Plant Bloom Research Articles

Эколого-биологическая характеристика медоносных растений Удмуртской Республики

Abstract. The purpose is to analyze honey–bearing resources, biological forms and species diversity of natural, cultural and adventitious honey-bearing flora in the territory of the Udmurt Republic to create a scheme-map of the honey conveyor. Methods. In the study of this issue “Methods of conducting research in beekeeping” (2003), “Plant determinant of Udmurtia” were used. Results. As of January 1, 2023, the area of agricultural land in all land categories amounted to 1838.3 thousand ha, or 43.7 %, non-gricultural land – 2367.8 thousand hectares, or 56.3 % of the total land fund of the Udmurt Republic. The area of coniferous plants has increased by an average of 38 % since 1966, and hardwood by 35 %. The dynamics of the increase in areas for many species is positive – pine, spruce, ash, elm, alder, linden, willows. The life forms of honey plants of the republic have a different ratio: the largest number of 73 species are grasses (65.2 %), 29 are trees (25.8 %) and 10 are shrubs (9 %). When analyzing data on the flowering of honey plants in Udmurtia, most plants bloom in the off-season – 72.5 %, 25.8 % – in summer, spring. There are plants of prolonged flowering, and honey plants that bloom only in September are absent. The main honey-bearing crop is small-leaved linden. It has a large honey reserve; its specific weight of honey reserve is 90.92 %. To develop the honey reserve of the Udmurt Republic, it is necessary to have a number of bee colonies 4.5 times higher than the current level, which is 224.75 thousand bee colonies. Scientific novelty. Beekeeping in the Udmurt Republic is a promising area of agriculture in the development of forest and agricultural lands, the possibility of improving it and using the export of bees to the honey harvest, taking into account the flowering time of honeybees of natural and agricultural honeybees and active nomads.

Molecular organic geochemistry and origin of oil in the Potwar Basin, Pakistan

The Potwar Basin (PTB) is a prominent geological feature located in northern part of Pakistan, and is considered as one of the active and productive regions for petroleum and gas exploration in Pakistan. In this study, eight crude oil specimens originating from three distinct fields within the PTB were comprehensively examined to decipher the environmental conditions, source of organic matter (OM) and oil-oil correlations using gas chromatography coupled with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC–MS). The molecular marker and hierarchical cluster analysis of PTB oils reveal two different crude oil families. Family-I showed relatively low values of Pr/Ph, C19TT/C23TT and C25TT/C24TeT, C27-C29 regular steranes, dibenzothiophene (DBT), fluorene (FL) and dibenzofuran (DBF), as well as C26/C28 TAS (20S) and C27/C28 TAS (20R). These results suggest that Family-I crude oils derived from marine environment of suboxic water bodies with higher contribution from green algae or planktonic microbes. However, Family II contains comparatively high values of the aforementioned molecular parameters, indicating that crude oils mainly originated from a lacustrine environment with a higher contribution of plant organisms under oxidizing conditions. Saturated hydrocarbon maturity parameters such as CPI and OEP, and C3122S/(C3122S + C3122R) and C3222S/(C3222S + C3222R) indicate PTB crude oils are thermally mature, while aromatic indices reveal that Family-II crude oils are high mature. The present research defines that PTB crude oils contributed from mixed organic matter sources of marine and lacustrine majorly from marine sedimentary environment with the bloom of algae and/or higher plants.

