Search Results (64)

Kiwifruit (Actinidia deliciosa) is a globally important crop presenting challenges for ensuring cross-pollination. This study aimed to (1) record the entomological fauna visiting flowers; (2) evaluate the visitation frequency of pollinators; and (3) test the use of lavender extract to enhance cross-pollination by honeybees and assess the impacts on fruit quality. Nine species of floral visitors were recorded as pollinators, although the most frequent were the exotic honeybee (Apis mellifera) and the native bees Bombus pauloensis and Xylocopa augusti. Honeybees increased their visitation to flowers when the attractant was used, improving pollination service and fruit quality compared to the control-bagged treatment, resulting in fruits that were 20 g heavier (115.4 g vs. 95.6 g, 95% CI). Similarly, the number of seeds per fruit and the fruit shape index (FSI) increased in treatments exposed to bee visitation when compared to the bagged control. However, differences in bee visitation among treatments suggested a non-linear relationship between bee activity and fruit quality. Nevertheless, achieving high-quality fruit standards across treatments could be explained by the extended floral lifespan, which allowed for a high number of visits and ensured pollination. Finally, we did not observe any bias in honeybee visitation by applying sugar syrup combined with the attractant. Hence, to increase honeybees’ visits to flowers, we recommend applying the scent directly in a water solution. Full article

Background/Objectives: In flowering plants, hybridization is an important evolutionary force that might change sex distributions and sex determination systems (SDSs). However, little is known about processes in the first hybrid generations. Here, we study a cultivated putative hybrid cross of weeping willows (genus Salix, S.), S. alba × babylonica to gain insights into the effects of hybridization into SDSs. Methods: We analyzed the genetic structure of pure S. alba, pure S. babylonica, and the putative hybrid crosses in Central Europe using RADSeq data and five independent methods (NeighborNet, genetic structure analysis, Principal Component Analysis, hybrid index and heterozygosity analysis, and hybrid class analysis). The genetic SDS was analyzed on male, female, and mixed (monoecious) phenotypes by detecting sex-specific genomic markers using RADSex. Results: Genetic analyses indicate that most of the weeping willows represent F1 hybrids (S. alba × babylonica), and only two putative S. alba backcrosses. Hybrid index, heterozygosity, and hybrid class analyses provided more interpretable results than the other methods. The parental species were consistently dioecious, whereas hybrids had male, female, and monoecious phenotypes. RADSex revealed a male heterogametic XY system for S. alba, and this was combined in the hybrids with the previously known ZW system of S. babylonica. Conclusions: We confirmed the historical records stating that S. alba × babylonica are mostly F1 hybrids. We report for the first time that the combination of XY and ZW systems in primary hybrids results in regular shifts to monoecy. Full article

Cannabis sativa L. is a versatile plant with applications in various sectors such as agriculture, medicine, food, and cosmetics. The therapeutic properties of cannabis are often linked to its secondary compounds. The worldwide cannabis market is undergoing swift changes due to varying legal frameworks. Medicinal cannabis (as a heterozygous and dioecious species) is distinct from most annual crops grown in controlled environments, typically propagated through stem cutting rather than seeds to ensure genetic uniformity. Consequently, as with any commercially cultivated crop, biomass yield plays a crucial role in overall productivity. The key factors involved in cultivation conditions, such as successful root establishment, stress tolerance, and the production cycle duration, are critical for safeguarding, improving, and optimizing plant yield. Grafting is a long-established horticultural practice that mechanically joins the scion and rootstock of distinct genetic origins by merging their vascular systems. This approach can mitigate undesirable traits by leveraging the strengths of particular plants, proving beneficial to various applications. Grafting is not used commercially in Cannabis. Only three very recent investigations suggest that grafting holds significant promise for enhancing both the agronomic and medicinal potential of Cannabis. This review critically examines the latest advancements in cannabis grafting and explores prospects for improving biomass (stem, root, flower, etc.) yield and secondary metabolite production. Full article

