Fertilization Success Research Articles

Acidification prior to drying of digestate solids affects nutrient uptake and fertilizer value when applied to maize

Acidification has proven effective in minimizing NH3 emissions during the drying of digestate bio-solids, but its impact on soil nutrient dynamics and plant growth is less understood. This study aimed to assess the nitrogen and phosphorus efficiency of acidified-dried digestate solids as starter fertilizer for maize through a pot experiment and a soil incubation study. Two types of digestates (MDS and SDS) and two acidifying agents (concentrated H2SO4 and alum) were used. Drying significantly lowered the nitrogen fertilizer replacement value (N-FRV) from 42% in untreated to 12% in the dried material, reducing maize biomass and N uptake by 34% and 54%, respectively. The decline mitigated by acidification, which doubled N-FRV to 28%. Drying enhanced maize P uptake by 25%, indicating dried MDS as an effective P fertilizer (P-FRV of 82%). However, alum negated the drying benefits for P uptake, aligning it with raw MDS levels. The SDS treatments showed no significant effects on maize growth or nutrient uptake, though dried SDS indicated a high N mineralization potential, N-FRV and P-FRV remained around 33% and 26%, respectively. The study concludes that H2SO4-acidified dried MDS could serves as a suitable starter fertilizer with balanced N and high P availability, supporting early maize development. Alum may serve to preserve N value while reducing P solubility to prevent runoff. Dried SDS is less effective as a mineral fertilizer replacement, better suited for sustaining soil organic N and P levels.

Green synthesis of a dual-functional sulfur nanofertilizer to promote growth and enhance salt stress resilience in faba bean

BackgroundSalinity is a major abiotic stress, and the use of saline water in the agricultural sector will incur greater demand under the current and future climate changing scenarios. The objective of this study was to develop a dual-functional nanofertilizer capable of releasing a micronutrient that nourishes plant growth while enhancing salt stress resilience in faba bean (Vicia faba L.).ResultsMoringa oleifera leaf extract was used to synthesize sulfur nanoparticles (SNPs), which were applied as a foliar spray at different concentrations (0, 25, 50, and 100 mg/l) to mitigate the negative effects of salt stress (150 mM NaCl) on faba bean plants. The SNPs were characterized and found to be spherical in shape with an average size of 10.98 ± 2.91 nm. The results showed that salt stress had detrimental effects on the growth and photosynthetic performance (Fv/Fm) of faba bean compared with control, while foliar spraying with SNPs improved these parameters under salinity stress. SNPs application also increased the levels of osmolytes (soluble sugars, amino acids, proline, and glycine betaine) and nonenzymatic antioxidants, while reducing the levels of oxidative stress biomarkers (MDA and H2O2). Moreover, SNPs treatment under salinity stress stimulated the activity of antioxidant enzymes (ascorbate peroxidase (APX), and peroxidase (POD), polyphenol oxidase (PPO)) and upregulated the expression of stress-responsive genes: chlorophyll a-b binding protein of LHCII type 1-like (Lhcb1), ribulose bisphosphate carboxylase large chain-like (RbcL), cell wall invertase I (CWINV1), ornithine aminotransferase (OAT), and ethylene-responsive transcription factor 1 (ERF1), with the greatest upregulation observed at 50 mg/l SNPs.ConclusionOverall, foliar application of sulfur nanofertilizers in agriculture could improve productivity while minimizing the deleterious effects of salt stress on plants. Therefore, this study provides a strong foundation for future research focused on evaluating the replacement of conventional sulfur-containing fertilizers with their nanoforms to reduce the harmful effects of salinity stress and enhance the productivity of faba beans.