IDENTIFICATION OF THE BOTANICAL ORIGIN AND DETERMINATION OF PHYSICOCHEMICAL PARAMETERS OF HONEY SAMPLES COLLECTED FROM THE SARY-CHELEK BIOSPHERE RESERVE OF KYRGYZSTAN

Sary-Chelek Biosphere Reserve is one of the richest rare flora and animal reserves in Kyrgyzstan. The natural environment of the Sary-Chelek Biosphere Reserve is exceptionally favourable to high-quality honey production. Botanical authenticity is the main factor influencing honey prices, as it has a direct impact on the quality of honey. Producing monofloral honey in a natural landscape is challenging because, throughout the beekeeping season, multiple melliferous plants bloom at the same time. The article describes for the first time the botanical origin and physicochemical characteristics of honey collected in this biosphere reserve and also determines the influence of the dominant honey plant on organoleptic, physicochemical, and food safety indicators. Pollen grains of 50 taxa of nectar sources and about 10 taxa of pollen sources were identified. There were unique plant pollens in the samples; nine of the samples were monofloral honey—three of sage (Salvia officinalis L.), four of thyme (Thymus vulgaris L.), and two of eremurus (Eremurus fuscus O.Fedtsch), and eight samples were polyfloral honey. High diastase activity was found in samples of thyme honey (41.1 ± 2.9 Gothe) and in samples of sage honey (31.3 ± 2.2 Gothe). The physicochemical and food safety parameters of the honey samples comply with the established norms and international standards.

Unveiling the phenology and associated floral regulatory pathways of Humulus lupulus L. in subtropical conditions.

The hop phenological cycle was described in subtropical condition of Brazil showing that flowering can happen at any time of year and this was related to developmental molecular pathways. Hops are traditionally produced in temperate regions, as it was believed that vernalization was necessary for flowering. Nevertheless, recent studies have revealed the potential for hops to flower in tropical and subtropical climates. In this work, we observed that hops in the subtropical climate of Minas Gerais, Brazil grow and flower multiple times throughout the year, independently of the season, contrasting with what happens in temperate regions. This could be due to the photoperiod consistently being inductive, with daylight hours below the described threshold (16.5h critical). We observed that when the plants reached 7-9 nodes, the leaves began to transition from heart-shaped to trilobed-shaped, which could be indicative of the juvenile to adult transition. This could be related to the fact that the 5th node (in plants with 10 nodes) had the highest expression of miR156, while two miR172s increased in the 20th node (in plants with 25 nodes). Hop flowers appeared later, in the 25th or 28th nodes, and the expression of HlFT3 and HlFT5 was upregulated in plants between 15 and 20 nodes, while the expression of HlTFL3 was upregulated in plants with 20 nodes. These results indicate the role of axillary meristem age in regulating this process and suggest that the florigenic signal should be maintained until the hop plants bloom. In addition, it is possible that the expression of TFL is not sufficient to inhibit flowering in these conditions and promote branching. These findings suggest that the reproductive transition in hop under inductive photoperiodic conditions could occur in plants between 15 and 20 nodes. Our study sheds light on the intricate molecular mechanisms underlying hop floral development, paving the way for potential advancements in hop production on a global scale.

Preliminary Phytochemicals Investigation in Begonia cucullata

People specifically or by implication profited of plants. Begonia cucullata, a perpetual blooming plant taxonomically considered to the family of Begoniaceae. Begonia cucullata is local to the all South American nations. In India found in Assam, Meghalaya and Manipur. The shade dried plant powder was taken for extraction through organic solvents like petroleum ether, chloroform, methanol and water extract. The Biochemicals investigation is performed by taking after standard methods. Primary phytoconstituents investigation of the plant extract indicated the existence of carbohydrates, glycosides, flavonoids, phytosterols, and saponins in methanol and watery extricate. The plant extricate of methanol and refined water have appeared most extreme positive tests for Phytochemicals, which clearly shows that the existence of a few dynamic standards within the plant that are having vital restorative esteem.

Uses Eriobotrya japonica (Thunb.) Lindl. in Greening in Azerbaijan

Information is provided on the structure, reproduction and decorative properties of Eriobotrya japonica (Thunb.) Lindl. In Absheron it is used as an ornamental plant. The plant blooms and bears fruit within 7-8 months; 6-7-year-old trees begin to bear fruit. This is a light-loving plant. Easily propagated by seeds. It is advisable to use the plant as a promising species in landscaping, landscape architecture and horticulture, taking into account the characteristics of its flowering and fruiting. The biological and ecological characteristics of the plant are analyzed.

