the detection and characterization of black holes in the first few hundred million years after the Big Bang to be validated. Here we present an extensive analysis of the JWST-NIRSpec spectrum of GN-z11, an exceptionally luminous galaxy at z = 10.6, revealing the detection of the [Neiv]λ2423 and CII*λ1335 transitions (typical of active galactic nuclei), as well as semi-forbidden nebular lines tracing gas densities higher than 109 cm−3, typical of the broad line region of active galactic nuclei. These spectral features indicate that GN-z11 hosts an accreting black hole. The spectrum also reveals a deep and blueshifted CIVλ1549 absorption trough, tracing an outflow with velocity 800−1,000 km s−1, probably driven by the active galactic nucleus. Assuming local virial relations, we derive a black hole mass of log(MBH/M⊙)=6.2±0.3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\log ({M}_{{\\rm{BH}}}/{M}_{\\odot })=6.2\\pm 0.3$$\\end{document}, accreting at about five times the Eddington rate. These properties are consistent with both heavy seeds scenarios and scenarios considering intermediate and light seeds experiencing episodic super-Eddington phases. Our finding explains the high luminosity of GN-z11 and can also provide an explanation for its exceptionally high nitrogen abundance.

The dispersal potential of endangered plants versus non‐native garden escapees

Abstract Amidst climate change, enhancing plant dispersal pathways is crucial for adapting ecosystems and preserving biodiversity. In our human‐dominated landscapes, urban and rural green spaces, especially gardens, are promising conduits for plant dispersal. Non‐native plants are known to benefit from these spaces, yet the potential benefits for at‐risk native plants remain unclear. Here, I synthesized data on dispersal traits, comparing endangered native plants with non‐endangered and non‐native species in Germany. To make my analysis pertinent to understanding the potential role of gardens in aiding the dispersal of at‐risk native plants, I further contrasted the dispersal ecology of garden‐friendly endangered plants with non‐native plants known to escape gardens. I analysed several traits including seed weight, terminal velocity, dispersal distance, germination rate, dispersal mode, seed structures and seedbank type. Overall, dispersal traits between native and non‐native plants showed minor, but in some cases statistically significant differences. Endangered plants were more often wind‐dispersed and more frequently had seed appendages conducive to a wider range of dispersal vectors. Conversely, non‐native plants leaned more towards non‐assisted local dispersal, heavier seeds and more persistent seed banks. Other traits were largely consistent across groups. This research shows that endangered native plants possess a dispersal ecology similar to non‐native species, which frequently spread from green spaces like gardens. Thus, integrating endangered flora into our green spaces could help to promote an essential aspect of species survival: dispersal.

Sunflower hybrid “Linzi” and its agronomic response to the main soil tillage systems in the region of South Dobrudzha

Sunflower (Helianthus annuus – hybrid “Linzi”) yield obtained under different main soil tillage systems in 4-field crop rotation (common bean-wheat-sunflower-grain maize), is strongly influenced by the properties of the slightly leached chernozems the (Haplic Chernozems) and the climatic conditions. This study was carried out at the stationary field trial of Dobrudzha Agricultural InstituteGeneral Toshevo from 2016 to 2018. The influence of seven main soil tillage systems (MSTS) on the yield and the physical properties of sunflower seeds were investigated. The aim of this study was to trace the influence of different types of main soil tillage on seed yield, oil content and seed physical properties of sunflower hybrid ”Linzi”. Regardless of the meteorological conditions during the studied period, the main tillage systems are a powerful agrotechnical tool for managing sunflower productivity in all its aspects. The yield of seeds and kernels of hybrid ”Linzi”, as well as that of their oil content, is highest in years with a relatively favorable distribution of precipitation during the growing season. For the region of haplic Chernozems in Dobrudzha, the most effective systems for sunflower are the systems including the mould board plough of the soil. The best results were obtained when, in the 4-field crop rotation against wheat, deep tillage was replaced by Disking or No-till. The obtained oil yields are respectively: 2420.10 kg/ha (Plowing- -Disking); 2280.80 kg/ha (Plowing-No-till) 2244.70 kg/ha (Plowing-Plowing). The largest seeds were obtained in the under permanent shallow treatment against all crops in crop rotation - 62.66 g (Disking-Disking). The best results for the hectoliter weight were obtained in the two deep treatments with and without turning/inversion of the cultivated layer. However, the heaviest seeds were obtained when deep plowing is interrupted with direct seeding or disking, respectively. The positive correlation with the production of husks and kernels is strongly expressed. Averaged over the period, the correlation between the yield of seeds and that of husks has lower values compared to each of the years.

Effect of micron (micronutrients) fertilizer on the growth and yield of Wheat variety Sarsabz

The Department of Chemistry Soil Section Agriculture Research Institute, Tando Jam, conducted an examination in order to find out how micron (micronutrient) fertilizer affected the growth and yield of the wheat variety Sarsabz. Three replicates of a Randomized Complete Block Design were used to investigate the effects of micron (micronutrients) fertilizer utilized at rates of 0, 50, 100, and 150 kg ha-1 having a plot size of 46 m x 44 m. The results of the study revealed that applying micronutrient fertilizer to crops significantly altered the crop’s parameters. The application of Micron (micronutrients) fertilizer applied at a rate of 150 kg ha-1, with proposed N (168) and P (84) doses, resulting in the maximum wheat plant height (101.73), more tillers plant-1 (9.73), spike length (13.7), more grain spike-1 (51.66), heavier seeds (39.3), and higher grain yield (3453.3 kg ha-1). Therefore the micro nutrient is essential for achieving maximum yield production and should be applied with recommended doses on the wheat crop, performed better results in soil conditions of Tando Jam.