Characteristics of markers of ovarian reserve in women with transfusion-dependent beta thalassaemia major with a successful pregnancy outcome

Objective: Spontaneous fertility and successful pregnancies have been reported in well-chelated and transfused women with beta thalassaemia major (BTM) however majority of women are sub fertile due to hypogonadotropic hypogonadism (HH) and lack of ovulation. Little is known about the effect of iron overload on ovarian follicles and whether ovarian reserve is affected by the condition or treatment. The predictive value of markers of ovarian reserve in relation to live birth in this group of women remains unclear. The aim of this study was to characterize the markers of ovarian reserve in women with transfusion-dependent beta thalassaemia major who had at least one successful live birth. Study design: This is a retrospective study in which we collected data from 12 women with transfusion-dependent BTM and at least one successful live birth from our thalassaemia clinic between July 2007 to June 2022. Patient demographics, medical history, menstrual history, hormonal parameters (serum levels of FSH, oestradiol, TSH and AMH) and antral follicle count were recorded. Serum levels of ferritin, cardiac T2*, liver iron concentration and thyroid function results were recorded from clinic visit prior to either natural conception or assisted conception treatments. Results: There was a wide variation in serum levels of AMH and antral follicle counts amongst women with BTM who had a successful live birth. Low serum AMH levels were noted in 4 women with HH with a background of BTM (33.3%) as compared to the established normal ranges for women of similar age. Also, low AFC counts were noted in 7 women (out of which 6 had HH) with BTM (58.3%) as compared to the established normal ranges for women of similar age. Conclusion: Levels of serum AMH and antral follicle counts appeared lower in up to half the women with BTM and hypogonadotropic hypogonadism with a successful live birth as compared to established normal ranges for women of similar age suggesting that these markers may not accurately reflect the ovarian reserve for all in this group of women. There are limited data about the predictive value of contemporary markers ovarian reserve such as serum AMH and AFC levels in predicting successful fertility or pregnancy outcomes in women with transfusion dependent BTM and larger studies are needed.

Vaginal microbiota and fertility: an integrative review

The vaginal microbiota is made up of countless microorganisms that help to make it healthy and resistant to invasion by pathobionts, and studies suggest that there is an association between fertility and the balance/unbalance of this microenvironment. The aim of this study was to learn more about the vaginal microbiota and its influence on female (in)fertility. This is an integrative review guided by the steps of the PRISMA flowchart, searching for scientific articles in the BVS, Nature, PubMed and Scielo databases published in the years 2018-2022, in Portuguese, English and Spanish. Inclusion and exclusion criteria were used, and they were categorized into levels of evidence. This review consisted of twelve articles which show that vaginal dysbiosis causes changes in the metabolome of this environment, triggering inflammatory activation, which impacts on female fertility. In this sense, there is a need for further research into the interaction of microorganisms with each other and with male gametes, in eubiosis and vaginal dysbiosis, in order to facilitate or restrict their passage to the uterus and achieve successful fertilization.

Factors influencing variation in reproduction in invasive species: a case study of the Asian shore crab Hemigrapsus sanguineus

Reproductive success is a strong determinant of invasive species success. It is common for studies on invasive species to assess reproduction by measuring size-specific fecundity and scaling this up using population size or densities. Yet, reproductive success is influenced by numerous factors that are not accounted for in such calculations. We examined the influence of several factors on fecundity (clutch size) and egg size in the Asian shore crab Hemigrapsus sanguineus, including body size, spatial variation throughout the invaded range, season, fertilization success, brood loss, and diet. We show that all of these factors influence reproduction simultaneously within the invaded North American range of this species, though the relative importance of these different factors varied across sites or sampling times. Our study demonstrates that numerous factors may influence the reproductive success of invasive species and that studies that rely on fecundity measured at a single place and time, or that ignore factors such as offspring quality or brood loss, may provide a skewed picture of reproduction, and thus of potential invasive success.

