Formation Of Flower Primordia Research Articles

Response of Four O’clock Flowers (Mirabilis jalapa L.) to the Short Length of Illumination (Photoperiodism)

Long photoperiods can delay flower initiation and slow down the formation of flower primordia, so they can delay flowering. This study aims todetermine the photoperiodism response of four o'clock flowers (Mirabilis jalapa L.) to the short length of irradiation. The research was carried out for 3months (April-June 2024) and specifically data collection was carried out on 8 June 2024 in Bulurejo village, RT.03 RW. 04, Karangmojo, Weru District,Sukoharjo Regency, Central Java. From 05.53 WIB to 17.30 WIB. Samples of 15 plants growing in Bulurejo village, observed when the flowers bloom. Datawere analysed descriptively qualitative and combined with literature studies. The results of research on 15 plants of four o'clock flower (Mirabilis jalapa L.),the same species and location of four o'clock flower blooming turned out to be different times even though the difference was only slight. The average time ittakes to bloom is 10 hours 42 minutes. Further research needs to be done with a variety of different flowers, not only red flowers, but plus white, red andmixed colours with varied village locations, especially at differentaltitudes.Four o'clock flower (Mirabilis jalapa L) is a member of the family Nyctaginaceae, order Centrospermae, and is easy to grow in the yard withoutmuch care.

The AtERF19 gene regulates meristem activity and flower organ size in plants.

Ethylene-responsive factors (ERFs) have diverse functions in the regulation of various plant developmental processes. Here, we demonstrate the dual role of an Arabidopsis ERF gene, AtERF19, in regulating reproductive meristem activity and flower organ size through the regulation of genes involved in CLAVATA-WUSCHEL (CLV-WUS) and auxin signaling, respectively. We found that AtERF19 stimulated the formation of flower primordia and controlled the number of flowers produced by activating WUS and was negatively regulated by CLV3. 35S::AtERF19 expression resulted in significantly more flowers, whereas 35S::AtERF19 + SRDX dominant-negative mutants produced fewer flowers. In addition, AtERF19 also functioned to control flower organ size by promoting the division/expansion of the cells through activating Small Auxin Up RNA Gene 32 (SAUR32), which positively regulated MYB21/24 in the auxin signaling pathway. 35S::AtERF19 and 35S::SAUR32 resulted in similarly larger flowers, whereas 35S::AtERF19 + SRDX and 35S::SAUR32-RNAi mutants produced smaller flowers than the wild type. The functions of AtERF19 were confirmed by the production of similarly more and larger flowers in 35S::AtERF19 transgenic tobacco (Nicotiana benthamiana) and in transgenic Arabidopsis which ectopically expressed the orchid gene (Nicotiana benthamiana) PaERF19 than in wild-type plants. The finding that AtERF19 regulates genes involved in both CLV-WUS and auxin signaling during flower development significantly expands the current knowledge of the multifunctional evolution of ERF genes in plants. The results presented in this work indicate a dual role for the transcription factor AtERF19 in controlling the number of flowers produced and flower organ size through the regulation of genes involved in CLV-WUS and auxin signaling, respectively. Our findings expand the knowledge of the roles of ERF genes in the regulation of reproductive development.

Flowering ability and expression of the shLFY (shallot-LFY) gene in several Indonesian shallot (Allium cepa, aggregatum group) varieties

Abstract. Irawan J, Dinarti D, Sudarsono, Maharijaya A. 2021. Flowering ability and expression of the shLFY (shallot-LFY) gene in several Indonesian shallot (Allium cepa, aggregatum group) varieties. Biodiversitas 22: 5468-5474. Indonesian shallots (Allium cepa, Aggregatum group) have different flowering abilities. The direction of seed development in the form of true seed shallot (TSS) makes the study of shallot flowering important to support its breeding program. Flowering genes’ presence and their expression demonstrate their significance in inducing flowering. This study aimed to determine the ability of the shLFY gene expression in four shallots varieties (Bima Brebes, Batu Ijo, Biru Lancor, and Sumenep) and the level of expression in each variety during the formation of flower primordia. The research was arranged in a randomized complete block design (RCBD) with varieties as a single factor, for qRT-PCR relative expression data analysis using ??CT comparative method. The results showed that there were differences in flowering ability and the expression value of the shLFY gene between the tested shallot varieties. These differences also were shown within each variety when the umbels of varying ages were tested. There was a positive correlation between the ability to flower and the shLFY gene expression value. The greater shLFY gene expression will be followed by greater flowering ability. Bima Brebes was the variety with the highest flowering ability (91.66%) and highest shLFY gene expression value between other varieties.