What is an Herbarium and How Does it Help Us Protect Biodiversity?

When scientists study plants, they often collect, preserve, and store parts of the plants in a big collection called an herbarium. These plant specimens serve as proof that a species was growing in a certain place at a certain time. Herbaria (“herbaria” is the plural of herbarium) are where scientists describe new plant species and study how different species are related. Herbaria also contain lots of information about where certain plant species grow, what type of habitats species like, and at what time of year plants bloom and make fruits. Finally, herbaria are powerful tools for helping us understand how plants are affected by disturbances like habitat destruction and climate change. For all of these reasons, herbaria allow us to better understand and protect plant species all over the world. To continue benefitting from herbaria, we need to keep collecting plants and make these collections accessible to the world.

Patterns of floral resources and pollination interactions along dry grassland succession

Succession following the abandonment of traditional management practices can pose severe consequences for the conservation of semi-natural dry grassland communities. In the present study, we investigated whether the quantity of floral resources changes during succession of semi-natural dry grasslands and how this is related to pollinator richness and the number of pollination interactions at the community level. We addressed this issue by quantifying floral resources (i.e., number of flowers, nectar volume and number of pollen grains) and monitoring pollination interactions in dry grassland communities at different stages of succession, defined as the total cover of plant species of forest edges. The relationship between the quantity of floral resources and cover of plant species of forest edges was significantly hump-shaped, i.e., regardless of the type of floral resource, all peaked at intermediate values of cover of plant species of forest edges. The richness of animal-pollinated plants in bloom also showed a hump-shaped relationship with the cover of plant species of forest edges, while the richness of pollinator species and the number of pollination contacts were indirectly related to the cover of plant species of forest edges, as they were significantly associated with the number of flowers and the richness of animal-pollinated plants in bloom. Results suggest that succession of dry grasslands after abandonment may affect a crucial function in terrestrial ecosystems, namely animal-mediated pollination. Nevertheless, the conditions of early succession, which could be achieved by the presence of scattered shrubs, could ultimately be favourable for the pollination function in dry grasslands.

Drivers of sunbird‐plant interactions on Mount Cameroon: Between neutrality and niche‐based processes

AbstractThe drivers behind plant‐pollinator interactions still need to be fully understood. Previous research has suggested that observed interactions result from either neutral interaction between species based on their abundance or from niche‐based processes, which are reflected in the adaptations of both plants and pollinators. Furthermore, the importance of both scenarios can differ depending on seasonal dynamics translated into differences in resource availability. Extensive research has been conducted on New‐World hummingbirds (Trochilidae), whereas much less is known about Old World nectar‐feeding sunbirds (Nectariniidae). Our study aimed to explore whether sunbird‐plant interactions are explained by neutral and/or niche‐based processes. Thus, we tested the effects of abundance, morphology, and nectar sugar content on the observed interactions and the link between sunbirds and plant traits. Moreover, we explored the effects of robbing on these mechanisms. Finally, we investigated the partitioning of bird pollination niches, based on floral traits. We used a dataset of sunbird‐plant interactions collected at Mount Cameroon during two seasons (dry and wet seasons). Our study shows that sunbird‐plant interactions are influenced by both neutral and niche‐based processes. Neutral processes and nectar reward were the main mechanisms underlaying the observed interactions in the dry season. However, as more ornithophilous plants bloom during the rainy season, morphological trait‐matching becomes more important. We found a correlation between bill length and floral tube dimensions and observed niche overlap among the sunbird species. Considering this and other research, we suggest that plant‐pollinator interactions are influenced by a combination of both neutral and niche‐based processes.

