Search Results (164)

The undertaking of distant hybridization holds paramount significance for the innovation of tea germplasm resources and the cultivation of superior, specialized tea varieties. However, challenges manifest during the process of tea plant distant hybridization breeding, with reproductive barriers impeding the successful acquisition of hybrid progeny; the precise stages at which these barriers occur remain unclear. In this study, utilizing Camellia sinensis cv. Jinxuan as the maternal parent, as well as C. gymnogyna Chang and C. sinensis cv. Yinghong No.9 as the paternal parents, interspecific distant hybridization (DH) and intraspecific hybridization (IH) were conducted. The investigation involved the observation of pollen germination and pollen tube behavior on the stigma, the scrutiny of the developmental dynamics of the ovary post-hybridization, and the examination of the stages and reasons for reproductive disorders during tea tree distant hybridization. The findings indicate that both IH and DH exhibit pre-fertilization barriers. The pre-embryonic development of hybrids obtained from DH is normal, but there is a significant fruit drop during the stage of fruit development. The germination rate of mature seeds obtained from DH is low, and there are pronounced post-fertilization disorders, which are the primary reasons for the difficulty in achieving successful tea plant distant hybridization. An analysis of the genetic variation in phenotypes and chemical components in the progeny after distant hybridization revealed widespread variation and rich genetic diversity. The identification of progeny with a high amino acid and caffeine content holds promise for future production and breeding, providing valuable theoretical references for the selection of parents in the creation of low-caffeine-content tea germplasm resources. Full article

We report the development of a procedure for ultrasound-assisted microscale extraction of metabolites from the flowers of Saint John’s wort (Hypericum perforatum L.), designed for comparative metabolite analysis of plants from genetic resource collections and natural and segregating populations. The procedure involves high-throughput methanol extraction of metabolites from ground-frozen flowers at a selected stage of flower development, which is carried out in a standard 2 mL Eppendorf tube. A total of 18 compounds, including chlorogenic acid, catechins, glycosylated flavonoids, hypericins, and hyperforin, were identified based on LC/DAD/QTOF analysis, of which 16 could be detected in the UV-Vis spectrum. Two alternative versions of the procedure were evaluated: the “single-flower” procedure, including repeated collection and analysis of single flowers from the tested plant, and the “bulk-flower” procedure, employing the collection of a bulk flower sample from the tested plant and analysis of a portion of the ground sample. The results showed excellent technical reproducibility of the “single-flower” procedure when used with the suggested combination of the peak areas for the proto- and stable forms of pseudohypericin and hypericin. Application of the developed “single-flower” procedure for comparison of the plants derived from seed progeny of the apomictic line Hp93 revealed significantly lower metabolite variation among the apomictic progeny plants compared to the variation observed among plants belonging to different genotypes. Full article

The cotton-growing region in Southern Xinjiang is plagued by perennial drought and water scarcity, and there is a lack of research on the irrigation mechanism for the “one film, three tubes, four rows” new model of dry sowing and wet emergence of cotton. Therefore, this experiment explores the optimal irrigation regime for cotton under the “one film, three tubes, four rows” planting model in Southern Xinjiang, where a two-year field plot experiment was conducted. Three irrigation levels (W1: 360 mm, W2: 450 mm, W3: 540 mm) were set, with three replications each, to study the effects of different irrigation amounts on cotton growth, soil water content (SWC), irrigation water productivity (IWP), water productivity (WP), and yield (Y). Additionally, the AquaCrop model was used to optimize the irrigation regime. The results showed that irrigation amount significantly affected cotton growth, with plant height, stem diameter, and leaf area index following the order of W3 > W2 > W1. Compared to W1 and W2 treatments, the final biomass (B) and average SWC in the W3 treatment increased by 32.71%, 19.59% and 8.26%, 3.23%, respectively. The seed cotton yield under the W3 treatment was significantly higher than other treatments, being 6575.91 kg/ha in 2023 and 7252.16 kg/ha in 2024. IWP and WP were inversely related to irrigation amount. After two years of data calibration and validation, the model showed good simulation performance for canopy cover (CC), B, WP, and Y (with a concordance index d ≥ 0.904 and a coefficient of determination R² ≥ 0.846). Among the 11 simulated irrigation scenarios (ranging from 360 to 660 mm in 30 mm increments), yield increased with irrigation amount but began to decline slowly beyond 570 mm, peaking at 7.45 t/ha, with IWP and WP being 1.307 kg/m³ and 1.294 kg/m³, respectively. Considering both water conservation and yield increase, an irrigation level or amount of 570 mm under the one-film, three-pipe, four-row planting pattern for dry sowing, wet emergence cotton in Southern Xinjiang can achieve good yields, benefiting the sustainable production of the local cotton industry. Full article

