Flowering Response Research Articles

Hydrothermally derived zinc sulfide sphere-decorated titanium dioxide flower-like composites and their enhanced ethanol gas-sensing performance

Zinc sulfide (ZnS) sphere-decorated titanium dioxide (TiO2) flowers at various ZnS hydrothermal synthesis durations were synthesized using a two-step facile hydrothermal methodology. The ZnS hydrothermal synthesis duration affected the content and distribution of ZnS spheres decorated on the surfaces of TiO2 petals. Thus, the separate and random distribution of these spheres, without considerable aggregation, could be obtained by adequately controlling the ZnS hydrothermal synthesis duration. A structural analysis demonstrated that the as-synthesized ZnS spheres and TiO2 flowers were in crystalline cubic zinc blend and rutile phases, respectively. Moreover, the gas-sensing response of the TiO2 flowers to ethanol vapor markedly enhanced after the decoration of the ZnS spheres. An optimal ZnS hydrothermal synthesis duration of 2 h for the TiO2–ZnS composites was determined to result in the highest gas-sensing response at the given gas-sensing test condition. The strongly favorable ion–species interactions in the gas sensing of ZnS spheres and the formation of TiO2/ZnS heterojunctions in the TiO2–ZnS composites accounted for the enhanced gas-sensing responses of TiO2 flowers decorated with ZnS spheres in this study.

Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco

Optimal defense (OD) theory predicts that within a plant, tissues are defended in proportion to their fitness value and risk of predation. The fitness value of leaves varies greatly and leaves are protected by jasmonate (JA)-inducible defenses. Flowers are vehicles of Darwinian fitness in flowering plants and are attacked by herbivores and pathogens, but how they are defended is rarely investigated. We used Nicotiana attenuata, an ecological model plant with well-characterized herbivore interactions to characterize defense responses in flowers. Early floral stages constitutively accumulate greater amounts of two well-characterized defensive compounds, the volatile (E)-α-bergamotene and trypsin proteinase inhibitors (TPIs), which are also found in herbivore-induced leaves. Plants rendered deficient in JA biosynthesis or perception by RNA interference had significantly attenuated floral accumulations of defensive compounds known to be regulated by JA in leaves. By RNA-seq, we found a JAZ gene, NaJAZi, specifically expressed in early-stage floral tissues. Gene silencing revealed that NaJAZi functions as a flower-specific jasmonate repressor that regulates JAs, (E)-α-bergamotene, TPIs, and a defensin. Flowers silenced in NaJAZi are more resistant to tobacco budworm attack, a florivore. When the defensin was ectopically expressed in leaves, performance of Manduca sexta larvae, a folivore, decreased. NaJAZi physically interacts with a newly identified NINJA-like protein, but not the canonical NINJA. This NINJA-like recruits the corepressor TOPLESS that contributes to the suppressive function of NaJAZi on floral defenses. This study uncovers the defensive function of JA signaling in flowers, which includes components that tailor JA signaling to provide flower-specific defense.

Phylogenetic conservatism and trait correlates of spring phenological responses to climate change in northeast China.

Climate change has resulted in major changes in plant phenology across the globe that includes leaf‐out date and flowering time. The ability of species to respond to climate change, in part, depends on their response to climate as a phenological cue in general. Species that are not phenologically responsive may suffer in the face of continued climate change. Comparative studies of phenology have found phylogeny to be a reliable predictor of mean leaf‐out date and flowering time at both the local and global scales. This is less true for flowering time response (i.e., the correlation between phenological timing and climate factors), while no study to date has explored whether the response of leaf‐out date to climate factors exhibits phylogenetic signal. We used a 52‐year observational phenological dataset for 52 woody species from the Forest Botanical Garden of Heilongjiang Province, China, to test phylogenetic signal in leaf‐out date and flowering time, as well as, the response of these two phenological traits to both temperature and winter precipitation. Leaf‐out date and flowering time were significantly responsive to temperature for most species, advancing, on average, 3.11 and 2.87 day/°C, respectively. Both leaf‐out and flowering, and their responses to temperature exhibited significant phylogenetic signals. The response of leaf‐out date to precipitation exhibited no phylogenetic signal, while flowering time response to precipitation did. Native species tended to have a weaker flowering response to temperature than non‐native species. Earlier leaf‐out species tended to have a greater response to winter precipitation. This study is the first to assess phylogenetic signal of leaf‐out response to climate change, which suggests, that climate change has the potential to shape the plant communities, not only through flowering sensitivity, but also through leaf‐out sensitivity.

