Annual Flowering Research Articles

A Three-dimensional Analysis of Summer Dormancy in the Red Spider Lily (Lycoris radiata)

Lycoris radiata has beautiful bright-red flowers with both medicinal and ornamental value. However, the mechanisms underlying an unusual characteristic of Lycoris radiata, flowering without leaves, remain unclear. In this study, climatic influences, biomass composition, and yearly variations in bulb contents across eight developmental stages of L. radiata were analyzed. Thus, L. radiata summer dormancy was investigated in three dimensions: climate-associated phenology, biomass distribution characteristics, and physiologic bulb changes. The results showed that dormancy was most strongly affected by high ambient temperature, followed by scape development, flowering, leafing out, vigorous leaf growth, flower bud differentiation, flower bud predifferentiation, and leaf maturation. Biomass allocation, bulb contents, oxidoreductase activity, and root activity fluctuated significantly in L. radiata among developmental stages. Relative bulb dry weight was greatest during the dormant period (95.95% of total dry weight) and lowest during vigorous leaf growth (November–December). Root biomass was also significantly greater during dormancy than during flowering, leaf maturation, and flower bud differentiation. Only root biomass during vigorous leaf growth was greater than root biomass during dormancy. However, in dormant bulbs, soluble sugar content, soluble protein content, root activity, superoxide dismutase (SOD) activity, and peroxidase (POD) activity decreased. Thus, summer dormancy in L. radiata only constitutes a morphologic dormancy of the aboveground plant; the bulb and root remain physiologically active. The results suggest that L. radiata is sensitive to both ambient temperature and light, and that summer dormancy is triggered by the synergistic stimulation of these two factors. Although temperature controls dormancy, it plays only a limited regulatory role during the L. radiata flowering period. Thus, it is difficult to induce flowering or regulate annual flowering in this species through temperature control alone.

Effect of silicon on protein and lignin contents of two annual flower species

Abstract The beneficial effect of silicon on plants is known, but there are no studies demonstrating the effect of this element on protein and lignin production in ornamental plants. This study aimed to assess the effects of monosilicic acid fertigation at 0, 2, 4, and 8 mmol L-1 of Si on protein and lignin production of two ornamental species: Viola x wittrockiana Gams ex Nauenb. & Buttler ‘Majestic Giants II Fire’ e Tagetes erecta L. ‘Hero’ (color mix). The experiment was installed in a 4 × 2 factorial arrangement using a completely randomized design with five replications. After 90 days of the sowing, we assessed N and Si contents in shoot system, Si accumulation in shoot system, root, and total, and lignin and protein production. An increase in lignin followed by its reduction was observed from the concentration of 2.0 (4.29) and 4.3 (5.72) mmol L-1 of Si for Viola and Tagetes species, respectively. Silicon application promoted higher lignin content in T. erecta and V. x wittrockiana.

Identification of flowering-time genes in mast flowering plants using De Novo transcriptomic analysis.

Mast flowering is synchronised highly variable flowering by a population of perennial plants over a wide geographical area. High seeding years are seen as a threat to native and endangered species due to high predator density caused by the abundance of seed. An understanding of the molecular pathways that influence masting behaviour in plants could provide better prediction of a forthcoming masting season and enable conservation strategies to be deployed. The goal of this study was to identify candidate flowering genes that might be involved in regulating mast flowering. To achieve this, high-throughput large-scale RNA-sequencing was performed on two masting plant species, Celmisia lyallii (Asteraceae), and Chionochloa pallens (Poaceae) to develop a reference transcriptome for functional and molecular analysis. An average total of 33 million 150 base-paired reads, for both species, were assembled using the Trinity pipeline, resulting in 151,803 and 348,649 transcripts respectively for C. lyallii and C. pallens. For both species, about 56% of the unigenes were annotated with gene descriptions to known proteins followed by Gene Ontology analysis, categorising them on the basis of putative biological processes, molecular function, and cellular localization. A total of 543 transcripts from C. lyallii and 470 transcripts from C. pallens were also mapped to unique flowering-time proteins identified in Arabidopsis thaliana, suggesting the conservation of the flowering network in these wild alpine plants growing in natural field conditions. Expression analysis of several selected homologous flowering-pathway genes showed seasonal and photoperiodic variations. These genes can further be analysed to understand why seasonal cues, such as the increasing photoperiod in spring, that triggers the annual flowering of most plants, are insufficient to always trigger flowering in masting plants and to uncover the molecular basis of how additional cues (such as temperature during the previous growing seasons) then determines flowering in mast years.