Paeonia ludlowii is a threatened and valuable germplasm in the cultivated tree peony gene pool, with distinctive traits such as tall stature, pure yellow flowers, and scarlet foliage in autumn. However, the crossability barrier limits gene transfer from P. ludlowii to cultivated tree peony. Therefore, our study investigated the reasons for the lack of crossability between P. ludlowii and Paeonia ostii ‘Fengdan’. Distant cross pollination (DH) resulted in the formation of many calloses at the ends of the pollen tubes, which grew non-polar, twisted, entangled, and often stopped in the style. Pollen tubes elongated the fastest in self-pollination (CK), and pollen tubes elongated faster and fewer pollen tube abnormalities were observed in stigmas treated with KCl solution before pollination (KH) than in DH. During pollen–pistil interactions, the absence of stigma exudates, high levels of H₂O₂, O₂⁻, MDA, ^•OH, ABA, and MeJA, and lower levels of BR and GA₃ may negatively affect pollen germination and pollen tube elongation in the pistil of P. ostii ‘Fengdan’. Pollen tubes in CK and KH penetrated the ovule into the embryo sac at 24 h after pollination, whereas only a few pollen tubes in DH penetrated the ovule at 36 h after pollination. Pre-embryo abnormalities and the inhibition of free nuclear endosperm division resulted in embryo abortion in most of the fruits of DH and many fruits of KH, which occurred between 10 and 20 days after pollination, whereas embryos in CK developed well. Early embryo abortion and endosperm abortion in most of the fruits of DH and KH led to seed abortion. Seed abortion in KH and DH was mainly due to an insufficient supply of auxins and gibberellins and lower content of soluble protein and soluble sugars. The cross failure between P. ludlowii and P. ostii ‘Fengdan’ is mostly caused by a pre-fertilization barrier. KH treatment can effectively promote pollen tube growth and facilitate normal development of hybrid embryos. These findings provide new insights into overcoming the interspecific hybridization barrier between cultivated tree peony varieties and wild species. Full article

In view of the problem that the qualified index of grain spacing deteriorates during high-speed operation of the pneumatic corn seed dispenser, a new method of homologous dual-action positive-pressure-assisted seed filling and seed release is proposed, and a pneumatic corn seed dispenser with assisted inflow filling is designed. The structure and working principle of the seed dispenser are explained, and a theoretical analysis is carried out on the seed filling and seed release process in the seed guide tube. The key structural parameters of the conical deflector-groove seed metering disc and the homologous airflow-assisted seed release mechanism are determined. The test factors were working pressure and operating speed, and the evaluation indicators were the qualified particle spacing index, missed sowing index, resowing index, and qualified particle spacing variation coefficient. A full-factor bench test was carried out, and the test results showed that when the sowing speed was 6 km/h and the working pressure was 5 kPa, the qualified particle spacing index was 96.37%, the missed sowing index was 0.30%, the resowing index was 3.33%, and the coefficient of variation in the qualified particle spacing was 17.37%. The results of the field test showed that when the operating speed was 6 km/h and the working pressure was 5 kPa, the qualified particle spacing index was 95.30%, the missed sowing index was 2.33%, and the resowing index was 2.37%. All indicators met the technical requirements for precision single-seed maize sowing. Full article

