Molecular regulatory events of flower and fruit abscission in horticultural plants

Flower and fruit abscission is a highly programmed physiological process,which is closely related to the yield of horticultural plants.The coordination of many regulatory factors associated with metabolic and signaling pathways plays a key role in the flower and fruit shedding.Hormones,peptides,carbohydrates,polyamines or cell wall modifying proteins regulate flower and fruit shedding.This article reviewed the recent studies of flower and fruit abscission,including the molecular regulation mechanism of abscission zone formation,typical structure and location of abscission zones,and other factors affecting flower and fruit abscission,such as stresses,hormones,peptides,carbohydrates,polyamines and cell wall modifying proteins.Overall,the review summarizes the developmental mechanism and the diversity of abscission zones,and the key factors affecting flower and fruit abscission of horticultural plants,aiming to provide guidance for studying the molecular regulatory mechanism of flower and fruit abscission.

Convergent relationships between flower economics and hydraulic traits across aquatic and terrestrial herbaceous plants

Maintaining open flowers is critical for successful pollination and depends on long-term water and carbon balance.Yet the relationship between how flower hydraulic traits are coordinated in different habitats is poorly understood.Here,we hypothesize that the coordination and trade-offs between floral hydraulics and economics traits are independent of environmental conditions.To test this hypothesis,we investigated a total of 27 flower economics and hydraulic traits in six aquatic and six terrestrial herbaceous species grown in a tropical botanical garden.We found that although there were a few significant differences,most flower hydraulics and economics traits did not differ significantly between aquatic and terrestrial herbaceous plants.Both flower mass per area and floral longevity were significantly positively correlated with the time required for drying full-hydrated flowers to 70%relative water content.Flower dry matter content was strongly and positively related to drought tolerance of the flowers as indicated by flower water potential at the turgor loss point.In addition,there was a trade-off between hydraulic efficiency and the construction cost of a flower across species.Our results show that flowers of aquatic and terrestrial plants follow the same economics spectrum pattern.These results suggest a convergent flower economics design across terrestrial and aquatic plants,providing new insights into the mechanisms by which floral organs adapt to aquatic and terrestrial habitats.

Analysis on Effects of Chilling Damages on Flowers and Plants at Beibei Area in Winter and Its Prevention Countermeasures

[Objective] The aim was to provide direction for the development of flowers and plants industry at Beibei area of Chongqing.[Method] Effects of temperature ranges and influencing time of chilling damages in winter on local flowers and plants at Beibei area were analyzed,using extreme minimum temperature data during 1960 to 2009 and the phenological growth conditions and phenological observation data of Bougainvillea spectabilis Willd and Michelia champaca during 2005 to 2007 at Beibei area.[Result] Chilling damages affecting flowers and plants at Beibei area mostly emerged from late December to early February,the effects of which were relative serious in January with a temperature range from-2 to 5 ℃;the optimum temperatures were 12-28 ℃ for flowers and plants grown at Beibei area in Chongqing,being higher or lower than that temperature range will affect the normally overwintering flowering and growing;chilling damages affecting the flower seedlings would appear when being at extreme minimum temperatures lower than 6 ℃ for 3 d in any phenophase in winter.[Conclusion] According to the characters of chilling damages in winter,the influences of which on flowers and plants can be reduced through combining tendency prediction and adopting corresponding measures.

Both small and large plants are likely to produce staminate(male)flowers in a hermaphrodite lily

Resource allocation to female and male function may vary among individual plants in species with variable sex expression.Size-dependent sex allocation has been proposed in hermaphrodites,in which female-biased allocation may increase with plant size.In many hermaphrodites with large floral displays,however,later-produced flowers tend to be functionally male.This paradoxical relationship between female and male function and plant size remains poorly understood.The subalpine lily Lilium lankongense has individuals of three sexual types:males with only staminate flowers,hermaphrodites with only perfect flowers,and andromonoecious plants with both perfect and staminate flowers.Here we tested theoretical predictions of size-dependent sex allocation in L.lankongense by measuring plant height and flower number of individuals of each sex at five field sites in the mountainous region of Shangri-La,southwestern China.To investigate variation in phenotypic gender,we identified sex expression of 457 individuals one year later.Our investigation showed that male plants,which usually produced one flower,were significantly smaller than and ro monoecious and hermaphrodite plants.In addition,the total flower numbers of andromonoecious and hermaphrodite plants increased significantly with plant size.Large individuals were more likely to produce terminal staminate flowers,as there were more flowers in andromonoecious than in hermaphrodite individuals.Non-flowered plants were significantly smaller than flowering ones.Perfect flowers had significantly larger petals and pistils than staminate flowers,but they did not differ in dry weight of stamens.Our findings indicate that when plants are small,the less costly sex is favored,consistent with the‘size-advantage hypothesis’.When plants are large,both female and male investments change isometrically,as later-produced flowers tend to be functionally male.