Dynamic transcriptomic analysis of the early response of female flowers of Populus alba\u2009\xd7\u2009P. glandulosa to pollination

Pollination is an important event in plant sexual reproduction, and post-pollination response is an essential process for reproduction. Populus alba × P. glandulosa is used widely in scientific research, especially in cross breeding as parents. Adult female P. alba × P. glandulosa flowers are highly compatible with pollen from male P. tomentosa, but the early post-pollination response of flowers at the molecular levels is unclear. In this study, RNA-seq was employed to comprehensively understand the response of female P. alba × P. glandulosa flowers to pollination. Enrichment analysis reveals that the ‘plant hormone signal transduction’ pathway is enhanced during pollen-pistil interaction. Moreover, genes related to auxin, gibberellin and ethylene biosynthesis were significantly up-regulated. Ca2+ and H+-related genes and cell wall-related genes are interrelated, and all of them are essential for pollen tube elongation in pistil, especially, free Ca2+ providing a concentration gradient for pollen tube guidance and involved in signal transduction. Furthermore, RNA-seq results indicate that genes involved in the adhesion and guidance for pollen germination and pollen tube growth are abundantly present in the extracellular matrix. Our study provides an overview and detailed information for understanding the molecular mechanism of early post-pollination response in this hybrid poplar reproduction.

Crop-model assisted phenomics and genome-wide association study for climate adaptation of indica rice. 1. Phenology.

Phenology and time of flowering are crucial determinants of rice adaptation to climate variation. A previous study characterized flowering responses of 203 diverse indica rices (the ORYTAGE panel) to ten environments in Senegal (six sowing dates) and Madagascar (two years and two altitudes) under irrigation in the field. This study used the physiological phenology model RIDEV V2 to heuristically estimate component traits of flowering such as cardinal temperatures (base temperature (Tbase) and optimum temperature), basic vegetative phase, photoperiod sensitivity and cold acclimation, and to conduct a genome-wide association study for these traits using 16 232 anonymous single-nucleotide polymorphism (SNP) markers. The RIDEV model after genotypic parameter optimization explained 96% of variation in time to flowering for Senegal alone and 91% for Senegal and Madagascar combined. The latter was improved to 94% by including an acclimation parameter reducing Tbase when the crop experienced low temperatures during early vegetative development. Eighteen significant (P<1.0 × 10-5) quantitative trait loci (QTLs) were identified, namely ten for RIDEV parameters and eight for climatic index variables (difference in time to flowering between key environments). Co-localization of QTLs for different traits were rare. RIDEV parameters gave QTLs that were mostly more significant and distinct from QTLs for index variables. Candidate genes were investigated within the estimated 50% linkage disequilibrium regions of 39 kB. In addition to several known flowering network genes, they included genes related to thermal stress adaptation and epigenetic control mechanisms. The peak SNP for a QTL for the crop parameter Tbase (P=2.0 × 10-7) was located within HD3a, a florigen that was recently identified as implicated in flowering under cool conditions.