Citizen science data reveal altitudinal movement and seasonal ecosystem use by hummingbirds in the Andes Mountains

Ensuring connectivity is crucial to protect landscapes but it requires knowledge about how animals use ecosystems throughout the year. However, animal movements remain largely unknown in biodiversity hotspots, even for species that fulfill key ecological roles, as is the case of hummingbirds in the Andes. In the complex topography of mountain slopes, movement of these avian pollinators may occur either between habitat patches with asynchronous plant blooms or across ecosystems that are located within the same elevation bands or along altitudinal gradients. Here, we used two decades (2000–2020) of records from citizen science data and boosted regression trees to predict monthly distributions for 55 hummingbird species in the Andes. We identified shifts in altitudinal distribution between contiguous months and calculated changes in the proportion of predicted distributions occupied by ecosystem types. Our findings reveal substantial altitudinal movement and differences in the proportion of ecosystem types utilized throughout the year that had not been previously reported for several species. Yet the magnitude of altitudinal and ecosystem shifts varies between hummingbird clades, and in some cases changes in the proportion of ecosystem types within estimated distributions occurs with little variation in altitude. All ecosystems across the Andes show temporal changes in hummingbird occurrence, but these are higher in natural landscapes compared to croplands or urban areas. Finally, we used phylogenetic logistic regression to test whether altitudinal and ecosystem shifts affect population trends. We found that higher ecosystem seasonality is more strongly associated with decreasing populations in comparison to altitudinal shifts. Altogether, our study reveals complex patterns of movement in hummingbirds and highlights the importance of ecological connectivity across different ecosystem types. More generally, it demonstrates the opportunity of using citizen science data to increase understanding about species' seasonal occurrences, so that landscapes can be better managed to protect animal movement.Keywords: boosted regression trees, eBird, ecological connectivity, species distribution models

Vertical greening systems serve as effective means to promote pollinators: Experimental comparison of vertical and horizontal plantings

To counteract the ongoing decline of pollinators, we need innovative and effective promotion strategies. Urban areas often function as pollinator refugia, but lack of open spaces can limit promotion measures. This scarcity in open surfaces requires rethinking the conventional flower bed. Can green walls, planted with pollinator-friendly plants, provide an alternative and attractive food source for wild and managed pollinators?We compared pollinator-friendly vertical greening systems covering approximately 6 m2 with identically planted, adjacent horizontal beds consisting of wild perennials and cultivated plant varieties at two different test sites in Baden-Württemberg, Germany. With a total of 92 planting observations and more than 2,800 single plant genera observations, we documented 12,963 pollinators and their individual plant preferences over a two-year period.While our results show no differences in the total attractiveness across all pollinators between vertical systems and horizontal plantings, honey bees had a highly significant preference for the horizontal plantings, while wild bees preferred the vertical systems. Pollinator visits increased with the height of the vertical systems, indicating that pollinators will find such vertical sources and that there are advantages to higher plantings above foot traffic. These results suggest that vertical systems are highly attractive spaces for flower visitors, especially for bumble bees and other wild bees, when planted with appropriate blooming plants and thus an innovative means to promote pollinators where horizontal open spaces are limited.

Influence of flowering on the anatomical structure, chemical components and carbohydrate metabolism of Bambusa tuldoides culms at different ages.