Inflorescence shoot elongation, but not flower primordia formation, is photoperiodically regulated in Arabidopsis lyrata.

Photoperiod contains information about the progress of seasons. Plants use the changing photoperiod as a cue for the correct timing of important life history events, including flowering. Here the effect of photoperiod on flowering in four Arabidopsis lyrata populations originating from different latitudes was studied, as well as expression levels of candidate genes for governing the between-population differences. Flowering of plants from four A. lyrata populations was studied in three different photoperiods after vernalization. Flowering development was separated into three steps: flower primordia formation, inflorescence shoot elongation and opening of the first flower. Circadian expression rhythms of the A. lyrata homologues of GIGANTEA (GI), FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1), CONSTANS (CO) and FLOWERING LOCUS T (FT) were studied in three of the populations in the intermediate (14 h) photoperiod treatment. Most plants in all populations formed visible flower primordia during vernalization. Further inflorescence development after vernalization was strongly inhibited by short days in the northern European population (latitude 61°N), only slightly in the central European population (49°N) and not at all in the North American populations (36°N and 42°N). In the 14 h daylength, where all plants from the three southernmost populations but only 60 % of the northernmost population flowered, the circadian expression rhythm of the A. lyrata FT was only detected in the southern populations, suggesting differentiation in the critical daylength for activation of the long-day pathway. However, circadian expression rhythms of A. lyrata GI, FKF1 and CO were similar between populations. The results indicate that in A. lyrata, transition to flowering can occur through pathways independent of long days, but elongation of inflorescences is photoperiodically regulated.

The mvp2 mutation affects the generative transition through the modification of transcriptome pattern, salicylic acid and cytokinin metabolism in Triticum monococcum

Wild type and mvp2 (maintained vegetative phase) deletion mutant T. monococcum plants incapable of flowering were compared in order to determine the effect of the deleted region of chromosome 5A on transcript profile and hormone metabolism. This region contains the vernalization1 (VRN1) gene, a major regulator of the vegetative/generative transition. Transcript profiling in the crowns of T. monococcum during the transition and the subsequent formation of flower primordia showed that 306 genes were affected by the mutation, 198 by the developmental phase and 14 by the interaction of these parameters. In addition, 546 genes were affected by two or three factors. The genes controlled by the deleted region encode transcription factors, antioxidants and enzymes of hormone, carbohydrate and amino acid metabolism. The observed changes in the expression of the gene encoding phenylalanine ammonia lyase (PAL) might indicate the effect of mvp2 mutation on the metabolism of salicylic acid, which was corroborated by the differences in 2-hydroxycinnamic acid and cinnamic acid contents in both of the leaves and crowns, and in the concentrations of salicylic acid and benzoic acid in crowns during the vegetative/generative transition. The amount and ratio of active cytokinins and their derivatives (ribosides, glucosides and phosphates) were affected by developmental changes as well as by mvp2 mutation, too.

Arabidopsis Phyllotaxis Is Controlled by the Methyl-Esterification Status of Cell-Wall Pectins

Plant organs are produced from meristems in a characteristic pattern. This pattern, referred to as phyllotaxis, is thought to be generated by local gradients of an information molecule, auxin. Some studies propose a key role for the mechanical properties of the cell walls in the control of organ outgrowth. A major cell-wall component is the linear alpha-1-4-linked D-GalAp pectic polysaccharide homogalacturonan (HG), which plays a key role in cell-to-cell cohesion. HG is deposited in the cell wall in a highly (70%-80%) methyl-esterified form and is subsequently de-methyl-esterified by pectin methyl-esterases (PME, EC 3.1.1.11). PME activity is itself regulated by endogenous PME inhibitor (PMEI) proteins. PME action modulates cell-wall-matrix properties and plays a role in the control of cell growth. Here, we show that the formation of flower primordia in the Arabidopsis shoot apical meristem is accompanied by the de-methyl-esterification of pectic polysaccharides in the cell walls. In addition, experimental perturbation of the methyl-esterification status of pectins within the meristem dramatically alters the phyllotactic pattern. These results demonstrate that regulated de-methyl-esterification of pectins is a key event in the outgrowth of primordia and possibly also in phyllotactic patterning.

