Search Results (83)

The Archaic period in the Maya lowlands of Mesoamerica emerged around 8000 BCE and likely lasted until about 1000 BCE; however, both the development and complex cultural adaptations representative of Archaic peoples present challenges for archaeologists. In central Belize, archaeological evidence for Archaic people is limited, especially when compared to northern and southern Belize. Nevertheless, our knowledge of Archaic lifestyles in this part of the world has substantially increased over the last twenty years or so. This paper reviews the current understanding of the Archaic period in central Belize based primarily on radiocarbon dates from stratigraphic excavations, diagnostic lithic artifacts, and both faunal and floral remains recovered from excavations, and compares these data to archaeological evidence from northern and southern Belize for regional contextualization and synthesis. Although some aspects of Archaic lifestyles in central Belize appear quite clear based on the available archaeological evidence, others remain elusive. More regional surveys to find sites and an increased number of excavations with datable stratigraphic contexts are needed to more accurately reconstruct the lives of the people who initially inhabited central Belize prior to the emergence of the first culturally recognizable Maya. Full article

This study comprehensively characterizes the PEBP gene family in Cymbidium sinense, an orchid with a prolonged vegetative phase that limits its industrial production. Genome-wide analysis identified six CsPEBPs, classified into FT-like, TFL1-like, and MFT-like subfamilies. Evolutionary, gene structure, and collinearity analyses revealed both conservation and lineage-specific diversification of these genes. CsFTL3, a distinctive FT-like member, displayed notably high expression during the bud undifferentiated stage, followed by a sharp downregulation upon floral initiation. Functional studies identified CsFTL3 as a key floral repressor. Heterologous overexpression in Arabidopsis delayed flowering time from 32.0 days (wild-type) to 63.0–75.3 days (transgenic) and increased rosette leaf number from 12.6 to 33.0–34.5, while its knockdown via virus-induced gene silencing (VIGS) in C. sinense accelerated floral bud development and upregulated flowering-promoter genes. Phylogenetically, CsFTL3 falls within the flowering repressor FT-I clade, and multiple sequence alignment identified critical amino acid substitutions (Y134S, W138L, Q140E) that likely underpin its functional divergence from typical flowering promoters. Furthermore, promoter analysis revealed an enrichment of light-, hormone-, and stress-responsive cis-elements, and its expression was modulated by gibberellin (GA), abscisic acid (ABA), and low-temperature treatments. Predicted protein–protein interaction and transcriptional regulatory networks provide preliminary insights into its complex regulation. We conclude that CsFTL3 acts as a crucial floral inhibitor, integrating environmental and endogenous cues to repress flowering. These findings offer fundamental insights into the molecular mechanisms of flowering in orchids and provide a valuable genetic resource for molecular breeding programs aimed at achieving precise flowering time control. Full article

Pile fermentation is a crucial process for developing the characteristic mellow taste and aged aroma of dark tea, yet the internal quality transformation mechanism of this process is still unclear. This study employed a high-sensitivity analytical platform based on gas chromatography–mass spectrometry (GC-MS) to systematically investigate the dynamic interplay between key chemical components, enzyme activities, and volatile compounds during the pile fermentation of primary dark tea. Our findings revealed a significant decrease in ester-type catechins, crude protein, and protopectin, alongside a notable accumulation of non-ester-type catechins, gallic acid, and soluble components. The multi-enzyme system—comprising PPO/POD, pectinase/cellulase, and protease—cooperatively drove the oxidation of phenols, cell wall degradation, and the release of aromatic precursors. This was complemented by GC-MS analysis, which identified and quantified 103 volatile compounds across nine chemical classes. The total content of volatile compounds increased significantly, with alcohols, esters, and aldehydes/ketones being the dominant groups. Floral and fruity compounds such as linalool and geraniol accumulated continuously, while esters exhibited an initial increase followed by a decrease. Notably, carotenoid degradation products, including β-ionone, were significantly enriched during the later stages. This study revealed a “oxidation–hydrolysis–reconstruction” metabolic mechanism co-driven by microbial activity and a multi-enzyme system, providing a theoretical foundation for the precise regulation of pile fermentation and targeted quality improvement of primary dark tea. Full article