Using Annual Resolution Pollen Analysis to Synchronize Varve and Tree-Ring Records

Fossil wood and varved lake sediments allow proxy analysis with exceptionally high, (sub-)annual resolution. Both archives provide dating through ring and layer counting, yet with different accuracy. In wood, counting errors are small and can be eliminated through cross-dating because tree-rings show regionally synchronous patterns. In varved sediments, counting errors are larger and cross-dating is hampered by missing regional patterns in varve parameters. Here, we test whether annual pollen analysis is suited to synchronize varve records. To that end, annual pollen deposition was estimated in three short cores from two lakes in north-eastern Germany for the period 1980–2017 CE. Analysis has focused on Fagus sylvatica and Picea abies, which show the strongest annual variations in flowering (mast). For both tree taxa, annual flowering variations recorded by forest and pollen monitoring are well represented in varved lake sediments, hence indeed allow us to synchronize the records. Some pollen mast events were not recognized, which may relate to sampling uncertainties, redeposition or regional variations in flowering. In Fagus sylvatica, intense flowering limits wood growth in the same year. Peaks in pollen deposition hence correlate with minima in tree-ring width, which provides a link between varved lake sediments and fossil wood.

Complete chloroplast genome sequence of bamboo Dendrocalamopsis vario-striata (Gramineae Bambusoideae)

Dendrocalamopsis vario-striata is one of the most economical and ornamental significant bamboo. It has the characteristics of annual flowering but no death. Here, we report on the first complete chloroplast (cp) genome of D. vario-striata. Its full-length of 139,458 bp, include large single-copy (LSC) region of 83,279 bp, small single-copy (SSC) region of 12,143bp, a pair of invert repeats (IR) regions of 22,018bp. Plastid genome contains 264 genes, 170 protein-coding genes, 78 tRNA genes, and 16 rRNA genes. The maximum likelihood phylogenetic analysis shows that D. vario-striata was sister to all other species of Bambusoideae.

Сирень Звегинцова (<i>Syringa sweginzowii</i> Koehne et Lingelsh.) — перспективная культура для озеленения в Республике Башкортостан

В настоящее время практика озеленения населенных пунктов и объектов различного назначения требует введения новых неприхотливых и устойчивых в новых условиях интродукции видов и сортов декоративных растений. Представлены результаты многолетнего (2005 – 2017 гг.) интродукционного изучения сирени Звегинцова, культивируемой в Башкирском Предуралье. Приведены данные по сезонному развитию, зимостойкости, уровню плодоношения, качеству семян, жизнеспособности пыльцы. Оценена декоративность, охарактеризована перспективность и интродукционная устойчивость в условиях Башкирского Предуралья. Сирень Звегинцова имеет один из самых высоких показателей плодоношения — 134,5 шт./пог. м. В пересчете на куст общее количество плодов составляет в среднем 12 162. Общий период вегетации составляет 165 дней. Как и у большинства видов сирени — балл зимостойкости I. Лабораторные энергия прорастания и всхожесть сирени Звегинцова оказались довольно высокими: всхожесть — 86 % в среднем, энергия прорастания — 83 %; грунтовые показатели были несколько ниже — соответственно 60 и 49 %. Сирень Звегинцова сохраняет последовательность прохождения фенофаз, характеризуется ежегодным обильным цветением, высокой способностью к завязыванию плодов и наличию самосева, что служит доказательством ее хорошей адаптации к условиям интродукции. Сделано заключение о перспективности сирени Звегинцова для широкого применения в озеленении населенных пунктов Республики Башкортостан.

Realistic low-doses of two emerging contaminants change size distribution of an annual flowering plant population.