Chromosome doubling of haploid maize seedlings using nitrous oxide gas at the flower primordial stage

AbstractIn maize, inbred lines are used for the production of hybrid varieties. Corn breeders and researchers have considered using haploids to develop inbred lines; however, this procedure has not been practically applied because of the inefficiency of chromosome doubling of maize haploid seedlings. In this report, a procedure has been developed to overcome this difficulty. Maize haploid seedlings obtained from eight different genotypes were treated with nitrous oxide gas (2 days at 600 kPa). Treatment at the six‐leaf stage (flower primordia formation stage) significantly increased the occurrence of fertile sectors on both tassels and ears so that approximately half (44%) of the treated haploids produced kernels after self‐pollination. In the control, only 11% of haploids produced selfed kernels owing to spontaneous chromosome doubling. A strong genotypic effect on the occurrence of fertile sectors after the treatment was observed. This procedure can be used for inbred line development in maize breeding programmes.

Induction photopériodique de l'organogenèse et de la floraison in vitro chez le Cichorium intybus: aspects histologiques

In root explants of a long-day plant, Cichorium intybus L., grown in vitro, inflorescences were produced under short-day conditions (9 h) if long days were applied on days 10 to 18 of culture. Long days consisted of either 16 h fluorescent light (5.6 W∙m−2) or daily cycles of 9 h white fluorescent plus 15 h red (660 nm, 0.3 W∙m−2) or blue (440 nm, 0.5 W∙m−2) light. The structural changes in the meristems of buds regenerated under these conditions were studied. The influence of photoperiod appeared to be critical between the 10th and 16th days, during the progressive transition from vegetative to prefloral stage, which occurred more rapidly under photoperiodic conditions with red or blue light. In noninductive short days, intermediate meristems could be observed tardily on day 24, but no flower formation took place after transfer to long days. Increasing the quantity of light under short-day conditions up to a level comparable to long-day conditions resulted in a rise in mitotic activity, mainly in the peripheral zone of the meristem, but the vegetative zonation was retained. These data therefore indicate that the duration of light really commits the meristem to the subsequent formation of flower primordia; in contrast, the quantity of light controls the bud formation during the first part of development. Key words: Cichorium, tissue cultures, flowering, meristems, organogenesis, photoperiodism.

Kinetics Studies on the Photoinduction of Xanthium strumarium L. and Isolation of a Flower Primordia Growth-Regulating Fractionl1

The kinetics of flower primordia formation have been re-examined in photoinduced Xanthium strumarium L. to determine the number of short-day treatments that promote optimum primordia initiation and development. Plants given 4 short-day cycles showed the highest rate of primordia development. Attempts were made to isolate flower-promoting substance(s) from the young leaves of such optimally induced plants by methanol extraction followed by ether fractionation. A Xanthium bioassay was developed for testing the flower-promoting activity of aqueous concentrates obtained from the acidic, neutral-basic and total ether extracts. No flower-primordia inducing activity was found in any of the fractions, but growth-accelerating activity on young primordia was shown by substance(s) present in the combined neutral-basic fraction isolated from photoinduced leaves.

Flowering Responses of the Long-day Plant Lemna gibba G3

Lemna gibba L., strain G3, exhibits a qualitative long-day flowering response with a critical daylength on a 24-hour cycle of about 10 hours. Evidence is presented that the onset of daughter frond formation in a given frond inhibits the activity of the flowering meristem. Consequently, flower induction can only occur in fronds smaller than about 0.05 to 0.07 mm long. Although a minimum of 1 long day seems to be sufficient to induce the formation of flower primordia, at least 6 long days are required to obtain mature flowers since long days are also required for the early stages of flower development. The critical night length on 24, 48 and 72-hour cycles is respectively 14, 16, and 18 to 22 hours. The close similarity between the critical night length for the different cycle lengths is explained in terms of an inhibitory effect of darkness both on flower initiation and flower development. A 10-hour dark period is more inhibitory to flowering on a 36-hour cycle than on 24, 48, 60 or 72-hour cycles. It is suggested that darkness inhibits flowering through the formation of a light-labile flower inhibitor which acts to inhibit the functioning of the flowering stimulus.

Selection of Index Leaf for Studying the Critical Concentration of Nitrogen in Rice Plants1

AbstractChanges in nitrogen (N) concentration in the last four leaves formed on rice (Oryza sativa L.) culms of three varieties growing in paddy in the Philippines during the rainy season were studied during the period from formation of flower primordia until after flower emergence. On the basis of stability of N concentration and sensitivity to N supply, the blade of the next‐to‐last leaf (second leaf below the panicle), excised at the time of flower emergence, was chosen as the index leaf.