Angiosperms include many taxa with dimorphic unisexual reproductive structures. These are well studied in some grasses, with maize as a key model, but other wind-pollinated lineages in Poales remain less explored. Within Poales, the family Restionaceae has the highest known proportion of dioecious species. In its Australian subfamily Leptocarpoideae, the sexually dimorphic Leptocarpus denmarkicus has raised questions about the basic flowering unit and the developmental basis of dimorphism. Here, we analyze inflorescence architecture and floral development in Eurychorda complanata, the sister lineage to the remainder of Leptocarpoideae. Using comparative morphology, light microscopy and scanning electron microscopy, we reconstruct synflorescence topology, floral organography, and ontogeny in both sexes and compare them with those in L. denmarkicus. In Eurychorda, both sexes produce polytelic paniculate synflorescences with distinct inhibition zones and many-flowered simple spikelets as the basic flowering unit. Male and female spikelets bear up to 50 and up to 15 fertile flowers, respectively. Male flowers have two stamens and a dimerous pistillode, whereas female flowers possess two long filamentous staminodes and a dimerous gynoecium. Ontogenetic series show that flowers of both sexes initiate both androecial and gynoecial structures, and that functional unisexuality is achieved through late arrest of the organs of one sex. Defining spikelets as racemose axes with lateral sessile flowers clarifies homologies of reproductive structures and supports reinterpretation of the dimorphic female unit in L. denmarkicus as a derived compound spike generated through shifts in branching rank and the timing of lateral initiation. The compound female spike of L. denmarkicus has a striking overall similarity to the simple female spikelet in Eurychorda, illustrating fascinating parallelism in the evolution of reproductive organs within Restionaceae and Poales more broadly. At the male side, Eurychorda achieves anther exsertion via filament elongation, whereas in L. denmarkicus filaments are very short and anthers remain within the perianth, but male spikelets sit on long, flexible peduncles that invert the spikelet and promote trembling, thereby ventilating the perianth chamber and aiding pollen escape. These two solutions—filament elongation versus spikelet-peduncle flexibility—represent alternative strategies of pollen release in wind-pollinated flowers. Full article

High temperature is a major environmental stress that severely limits passionfruit (Passiflora edulis) productivity by impairing floral initiation. However, the physiological and molecular mechanisms underlying this process remain poorly understood. In this study, we investigated the effects of varying durations and intensities of heat stress on flower bud differentiation in passionfruit. Our results showed that prolonged exposure to temperatures above 35 °C significantly delayed or completely inhibited bud formation, accompanied by altered carbohydrate and nitrogen metabolism, accumulation of osmolytes (soluble protein and proline), and dynamic changes in antioxidant enzyme activities (SOD, POD, CAT). Notably, short-term heat stress induced a transient increase in salicylic acid (SA) levels and upregulation of SA biosynthesis genes (PeEDS1.2, PeICS1) and WRKY transcription factors (PeWRKY11/15), which were associated with sustained floral initiation. In contrast, prolonged stress suppressed SA accumulation and signaling, leading to bud abortion. Comparative transcriptomic analysis further revealed enrichment of pathways related to secondary metabolite biosynthesis, plant hormone signal transduction, and phenylpropanoid biosynthesis under heat stress. These findings highlight the critical role of SA in balancing heat tolerance and reproductive development and provide candidate gene resources for the molecular breeding of heat-resistant passionfruit varieties. This study offers new insights into the thermotolerance mechanisms of fruit crops under sustained high-temperature stress. Full article

Selective pressure targeting male functions plays a crucial role in the evolution of floral morphological traits. In some angiosperm groups, flowers contain two or more sets of stamens that vary in size, color, and morphology, a phenomenon known as heteranthery. This reflects an evolutionary adaptation of stamens. However, the developmental basis and molecular mechanisms remain poorly understood. This study integrates transcriptomic and developmental approaches to elucidate the molecular and morphological mechanisms underlying intra-floral stamen differentiation in Cassia fistula L., an economic leguminous tree exhibiting heteranthery with three distinct stamen types: long stamens (LS), short stamens (SS), and degenerated stamens (St). We documented asynchronous stamen primordia initiation and development trajectories across stamen types. Transcriptomic profiling and protein–protein interaction analysis identified differentially expressed genes (DEGs) between filaments of the three stamen sets, with significant enrichment in brassinosteroid (BR) related pathways. CYP90D1 (Cf_f49903) and CYP90C1 (Cf_f56973) emerged as candidate genes related to stamen length differentiation in C. fistula. This study not only helped elucidate the developmental and genetic framework of heteranthery in C. fistula but also provided new insights for exploring floral organ evolution in leguminous plants. Full article