HHCB [1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran] and 4-tert-octylphenol [4-(1,1,3,3-tetramethylbutyl)phenol] are widely used emerging contaminants that have the potential to cause adverse effects in the environment. The purpose of this study was to observe if and how environmentally realistic concentrations of these contaminants alter growth in plant populations. It was hypothesized that within an exposed Gypsophila elegans Bieb (annual baby's breath) population especially fast-growing seedlings are impaired even when the population mean is unaffected, and small doses can cause hormesis and, thus, an increase in shoot or root length. In a dose-response experiment, an experimental population of G. elegans was established (total 15.600 seeds, 50 seeds per replicate, 24 replicates per concentration, 5.2 seedlings/cm2) and exposed to 12 doses of HHCB or 4-tert-octylphenol. After five days, shoot and root length values were measured and population averages, as well as slow- and fast-growing subpopulations, were compared with unexposed controls. Growth responses were predominantly monophasic. HHCB seemed to selectively inhibit both root and shoot elongation among slow- and fast-growing individuals, while 4-tert-octylphenol selectively inhibited both root and shoot elongation of mainly fast-growing seedlings. The ED50 values (dose causing 50% inhibition) revealed that the slow-growing seedlings were more sensitive and fast-growing seedlings less sensitive than the average of all individuals. Although there was toxicant specific variation between the effects, selective toxicity was consistently found among both slow- and fast-growing plants starting already at concentrations of 0.0067 µM, that are usually considered to be harmless. This study indicates that these contaminants can change size distribution of a plant population at low concentrations in the nM/µM range.

Фенологические и морфометрические характеристики Padus asiatica Kom. при интродукции в Кольской Субарктике

В условиях интродукции Кольского полуострова Padus asiatica характеризуется ранним началом икороткой продолжительностью вегетации, своевременным завершением процессов роста и одревеснения побегов, ежегодным цветением и плодоношением. Ритм развития P. asiatica близок ритмам местных видов черемухи.В 2018 г. P. asiatica характеризовалась бо́льшим годичным приростом по сравнению с образцами местной дендрофлоры. Морфометрические показатели соцветий занимают промежуточное положение между P. avium и P. borealis. Растения P. asiatica, P. avium, P. borealis характеризуются высоким уровнем жизнеспособности и декоративности, дают всхожие семена, способны к естественному и искусственному вегетативному размножению, но имеютповреждения различного происхождения.

Perceptions of the local beekeepers on the diversity and flowering phenology of the melliferous flora in the community of Xmab\xe9n, Hopelch\xe9n, Campeche, Mexico

BackgroundThe knowledge of native melliferous flora (MF) may contribute to identify the diversity of species available for beekeeping activities during the dry and rainy seasons of the year in the Yucatan Peninsula (YP) region. The acute shortage of food resources considerably reduce local honey production and needs to be addressed appropriately. The objective of this study has been identifying the local MF, their nectar and pollen contribution, their flowering patterns, and the criteria of the vegetation to be established adjacent to local apiaries for stable production of quality honey. The study also investigates how this approach helps to complete the annual flowering cycle required to maintain the honeybee colonies, thereby preventing swarm escapes during periods of acute food stress in the community of Xmabén, Hopelchén, Campeche, Mexico.MethodologyWe conducted a comprehensive survey based on interviews with 40 local beekeepers and a review of herbarium specimens (CICY) of the database of the global information network on the native MF biodiversity with high apiculture potential, the contribution of nectar and pollen they provide, and their flowering patterns. Furthermore, we documented interviews with the same beekeepers on the necessary conditions for establishing the ideal components of vegetation in areas adjacent to apiaries for high-quality honey production in the Xmabén community of Hopelchén, Campeche, Mexico.ResultsWe have identified 56 native MF species with apiculture potential, that need to be planted around the apiaries for assisting honeybees in successfully running the beekeeping production cycle. Hence, the MF diversity of Xmabén community constitutes a valuable resource for successful beekeeping in the region and adjoining localities. We found that 22.5% of local beekeepers are dedicated exclusively to apilcilture, while 77.5% practice it as a secondary activity due to better sources of income in agriculture (60%), masonry (10%), and livestock management (7.5%). The data generated can help in further expansion of the local apiaries, beekeeping business, and in building future opportunities for the local apiculture industry. Indigenous knowledge of the beekeepers was comprehensive and corroborated the technical information on MF collected from the herbarium, further emphasizing the value of indigenous knowledge on traditional beekeeping practices.ConclusionFrom the perspective of human ecology, our study reveals the need of collecting, analyzing, and interpreting indigenous knowledge to facilitate traditional beekeeping practices of the region without using expensive, modern technology to solve ecosystem-based problems through long-term, sustainable, traditional, and environment friendly approaches.