Growth and nutrient composition of platycodon grown in media amended with pellets processed with poultry feathers

Growth and flowering of Platycodon grandiflorus (Jacq.) A. DC. ‘Sentimental Blue’ was evaluated in growing media amended with pellets (P) processed with poultry feather keratins with and without application of slow-release fertilizer. Macro- and micro-nutrients in the media were analyzed in pellets before and after mixing them with peatmoss (PM) during plant growth and flowering. Peatmoss was mixed with pellets at the ratio of 4 to 1 by volume. Leachates and leaf tissues were analyzed during plant culture. Pellets were grouped into treatments of (a) pellets with shredded or powdered forms of poultry feather keratin, (b) pellets containing polyactide as a substitution for perlite, and (c) pellets enriched with urea to evaluate if these pellets function as a slow-release fertilizer when mixed with PM. The number of days to anthesis was shorter in PM medium supplemented with P45-1, P45-2, and P84 than in other media. The number of branches, flowers, and fresh weight was greater in the media with P45-2 mixed in with PM and Osmocote (OS) application. Pellet45-2 is recommended as an inert material to prepare a new soilless growing medium. Pellets made from long fiber or long fiber plus powder forms of feather keratin did not affect growth and flowering. Low levels of soluble salts (EC) in the media and leachates 60 days after seedling transplantation suggested that additional fertilizer is required during culture. Inferior plant growth and flowering in the medium containing polylactide was not observed with Osmocote application during 60 days of growth. The feasibility of testing pellets enriched with urea (P73 Urea) as a source of slow release nitrogen should be considered carefully due to the high concentration of NH4-N in the media. Based on the growth and flowering responses and on the concentrations of macro- and micro-nutrients in the media, leachates, and leaf tissue, P45-2 can be used to prepare a growing medium with PM. The suggested ranges compiled for general ornamental plants can be recommended for platycodon ‘Sentimental Blue’ based on concentrations of macro- and micro-nutrients in growing media, leachates, and leaf tissue.

Artificial targeting of a nucleus-encoded RNA-binding protein AtRZ1a to chloroplasts affects flowering and ABA response of Arabidopsis thaliana

Despite the fact that many nucleus-encoded RNA-binding proteins (RBPs) are targeted to chloroplasts and play essential roles in RNA metabolism in chloroplasts, the question of whether artificial targeting of a nucleus-encoded RBP to chloroplasts affects chloroplast function and plant growth has never been addressed. In this study, a nuclear zinc finger-containing Arabidopsis RBP, designated AtRZ1a, which was previously shown to play a role in stress response, was artificially targeted to chloroplasts, and the growth and stress response of the transgenic plants were evaluated. Confocal analysis of the cellular localization of the cTP_AtRZ1a protein containing the N-terminal chloroplast transit peptide (cTP) from rubisco small subunit revealed that the cTP_AtRZ1a fusion protein is successfully targeted to chloroplasts. When grown under normal conditions, flowering of the transgenic plants was delayed, and the FLC expression was significantly upregulated in the transgenic plants. Artificial targeting of AtRZ1a to chloroplasts severely inhibited seedling growth of the plants in the presence of ABA by upregulating expression of ABA signaling-related genes ABI3 and ABI4. Taken together, these results suggest that artificial targeting of a nucleus-encoded AtRZ1a to chloroplasts affects the growth and development of Arabidopsis under normal or ABA treated conditions.

Growth and flowering response of Chrysanthemum morifolium cultivar Anmol to different growth retardants

An experiment was conducted at the experimental farm of Department of Floriculture and Landscaping, Punjab Agricultural University from 2015 to 2016 with the objective to standardize the optimum concentration of different growth retardants for alteration of plant architecture and improvement of flowering parameters in chrysanthemum (Chrysanthemum morifolium Ramat.) cv. Anmol. The experiment was conducted in completely randomized design (CRD) with three replications comprising ten pots per replication. Cycocel (@ 500, 750, 1000, 1250 and 1500 ppm), Daminozide (@ 500, 750 and 1000 ppm) and Ethephon (@ 250, 500 and 1000 ppm) were sprayed on chrysanthemum cv. Anmol (spray type) after one month of transplanting. The effect of growth retardants in reduction of plant height followed the order daminozide&gt; ethephon&gt; cycocel. Internodal length was much reduced by daminozide @ 1000 ppm. Highest plant spread, diameter of main stem and leaf area was obtained under daminozide @ 1000 ppm. Floral characters like days to bud appearance, days to colour break stage and days to full bloom stage was obtained earlier in daminozide @ 1000 ppm and later in ethephon @ 1000 ppm. Flower diameter was much increased by daminozide @ 500 ppm. Highest number of flowers/plant was obtained under daminozide @ 1000 ppm. Highest duration of flowering was obtained under daminozide @ 1000 ppm and minimum under ethephon @ 1000 ppm.