Onion (Allium cepa L.) plants produce umbellate inflorescences that bear dozens of hermaphrodite flowers. Outcrossing is encouraged by a strong protandrous dichogamy. Honeybees are reported as the most suitable pollinator for this crop due to their efficiency in pollen transfer. However, bee activity does not always guarantee pollination success and an adequate seed set. This work aimed to analyze the developmental changes of the pistil along the flower lifespan to determine the reasons for common failures in the onion seed set. Studies were carried out in two productive seasons, in a male sterile line and a fertile line, using two different pollination procedures. The results showed that the stigma papillae did not fully develop until 4 days after anthesis (DAA), reducing the stigma receptivity to only 4 days. The style did not reach its maximum length until 8 DAA, when ovule fertility was achieved. Eight days were needed for the pollen tube to grow, reach, and fertilize the ovules. The results were consistent over two consecutive years. The short period of stigmatic receptivity and strong protandrous dichogamy limit the duration of the effective pollination period and could explain the poor cropping performance in obtaining seeds from some onion hybrid lines. Full article

During high-speed corn sowing at 10 km/h, the rapid seed discharge resulting from the high rotation speed of the seed disc escalates the impact force of seeds as they are released from the seed metering device into the seed guiding apparatus, consequently diminishing the overall seeding efficiency of the seeder. This study employed high-speed videography to conduct experiments and optimize parameters for the seed-receiving mechanism of a belt-driven seed guide tube. By changing the clamping wheel speed and seed-receiving angle, the speed change curve and displacement trajectory of seeds under different conditions were obtained and analyzed. The findings demonstrate that the seed speed fluctuation is more stable, and the seed displacement trajectory achieves greater stability at a clamping wheel speed of 560 r·min⁻¹. When the seed-receiving angle is set at 85°, the seed speed fluctuation becomes less apparent, resulting in a smoother seed displacement trajectory. Finally, the experimental results of high-speed cameras are confirmed by field tests. The findings of this study can act as a theoretical basis for the further optimization of the experimental belt-driven seed guide tube. Full article

This study investigates the impact of Aerated Subsurface Drip Irrigation (ASDI) on the growth and yield of mulched cotton, aiming to identify the optimal water-air combination pattern for ASDI in cotton cultivation. Conducted during 2021–2022, the experimental setup involved two aeration modes (aerated A₁ and unaerated A₀) and four irrigation quotas (W₁, W₂, W₃, and W₄), organized in a two-factor randomized block design resulting in eight distinct treatments. The findings revealed that ASDI significantly promoted soil moisture depletion from 0 to 40 cm during the cotton flowering and boll opening stages. Specifically, aerated A₁ reduced soil water content by 5.84% to 7.83% during the flowering stage and 7.45% to 13.39% during the boll opening stage compared to unaerated A₀. Additionally, both aerating and increasing irrigation quotas not only enhanced the cotton leaf area index (LAI) but also delayed leaf area decay, contributing to prolonged photosynthetic activity. Aerating also favorably influenced the distribution of above-ground biomass in cotton towards budding and boll stages, with the biomass share of buddings, flowers, and bolls averaging 62.98% under aerated conditions versus 62.27% under non-aerated conditions during the boll opening stage. Furthermore, aerating combined with increased irrigation quotas resulted in higher seed cotton yields, with aerated irrigation boosting yields by 1.79% in 2021 and 4.43% in 2022 compared to non-aerated irrigation. This approach also increased cotton’s water demand and average daily water consumption significantly (p < 0.01). Importantly, aerating improved IWUE, achieving 1.72 kg/m³ in 2021 and 1.62 kg/m³ in 2022 for ASDI, versus 1.69 kg/m³ and 1.57 kg/m³ for unaerated subsurface drip irrigation, respectively. In conclusion, from a water conservation and yield enhancement perspective, an irrigation quota of 337.4 mm during the reproductive stage under ASDI is recommended as an effective strategy for “one film three tubes and six rows” mulched cotton in Southern Xinjiang. Full article