A phenology model for tropical species that flower multiple times each year

AbstractPhenology models developed for temperate and boreal plants predict a single, population‐level first flowering date for each year. These models cannot accommodate species that flower multiple times each year in humid tropical forests nor flowering data with census‐interval rather than daily temporal resolution. Here, we present a new model framework able to predict the timing of multiple annual flowering events from census data. We extend a recent model, which predicted tropical flowering probabilities as discrete events occurring on census dates, by integrating predicted flowering probabilities over all dates between censuses. We evaluate our model against 29 years of daily climate and weekly flowering records for Hybanthus prunifolius (Violaceae) and Handroanthus guayacan (Bignoniaceae) from Barro Colorado Island, Panama. Previous experiments demonstrate that both species flower shortly after a heavy, dry‐season rain interrupts an extended dry period. Our model captures this sequence of rainfall events. Best‐fit model parameters are consistent with previous experimental results. This match suggests the new model framework will provide novel insights for other humid tropical forest species.

Complete Genome Sequence of Cluster C2 Bacillus Phage Maceta.

Bacillus phage Maceta was isolated from the soil of commercially purchased annual flowers using the host Bacillus thuringiensis serovar kurstaki. Isolated DNA was then sequenced and annotated. Maceta has a relatively small genome, containing 45,023 bp, and shares an average nucleotide identity of 96% with other cluster C2 Bacillus phage.

Spatio-temporal patterns of orchids flowering in Cameroonian rainforests.

We characterized the flowering patterns of 45 epiphytic orchid species occurring in Cameroonian rainforests to explore the environmental and evolutionary forces driving their phenology. We used a dataset of 3470 flowering events recorded over a period of 11years in the Yaoundé living collection (82% of the flowering events) and from in situ observations (18% of the flowering events) to (i) describe flowering frequency and timing and synchronization among taxa; (ii) test flowering patterns for phylogenetic relatedness at the generic level; and (iii) investigate the spatial patterns of phenology. An annual flowering pattern prevailed among the species selected for this study. The species-rich African genera Angraecum and Polystachya are characterized by subannual and annual frequency patterns, respectively. However, in terms of flowering time, no phylogenetic signal was detected for the four most diverse genera (Ancistrorhynchus, Angraecum, Bulbophyllum, and Polystachya). Results suggest also an important role of photoperiod and precipitation as climatic triggers of flowering patterns. Moreover, 16% of the taxa cultivated ex situ, mostly Polystachya, showed significant differences in flowering time between individuals originating from distinct climatic regions, pointing toward the existence of phenological ecotypes. Phenological plasticity, suggested by the lack of synchronized flowering in spatially disjunct populations of Polystachya, could explain the widespread radiation of this genus throughout tropical Africa. Our study highlights the need to take the spatial pattern of flowering time into account when interpreting phylogeographic patterns in central African rainforests.

Effect of sowing substrate on coverage and rate of weeding of directly sown annual flower beds

The method of establishing directly sown annual flower beds has its benefits as well as problems. One of them is particularly surface weeding before sowing. The aim of the experiment was to find a solution to this problem, i.e. whether covering sowing substrates can suppress the germination and growth of weeds and improve growth parameters of annuals. The certified seed mixture of annuals and three variants of substrates that differed in ability to retain water were chosen for the experiment. Substrate A contained 70% vol. of sand and 30% vol. of peat; substrate B 50% vol. of sand, 20% vol. of siliceous marlite, 30% vol. of peat; and substrate C 30% vol. of sand, 40% vol. of siliceous marlite, 30% vol. of peat. In the control variant annuals were sown directly into the soil. The experiment was established in two different sites. Development of the mixture was monitored and evaluated all the season; the coverage with annuals and weed, the height of annuals and flowering time were evaluated. According to the results the use of sowing substrates ensured the successful development of mixtures of annuals, particularly in the initial stand development.