Cannabis sativa L. is a dioecious species known to produce over 1600 chemical constituents, including more than 180 cannabinoids classified into 11 structural groups. These bioactive compounds are predominantly synthesised in the glandular trichomes of female inflorescences. However, sex determination in C. sativa is influenced by both genetic and environmental factors, often leading to the development of male flowers on female plants. This unintended fertilisation reduces cannabinoid yield and increases genetic heterogeneity and challenges in medical cannabis production. Haploid and doubled haploid (DH) technologies offer a promising solution by rapidly generating homozygous lines from gametophytic (e.g., unpollinated ovaries and ovules) or sporophytic tissues (e.g., anthers and microspores) via in vitro culture or chromosome reduction during hybridisation. In land plants, the life cycle alternates between a diploid sporophyte and a haploid gametophyte generation, both capable of mitotic division to form multicellular bodies. A single genome regulates this phase transition and encodes the molecular, genetic, and epigenetic mechanisms that precisely control the developmental processes unique to each generation. While the application of haploid technology in C. sativa remains limited, through recent progress in haploid induction (HI) and CRISPR-based genome editing, the direct modification of haploid gametes or embryos enables the creation of null homozygous lines following chromosome doubling, improving genetic uniformity. Understanding the molecular mechanisms of spontaneous chromosome doubling may further facilitate the development of elite cannabis genotypes. Ultimately, enhancing the efficiency of DH production and optimising genome editing approaches could significantly increase the speed of genetic improvement and cultivar development in Cannabis sativa. Full article

RNA silencing regulates diverse cellular processes in plants. Argonaute (AGO), Dicer-like (DCL), and RNA-dependent RNA polymerase (RDR) proteins are core components of RNA interference (RNAi). Despite their functional significance, the systematic identification and characterization of these families have remained largely unexplored in Siraitia grosvenorii. Using HMMER and Pfam analyses, we identified six SgAGO, four SgDCL, and six SgRDR genes. Phylogenetic analysis classified SgAGOs, SgDCLs, and SgRDRs into five, four, and four clades, respectively, all of which clustered closely with homologs from other Cucurbitaceae species, demonstrating lineage-specific evolutionary conservation. Promoter cis-element analysis revealed the significant enrichment of hormonal (methyl jasmonate, abscisic acid) and stress-responsive (light, hypoxia) elements, indicating their roles in environmental adaptation. Tissue-specific expression profiling showed that most SgAGO, SgDCL, and SgRDR genes were highly expressed in flowers and mid-stage fruits (35 days after pollination), while SgAGO10.1 exhibited stem-specific expression. By contrast, SgRDR1.2 displayed no tissue specificity. Notably, sex-biased expression patterns in dioecious flowers suggested the RNAi-mediated regulation of gametophyte development and their potential roles in reproductive and secondary metabolic processes. This study lays the foundation for further exploration of RNAi machinery’s role in coordinating mogroside biosynthesis and stress resilience in S. grosvenorii while providing potential targets for genetic improvement. Full article

Industrial hemp (Cannabis sativa L.) is a versatile and sustainable multipurpose plant for agroecology services and a zero-waste circular economy. While the focus has traditionally been on primary products like fiber and seeds, nowadays there is an increasing awareness of the potential value of the by-products generated during hemp cultivation and processing. This article explores various methods of valorizing industrial hemp wastes, focusing on their mineral and biochemical composition, highlighting the benefits of utilizing what was once considered a mere by-product. The apical and the basal leaves of 12 industrial hemp varieties, six monoecious, and six dioecious, representing the main by-product of fiber supply chain, were assessed for their mineral (N, K, Na, Ca; Mg, Cu, Mn, Fe, and Zn), chlorophyll, carotenoids, and total soluble phenols contents, as well as for their antioxidant activity. The same parameters were also evaluated in the inflorescences; the main waste was derived from both hemp fiber and seed harvesting, which were collected at three stages of flower development for four selected genotypes, together with the yield and chemical composition of their essential oils. Differences in the evaluated parameters among genotypes and tissues were highlighted, showing the potential for diversifying the utilization of industrial hemp wastes. The possible uses of these residual biomasses are discussed based on their composition. Full article