Effects of thyroxin and luteinizing hormone releasing hormone on reproductive physiology of Rohu (Labeo rohita): Insights into spawning performance, oocyte maturation, steroidogenesis, and follicular development genes

As the global aquaculture industry grows, attention is increasingly turning towards assisted reproductive technologies. In this study, we examined the impact of D-Ala6, Pro9-Net-mGnRH (LHRHa: 0.4 mL/kg) and two doses (1 and 10 μg/kg fish) of thyroxin (T4) administered through a single injection on oocyte maturation, spawning performance, sex steroid hormone levels, as well as the expression of genes related to steroidogenesis and follicle development (ZP2, Cyp19a1a and SF-1) in Rohu (Labeo rohita). The study found that untreated female Rohu did not spawn, while those treated with LHRHa and thyroxin ovulated and spawned across a hormonal gradient. The highest spawning success was observed with a thyroxin dosage of 10 µg/kg (no significant change with a dose of 1 μg/kg), and female latency period decreased with increasing dosage. Additionally, females treated with thyroxin exhibited significantly higher fecundity than other experimental groups. Treatment with LHRHa and two doses of thyroxin significantly increased the gonadal somatic index compared to the control and sham groups. Hormonal treatment also led to increased fertilization success, hatching rate, and larval survival. At 12 h post-injection, females treated with thyroxin exhibited a significant decline in estradiol levels and expression of Zp2, Cyp19a1a, and SF-1 compared to other experimental groups. Levels of DHP significantly increased across the hormonal gradient. Histological analyses supported a steroidogenic shift, where oocyte maturation was accelerated by hormone administration, particularly with both doses of thyroxin. In conclusion, the findings suggest that thyroxin is a recommended treatment for assisted reproduction of Rohu due to its ability to induce spawning, increase fecundity and improve larval survival.

Proteomic analysis reveals dynamic changes in cloacal fluid composition during the reproductive season in a sexually promiscuous passerine

Cryptic female choice (CFC) is a component of postcopulatory sexual selection that allows females to influence the fertilization success of sperm from different males. While its precise mechanisms remain unclear, they may involve the influence of the protein composition of the female reproductive fluids on sperm functionality. This study maps the protein composition of the cloacal fluid across different phases of female reproductive cycle in a sexually promiscuous passerine, the barn swallow. Similar to mammals, the protein composition in the female reproductive tract differed between receptive (when females copulate) and nonreceptive phases. With the change in the protein background, the enriched gene ontology terms also shifted. Within the receptive phase, distinctions were observed between proteomes sampled just before and during egg laying. However, three proteins exhibited increased abundance during the entire receptive phase compared to nonreceptive phases. These proteins are candidates in cryptic female choice, as all of them can influence the functionality of sperm or sperm-egg interaction. Our study demonstrates dynamic changes in the cloacal environment throughout the avian breeding cycle, emphasizing the importance of considering these fluctuations in studies of cryptic female choice.

Ecotoxicty of 3D printing material Polylactic Acid (PLA) on sea urchin Paracentrotus lividus

In this study the ecotoxicity of 3D printing material [polylactic acid (PLA) investigated with marine echinoderm; sea urchin Paracentrotus lividus. To achieve this goal, (i) fertilization success, spermiyotoxicity and embriyotoxicity exposed to PLA concentrations (0.001, 0.005, 0.01, 0.1 and 1 g/L) were assessed for 72 h. For this purpose, our study is important to make comprehensive evaluations to ensure the safety of bioplastic formulations and to take measures to regulate the use of additives. At the same time, the additive used to increase the durability of bioplastic materials will also allow us to understand the long-term effects on ecosystems, wildlife and human health. Our aim is to minimize possible harm and ensure that the overall environmental impact of bioplastics remains positive.

Modeling Fertilization Outcome in a Changing World.

Marine organisms have complex life histories. For broadcast spawners, successful continuation of the population requires their small gametes to make contact in the water column for sufficiently long periods for fertilization to occur. Anthropogenic climate change has been shown to impact fertilization success in various marine invertebrates, including sea urchins, which are key grazers in their habitats. Gamete performance of both sexes declined when exposed to elevated temperatures and/or pCO2 levels. Examples of reduced performance included slower sperm swimming speed and thinning egg jelly coat. However, such responses to climate change stress were not uniform between individuals. Such variations could serve as the basis for selection. Fertilization kinetics have long been modeled as a particle collision process. Here, we present a modified fertilization kinetics model that incorporates individual variations in performance in a more environmentally relevant regime, and which the performance of groups with different traits can be separately tracked in a mixture. Numerical simulations highlight that fertilization outcomes are influenced by changes in gamete traits as they age in sea water and the presence of competition groups (multiple dams or sires). These results highlight the importance of considering multiple individuals and at multiple time points during in vivo assays. We also applied our model to show that interspecific variation in climate stress vulnerabilities elevates the risk of hybridization. By making a numerical model open-source, we aim to help us better understand the fate of organisms in the face of climate change by enabling the community to consider the mean and variance of the response to capture adaptive potential.