Evaluation of growth, flowering characters and yield of commercial annual flower crops as intercrop in coconut ecosystem

An investigation was carried out to evaluate the growth and the flowering of some of the commercial annual flower crops as intercrop in coconut ecosystem. Commercial annual flower crops viz., African marigold, French marigold, celosia, gomphrena and China aster were grown as an intercrop in coconut plantation and also under open condition for comparison. The results of the experiment showed that all of the crops performed to its optimum in the coconut shade, but less well than the open condition. The parameters viz., Plant height, internodal length, number of lateral branches, days taken for first flowering, flower diameter and yield were recorded. The yield was relatively higher in the open condition. The morphological characters were higher in the open condition and the earliness to flower bud initiation and flowering were observed in the open condition.

Annual flower strips support pollinators and potentially enhance red clover seed yield.

Ecological intensification provides opportunity to increase agricultural productivity while minimizing negative environmental impacts, by supporting ecosystem services such as crop pollination and biological pest control. For this we need to develop targeted management solutions that provide critical resources to service‐providing organisms at the right time and place. We tested whether annual strips of early flowering phacelia Phacelia tanacetifolia support pollinators and natural enemies of seed weevils Protapion spp., by attracting and offering nectar and pollen before the crop flowers. This was expected to increase yield of red clover Trifolium pratense seed. We monitored insect pollinators, pests, natural enemies and seed yields in a total of 50 clover fields along a landscape heterogeneity gradient, over 2 years and across two regions in southern Sweden. About half of the fields were sown with flower strips of 125–2,000 m2. The clover fields were pollinated by 60% bumble bees Bombus spp. and 40% honey bees Apis mellifera. The clover seed yield was negatively associated with weevil density, but was unrelated to bee species richness and density. Flower strips enhanced bumble bees species richness in the clover fields, with the strongest influence in heterogeneous landscapes. There were few detectable differences between crop fields with and without flower strips. However, long‐tongued bumble bees were redistributed toward field interiors and during phacelia bloom honey bees toward field edges. Clover seed yield also increased with increasing size of the flower strip. We conclude that annual flower strips of early flower resources can support bumble bee species richness and, if sufficiently large, possibly also increase crop yields. However, clover seed yield was mainly limited by weevil infestation, which was not influenced by the annual flower strips. A future goal should be to design targeted measures for pest control.

Pollination biology of melittophilous legume tree species in the Atlantic Forest in Southeast Brazil

This study describes the floral phenology and morphology, reproductive biology and pollinators for eight legume tree species, Schizolobium parahyba, Senna macranthera, and Senna multijuga (Caesalpinioideae), as well as Andira fraxinifolia, Lonchocarpus cultratus, Pterocarpus violaceus, Swartzia oblata, and S. simplex (Papilionoideae), in the Atlantic Forest in Southeast Brazil. All the studied species showed an annual flowering pattern, and almost all are of the cornucopia-flowering type, with the only exception being Swartzia oblata, which was of the steady-state type. In general, the legume flowers studied are conspicuous, mostly medium-sized, and offer nectar and/or pollen as a resource. Self-incompatibility associated with the production of many flowers and consequent pollen discounting due to self-pollination may contribute to low fruit set of these species in natural conditions. Fifty bee species were recorded visiting the flowers, with medium to large-sized Apidae bees, such as Bombus morio, and species of Xylocopa, Centridini and Euglossina, which were among the most frequent visitors and major pollinators. These bees showed high floral constancy, thus they are significant to the reproductive success of these tree species. This study provides information regarding the interactions between bees and these eight legume species and evaluates the importance of pollinators for their sexual reproduction.

Selected Cardoon (Cynara cardunculus L.) Genotypes Suitable for PDO Cheeses in Mediterranean Regions.

Cardoon flower extract is a traditional and exclusive rennet used for some PDO cheeses in several Mediterranean regions, due to its extremely high concentration in cardosins. In this preliminary study, six individual cardoon genotypes (1M-6M) were selected because they revealed a wide and consistent diversity of total and specific cardosin concentrations in flowers. During three growing seasons, the stability of 12 biochemical characteristics of flower extracts and 26 plant morphological descriptors was confirmed. Surprisingly, the cardosin profiles of each genotype, based on four main groups A0, A1, A and B, were stable during the annual flower harvesting period and over all threeyears using ion-exchange chromatography and native-PAGE electrophoresis. This knowledge will allow an improvement in the quality and standardization of cardosin profiles from cardoon flowers used for cheese production and other innovative applications. The results obtained are promising for the development of a plant breeding program based on biochemical and morphological characteristics in order to obtain the most adapted plant architecture for combined purposes related to specific cardosins composition, flower and plant biomass production, and ease of harvesting.