Kiwifruit is a dioecious woody liana fruit tree, and the non-fruitfulness of male plants leads to a great deal of blindness in the selection of male plants in crossbreeding. In this study, we induced the development of male plant ovary by externally applying plant growth regulators (PGRs) and performed histological observation, phytohormone content determination and transcriptome analysis on the abortive ovary of the male kiwifruit (Con), the ovary of the female kiwifruit (Fem) and the PGR-induced developing ovary of the male kiwifruit (PT). Histological analysis showed that the Con ovary was devoid of ovules and the carpels were atrophied, the Fem ovary had ovules and the PT ovary was devoid of ovules, but the carpels developed normally and were not atrophied. Endogenous phytohormone content measurements displayed higher levels of trans-zeatin (tZT) in PT and Fem than Con, and lower levels of gibberellin (GA3) and abscisic acid (ABA) than Con. Transcriptome analysis revealed significant differences in many key genes in the cytokinin and auxin pathways, which were consistent with the results of phytohormone content measurements. Meanwhile, the genes related to carpel development, SPT (DTZ79_04g03580) and SK41 (DTZ79_19g04340), were highly expressed in PT, suggesting that they may play a key role in PGR-induced development of the ovary in male kiwifruit. These results provide information for elucidating the potential regulatory network of PGR-induced ovary development in male flowers and contribute to further identification of valuable target genes. Full article

Understanding the complex mechanisms underlying sex differentiation in dioecious plants is fundamental to elucidating plant reproductive strategies and their adaptive responses to environmental stresses. Pistacia chinensis, previously considered a strictly dioecious species, has been found to exhibit monoecy, with sex differentiation closely linked to environmental stress during floral development. However, the underlying molecular mechanisms remain poorly understood. This study explores the influence of environmental stress on sex differentiation with a focus on heat shock proteins (Hsps). Biochemical analyses revealed higher proline content and SOD activity in dioecious and monoecious females compared to males during the sex differentiation phase. Two key genes, PcHsp70-1 and PcHsp90, were identified as differentially expressed between sexes. Subcellular localization analysis showed that these proteins are present in both the nucleus and cytoplasm. Overexpression of PcHsp70-1 in Arabidopsis promoted bolting and flowering by upregulating flowering-related genes and also enhanced drought resistance. Similarly, PcHsp90 contributed to drought tolerance through multiple mechanisms. These findings suggest that Hsps play a key role in linking environmental stress responses to sex differentiation, thus laying the foundation for further research on plant–environment interactions and stress-adaptive mechanisms in P. chinensis. Full article

Industrial hemp (Cannabis sativa L.) is primarily a dioecious plant, and monoecious varieties have been developed for high yield. Production practices vary for each variety, prompting the need for the present study to describe the floral characteristics and evaluate pollen quantity and viability of monoecious and dioecious hemp varieties. All four hemp varieties, Henola, CFX-2, Canda, and Joey, have five lanceolate anthers, basifixed to a threadlike filament. Anther length was significantly different among varieties, but not anther width. The longest length (0.38 ± 0.046 cm) was recorded in Henola, and the shortest (0.34 ± 0.043 cm) in CFX-2. Anther width ranged from 0.088 ± 0.0024 to 0.095 ± 0.0021 cm. Pollen grains were triporate and spheroidal in shape and size and differed significantly, with the largest in Joey (27.83 ± 0.78 μm) and Henola (27.489 ± 0.99 μm), and smallest in Canda (22.04 ± 0.56 μm). The number of pollen grains per flower differed significantly among varieties, ranging from 29,183 in Henola to 104,548 in Joey. Even though Henola recorded the lowest pollen number, it had the highest percentage (69.3%) of viable pollen after 24 h of storage 4 °C and Canda had the lowest (54%). Three weeks after storage at the same temperature, pollen viability decreased for all the hemp varieties and ranged from 52% to 58%. There was a moderate, positive and significant relationship (r = 0.496) between anther length and the number of pollen grains in Joey. The relationship in Henola was moderate and non-significant (r = 0.356), and it was weak and non-significant in Canda (r = 0.188) and in CFX-2 (r = 0.037). The findings from this study provide information for growers and researchers on hemp breeding and cultivation practices that may contribute to the prevention of cross-pollination. Full article