To Assess or Not to Assess: Reconsidering Day 3 Embryo Quality in Planned Freeze-All Blastocyst Cycles.

Day 3 embryo quality is a predictor of in vitro fertilization (IVF) success rates in cleavage-stage embryo transfer. However, the association between day 3 embryo quality and clinical outcomes in blastocyst transfer policy is largely unknown. This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfers between January 2019 and December 2022. Three groups were assessed depending on whether the transferred blastocyst derived from a top-quality, good-quality, or poor-quality embryo at day 3. The analysis was conducted independently for each blastocyst quality group (top, good, and poor) using multivariable logistic regression. We applied a Factorial Analysis of Mixed Data (FAMD) to reduce the potential collinearity between the covariates used in the model. All the blastocysts included in this study were obtained from the first ICSI freeze-all cycles. The cleavage and blastocysts stages were assessed between 67 ± 0.5 (day 3), 115 ± 0.5 (day 5), and 139 ± 0.5 (day 6) hours post-insemination (hpi), respectively. After adjusting for the day of transfer (day 5 or day 6) and FAMD dimensions, no statistical differences in a β-HCG, clinical pregnancy, and live birth were observed among the same-quality blastocysts derived from different day 3 embryo quality groups (top = A, good = B, and poor = C). Our findings showed that a day 3 embryo quality assessment may be unnecessary in planned freeze-all blastocyst cycles.

Nitrogen fertilizer replacement value of stockpiled and rotted dairy cattle manures for corn (Zea mays L.) from a long-term study

Context or problemAnimal manure is an excellent renewable source of plant nutrients, but the correct quantification of nutrient equivalents is affected by manure type and application rate as well as weather conditions that impact crop yields Objective or research questionThe objectives from a 32-year field experiment were to (1) compare the effects of mineral N fertilization and solid dairy cattle manure on corn grain yield; (2) determine the manure N fertilizer replacement value (NFRV), and (3) quantify environmental factors, mainly the impact of total precipitation during the critical period (silking) on corn yield and manure NFRV. MethodsA field experiment under continuous corn with annual manure application was conducted over 32 years in Ottawa, Ontario, Canada. Corn yield data were categorized into low, intermediate, and high N response groups. ResultsOn an equivalent amount of manure organic N basis, NFRVs were, on average, 0.38 (±0.02) for stockpiled manure (SM) and 0.27 (±0.02) for incompletely composted or rotted manure (RM), with a wide range of 0.12 (±0.02), 0.28 (±0.02), and 0.37 (±0.04) for RM, and 0.16 (±0.04), 0.39 (±0.03), and 0.48 (±0.04) for SM under the low, intermediate, and high N response conditions, respectively. Supplementing 100 kg synthetic fertilizer N ha−1 in low RM (50 Mg ha−1 fresh weight; f.w.), and 50 kg fertilizer N ha−1 in high RM (100 Mg ha−1 f.w.) application rates decreased NFRVs under low and intermediate N response conditions, whereas the addition of similar synthetic N in the corresponding SM rates reduced NFRVs only under low N response conditions. ConclusionsBased on the 32-year long-term study, we documented that the maximum economic synthetic N fertilizer rates for continuous corn cropping varied from 117 to 179 kg N ha−1 under the low N response, from 127 to 283 kg N ha−1 under the intermediate N response, and from 227 to 289 kg N ha−1 under the high N response conditions. The NFRVs of solid cattle manures varied according to corn yield-N response levels. Implications or significanceOur findings showed that the response of corn yields to manure NFRV depends on the level of yield-N response and climatic conditions. It also indicated the importance of soil organic amendments for improving the climate resilience of corn production, while simultaneously meeting the demand for more sustainable nutrient management of soil resources.