Bamboo forests, which have come to occupy large areas in recent years, naturally undergo the process of blooming. However, bamboo culms and rhizomes degenerate after the plants bloom, resulting in widespread loss of raw materials. Systematic research on the properties and physiology of bamboo culms after flowering is lacking, and whether flowering bamboo culms could be used as raw materials in industry is unclear. In this paper, we compared and measured the fiber morphology, chemical components, and sugar metabolism indexes of non-flowering and flowering Bambusa tuldoides culms at different ages. The results showed that the fibers in the middle internodes of both non-flowering and flowering B. tuldoides culms had the longest length. The fibers completed their elongation within 1 year, but the fiber walls were continually deposited with age. The levels of the chemical components in the nonflowering culms also continually increased with age. The nonstructural carbohydrate (NSC) content and sugar metabolism indexes showed the highest levels in the 2-year culms and then declined in the 3-year culms. Compared to young culms that had not yet flowered, the 3-month-old and 1-year-old flowering culms had a significant decrease in the fiber length and tangential diameter, and their holocellulose and lignin levels also decreased, while the levels of ash, SiO2, 1% NaOH extractives, and benzene-ethanol extractives increased. A correlation analysis showed that sugar catabolism was accelerated in the flowering cluster, which could lead to "starvation death" in bamboo and which had a significant negative impact on the anatomical and chemical properties of the bamboo culms. Generally, the flowering bamboo culms had shorter fibers, higher levels of extractives and ash, and lower holocellulose content, which indicated that bamboo flowering has an adverse effect on the application of such components in the production of pulp, in papermaking, and in other processing and utilization activities. This study revealed the physiological changes in flowering B. tuldoides culms and provided a theoretical basis to inform the utilization of culms in this species.

Biological features of the rare species <i>Ixiolirion tataricum</i> (Pall.) Herb. in the forest-steppe conditions of Western Siberia

The results of a study of the development and seed reproduction of the Lavender Mountain Lily, Ixiolirion tataricum (Pall.) Herb. introduced to Novosibirsk are presented. Phenorhythmotype of the species is an early-summer flowering hemi-ephemeroid, which grows in the third decade of April, blooms in June, bears fruit in July, and completes the growing season in late Julyearly August. The seasonal development lasts 94102 days. The real seed productivity (RSP) averages 11 1 pcs. of seeds per capsule, while the conditional real seed productivity (CRSP) is three times higher. Laboratory germination of seeds in the harvest year up to 98% on stratification at +4C. The economic longevity of seeds at room storage is preserved for 34 years. With soil sowing of seeds, seedlings appear next spring and the plants bloom in the 4th6th year. I. tataricum is non-sustainable in the collection of the botanical garden, the duration from the appearance of seedlings to the complete death of individuals doesnt exceed 7 years. Maintaining of I. tataricum in the conditions of forest-steppe of Western Siberia as a rare species and valuable ornamental perennial is possible by regular renewal with local seed reproductions.

Pollinators limit seed production in an early blooming rare plant: evidence of a mismatch between plant phenology and pollinator emergence

The reproductive ecology of rare plants is seldom studied, yet the persistence of plant populations depends on successful mutualisms with pollinators. As atmospheric temperatures rise, phenology of plants and pollinators may become mismatched. We investigated the reproduction of Trifolium barnebyi (Barneby's clover), a mat‐forming perennial endemic to central Wyoming, USA, that grows in the crevices of sandstone bedrock. Our objectives were to evaluate a method for monitoring changes in cover as well as assess the pollination and seed‐set of T. barnebyi. We established five monitoring transects using a divided frame to estimate percent cover. We conducted seed‐set experiments at three locations to measure self‐pollination and the degree to which pollinating insects limited seed production. We used vane traps and bee bowls to capture pollinators, and examined pollen carried on bees. Percent cover along transects declined over the four year period and was associated with spring precipitation. Trifolium barnebyi did not self‐pollinate and relied on pollinators to produce seeds. The number and mass of viable seeds per flower, and the number of bees captured increased as the season progressed, indicating that more and larger seeds were made when more pollinators were present. Blooming of T. barnebyi ranged between April and June, depending on the microhabitat the plant lived in, and we observed much higher seed production in later‐blooming plants. Pollen from T. barnebyi was primarily carried by Andrena bees, although we found smaller amounts of pollen on seven other bee genera. A mismatch in timing between blooming and pollinating insect emergence could limit seed production in T. barnebyi if plants bloom earlier over time and bee emergence does not follow the same phenology. Rare plants can be pollinated by rare pollinators showing that conserving these pollinators is crucial for rare plants and early blooming species may be higher at risk.