The Divergence of Flowering Time Modulated by FT/TFL1 Is Independent to Their Interaction and Binding Activities.

FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) proteins share highly conserved amino acid residues but they play opposite regulatory roles in promoting and repressing the flowering response, respectively. Previous substitution models and functional analysis have identified several key amino acid residues which are critical for the promotion of flowering. However, the precise relationship between naturally occurring FT/TFL1 homologs and the mechanism of their role in flowering is still unclear. In this study, FT/TFL1 homologs from eight Rosaceae species, namely, Spiraea cantoniensis, Pyracantha fortuneana, Photinia serrulata, Fragaria ananassa, Rosa hybrida, Prunus mume, Prunus persica and Prunus yedoensis, were isolated. Three of these homologs were further characterized by functional analyses involving site-directed mutagenesis. The results showed that these FT/TFL1 homologs might have diverse functions despite sharing a high similarity of sequences or crystal structures. Functional analyses were conducted for the key FT amino acids, Tyr-85 and Gln-140. It revealed that TFL1 homologs cannot promote flowering simply by substitution with key FT amino acid residues. Mutations of the IYN triplet motif within segment C of exon 4 can prevent the FT homolog from promoting the flowering. Furthermore, physical interaction of FT homologous or mutated proteins with the transcription factor FD, together with their lipid-binding properties analysis, showed that it was not sufficient to trigger flowering. Thus, our findings revealed that the divergence of flowering time modulating by FT/TFL1 homologs is independent to interaction and binding activities.

Transcriptional changes in litchi (Litchi chinensis Sonn.) inflorescences treated with uniconazole.

In Arabidopsis, treating shoots with uniconazole can result in enhanced primary root elongation and bolting delay. Uniconazole spraying has become an important cultivation technique in controlling the flowering and improving the fruit-setting of litchi. However, the mechanism by which uniconazole regulates the complicated developmental processes in litchi remains unclear. This study aimed to determine which signal pathways and genes drive the responses of litchi inflorescences to uniconazole treatment. We monitored the transcriptional activity in inflorescences after uniconazole treatment by Illumina sequencing technology. The global expression profiles of uniconazole-treated litchi inflorescences were compared with those of the control, and 4051 differentially expressed genes were isolated. KEGG pathway enrichment analysis indicated that the plant hormone signal transduction pathway served key functions in the flower developmental stage under uniconazole treatment. Basing on the transcriptional analysis of genes involved in flower development, we hypothesized that uniconazole treatment increases the ratio of female flowers by activating the transcription of pistil-related genes. This phenomenon increases opportunities for pollination and fertilization, thereby enhancing the fruit-bearing rate. In addition, uniconazole treatment regulates the expression of unigenes involved in numerous transcription factor families, especially the bHLH and WRKY families. These findings suggest that the uniconazole-induced morphological changes in litchi inflorescences are related to the control of hormone signaling, the regulation of flowering genes, and the expression levels of various transcription factors. This study provides comprehensive inflorescence transcriptome data to elucidate the molecular mechanisms underlying the response of litchi flowers to uniconazole treatment and enumerates possible candidate genes that can be used to guide future research in controlling litchi flowering.

Growth and flowering response of flamingo flower on selected growth media

Growth and flowering response of flamingo flower on selected growth media

Flowering responses of North American strawberry cultivars

Flowering responses of North American strawberry cultivars

Growth and Flowering Response of Domestic Bred Gypsophila ‘Dream Song’ as Affected by Heating Time in Plain Area

Growth and Flowering Response of Domestic Bred Gypsophila ‘Dream Song’ as Affected by Heating Time in Plain Area

Influence of differing nitrate and nitrogen availability on flowering control in Arabidopsis.