Genetic control of flowering time in woody plants： Roses as an emerging model

Genetic control of the timing of flowering in woody plants is complex and has yet to be adequately investigated due to their long life-cycle and difficulties in genetic modification.Studies in Populus,one of the best woody plant models,have revealed a highly conserved genetic network for flowering timing in annuals.However,traits like continuous flowering cannot be addressed with Populus.Roses and strawberries have relatively small,diploid genomes and feature enormous natural variation.With the development of new genetic populations and genomic tools,roses and strawberries have become good models for studying the molecular mechanisms underpinning the regulation of flowering in woody plants.Here,we review findings on the molecular and genetic factors controlling continuous flowering in roses and woodland strawberries.Natural variation at TFL1 orthologous genes in both roses and strawberries seems be the key plausible factor that regulates continuous flowering.However,recent efforts suggest that a two-recessive-loci model may explain the controlling of continuous flowering in roses.We propose that epigenetic factors,including non-coding RNAs or chromatin-related factors,might also play a role.Insights into the genetic control of flowering time variation in roses should benefit the development of new germplasm for woody crops and shed light on the molecular genetic bases for the production and maintenance of plant biodiversity.

The BnTFL1–BnGF14nu–BnFD module regulates flower development and plant architecture in Brassica napus

Flower development and plant architecture determine the efficiency of mechanized harvest and seed yield in Brassica napus.Although TERMINAL FLOWER 1(AtTFL1)is a regulator of flower development in Arabidopsis thaliana,the function and regulatory mechanism of TFL1 orthologs in B.napus remains unclear.Six BnTFL1 paralogs in the genome of the B.napus inbred line‘K407’showed steadily increasing expression during vernalization.CRISPR/Cas-induced mutagenesis of up to four BnTFL1 paralogs resulted in early flowering and alteration of plant architecture,whereas seed yield was not altered in BnTFL1 single,double,or triple mutants.Six BnTFL1 paralogs,but not BnaA02.TFL1,showed an additive and conserved effect on regulating flowering time,total and terminal flower number,and plant architecture.BnaA10.TFL1 regulates flower development by interacting with BnaA08.FD through the protein BnaA05.GF14nu,resulting in the transcriptional repression of floral integrator and floral meristem identity genes.These findings about the regulatory network controlling flower development and plant architecture present a promising route to modifying these traits in B.napus.

The IDD Transcription Factors:Their Functions in Plant Development and Environmental Response

INDETERMINATE-DOMAIN proteins(IDDs)are a plant-specific transcription factor family characterized by a conserved ID domain with four zinc finger motifs.Previous studies have demonstrated that IDDs coordinate a diversity of physiological processes and functions in plant growth and development,including floral transition,plant architecture,seed and root development,and hormone signaling.In this review,we especially summarized the latest knowledge on the functions and working models of IDD members in Arabidopsis,rice,and maize,particularly focusing on their role in the regulatory network of biotic and abiotic environmental responses,such as gravity,temperature,water,and pathogens.Understanding these mechanisms underlying the function of IDD proteins in these processes is important for improving crop yields by manipulating their activity.Overall,the review offers valuable insights into the functions and mechanisms of IDD proteins in plants,providing a foundation for further research and potential applications in agriculture.

Diversity of Flowering Plants in Nubri Valley, Manaslu Conservation Area, Central Nepal