Background: Spinach (Spinacia oleracea L.) is an important leafy vegetable with dioecious and occasional monoecious plants. Monoecious lines are more suitable for hybrid production than dioecious lines due to their extended flowering period. However, genetic research on the sex determination of monoecism remains limited. Methods: In this study, RNA-seq analysis of monoecious and female spinach plants was performed at two distinct flowering stages. In total, we identified 4586 differentially expressed genes (DEGs), which were primarily involved in biological processes such as hormone signaling, cell wall biosynthesis, photosynthesis, and flower development, based on Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Results: Among these DEGs, 354 transcription factors, including 27 genes associated with the ABCDE gene, were discovered. Furthermore, a co-expression gene regulatory network was built, identifying nine key genes that play important roles in regulating sex differentiation between female and monoecious plants. Conclusions: Our findings provide crucial molecular insights into the mechanisms of monoecism in spinach and offer a scientific basis for future spinach breeding. Full article

Cultivated yam (Dioscorea rotundata) is a staple tuber crop in West Africa which is mainly vegetatively propagated. Although the majority of yam cultivars flower, the control of their sexual reproduction remains largely unknown despite its importance for plant-breeding programs. While described as a dioecious species, yam has several monoecious (mix) cultivars that are often subject to spontaneous sex changes. This study aims to evaluate the impact of phytohormones on sex expression and flower development in cultivated yams D. rotundata. Exogenous applications of 1 mM 6-benzylaminopurine (BAP) and 1 mM methyl jasmonate (MeJa) were performed on seedlings of female (Gnidou, Anago), male (Flou) and mix (Katala and Laboko) cultivars. The mix cultivars produced monoecious, male and female plants while the female and male cultivars had rather stable sex. Our results showed that MeJa exhibited a significant masculinising effect in mix cultivars and induced inflorescence and flower malformations in female cultivars (56% in Gnidou and 37% in Anago). Most malformations were inflorescence branching and sterile flowers (non-differentiated ovary) with extra cycles of sepals. Moreover, MeJa reduced flowering time in the cultivars of all sexes and increased the number of inflorescences per plant as well as the number of flowers per plant. Our results showed that BAP reduced the flowering time, synchronized flowering in female plants and increased the number of inflorescences per plant in monoecious plants. However, our results did not allow for strong conclusions regarding the effect of BAP on sex expression due to the high proportion of female flowering in both the control and BAP-sprayed plants. Nevertheless, we did not observe any masculinising effect for BAP. Further research that would highlight hormone and homeotic gene interactions in flowering could be of key interest in understanding the hormonal control of sex in cultivated yams D. rotundata. Full article

Arabidopsis AGAMOUS (AG) plays a crucial role in specifying stamen and carpel identities, floral meristem identity determination, and repression of the A-function. Ilex verticillata (Aquifoliaceae) is a dioecious shrub, whereby an individual plant has either male or female flowers with vestigial organs of the opposite sex. The molecular mechanism of male and female organ development in I. verticillata remains unknown. In order to identify the possible roles of AG-like genes in regulating floral development in I. verticillata, AG ortholog (IlveAG) and its promoter (pIlveAG) from the male and female flowers of I. verticillata were separately isolated. IlveAG is highly expressed in stamens, pistils, and sepals of male and female flowers. Moreover, obvious GUS staining was observed in the inflorescence and sepals, stamens, and pistils of mature flowers in pIlveAG::GUS Arabidopsis. The 35S::IlveAG Arabidopsis showed obviously early flowering. Moreover, IlveAG could substitute for endogenous AG to rescue the stamen and pistil in the Arabidopsis ag-1 mutant. In addition, expression of IlveAG can inhibit the development of sepals and petals (two outer whorls of floral organs) in wild-type and ag-1 Arabidopsis. Our findings suggest that IlveAG has a conservative C-function and plays key roles in determination of reproductive floral organs (stamen and carpel) identity and meristem determinacy. Our results provide more details to understand the role of AG orthologs in the development of male and female flowers in woody plants. Full article