Chrysanthemum (Chrysanthemum morifolium Ramat.), a typical short-day plant (SDP), relies on photoperiod and light quality signals to regulate flowering and growth. Red light interruptions inhibit its flowering, whereas supplemental blue light can counteract this inhibitory effect. To investigate how “high-blue/low-red” mixed light (RBL) regulates chrysanthemum flowering and growth, we treated ‘Gaya Glory’ plants with 4 h of supplemental or night-interruptional RBL (S-RBL4 or NI-RBL4, 0 or 30 ± 3 μmol m⁻² s⁻¹ PPFD) under 10 h short-day and 13 h long-day conditions (SD10 and LD13; white light, WL; 300 ± 5 μmol m⁻² s⁻¹ PPFD), recorded as SD10, SD10 + S-RBL4, SD10 + NI-RBL4, LD13, LD13 + S-RBL4, and LD13 + NI-RBL4, respectively. Under SD10 conditions, S-RBL4 promoted flowering and enhanced nutritional quality, whereas NI-RBL4 suppressed flowering. Under LD13 conditions, both treatments alleviated flowering inhibition, with S-RBL4 exhibiting a more pronounced inductive effect. Chrysanthemums displayed superior vegetative growth and physiological metabolism under LD13 compared to SD10, as evidenced by higher photosynthetic efficiency, greater carbohydrate accumulation, and more robust stem development. Furthermore, S-RBL4 exerted a stronger regulatory influence than NI-RBL4 on photosynthetic traits, the activities of sugar metabolism-related enzymes, and gene expression. The photoperiodic flowering of chrysanthemum was coordinately regulated by the photoreceptor-mediated and sugar-induced pathways: CmCRY1 modulated the expression of florigenic genes (CmFTLs) and anti-florigenic gene (CmAFT) to transmit light signals, while S-RBL4 activated sucrose-responsive flowering genes CmFTL1/2 through enhanced photosynthesis and carbohydrate accumulation, thereby jointly regulating floral initiation. The anti-florigenic gene CmTFL1 exhibited dual functionality—its high expression inhibited flowering and promoted lateral branch and leaf growth, but only under sufficient sugar availability, indicating that carbohydrate status modulates its functional activity. Full article

Background/Objectives: The basic helix–loop–helix (bHLH) transcription factor family regulates plant development, metabolism, and stress responses. Yet, its genome-wide composition remains unexplored in Lilium bakerianum var. rubrum (LBVR), an ornamental lily valued for its floral traits. This study aimed to identify, classify, and profile the bHLH family in LBVR using full-length transcriptomic resources. Methods: PacBio HiFi full-length transcriptome sequencing was combined with Illumina RNA-seq for accurate structural annotation and expression quantification. Candidate bHLHs were identified by iTAK and HMMER-Pfam, and their physicochemical properties, secondary structures, motifs, and phylogenetic positions were examined. Expression patterns were analyzed across four floral stages (bud, initial bloom, full bloom, and late bloom). Results: A total of 113 high-confidence bHLH genes were identified, with ~90% successfully annotated. The proteins displayed variation in molecular weight, isoelectric point, structural features, and motif composition. Phylogenetic analysis placed them into 13 clades consistent with Arabidopsis subfamilies, revealing lineage-specific expansions and contractions. Expression profiling showed that 95 genes were active in at least one stage, with two transcriptional waves: a strong bud-to-initial-bloom activation and a secondary wave spanning anthesis. Seventeen genes were expressed exclusively at the bud stage, suggesting roles in early floral-organ initiation and pigmentation. Conclusions: This work provides the first genome-wide characterization of bHLHs in LBVR. The integrated sequencing approach generated a robust catalogue and developmental expression map, offering candidates for functional studies and resources for breeding in lilies. Full article

The initiation, development, and morphological construction of floral organs constitute a highly intricate process, involving numerous factors and their interactions. MADS-box genes are key regulators of developmental processes and are consequently the most extensively studied gene family in floral organ research. By synthesizing current understanding of the regulatory roles of MADS-box genes in the initiation, differentiation, and morphogenesis of floral organ, this review provides novel insights into the floral development program and the general transcriptional regulatory mechanisms of this gene family. It also offers a reference for further in-depth exploration of this gene family and the refinement of theories governing floral development regulation. Full article