Central Nepal has long history in the field of botanical investigation in contrast with different parts of the nation. Nevertheless, the present study area (Manaslu Conservation Area) is still under-explored. The present floristic study was carried out with the aim of fulfilling this gap by giving particular attention on flowering plants and their documentation. Two field visits were directed in May-June 2012 and September-October 2012 in two unique seasons with a specific end goal to gather plant samples of both seasons. On the contrary, herbarium specimens were prepared and later identified at Tribhuvan University Central Herbarium (TUCH) and National Herbarium and Plant Laboratory (KATH). The present study uncovers the presence of 276 species of flowering plants belonging to 78 families and 200 genera of which 63 families belong to dicotyledons and 15 families belong to monocotyledons. Among these, 17 species (6.15%) of climbers, 178 species (64.49%) of herbs, 58 species (21.01%) of shrubs and 23 species (8.33%) of trees are found. Economically important flowering plants comprise about 156 species where 75 species are used as medicine, 29 species as fuel wood, 23 species as fodder, 29 species are edible, 6 species are for religious purpose, 5 specifically for construction purpose, 10 for ornamental and 13 species reported to have miscellaneous uses. MCA accounts to 9 flowering plant species for research and development and agro-technology development and 12 species are listed under IUCN and CAMP threatened categories. MCA and its affinity are likewise house to 10 endemic flowering plants. As from the study it can be inferred that Manaslu Conservation Area (MCA) is a treasure hub of flowering plants that not only represent its economic importance rather it is also a house to threaten and endemic flowering plants. Thus, proper management plans must be implemented for the conservation of resources in MCA.

Sex Determination and Sexual Organ Differentiation in Flowering Plants

The research in the genetics of sex determination and the differentiation of reproductive organs in flowering plants has long been a topic in recent years. Understanding the genetic and molecular mechanisms that control sex determination in flower- ing plants relies on detailed studies of the differentiation of sexual organs. Current theories about sex chromosomes have illuminated the mechanisms of plant sex determination. In addition, recent progress in cloning floral homeotic genes which regulate the identity of the floral organs has generated molecular markers to compare the developmental programs of male, female and hermaphrodite flowers in several species. In this review, the authors focus attention on these recent findings and provide a brief overview of the genetics of plant sex determination and the mechanism of sex determination gene expression and gene programs.

How Do Flowering Plants Make New Plants?

You have learned about seeds,pollen,stems,roots,flowers and pollination about some of the plants.Are you sure that you’re clear about them?Here are some questions below for you to test yourself.Just choose the correct option,A,B or C.

Effect of vernalization and plant growth regulators on flowering of Onithogalum ‘Chesapeake Snowflake’

The effect of vernalization and two growth regulators Fascination^TM and Pro-Gibb^R on the growth, inflorescence development and flowering of Omithogalurrt Chesapeake Snowflake＇ was studied. Regardless of growth regulator treatment, chilling bulbs for 3 weeks at 10℃ before planting accelerated flowering of the first inflorescence by 5 to 6 days, elongated floral stem length by 1.5 to 2 cm and shortened leaf length by 4 to 5 cm as compared with non-chilled bulbs. When bulbs were chilled 3 weeks at 10℃ before planting, Fascination 2% and Pro-Gibb accelerated flowering of the first inflorescence by 2 to 6 days respectively as compared with the control. When bulbs were not chilled before planting, Fascination 2% and Pro-Gibb accelerated flowering of the first inflorescence by 6 to12 days respectively as compared with the control. The lengths of the leaves and the inflorescences were not affected by PGR treatment. Higher rates of Pro-Gibb （100 mg.L^-1 and 200 mg.L^-1） and more amount of Fascination 2%（100 μL and 200 μL） can cause abortion of inflorescence.

Establishment and Application of Flower Border Plant Database for Beijing

Through field investigation and phenological observation, Microsoft Access database management system is used to establish a relatively comprehensive database of flower border plant materials for Beijing which can provide multi-perspective retrieval channels, so as to effectively select materials for designing and building flower borders.

Early Cretaceous Archaefructus eoflora sp. nov. with Bisexual Flowers from Beipiao, Western Liaoning, China

Recently, whether Archaefructus has bisexual multi-parted flowers or just inflorescences of unisexual flowers, and whether it is ancestral to all angiosperms or a derived eudicot have been debated. Here, from the same Yixian Formation, NE China, we report a new Archaefructus species, A. eoflora sp. nov., with the generic characteristics of dissected leaves and bisexual reproductive axes. It is entirely preserved with roots, rhizome, shoots and protogynous reproductive organs at different developmental stages. Its lateral and main fertile shoots form a pseudo-indeterminate pattern, while the reproductive branches on the main shoot form a cymose inflorescence. Subtended by 1-2 bract-like leaves, the section of stamen clusters changes into a much shorter section of carpels that have one row of orthotropous ovules. Significantly, one cluster bearing two carpels and one stamen between the two sections demonstrates a true bisexual flower, an important step of the origin of floral bisexuality, and the homology between the stamen and carpel. The complex reproductive axes represent a mix between flowers and inflorescences, and suggest that A. eoflora sp. nov. possesses the potential to evolve into a variety of diverse flower types as found in modern basal and early fossil angiosperms. A comparison with other two species also leads to a revision of the generic diagnosis.