Influence of Tank Water Depths on Reproductive Performance of Catfish (Heterobranchus longifilis) Valenciennes, 1840

Aims: To determine the optimum water depth required for catfish spawning in hatcheries. Study Design: Treatments were assigned using complete randomized design. Place and Duration of Study: Fish Farm Complex of the Akwa Ibom State University (AKSU), Nigeria. Methodology: Eighteen (18) similarly-sized H. longifilis broodstock (2.51-2.53 kg, 64 – 66 cm): comprising six broodstock of three males and three females, were held for six months at 0.50 m, 0.75 m and 1.0 m pond water depth. All males were sacrificed for milt extraction without hormonal inducement; with milt from each treatment diluted with normal saline solution. Female broodstock from each treatment were separately induced with ovaprim hormones at a single dosage of 0.5ml/kg body weight of fish and allowed for 16 hours before manual stripping; 3g of egg from each broodstock and mixed with the diluted milt and activated with 100 ml of normal saline. The fertilized eggs were incubated and thereafter assessed for percentage fertilization, hatchability, survival and fry production success. Results: broodstock reproductive parameters significantly increased (P = 0.00) with water depth of broodstock culture tank. Percentage fertilizations were: 49.50±0.78, 68.17±0.93, and 82.50±1.44; respectively. Percentage hatchability of broodstock eggs were: 91.37±1.65 significantly higher for 1.0 m water depth group than 67.79±4.58 from 0.75 m water depth treatment while the least value of hatchability 50.31± 0.78 was recorded for broodstock raised at 0.50 m water depth. The fish group raised at 1.0 m water depth also exhibited highest percentage survival value of 97.02 ± 1.09 and fry production success value of 73.08 ± 0.53 while broodstock raised at 0.50 m water depth indicated the least values: % survival, 8.38 ± 0.48 and fry production success of 2.07 ± 0.07. Conclusion: In times or places of water scarcity, H. longifilis broodstock may be raised at pond water of 0.5 m to 1.0 m. But the water depth that would afford the best breeding and reproductive performance is at 1.0 m depth.

The Impact of Embryo Quality on Pregnancy Outcomes in Single Day 5 versus Day 6 Euploid Blastocyst Transfer: A Retrospective Cohort Study.

Selecting embryos with the highest implantation potential is crucial for in vitro fertilization (IVF) success. Both the timing of blastulation, day 5 (D5) or D6, and the embryo quality have been suggested as influential factors in determining the clinical outcome of single euploid blastocyst transfers. However, evidence supporting the superiority of D5 over D6 blastocysts remains inconclusive. The aim of this study was to compare clinical outcomes following the transfer of euploid blastocysts with different quality and timing of blastulation. A retrospective cohort study was conducted at our Assisted Reproductive Center, analyzing the outcome of 774 transfers with D5 euploids and 155 transfers with D6 euploids performed between January 2019 and February 2022. The live birth rate was significantly lower in the euploid D6 group compared to the euploid D5 group (38.71vs. 55.04%, P=0.001). The outcome was significantly influenced by the quality of the embryos. Live birth rates were 62.14 and 53.61% following transfers of D5 and D6 excellent embryos respectively, 45.18 and 32.21% following transfer of D5 and D6 good embryos but only 28.64 and 19.32% following transfer of D5 and D6 fair embryos. The outcome difference was statistically significant across embryo quality categories (P=0.001). The adjusted risk ratios (RR) of clinical outcomes indicated that excellent euploid D5 embryos consistently outperformed other types of embryo quality. The timing of blastulation and embryo quality are crucial factors in determining the success of single euploid blastocyst transfers. Excellent euploid D5 transfers yielded superior clinical outcomes, providing valuable insights for IVF teams and patients when selecting embryos to be transferred.