Ageing in oak barrels affects the tertiary aroma of red wine, yet further research on the impact of different conditions used for medium toasting of barrels could still be conducted to optimise wine production and meet consumer preferences. In this study, using the GC/MS method, the aroma profiles of two consecutive vintages of Cabernet Sauvignon wine and samples aged for 12 months in different vessels were determined. Besides the stainless steel tanks, Excellence barrels with medium, medium plus, and medium long toasting, and Premium barrels with medium toasting were used. A total of 48 aroma compounds were identified, and their odour activity value (OAV ≥ 1) was calculated. According to it, 10 key compounds were selected: β-damascenone, ethyl octanoate, ethyl vanillate, ethyl cinnamate, lauric acid, linalool, hotrienol, ethyl hexanoate, diethyl succinate, and 2-phenylethanol. The results showed that wooden barrels have a greater impact on wine aroma during ageing, compared to stainless steel tanks. The initial wine aroma and key compounds with fruity, floral, and fatty notes were most preserved in the stainless steel tank. The study highlights that controlled selection of barrel type (grain density) and toasting method can significantly modulate the aromatic complexity of Cabernet Sauvignon wines. Toasted barrels resulted in an increase in smoky and woody notes (volatile phenols and lactones), and a decrease in fruity and floral notes (β-damascenone, 2-phenylethanol, hotrienol, linalool, etc.). These findings could provide practical guidelines for winemakers for optimising ageing strategies and contributing new insights into the impact of wine vessels on aroma development and sensory perception. Full article

Carpel number has been recognized as a critical factor influencing fruit size, ultimately determining yield and economic efficiency. The WUSCHEL (WUS) protein is essential for maintaining stem cell homeostasis in the floral meristem. Its expression level directly influences the size of the floral meristem (FM), thereby determining the number of floral organs in Arabidopsis thaliana, Solanum lycopersicum, and Cucumis sativus. While its role remained largely unexplored in grapevine (Vitis vinifera). This study cloned the VvWUS gene from the polycarpic grape cultivar ‘Jizaomi’. Transgenic tomato lines expressing VvWUS heterologously exhibited accelerated floral transition, enhanced carpel/floral organ initiation, and had significantly higher locule numbers relative to wild type. Furthermore, direct binding of VvWUS to the VvAGAMOUS (VvAG) promoter and activation of VvAG expression were demonstrated through yeast one-hybrid (Y1H) and dual-luciferase (LUC) assays. These findings elucidated the molecular function of VvWUS in grape carpel development, providing a foundational basis for molecular breeding strategies targeting large-berry grape varieties. Full article

Litchi (Litchi chinensis Sonn.) is a kind of evergreen fruit tree with good flavor and taste which has high economic value. Sufficiently low temperature in winter is essential for the successful flower formation of litchi. Therefore, in the context of global warming, litchi often experiences unstable flower formation, ultimately resulting in a decrease in litchi production. Our previous research has highlighted the pivotal role of the LcFT1 gene in regulating the flower formation of litchi and identified two AP1 homologous genes associated with LcFT1 (named LcAP1-1 and LcAP1-2) based on RNA-Seq and weight gene co-expression network analysis (WGCNA). In this study, the functions of the two AP1 homologous genes in regulating flowering time were investigated. Result showed that LcAP1-1 and LcAP1-2 were expressed in all litchi tissues. LcAP1-1 was more highly expressed in mature leaves compared to other tissues, while the LcAP1-2 has the highest expression level in flower buds. Both of them exhibited upregulation in the terminal bud of litchi under low temperature. The expression of LcAP1-1 and LcAP1-2 was highly correlated with the initiation of flower buds and the development of flower organs. They increased gradually during the floral initiation but decreased gradually during flower bud development. The transgenic tobacco of LcAP1-2 flowered about 55 days earlier than wild-type, while tobacco overexpressing the LcAP1-1 gene had no significant changes in flowering time compared to the wild-type. These results indicate that the two genes have divergent regulatory functions, and that the LcAP1-2 gene may be involved in the regulation of flower transformation and flower organ development in litchi. Our research will further reveal the molecular regulatory mechanisms of flower formation in litchi and will also provide theoretical guidance for the molecular breeding of litchi. Full article