The control by gibberellic acid of stem elongation and flowering in biennial plants of Centaurium minus Moench

Application of a small amount of gibberellic acid (GA3) to unvernalized rosettes of a biennial strain of Centaurium minus MOENCH brings about immediate stem elongation under both long days (LD) and short days (SD), but the rate of stem elongation falls after the cessation of treatment. Under LD, but not SD, a second period of rapid and prolonged stem elongation may subsequently take place, associated with flowering. Extended GA3 treatment under SD leads to the formation of a long stem but not to flowering; after the treatment the plants revert to vegetative "aerial rosettes" unless transferred to LD prior to the cessation of stem elongation; after such a transfer, rapid stem elongation and flowering may be initiated. If flower primordia are initiated under LD, stem elongation and formation of flower primordia continue after transfer to SD, though flowers do not develop fully. It is suggested that under LD but not SD applied GA3 may bring about the production of endogenous gibberellin, and that this synthesis of endogenous gibberellin occurs in the flower primordia.

Photoperiodic Responses of Two Cestrum Species and Non-Interchangeability of Their Flowering Hormones

Recently Lincoln et al. (2) isolated a fraction from the leaves of induced Xanthium strumarium L. which, when applied to the leaves of noninduced plants of X. pennsylvanicum Wallr., caused formation of flower primordia. With this discovery it becomes more important that we examine various species to determine, if possible, whether a single flowering hormone is present in Angiosperms, or a series of such hormones. This report offers some evidence in this area. Evidence concerning photoperiodic response of Cestrum nocturnum L. has been previously reported by Sachs (4). In his work it was demonstrated that C. nocturnum is a long-short day (LSD) plant; that the hormone is synthesized in mature leaves and is transported through the stem to the potential floral buds both acropetaly and basipetaly. This present investigation gives evidence that C. nocturnlem responds with flower formation to a long day (LD) treatment as well as to a LSD treatment.

The Effects of the Photoperiod and Temperature on the Time of Flower Primordia Formation and Flowering and the Expansion of Leaves on the Main Stem of the Late Soybean Variety (Oshoku-Aki)

Experimental results obtained may be summarized as follows : 1) There is a critical photoperiod between 15 and 16 hours for the flowering of Oshoku-Aki soybean. (Fig. 2, 3). 2) The time of flower primordia formation of Oshoku-Aki soybean plant is not determined only by the gradual change of photoperiod such as the succession of seasons. (Fig. 2). 3) The time of expansion of leaves on the main stem is not affected by the photoperiod within the limits of 10-16 hours. (Fig. 3). 4) The time of flower primordia formation and flowering and the expansion of leaves on the main stem is more hastened by high temperatures (26°-30°C) than by low temperatures (14°-26°C). But, these are hastened no longer by temperature higher than 30°C. (Fig. 4, 5, 6, 7). 5) The rate of hastening time of flower primordia formation and flowering caused by high temperature is nearly equal to that of expansion of leaves on the main stem. (Fig. 4, 5, 7).

Influence of photoperiod and other factors on the formation of flower primordia in the potato

The first inflorescence of the potato was differentiated at approximately the same node under a range of conditions including size of seed piece, temperature and photoperiod. The small size of seed piece (5 grams), both the high temperature (8o° during the day, and 55° night), and the short photoperiod (9 hours) had a tendency to increase the node number to the first inflorescence. Flower primordia were differentiated in total darkness.

Interrelation of Relative Day Length and Temperature

1. Growth experiments and chemical analyses were made with plants of Xanthium pennsylvanicum, grown under known conditions of temperature and relative day length. 2. Temperature was found to be a determining factor in influencing the time of flower primordia formation. This temperature effect, however, was closely associated with a response to relative day length. 3. The interrelation of day length and temperature was shown to be as follows: (1) high-temperature short-day plants gave indications of flowering 12-15 days after planting; (2) high-temperature long-day plants were found to flower 47 days after planting; (3) low-temperature short-day plants vegetated actively for 116 days before staminate flower buds were produced; (4) low-temperature long-day plants remained actively vegetative for a minimum of 92 days. 4. Chemical analyses of high-temperature short-day and low-temperature long-day plants resulted in ascending carbohydrate nitrogen ratios in both cases as the plants approached flower primordia...