Nitrogen, an essential macronutrient for plants, regulates many aspects of plant growth and development. Nitrate is one of the major forms of nitrogen taken up by plants from the soil. Nitrate and nitrogen have been reported to regulate flowering; while some studies have shown that lower nitrate/nitrogen promoted flowering, others have reported the opposite trend. To elucidate how nitrate/nitrogen affects flowering, we reviewed the existing literature and conducted experiments to examine flowering time under a wide range of nitrate concentrations using two growth systems. From the literature review and our experiments, we established that differing nitrate availability results in a U-shaped flowering curve, with an optimal concentration of nitrate facilitating flowering and concentrations above or below this optimal concentration delaying flowering. The role of nitrate and nitrogen in regulating flowering has been elucidated by several transcriptomic and mutant studies, which have suggested close interactions between nitrate/nitrogen, phosphate, the circadian clock, photosynthesis, and, potentially, hormones. We discuss several possible molecular mechanisms underlying the U-shaped flowering response.

Progress towards flowering of faba bean (Vicia faba L.) is more than photothermal

AbstractPredicting and understanding the progress towards flowering in faba bean are important to achieve the adaptation and high productivity of the crop under varying environmental conditions. Traditional controlled‐environment experiments showed that the rate of progress towards flowering was dependent mainly on photoperiod and temperature. Here, we highlight the need to include measures of solar radiation and water deficit in order to achieve an adequate model for field conditions. The improved model was assessed in two steps: first with a “basic” model across all 20 cultivars and then with an “extended” model that included terms to fit exceptional cultivars. The two new parameters were necessary to achieve an acceptable fit of progress towards flowering and clearly separated two cultivars, “Kontu” and “Witkiem Manita,” that were significantly quicker to flower than the other 18, which fit a single line. As the regression coefficients of the two exceptional cultivars differed only in intercept, not slope, we conclude that flowering responses to day length, temperature, solar radiation and drought stresses were consistent in this set of germplasm and that the two cultivars differed in earliness “per se.” Growth‐chamber experiments added information about differing ceiling temperatures for progress to flowering in four cultivars and different sensitivities to supraoptimal temperatures.

Delayed response of spring phenology to global warming in subtropics and tropics

Climate drivers of plant phenology in the subtropics and tropics are still unclear, which significantly hinders accurate prediction of climate change impacts on vegetation growth and carbon balance in these unique ecoregions. The basic hypothesis of process-based phenology models is that spring tree phenology is regulated by temperature and triggered by chilling temperatures during the dormancy period, followed by forcing temperatures during the growth period. That is, trees require cool temperatures during a chilling period to break endodormancy, and then enter the phase of ecodormancy during which the rate of ontogenetic development increases with increasing air temperature. Therefore, insufficient chilling requirements may slow bud growth and consequently delay budburst. Many studies have shown that chilling requirement is at present sufficient to release bud dormancy fully in temperate regions, and thus forcing temperatures play a dominant role in triggering spring tree phenology. To identify differences in mechanisms of spring tree phenology responses to air temperature between the subtropics/tropics and the temperate zone, and their possible effects on future phenological trends under global warming, we used leaf unfolding and flowering data from a tree species of tropical origin, Melia azedarach, and output daily mean air temperature data from a regional climate model (HadGEM3-RA) for the period 1981–2005 at 42 stations in southeastern China to fit unified forcing and chilling phenology models. Then, we selected optimum models for each phenophase at each station. Moreover, we predicted leafing and flowering dates across the research region over 2021–2100 under global climate warming scenarios. The results show a previously unreported phenological phenomenon: chilling will often be insufficient to break bud dormancy in the northern tropical zone and may become a crucial factor limiting leafing and flowering responses to spring warming. However, chilling will still be sufficient to break bud dormancy in the warm temperate zone, and thus may not limit leafing and flowering responses to spring warming there. Consequently, predicted leafing and flowering dates both will be delayed in the northern tropical zone but will advance in the warm temperate zone from 2021 to 2100. In the subtropical zone, the effect of chilling temperature on spring phenology will be reduced gradually from earlier to later phenophases. Thus, predicted leafing and flowering dates show decreased delaying trends and increased advancing trends from earlier to later phenophases in the subtropical zone. Our findings suggest that insufficient chilling temperature accumulation during the dormancy period may counteract the forcing temperature accumulation during the growth period in the northern tropical zone and parts of the subtropical zone, resulting in delayed leafing and flowering dates.