Nutrient enrichment and rainfall affect plant phenology and floral resource availability for pollinators

Wild pollinators are critical to maintaining ecosystem services and facilitating crop production, but habitat degradation and resource loss are leading to worldwide pollinator declines. Nutrient enrichment and changes in rainfall due to global warming are drivers of global environmental change, and likely to impact pollinator foraging behavior and reproductive success through changes to the growth and phenology of flowering plants. Here, we provide a short review of pollinator conservation in the context of nutritional ecology and plant-pollinator interactions. Then, we present novel research into the effects of nutrient and rainfall variation on plant phenology. In this study, we experimentally manipulated the amount of water and supplemental nutrients available to wild sunflower (Helianthus annuus) and goldenrod (Solidago spp.) throughout their growing season. We evaluated how changes in growth and bloom time could impact resource availability for bumble bee (Bombus impatiens) queens preparing to overwinter. We found that fertilizer and rainfall alter plant bloom time by 2–18 days, though flowering response was species-specific. Fertilizer did not significantly affect plant growth or number of flowers produced when plants were grown under drought conditions. When water was not limiting, fertilized sunflowers bloomed in floral pulses. These findings carry important implications for growers and land managers, providing insight into potential drivers of wild pollinator decline and possible conservation strategies.

Jardim de Sequeiro: uma técnica paisagista inovadora na estética e na qualidade ambiental, inspirada no Cerrado

Abstract The “Jardim de Sequeiro” (rainfed garden) is an innovative technique of naturalistic and seasonal rainfed gardening developed by Prof. Julio Pastore and a team of professionals and students at the University of Brasilia (UnB). The first experimental garden was planted at the Instituto Central de Ciências (ICC), an iconic brutalist building at the University of Brasília and a landmark of modern Brazilian architecture. The garden extends through the 732 meters of the mega-structure, encompassing more than 5,000 square meters of rooftop gardens planted on a thin layer of soil. The experimental garden is primarily grown from seeds, making it a dynamic space. Beginning with fast-growing species, plants bloom in succession throughout the summer and early autumn. The garden is “rainfed,” relying entirely on rainfall for water, and it withers and dries with the onset of the winter drought. As such, it can be considered a garden-installation: a temporary occupation that is redesigned and improved every year. Conceived and planned during the initial months of the COVID-19 pandemic, the garden’s first cycle occurred between December 2020 and May 2021, when the university was closed. Despite the difficulties inherent to the pandemic period, the innovative nature of the project has yielded promising results.

Foraging activity and breeding system of Avicennia officinalis L. (Avicenniaceae) in Kerala, India

Field studies were carried out to assess the foraging activity and the breeding system of Avicennia officinalis L. in Chettuwa, Thrissur, India during the two flowering seasons of 2018–2019. A. officinalis, also known as the Indian mangrove is a common mangrove occupying the river banks of the Kerala coast of southern India. The plant blooms massively during the onset of the first summer showers. The flowering to fruiting period lasted from April to July. Bagging experiments revealed that A. officinalis preferred a mixed breeding system though they had a low fruit set recorded in self-pollination experiments. A total of 15 species of foraging insects belonging to three orders, Hymenoptera, Diptera, and Lepidoptera, were observed. The three most abundant insect foragers were Apis florea Fabr., Campsomeriella collaris Fabr., and Chrysomya megacephala Fabr. Among these, A. florea showed a significantly high visitation rate followed by C. collaris and then C. megacephala. C. collaris, however, had the highest and most significant handling time for Avicennia officinalis than A. florea. The peak foraging activity was recorded from 1000h to 1100h and from 1500h to 1700h. These findings emphasize the importance of insect flower visitors in the breeding of A. officinalis, highlighting the need to maintain the plant-pollinator relationships for the protection of mangrove ecosystems.