Effect of Partial Substitution of Chemical Fertilizers with Organic Fertilizers on N2O and NO Emissions from a Peach Orchard

Organic fertilizer substitution has been promoted as a weight loss, efficient, and diversified fertilizer substitution technology in agricultural production. However, there is a lack of comprehensive assessment of the impact of organic fertilizers on N2O and NO emissions from orchards. In this study, N2O and NO emissions from peach orchards were observed annually using static dark box-gas chromatography to compare the effects of chemical fertilizer application alone and partial replacement of chemical fertilizer treatment on NO emissions from peach orchards. The results showed that the partial replacement of chemical fertilizers with organic fertilizers reduced the total N2O and NO emissions from peach orchards by 15.0 % and 9.4 %, respectively. The N2O and NO emission factors were reduced by 21.3 % and 21.1 %. The mineral N content of the soil in the organic fertilizer treatment was lower than that in the chemical fertilizer treatment alone. The organic fertilizer treatment increased the contribution of AOA to nitrification and decreased the contribution of AOB, thus reducing N2O and NO from nitrification. In addition, the results of the dual isotope mixing model[δ18O(N2O/H2O) vs. δ15NSP] indicated that the bacterial denitrification/nitrifying bacterial denitrification (bD/nD) process served as the primary pathway for N2O emissions in peach orchards. Partial substitution with organic fertilizers enhanced soil denitrification, resulting in larger reductions in the amounts of N2O and NO. Therefore, partial substitution of organic fertilizer is a viable measure to mitigate nitrogen oxide emissions from orchards and to achieve green and low-carbon development in agriculture.

Predicting personalized cumulative live birth rate after a complete in vitro fertilization cycle: an analysis of 32,306 treatment cycles in China

BackgroundThe cumulative live birth rate (CLBR) has been regarded as a key measure of in vitro fertilization (IVF) success after a complete treatment cycle. Women undergoing IVF face great psychological pressure and financial burden. A predictive model to estimate CLBR is needed in clinical practice for patient counselling and shaping expectations.MethodsThis retrospective study included 32,306 complete cycles derived from 29,023 couples undergoing IVF treatment from 2014 to 2020 at a university-affiliated fertility center in China. Three predictive models of CLBR were developed based on three phases of a complete cycle: pre-treatment, post-stimulation, and post-treatment. The non-linear relationship was treated with restricted cubic splines. Subjects from 2014 to 2018 were randomly divided into a training set and a test set at a ratio of 7:3 for model derivation and internal validation, while subjects from 2019 to 2020 were used for temporal validation.ResultsPredictors of pre-treatment model included female age (non-linear relationship), antral follicle count (non-linear relationship), body mass index, number of previous IVF attempts, number of previous embryo transfer failure, type of infertility, tubal factor, male factor, and scarred uterus. Predictors of post-stimulation model included female age (non-linear relationship), number of oocytes retrieved (non-linear relationship), number of previous IVF attempts, number of previous embryo transfer failure, type of infertility, scarred uterus, stimulation protocol, as well as endometrial thickness, progesterone and luteinizing hormone on trigger day. Predictors of post-treatment model included female age (non-linear relationship), number of oocytes retrieved (non-linear relationship), cumulative Day-3 embryos live-birth capacity (non-linear relationship), number of previous IVF attempts, scarred uterus, stimulation protocol, as well as endometrial thickness, progesterone and luteinizing hormone on trigger day. The C index of the three models were 0.7559, 0.7744, and 0.8270, respectively. All models were well calibrated (p = 0.687, p = 0.468, p = 0.549). In internal validation, the C index of the three models were 0.7422, 0.7722, 0.8234, respectively; and the calibration P values were all greater than 0.05. In temporal validation, the C index were 0.7430, 0.7722, 0.8234 respectively; however, the calibration P values were less than 0.05.ConclusionsThis study provides three IVF models to predict CLBR according to information from different treatment stage, and these models have been converted into an online calculator (https://h5.eheren.com/hcyc/pc/index.html#/home). Internal validation and temporal validation verified the good discrimination of the predictive models. However, temporal validation suggested low accuracy of the predictive models, which might be attributed to time-associated amelioration of IVF practice.