Multivariate Analysis in Determining Morphologically Diverse Sugarcane Genotypes (Saccharum officinarum L.) and their Flowering Response at Arja, Azad Kashmir

Multivariate Analysis in Determining Morphologically Diverse Sugarcane Genotypes (Saccharum officinarum L.) and their Flowering Response at Arja, Azad Kashmir

シュッコンカスミソウにおける青色光に関連した花成関連遺伝子と花成応答の解析

シュッコンカスミソウにおける青色光に関連した花成関連遺伝子と花成応答の解析

Changes in postharvest physio-biochemical characterustics and antioxidant enzymes activity of cut alsteroemeria aurantiaca flower as affected by cycloheximide, coconut water and 6-benzyladenine

Early leaf yellowing in cut alstroemeria ( Alstroemeria aurantiaca ) flowers before flower development and petal abscission is an important limiting postharvest quality and vase life factors. Early leaf senescence reduces postharvest longevity of cut flowers and promotes petal's wilting. A study was made to evaluate the response of cut alstroemeria flowers at varying concentrations of cycloheximide (CHI) (50, 100 and 200 mg l -1 ), coconut water (5, 10 and 20%) and 6-benzyladenine (BA) (50, 100 and 200 mg l -1 ). CHI, coconut water and BA extended the vase life at all concentrations compared to the control, but coconut water at 5% concentration (with 17.39 days) was the most effective treatment. Control cut flowers showed the least vase life (10.76 days). Ethylene production in cut flowers promoted flower senescence. All concentrations of CHI, coconut water and BA delayed ethylene production compared to the control. Treatment of cut flowers with coconut water at concentration of 5% maintained the highest fresh weight of flowers and increased the content of water uptake. The chlorophyll degradation was significantly reduced by the application of CHI, coconut water and BA. The maximum content of membrane's lipid peroxidation and antioxidant enzymes activity (super oxide dismutase and peroxidase) was obtained in control cut flowers. Thus, 5% fresh coconut water has the potential to be applied as vase solution (preservative medium) due to prolongs of cut alstroemeria flowers.

Fall nitrogen enhances spring nitrogen enhanced flowering in the long day strawberry cultivar ‘Elan’

Architectural analysis describes the position and fate (vegetative or floral) of plant meristems to account for differences in their sensitivity to stimuli depending on developmental stage and position on the plant. To provide further insight into the flowering responses of long day strawberries to nitrogen, ‘Elan’ seedlings were fertilized in mid-October, overwintered in a greenhouse, then dissected the following March and their floral architecture evaluated. Additional plants from fall N treatments were placed under ND and fertilized weekly for four weeks with 100, 400, 800 or 1200 ppm N during greenhouse-forcing under ND and growth monitored until June. Plants were dissected after forcing and their floral architecture evaluated. Fall fertilized plants were significantly more floral than non-fertilized controls before forcing. Some axillary buds of fertilized plants formed floral branch crowns but there were no floral branch crowns on non-fertilized plants. Precocity was not affected by fall N and 400, 800 or 1200 ppm spring N were equally effective in accelerating flowering (+1 week) compared to 100 ppm spring N. Fall N enhanced the number of inflorescences and flowers produced by the primary crown. Spring N enhanced flowering of branch crowns and the total numbers of inflorescences and flowers per plant. Inflorescence production was a qualitative response to N while flower production was quantitative. Architectural models of post-forcing dissected plants provided additional insight. All 100 ppm spring N terminal meristems were floral while 400 and 800 ppm spring N meristems were less floral. All terminal meristems of plants receiving 100 ppm fall N before 1200 ppm spring N were floral but meristems from plants that did not receive fall N before 1200 ppm spring N were much less floral. Branch crown formation was enhanced with elevated (400, 800 or 1200 ppm) spring N and prior fall N enhanced their floral nature.