Volatiles from Sophora japonica flowers attract Harmonia axyridis adults(Coleoptera: Coccinellidae)

The multicolored Asian lady beetle, Harmonia axyridis(Coleoptera: Coccinellidae), is a common generalist predator in China and is occasionally found gathering on the Chinese pagoda tree, Sophora japonica, in summer. In a field investigation, we found that H. axyridis adults preferred S. japonica during its flowering period even though their optimal prey(aphid) is absent at this time. In addition, male and female adults were attracted to S. japonica flowers to a similar extent in a Y-tube olfactometer assay. Using coupled gas chromatography-electroantennogram detection(GC-EAD), we identified a flower odor component(nonanal) that elicited a significant electrophysiological response in H. axyridis. Electroantennogram(EAG) dose-dependent responses revealed that the amplitude of the adult beetle's EAG response increased with increasing concentration of nonanal, peaking at 10 mg mL^(–1). In Y-tube olfactometer behavioral tests, H. axyridis adults preferred a 10 mg mL^(–1) nonanal source over a 100 mg mL^(–1) diluent. Under field conditions, the adults were significantly attracted to both concentrations(10 and 100 mg mL^(–1)), and high concentrations generally had greater attraction. All these results suggest that nonanal, a volatile compound of S. japonica flowers, greatly attracts H. axyridis adults. This study provides a basis for the development of synthetic attractants of H. axyridis, with the potential to promote biocontrol services of this generalist predator in the native area(e.g., China) and to suppress its population by mass trapping in its invasive areas.

Effects of Two Composted Plant Pesticide Residues,Incorporated with Trichoderma viride,on Root-Knot Nematode in Balloonflower

Plant pesticide residues, such as chinaberry （Melia toosendan） residue and sand cypress （Sabina vulgaris） residue, are pesticidal plant materials discarded after the bioactive ingredient has been extracted with organic solvents. The only option for botanical pesticide residue utilization has been as landfill. Chinaberry residue （CBR） and sand cypress residue （SCR） were collected and composted in Yangling, Shaanxi Province, China. We studied the effects of chinaberry residue compost （CBRC）, CBRC incorporated with Trichoderma viride （CBRCT）, sand cypress residue compost （SCRC）, and SCRC incorporated with T. viride （SCRCv） on the root-knot nematode, Meloidogyne incognita, infesting the balloonflower （Platycodon grandiflorum）. Bioassay results indicated that stock solutions of the CBRCT and SCRCT extracts significantly inhibited egg hatching and caused high larval mortality, followed in degree by the CBRC and SCRC extracts. The CBR and SCR extracts caused very low inhibition of eggs and larvae. Supplementing potting mixtures with these four composts reduced the severity of root galling and increased the proportion of marketable roots. The severity of root galling decreased and the average weight of the marketable roots increased with an increase in all the composts when supplemented at rates from 5 to 30%. CBR- and SCR-supplemented pot soils also inhibited the nematodes, but CBR and SCR applied to the soil had a phytotoxic effect and inhibited balloonflower growth. Supplementing field soil with the composts reduced the severity of root galling and the populations of southern root-knot nematodes in the soil. CBRCT and SCRCT clearly enhanced the average weight of the marketable roots by 30.45 and 26.64%, respectively. Continuous supplementation with CBRCT or SCRCT in the same field significantly enhanced the control of the root-knot nematode, and the populations of nematodes continued to decrease with second inoculations. The populations of total Trichoderma spp. were distinctly enhanced and were maintained at high levels for a long time in the supplemented soils.

Exploitation of Wild Flowers and the Sustainable Development of Flowers Industry in China

This article introduced the new methods on the research of the wild flowers and plants idioplasmic resources, elaborated the introduction and domestication and exploitation of wild flowers and plants idioplasmatic resources and the sustainable development of flowers and plants industry in China, and put forward some proposals on the existing question and the prospects for the development.