Multiple paternity, fertilization success, and male quality: Mating system variation in the eelgrass, Zostera marina.

Genetic diversity can modulate a population's response to a changing environment and plays a critical role in its ecological function. While multiple processes act to maintain genetic diversity, sexual reproduction remains the primary driving force. Eelgrass (Zostera marina) is an important habitat-forming species found in temperate coastal ecosystems across the globe. Recent increases in sea surface temperatures have resulted in shifts to a mixed-annual life-history strategy (i.e., displaying characteristics of both annual and perennial meadows) at its southern edge-of-range. Given that mating systems are intimately linked to standing levels of genetic variation, understanding the scope of sexual reproduction can illuminate the processes that shape genetic diversity. To characterize edge-of-range eelgrass mating systems, developing seeds on flowering Z. marina shoots were genotyped from three meadows in Topsail, North Carolina. In all meadows, levels of multiple mating were high, with shoots pollinated by an average of eight sires (range: 3-16). The number of fertilized seeds (i.e., reproductive success) varied significantly across sires (range: 1-25) and was positively correlated with both individual heterozygosity and self-fertilization. Outcrossing rates were high (approx. 70%) and varied across spathes. No clones were detected, and kinship among sampled flowering shoots was low, supporting observed patterns of reproductive output. Given the role that genetic diversity plays in enhancing resistance to and resilience from ecological disturbance, disentangling the links between life history, sexual reproduction, and genetic variation will aid in informing the management and conservation of this key foundation species.

The surprising complexity and diversity of sperm storage structures across Galliformes.

In internal fertilisers, the precise timing of ovulation with the arrival of sperm at the site of fertilisation is essential for fertilisation success. In birds, mating is often not synchronised with ovulation, but instead females utilise specialised sperm storage tubules (SSTs) in the reproductive tract, which can ensure sperm are always available for fertilisation at the time of ovulation, whilst simultaneously providing a mechanism of post-copulatory sexual selection. Despite the clear importance of SSTs for fertilisation success, we know little about the mechanisms involved in sperm acceptance, storage, and release. Furthermore, most research has been conducted on only a small number of species, based on which SSTs are usually assumed to look and function in the same way across all species. Here, we conduct a comparative exploration of SST morphology across 26 species of Galliformes. We show that SSTs, and the surrounding tissue, can vary significantly in morphology across species. We provide observational evidence that Galliformes exhibit at least 5 distinct categories of tubule types, including distinctive coiled and multi-branched tubules, and describe 2 additional features of the surrounding tissue. We suggest functional explanations for variation in tubule morphology and propose next steps for future research. Our findings indicate that SSTs are likely to be far more variable than has previously been assumed, with potentially important consequences for our understanding of sperm storage in birds and post-copulatory sexual selection in general.

Bulked Segregant RNA-Seq Analysis of Pollinated Pistils Reveals Genes Influencing Spikelet Fertility in Rice