Idesia polycarpa Maxim is a high-value species of fruit oil with edible, abundant linoleic acid and polyphenols. Idesia polycarpa is described as a dioecious species, and the flowers are male; female and bisexual flowers are produced on separate plants. In order to explore the flower types of Idesia polycarpa, the morphology of its flowers and inflorescence were investigated in this study. The flower and inflorescence types, the diameter, and the flowering sequencing in male and female inflorescence were determined. We also detected the length, width, and fresh weight of leaves, shoots, and female inflorescence, as well as the length and fresh weight of the petiole during the development. Additionally, we compared the length, width, the length/width ratio, and the flowering density between 5- and 7-year-old female trees. The phenological period observation of Idesia polycarpa showed that the development process can be roughly divided into 12 stages, including bud burst, leaf expansion, inflorescence growth, initial flowering, full flowering, flower decline, initial fruiting, fruit enlargement, fruit color change, fruit ripening, post-ripening of fruit, and leaf fall periods. Furthermore, four elites’ fruit determined the oil content and the composition of fatty acid content during the development. The dynamic of fatty acids contents, the palrnitic acid, palmitoleic acid, stearic acid, oleic acid, and linolenic acid contents were detected during the fruit development of four elites. Moreover, the mineral elements content of fruit of four elites during development were determined. The patterns of vegetative and reproductive growth in young dioecious trees of Idesia polycarpa provided the theoretical basis for artificial pruning and training. Full article

Pistachio (Pistacia vera L.) is a dioecious, anemophilous, and drought-resistant fruit tree species. It is cultivated in new Mediterranean areas, including the regions of southern Italy (Apulia and Basilicata). It has been estimated that over 40,000 ha are suitable for pistachio cultivation in areas infected by Xylella fastidiosa subsp. pauca. As a newly introduced species, knowledge of its biological reproductive behaviors in its new areas of spreading is essential for appropriate agronomic planning and management. This two-year study (2022 and 2023), carried out in the countryside of Stigliano (MT, Italy), had the objective of evaluating the flowering phenograms, pollen production, and assessing protocols for the conservation and extension of pollen viability, of the most widespread cultivars. A slight delay was observed in the blooming phenograms, compared to other cultivation Mediterranean areas, such as Spain or Sicily. Furthermore, the overlap between female and male phenograms was partial. No significant differences were observed in the polliniferous aptitude of the two male cultivars. Among the different protocols tested, the pollen storage at 33% relative humidity and a temperature of −80 °C maintained the pollen germinability above 50% for up to three weeks. These findings highlight the importance of controlled environmental conditions in preserving pollen viability over extended periods, providing valuable insights for agricultural and botanical research that relies on maintaining pollen viability for breeding and genetic studies. Full article

Cannabis (Cannabis sativa) is a versatile crop belonging to the Cannabaceae family, and is dioecious, typically with separate male and female plants. The flowers of female plants, especially the trichomes, accumulate relatively higher contents of cannabinoids compared with those of male plants. For this reason, to obtain seeds that are genetically female, it is desirable to induce the development of male flowers on a female plant that produces genetically female haploid gametes. Silver thiosulfate (STS) is a highly effective chemical for male flower induction. We investigated male flower induction in three commercial cultivars of female cannabis (Spectrum303, SuperwomanS1, and CBGambit) regarding the treatment frequency, stage of application, and concentration of STS applied as a foliar spray. All three cultivars showed adequate induction of male flowers in response to 1.5 mM STS applied at the early reproductive stage. In particular, SuperwomanS1 was most highly responsive to induction of male flowers, even when treated with 0.3 mM STS at the early reproductive stage. Treatment with three applications of STS was more effective compared with a single application, but a single application of 1.5 mM STS at the early reproductive stage was sufficient for male flower induction. A single STS application during the middle stage of reproductive growth was inadequate for induction of male flowers. However, 6 weeks after three applications of STS, CBGambit exhibited approximately 54% male flower induction at 0.3 mM STS, Spectrum303 showed approximately 56% induction at 3 mM STS, and SuperwomanS1 yielded approximately 26% induction at 1.5 mM (expressed as percentage of total number of individuals with the induced male flowers). Pollen stainability tests using KI-I₂ solution and Alexander’s staining showed high pollen viability with over 65% at different single STS concentrations, indicating that pollen grains induced by STS have sufficient viability for the self-pollination. This study demonstrated that different cultivars of cannabis respond diversely to different STS concentrations and highlighted the potential benefits of three STS applications during the middle reproductive stage for cannabis breeding. Full article