Successful pollination and fertilization are crucial for grain setting in cereals. Wheat is an allohexaploid autogamous species. Due to its evolutionary history, the genetic diversity of current bread wheat (Triticum aestivum) cultivars is limited. Introducing favorable alleles from related wild and cultivated wheat species is a promising breeding strategy for resolving this issue. However, wide hybridization between bread wheat and its relatives is hampered by the presence of suppressor genes and difficulties in crossing. Optimized methods for observing pollen tubes are essential for understanding the mechanism of crossability between wheat and its relatives. Here, we improved the crossing procedure between bread wheat and rye (Secale cereale) and established an optimized protocol for visualizing pollen tube behavior. Crossing via detached spike culture significantly enhanced crossing efficiency and phenotypic stability. A combination of canonical aniline blue staining and optimized clearing and sectioning allowed us to visualize pollen tube behavior. The proportion of rye pollen tubes reaching the micropyle was lower than that for pollen tubes germinated on the stigmatic hair, explaining why the hybrid seed-setting rate was approximately 75% instead of 100%. This method sheds light on wide hybridization through deeper visualization of the insides of pistils. Full article

Cryopreservation protocols have not yet been defined for seeds of some Coffea species due to their high sensitivity to desiccation and to ultra-low temperatures, factors that lead to low seed survival rates after warming. This reduced rate occurs due to several factors that compromise cellular integrity during the steps of the process. In this study, we evaluated the effect of moisture content and the types of packaging on the cryopreservation of Coffea racemosa and Coffea liberica var dewevrei seeds. For that purpose, seeds were dried to moisture contents of 18, 20, and 25% (dry basis—db) for C. racemosa and to contents of 20, 25, 30, and 35% for C. liberica. The seeds were then packed in mesh bags, Falcon tubes, and triple-laminated aluminum foil pouches before being directly immersed in liquid nitrogen. Physiological and biochemical analyses were performed on the seeds. There was interaction between moisture content and the packaging of the seeds of the species. Drying the seeds to a 20% moisture content and packing them in triple-laminated aluminum foil pouches provided the best cryopreservation protocol among those studied, with survival rates of 79 and 8% for C. racemosa and C. liberica, respectively. Full article

This study proposes a positive pressure re-acceleration assisted seeding mechanism and analyzes the motion mechanism of corn seeds during the seeding process. By employing the CFD-EDEM gas-solid coupling simulation analysis method, the fluid characteristics, initial ejection velocity of seeds, seed dropping time difference, and sowing position difference in the seeding mechanism under different structural parameters of the air pressure valve body were investigated. The optimal structural parameters of the air pressure valve body were determined (nozzle gap c = 0.6 mm, throat constriction diameter d = 16 mm, and throat constriction length l = 44 mm). A multi-factor experimental method was used to explore the effects of airflow pressure, forward speed during sowing, and sowing distance on sowing performance, aiming to identify the optimal working parameters for the positive pressure re-acceleration seeding mechanism. High-speed camera technology was used to record and analyze the seed movement process. The results indicate that an increase in positive pressure within the seed guide tube shortens the sowing time of corn seeds, reduces the coefficient of variation of seed dropping time difference, and effectively improves the consistency of sowing distance. The optimal parameters are a forward speed of 8 km/h, sowing distance of 20 cm, airflow pressure of 10 kPa, with a sowing distance coefficient of variation of 7.56%, and a seed dropping time difference coefficient of variation of 5.35%. Full article

Antioxidants are essential for mitigating oxidative stress and maintaining vascular health. Endothelial colony-forming cells (ECFCs) are pivotal in endothelial regeneration and angiogenesis and serve as a model to study the diversity of endothelial cells across various organs. This study evaluated the effects of peel, pulp, and seed extracts from Diospyros digyna Jacq. fruit (black persimmon) on human cord blood-derived ECFCs (CB-ECFCs) to determine how the distinct antioxidant profiles of the fruit’s different parts influence cellular functions. The extracts did not affect endothelial marker expression, cell proliferation, or nitric oxide production, indicating no cytotoxic or inflammatory effects. However, functional assays revealed that the seed extract significantly enhanced tube formation, increasing closed tubular networks by 1.5-fold. All extracts promoted cell migration, with the seed extract demonstrating the most substantial effect, surpassing even vascular endothelial growth factor (VEGF). Additionally, the seed extract exhibited the strongest reduction in cellular senescence, both before and after oxidative stress induction with H₂O₂. These findings underscore the potential of black persimmon extracts, especially from the seed, to enhance the regenerative capabilities of CB-ECFCs and reduce cellular senescence without affecting the normal endothelial phenotype. This positions them as promising candidates for developing endothelial cell therapies and advancing vascular regeneration. Full article