Prezygotic isolation is important for successful fertilization in rice, significantly affecting yield. This study focused on F5:6 generation plants derived from inter-subspecific crosses (Nipponbare × KDML105) with low (LS) and high seed-setting rates (HS), in which normal pollen fertility was observed. However, LS plants showed a reduced number of pollen grains adhering to the stigma and fewer pollen tubes reaching the ovules at 4‒5 h post-pollination, compared with HS plants. Bulked segregant RNA-Seq analysis of pollinated pistils from the HS and LS groups revealed 249 and 473 differentially expressed genes (DEGs), respectively. Kyoto Encyclopedia of Genes and Genomes analysis of the HS and LS- specific DEGs indicated enrichment in metabolic pathways, pentose and glucuronate interconversions, and flavonoid biosynthesis. Several of these DEGs exhibited co-expression with pollen development genes and formed extensive clusters of co-expression networks. Compared with LS pistils, enzyme genes controlling pectin degradation, such as OsPME35 and OsPLL9, showed similar expression patterns, with higher levels in HS pistils pre-pollination. Os02g0467600, similar to cinnamate 4-hydroxylase gene (CYP73), involved in flavonoid biosynthesis, displayed higher expression in HS pistils post-pollination. Our findings suggest that OsPME35, OsPLL9, and Os02g0467600 contribute to prezygotic isolation by potentially modifying the stigma cell wall (OsPME35 and OsPLL9) and controlling later processes such as pollen-stigma adhesion (Os02g0467600) genes. Furthermore, several DEGs specific to HS and LS were co-localized with QTLs and functional genes associated with spikelet fertility. These findings provide valuable insights for further research on rice spikelet fertility, ultimately contributing to the development of high-yielding rice varieties.

Effect of exogenous sperm capacitation inducers on stallion sperm

Although under appropriate laboratory conditions, sperm from different mammalian species can be capacitated in vitro, the optimal conditions for sperm capacitation in the stallion have been elusive. This study evaluated the effect of different capacitating inducers in Whitten and Tyrode media and assessed their impact on capacitation-related factors. Stallion sperm were incubated with different combinations of capacitating inducers at 38.5 °C in an air atmosphere. Sperm quality variables such as motility, mitochondrial membrane potential, and lipid peroxidation were assessed. Membrane fluidity and intracellular calcium levels were evaluated as early markers of capacitation, while tyrosine phosphorylation events and the sperm's ability to perform acrosomal exocytosis were used as late capacitation markers. Finally, these sperm were evaluated using a heterologous zona pellucida binding assay. The findings confirm that capacitating conditions evaluated increase intracellular calcium levels and membrane fluidity in both media. Similarly, including 2 or 3 inducers in both media increased tyrosine phosphorylation levels and acrosomal exocytosis after exposure to progesterone, confirming that stallion sperm incubated in these conditions shows cellular and molecular changes consistent with sperm capacitation. Furthermore, the zona pellucida binding assay confirmed the binding capacity of sperm incubated in capacitation conditions, a key step for stallion in vitro fertilization success. Further studies are needed to evaluate the effect of these conditions on in vitro fertilization in the horse.

Temperature dependence of pollen germination and tube growth in conifers relates to their distribution along an elevational gradient in Washington State, USA.

Pollen germination and tube growth are essential processes for successful fertilization. They are among the most temperature-vulnerable stages and subsequently affect seed production and determine population persistence and species distribution under climate change. Our study aims to investigate intra- and inter-specific variations in the temperature dependence of pollen germination and tube length growth and to explore how these variations differ for pollen from elevational gradients. We focused on three conifer species, Pinus contorta, Picea engelmannii, and Pinus ponderosa, with pollen collected from 350 to 2200m elevation in Washington State, USA. We conducted pollen viability tests at temperatures from 5 to 40°C in 5°C intervals. After testing for four days, we took images of these samples under a microscope to monitor pollen germination percentage (GP) and tube length (TL). We applied the Gamma function to describe the temperature dependence of GP and TL and estimated key parameters, including the optimal temperature for GP (Topt_GP) and TL (Topt_TL). Results showed that pollen from three species and different elevations within a species have different GP, TL, Topt_GP, and Topt_TL. The population with a higher Topt_GP would also have a higher Topt_TL, while Topt_TL was generally higher than Topt_GP, i.e., a positive but not one-to-one relationship. However, only Pinus contorta showed that populations from higher elevations have lower Topt_GP and Topt_TL and vice versa. The variability in GP increased at extreme temperatures, whereas the variability in TL was greatest near Topt_TL. Our study demonstrates the temperature dependences of three conifers across a wide range of temperatures. Pollen germination and tube growth are highly sensitive to temperature conditions and vary among species and elevations, affecting their reproduction success during warming. Our findings can provide valuable insights to advance our understanding of how conifer pollen responds to rising temperatures.