Features of vegetation, flowering and fruiting of the genus <i>Spiraea</i> L. species in the cultivation in the European North-East (Republic of Komi)

The paper deals with the flowering and fruiting of introduced species of Spiraea L. genus in the collection of the Botanical garden of the Institute of biology of Komi SC of Ural branch of RAS, located in the middle taiga subzone of the European North-East of Russia. The collection of Spiraea genus by this time includes more than 40 taxa of plants of different geographical origin, including one species of local flora. Characteristics of vegetation, flowering and fruiting indicators of nine species of perennial plants of the genus are given based on the results of phenological observations during five years. It is shown that the seasonal rhythm of plant development in the new conditions corresponds to the climatic conditions of the subzone of the middle taiga. There are differences in the dates of beginning and duration of flowering in different species Spiraea of three sections, the total duration of flowering of studied species is almost 100 days. The species of Spiraria section are characterized by latest start and a long flowering period. Plants of all studied species are characterized by annual flowering and fruiting with the formation of benign seeds; some species are capable of self-seeding. The revealed characteristics allow us to consider that the studied species of Spiraea genus have successfully adapted in the Northern region and can be used in ornamental horticulture.

MicroRNA control of flowering and annual crop cycle in tropical/subtropical horticultural trees

The horticultural tree life cycle can be differentiated into two distinct growth stages – vegetative and reproductive. Unlike annual crops, horticultural tree crops enter into an annual flowering cycle once they attain the reproductive phase. Herein, they undergo various developmental changes including flowering, fruit set, fruit development, fruit ripening, fruit drop and vegetative growth. The annual crop cycle is critical for horticultural crops like Persea americana (avocado) and Macadamia integrifolia (macadamia) as their productivity depends upon successful flowering and fruit development. It is therefore important to understand flowering and the factors involved in the crop cycle in these horticultural trees. Various endogenous and exogenous factors are involved in flowering regulation. Among them a class of small non-coding RNAs known as microRNAs play a vital role. We investigated the expression of flowering-associated miRNAs in avocado and macadamia at distinctive time-points during their annual crop cycle. We looked at the expression of two miRNA that are known act antagonistically during flowering: the floral inhibitor miR156 and the floral promoter miR172, which regulates APETALA2 (AP2)-like transcription factors. Preliminary results from avocado showed no significant difference in the expression of miR156 during the crop cycle, while significant differences were observed for miR172. For both crops, abundance of miR172 was higher during flowering and initial fruiting but lower at fruit ripening and drop/harvest. These results will help us in understanding flowering regulation in horticultural trees by providing first insight into microRNAs and their putative targets in these crops.

Annual cycles are the most common reproductive strategy in African tropical tree communities

AbstractWe present the first cross‐continental comparison of the flowering and fruiting phenology of tropical forests across Africa. Flowering events of 5446 trees from 196 species across 12 sites and fruiting events of 4595 trees from 191 species across 11 sites were monitored over periods of 6 to 29 years and analyzed to describe phenology at the continental level. To study phenology, we used Fourier analysis to identify the dominant cycles of flowering and fruiting for each individual tree and we identified the time of year African trees bloom and bear fruit and their relationship to local seasonality. Reproductive strategies were diverse, and no single regular cycle was found in >50% of individuals across all 12 sites. Additionally, we found annual flowering and fruiting cycles to be the most common. Sub‐annual cycles were the next most common for flowering, whereas supra‐annual patterns were the next most common for fruiting. We also identify variation in different subsets of species, with species exhibiting mainly annual cycles most common in West and West Central African tropical forests, while more species at sites in East Central and East African forests showed cycles ranging from sub‐annual to supra‐annual. Despite many trees showing strong seasonality, at most sites some flowering and fruiting occurred all year round. Environmental factors with annual cycles are likely to be important drivers of seasonal periodicity in trees across Africa, but proximate triggers are unlikely to be constant across the continent.