Backcrossing between Sikitita and its male parent Arbequina, offers the possibility to check the suitability of different self-incompatibility models proposed for olive. To determine Sikitita’s response to self- and cross-pollination treatments, including pollination with its father Arbequina, we compared the parameters following pollen–pistil interaction, the resulting initial and final fruit set, and the paternity of the seeds produced under different crosses. The results showed that Sikitita behaves as a self-incompatible cultivar due to the inhibition of pollen tube growth in the pistil of self-pollinated flowers. This incompatibility reaction led to a significant reduction of self-fertilization and fruit set. Seed paternity analyses confirmed the self-incompatibility response of Sikitita. A similar incompatibility response was observed in Sikitita flowers when hand-pollinated with pollen of Arbequina and Koroneiki. On the contrary, cross-pollination with Arbosana gave excellent results, with analyses showing that pollen of Arbosana is largely preferred by Sikitita to father its seeds more than the pollen of other cultivars presented in the orchard. The backcross failure of Sikitita with Arbequina pollen suggests that the self-incompatibility system in olives is not of the gametophytic type. In contrast, pollination tests fit features of previously reported sporophytic self-incompatibility systems. However, some amendments are proposed, among them the incompatibility groups for Sikitita and Koroneiki. Full article

Rhododendron resources are abundant in China, and hybridization breeding technology is the primary method for cultivating Rhododendron varieties. In order to optimize the utilization of wild Rhododendron resources for distant hybridization, this study took three horticultural varieties of Rhododendron subgenus Tsutsusi and the Rhododendron decorum Franch. of the subgenus Hymenanthes as the research objects, and the cross-compatibility between subgenera was analyzed from the aspects of pollen tube growth and ovary and seed development. At the same time, the statistics of ovary swelling rate and fruit bearing rate, numbers of capsule seeds, 1000 seed weight of hybrid seeds, germination rate, green seedling rate, and other indexes were analyzed to comprehensively evaluate hybrid fertility. The results showed that there was obvious pre-fertilization and post-fertilization barriers existing in the hybridization of Rhododendron × hybridum hort. and R. decorum. During the growth of pollen tubes, a large amount of callus appeared, which led to the entanglement, distortion, and abnormal development of the pollen tubes; only part of the pollen tubes entered into the ovary or ovule. The pre-fertilization barriers can be overcome by early pollination and delayed pollination. According to the observation of the ovary paraffin section, 45 d after pollination, the seed was shriveled and developed abnormally. The comprehensive evaluation of hybrid fertility showed that ‘Sima’ × R. decorum was fertile, ‘Yin Taohong’ × R. decorum was a weakly fertile, and ‘Little Taohong’ × R. decorum was sterile. This study provided a scientific basis for intergeneric hybridization breeding between the subgenus Tsutsusi and the subgenus Hymenanthes. Full article

Previous studies on the mountain plant Ranunculus kuepferi concluded that apomictic self-compatible tetraploids have experienced a niche shift toward a colder climate during the Holocene, which suggests a fitness advantage over the sexual, self-sterile diploid parents under cold and stressful high-mountain conditions. However, there is still a lack of information on whether reproductive development would be advantageous for tetraploids. Here, we report on microsporogenesis, megagametogenesis, the dynamics of flower and seed development, and the consequences for reproductive success in a common garden experiment along a 1000 m climatic elevation gradient and in natural populations. Flower buds were initiated in the year preceding anthesis and passed winter in a pre-meiotic stage. Flower morphology differed in the known cytotype-specific way in that tetraploid flowers produced about twice as many carpels and fewer petals, stamens, and pollen grains than diploid flowers. Tetraploids developed precociously aposporous embryo sacs and showed a high rate of developmental disturbances. Sexual seed formation prevailed in diploids and pseudogamous apomixis in tetraploids. Along the elevation gradient, stigma pollen load, pollen performance, and seed output decreased. Combinations of reproductive traits, namely, bypass of meiosis irregularities and uniparental reproduction, might have promoted the vast expansion of apomictic R. kuepferi lines across the European Alps. Full article