Mapping QTL for flowering time-related traits under three plant densities in maize

Flowering time is an indicator of adaptation in maize and a key trait for selection in breeding.The genetic basis of flowering time in maize,especially in response to plant density,remains unclear.The objective of this study was to identify maize quantitative trait loci(QTL)associated with flowering time-related traits that are stably expressed under several plant densities and show additive effects that vary with plant density.Three hundred recombinant inbred lines(RIL)derived from a cross between Ye 478 and Qi 319,together with their parents,were planted at three plant densities(90,000,120,000,and 150,000 plants ha^(-1))in four environments.The five traits investigated were days to tasseling(DTT),days to silking(DTS),days to pollen shed(DTP),interval between anthesis and silking(ASI),and interval between tasseling and anthesis(TAI).A high-resolution bin map was used for QTL mapping.In the RIL population,the DTT,DTS,and DTP values increased with plant density,whereas the ASI and TAI values showed negligible response to plant density.A total of 72 QTL were identified for flowering time-related traits,including 15 stably expressed across environments.Maize flowering time under different densities seems to be regulated by complex pathways rather than by several major genes or an independent pathway.The effects of some stable QTL,especially qDTT8-1 and qDTT10-4,varied with plant density.Fine mapping and cloning of these QTL will shed light on the mechanism of flowering time and assist in breeding earlymaturing maize inbred lines and hybrids.

Impact of mechanical stimulation on the life cycle of horticultural plant

Mechanical stimulation technology is critical in agricultural crop production because it is constantly regarded as a developing green technology to regulate plants to meet people's need for green and healthy agricultural products. Various environmental mechanical stimulation impacts seed germination, seedling growth, flowering date, fruit quantity, and fruit quality throughout the life cycle of a horticultural plant. This study first outlines the basic characteristics of six types of common mechanical stimulation in nature:precipitation, wind, gravity,touch, sound, and vibration. The effects of various mechanical stimulation types on the seed, seedling, flowering, and fruit of horticultural plants throughout their whole life cycle are then presented, as reviewed in the recent 100 years of existing literature. Finally, potential future study directions are discussed. The main challenge in mechanical stimulation technology is to uncover its potential capabilities for regulating and controlling plant development and fruit quality in green agriculture instead of agricultural chemicals.

Foraging Behaviour of <i>Apis mellifera</i>L. and <i>Scaptotrigona bipunctata</i>on <i>Dombeya wallichii</i>Flowers in Southern Brazil

This research was carried out to evaluate the foraging behaviour of Apis mellifera and Scaptotrigona bipunctata and its relationship with environmental variables in Dombeya wallichii considering the following aspects: 1) Type of resource harvested, 2) Visitation rate, 3) Length of visit, 4) sugar concentration in the stored nectar in the honey crop of A. mellifera and secreted by the flower and 5) floral constancy. Both species collected mainly nectar, with a visitation rate of 4.2 flowers for A. mellifera and 1.1 flowers for S. bipunctata and visit length of 9.2 and 34.2 seconds, respectively. The sugar concentration had a positive relationship with temperature and luminosity, with mean values of 12.3% in the nectar and 14.2% in the honey crop. Bees were classified by specialists because the pollen of D. wallichii was predominant in the pollen basket, but the pollen of Emilia sonchifolia and Raphanus sativus was also found. These results suggest that the species under study take advantage of the resources offered by D. wallichii, therefore, this species is an important source for the maintenance of the bees in the season of lack of food.

Effect of Shoot Control on Flower Bud Differentiation,Flowering,and Fruit Setting in Zanthoxylum armatum DC.

In this study,newly sprouted shoots of Zanthoxylum armatum(Z.armatum),which were collected after the harvesting period,were used as the primary experimental specimens.A randomized block design and paraffin sectioning method were used to investigate the flower bud differentiation process and the quantity and vitality of buds.Furthermore,the study examined the response of flowering and fruiting to cultivation methods for shoot growth,including layering and plant growth regulator application.The results showed that(a)layering and application of plant growth regulators for Z.armatum accelerated the process of flower bud differentiation by approximately 20 days compared to the control group.Additionally,both shoot control methods generated more and larger bud primordia and perianth primordia during the same differentiation phase.(b)The application of plant growth regulators resulted in well-developed buds,exhibiting higher levels of flower bud differentiation than the layering method.The quality of flower bud formation for both shoot control methods was superior to that of the control group.(c)The flowering phenological period was relatively consistent between the two cultivation methods,but the fruit maturity phase for shoot-controlled trees occurred 20 days earlier than the control group.(d)Both layering and the application of plant growth regulators significantly decreased the rates of unfertilized flower shedding and fruit shedding.However,no significant difference was noted in fruit setting per inflorescence and per flower between the two methods and the control.The effect of altitude for both methods on the fruit setting was not significant.Under both shoot control methods,the Z.armatum exhibited earlier morphological differentiation of flower buds,faster differentiation process,improved flower bud quality,and significantly decreased rates of flower and fruit shedding.Thus,these cultivation methods demonstrated the potential to promote flowering,improve fruit setting,and reduce fruit shedding in Z.armatum.