Orchid bees enhance seed set production of an understory herb in the Western Brazilian Amazon

Bee pollination is an important ecosystem service related to the maintenance of many flowering plants. We evaluated the relationship between orchid bee foraging time and the density of flowering plants and whether visitation varied according to the sex and size class of bees, using Calathea mansonis as a model species. We monitored 10 plots between December 2009 and November 2010 in a forest fragment in Senador Guiomard, Acre, Brazil. We counted the number of flowering plants and flowers per plant and the behaviour of the observed bees. Additionally, we compared the bagged and exposed inflorescences for self-compatibility analysis. We sampled 173 orchid bees from 13 species, with Eulaema cingulata as the most abundant visitor. Eulaema (large bees) were more effective pollinators than Euglossa (small bees). We also found Eulaema polyzona individuals feeding on a Marantaceae species for the first time. The time spent by the bees visiting flowers did not differ with the density of flowering plants or the number of flowers per plant. However, flowers exposed to visitors produced 35% more seeds and 15% heavier seeds than bagged flowers. Considering plant–bee interactions, orchid bees may increase gene flow and compensate for the clonal reproduction of this herb.

Functional traits mediate seedling survival response to climate in a temperate forest

Functional traits are increasingly used to forecast the response of plant performance to abiotic and biotic conditions. However, it remains unclear how functional traits will mediate the complex responses of plants to interactive drivers in a rapidly changing world. Here, we collected 17-year monitoring data on seedlings of 28 locally coexisting species and 8 functional traits in a temperate forest, and built multi-level regression models to evaluate (1) whether seedling survival varied among species along the acquisitive-conservative strategy gradient, and which functional trait affected seedling survival; and (2) how survival of species with different functional strategies responded to negative density dependence (NDD) and climate variation. We found that species with an acquisitive strategy had higher seedling survival. Specifically, seedling survival was positively correlated with specific root length (SRL), specific leaf area (SLA), and leaf area (LA), but inversely correlated with leaf dry mass content (LDMC). Functional strategies along the acquisitive-conservative gradient showed no significant effects on survival response to conspecific and phylogenetic negative density dependence (CNDD and PNDD). Negative effects of heterospecific negative density dependence (HNDD) on seedling survival were weaker for species with higher LDMC, but stronger for seedlings with larger SRL. In addition, species with more conservative strategies had higher resistance to drought stress and freezing damage. For example, species with lower SRL and SLA, and higher LDMC had higher survival under severer seasonal drought. Also, heavier seeds and thicker roots enhanced freezing resistance, whereas higher SRL and LA intensified the negative effects of cold weather. Our study provides strong evidence that functional traits could widely mediate the effects of local biotic context and climatic variation on plant performance dynamics, and help to infer community assemblages and species coexistence in the context of a changing world.

Sexual dimorphism and female advantage hypothesis in the gynomonoecious-gynodioecious Dianthus plumarius (Caryophyllaceae)

Abstract To explain the co-existence and maintenance of females along with hermaphrodite plants, the female advantage hypothesis has been proposed where females should show greater fecundity compared to their conspecific hermaphrodites. On the other hand, greater attraction would be selected in the hermaphrodites to increase their male function, potentially leading to larger showier flowers, with more rewards. Here, I tested the sexual dimorphism trade-off hypothesis with the gynomonoecious-gynodioecious Dianthus plumarius (Caryophyllaceae), in the gardens of Bariloche (Patagonia, Argentina). I measured in female and hermaphrodite plants: flower size, nectar volume and concentration, flower lifespan, ovule production, seed number, seed set and seed weight. Additionally, bagging and pollen supplementation experiments were carried out to evaluate pollen limitation, probability of apomixis, if spontaneous autogamy is possible, and to examine the importance of pollen origin. I found that hermaphrodite flowers are more attractive, with larger-sized flowers and higher nectar volume, whereas female flowers compensate with longer lifespan of stigmatic receptivity and more concentrated nectar. Despite ovule number was lower in female flowers, these showed higher seed set and produced more and heavier seeds than hermaphrodites under open pollination. No evidence of apomixis was found in females, but spontaneous autogamy may occur in hermaphrodites. Hand-pollination experiments showed first that both flower types suffered pollen limitation, but it was higher on hermaphrodite flowers. Finally, despite self-compatibility, pollen origin is important because hand self-pollination decreases seed weight. These findings provide strong evidence in support of the mechanisms and underlying conditions that would allow the co-existence and maintenance of female and hermaphrodite individuals within populations.

Constraining the Properties of Black Hole Seeds from the Farthest Quasars

Over 60 yr after the discovery of the first quasar, more than 275 such sources are identified in the epoch of reionization at z > 6. JWST is now exploring higher redshifts (z ≳ 8) and lower-mass (≲107 M ⊙) ranges. The discovery of progressively farther quasars is instrumental to constraining the properties of the first population of black holes (BHs), or BH seeds, formed at z ∼ 20–30. For the first time, we use Bayesian analysis of the most comprehensive catalog of quasars at z > 6 to constrain the distribution of BH seeds. We show that the mass distribution of BH seeds can be effectively described by combining a power law and a lognormal function tailored to the mass ranges associated with light and heavy seeds, assuming Eddington-limited growth and early seeding time. Our analysis reveals a power-law slope of and a lognormal mean of . The inferred values of the Eddington ratio, the duty cycle, and the mean radiative efficiency are , , and , respectively. Models that solely incorporate a power law or a lognormal distribution within the specific mass range corresponding to light and heavy seeds are statistically strongly disfavored, unlike models not restricted to this specific range. Our results suggest that including both components is necessary to comprehensively account for the masses of high-redshift quasars, and that both light and heavy seeds formed in the early Universe and grew to form the population of quasars we observe.