Macadamia (Macadamia integrifolia), Macadamia tetraphylla and hybrids, a crop of high economic and nutritional importance, faces challenges with low fruit set rates and severe fruit drop. To address this, we investigated the effects of exogenous plant growth regulators (PGRs) and boron fertilizer on the development, fruit set, and yield of the A4 macadamia variety. The study was conducted in 2024 at the Lujiangba research base (China, Yunnan Province). Five treatments were applied during key growth stages: boron (B), brassinosteroids (BR), N-(2-Chloro-4-pyridyl)-N’-phenylurea (CPPU), 6-benzylaminopurine (6-BA), and gibberellic acid (GA₃). Growth stages include flower bud formation, peak flowering, and fruiting. Our findings revealed that B treatment significantly increased pollen viability (95.69% improvement) and raceme length (23.97% increase), while BR enhanced flower count per raceme (26.37% increase) and CPPU improved flower retention (10.53% increase). Additionally, GA₃ and 6-BA promoted leaf expansion in new shoots, increasing leaf length by 39.83% and 31.39%, respectively. Notably, B application significantly improved total yield (43.11% increase) and fruit number (39.12% increase), whereas BR maximized nut shell diameter (5.7% increase) and individual nut weight (19.9% increase). Furthermore, CPPU and 6-BA markedly improved initial fruit set rates, while GA₃, BR, and B effectively reduced early fruit drop. Physiological analyses indicated that elevated soluble sugars and proteins in flowers correlated with higher initial fruit set, whereas increased endogenous cytokinin and GA₃ levels improved fruit retention and reduced drop rates. Based on these findings, we propose an integrated approach to optimize productivity: applying 0.02% B at the floral bud stage, 2 mg/L 6-BA at full bloom, and a combination of 0.02% B and 0.2 mL/L BR during early fruit set. This strategy not only enhances yield but also mitigates fruit drop, offering practical solutions for macadamia production. Full article

Flowering is a key agronomic trait that directly influences the yield of the tea-oil tree (Camellia oleifera). Floral initiation, which precedes flower bud differentiation, represents a critical developmental stage affecting the flowering outcomes. However, the molecular mechanisms underlying floral initiation in C. oleifera remain poorly understood. In this study, buds from five key developmental stages of a 12-year-old C. oleifera cultivar ‘changlin53’ were collected as experimental samples. Scanning electron microscopy was employed to identify the stage of floral initiation. UPLC-MS/MS was used to analyze endogenous gibberellin (GA) concentrations, while transcriptomic analysis was performed to reveal the underlying transcriptional regulatory network. Six GA types were detected during floral initiation and petal development. GA₄ was exclusively detected at the sprouting stage (BII), while GA₃ was present in all samples but was significantly lower in BII and the flower bud primordium formation stage (BIII) than in the other samples. A total of 64 differentially expressed genes were concurrently enriched in flower development, reproductive shoot system development, and shoot system development. Weighted gene co-expression network analysis (WGCNA) identified eight specific modules significantly associated with different developmental stages. The magenta module, containing Unigene0084708 (CoFT) and Unigene0037067 (CoLEAFY), emerged as a key regulatory module driving floral initiation. Additionally, GA20OX1 and GA2OX8 were identified as candidate genes involved in GA-mediated regulation of floral initiation. Based on morphological and transcriptomic analyses, we conclude that floral initiation of C. oleifera is a continuous regulatory process governed by multiple genes, with the FT-LFY module playing a central role in the transition from apical meristem to floral meristem. Full article

Passion fruit (Passiflora edulis), a tropical crop of significant economic value, exhibits temperature-sensitive floral development. Here, we identified 23 TALE transcription factors (PeTALEs) and characterized their roles in floral organogenesis and thermal adaptation. Phylogenetic analysis classified PeTALEs into KNOX and BELL subfamilies, with conserved domain architectures and cis-regulatory elements linked to stress and hormone signaling. Spatiotemporal expression profiling revealed PeTALE21 as a key regulator of corona initiation, while PeTALE17 dominated in later floral stages. Temperature stress assays demonstrated cold-induced upregulation of PeTALE15/16/19/22 and heat-mediated suppression of PeTALE10/18/21. Yeast two-hybrid assays uncovered functional interactions between PeTALE3/16/18/22/23, highlighting a network governing floral thermoresilience. This study provides the first genome-wide analysis of PeTALEs, offering insights for breeding climate-resilient passion fruit varieties. Full article