Damage dynamics of introduced trees from the genus Prunus L. by Eriophyes padi Nal. in the Polar Alpine Botanical Garden Institute

Despite the harsh climatic conditions of growth, introduced bird cherry samples in the collection of the Polar Alpine Botanical Garden Institute (Kirovsk and Apatity, Murmansk region) are quite life-saving highly ornamental flowering and fruiting plants, however, Eriophyes padi Nal. (Phytoptus padi Nal.) has a effect on the preservation of bird cherry plants in the PABSI collection is a bird cherry gall mite that causes the formation of galls on the leaves of the plant, as a result of which the crown loses its decorative effect. However, the plants bloom and bear fruit. The article presents the results of observations of Eriophyes padi Nal., the dynamics of crown damage and leaf blade damage for introduced species of Prunus padus L., P. padus L. ssp. borealis (Schubeler) Cajander, and P padus L. f. colorata Almquist. The greatest proportion of damage is observed in P. padus f. colorata. Regular observations made it possible to note that not for all types of bird cherry plants, gallo formation occurs during leaf growth, as previously assumed. Trial chemical treatments (20192020) by irrigation under the root of affected plants against E. padi - with broad-spectrum drugs “Danadin” and “Aliot” (in a concentration of 0.2 % working solution) and biochemical insecticide “Kleschevit” (1.0 %) reliably indicate the high effectiveness of pesticides: “Aliot” (98 %) against E. padi.

Improving paleoenvironment in North China aided Triassic biotic recovery on land following the end-Permian mass extinction

The driver of the Early–Middle Triassic biotic recovery on land following the end-Permian crisis is puzzling. Here, we show the biotic recovery was gradual and spanned up to 8 Myr after the end-Permian mass extinction, based on continuous, well-dated sections over large areas in the northeastern Ordos Basin, North China. Initial recovery began in the Olenekian, marked by the disappearance of microbially induced sedimentary structures and reappearance of bioturbation, and continued in the Anisian, with a bloom of plants and tetrapods and intense bioturbation. Sedimentary environments changed from Induan braided-eolian conditions to Olenekian–Anisian shallow lacustrine and meandering river systems, marking an overall deepening lacustrine system. Carbonate δ13C and geochemical proxies of weathering intensity, salinity and clayiness reveal an overall warm and semi-humid paleoclimate in the Olenekian–Anisian. This improved stable paleoenvironment of warm and semi-humid conditions likely contributed to the biotic recovery following the Permian-Triassic hyperthermal-related crisis.

Exogenous application of ethephon regulates flower abscission, shoot growth, and secondary metabolites in Camellia sinensis

Tea plant (Camellia sinensis (L.) O. Kuntze) consumes a large amount of nutrients and water during the flowering stage, which compromises the tea growth and yield. Ethylene is an important plant hormone that plays pivotal roles in regulating plant growth and flowering. but there are few studies on flowering and growth of tea plants regulated by this plant hormone. Here, we investigated the effects of exogenous ethephon application on the abscission of flowers and flower buds in tea plants. The results showed that application of ethephon induced the production of endogenous ethylene and the peak of ethylene production occurred three days post ethephon spraying on the tea plants. Ethephon treatment induced the abscission of tea flowers and flower buds, leading to reduced amount of flowers in the tea plantations. Ethylene receptors (ETRs) play critical roles in ethylene-mediated cellular responses, and we found that there was a certain correlation between the effect of ethephon on the flower abscission and the expression of several CsETRs, including CsETR3, CsETR4, CsETR5, and CsETR6. Ethephon also induced the high activities of superoxide dismutase, peroxidase, and catalase three days after treatment. In addition, ethephon obviously reduced the tea polyphenol content and enhanced the caffeine content in tea plants. Treatment with ethephon (3000 mg L–1) significantly increased tea shoot length and production in the tea plantations in the following early spring. Overall, ethephon, in a range of concentrations, could effectively suppress the tea plant blooming and improve tea yield and quality to a certain extent.