Effects of ascochyta blight (Mycosphaerella pinodes Berk. & Blox.) on biomass production, seed number and seed weight of dried-pea (Pisum sativum L.) as affected by plant growth stage and disease intensity

The effects of ascochyta blight due to Mycosphaerella pinodes on biomass production, seed number and seed weight according to physiological stage and disease intensity were examined. Pea plants were grown in a glasshouse and inoculated with various concentrations of conidia before flowering, at flowering of the second fructifer node (FLO2), at the start of seed filling of the first fructifer node (FSSA1) or the second fructifer node (FSSA2). Uninoculated plants were used as controls. Whatever the stage of inoculation (FLO2 or FSSA2), the disease reduced plant growth and the decrease depended on disease intensity on foliar organs. The seed number was reduced for plants inoculated before flowering, at FLO2 and at FSSA1 and the reduction was linked to disease intensity on foliar organs. At each node, seed number was reduced if the disease occurred before FSSA of the node. The mean seed weight per plant was decreased in plants inoculated at FSSA1 and FSSA2 and the higher the disease intensity on aerials organs, the greater was the reduction of the seed weight. For individual nodes, only inoculations after the beginning of seed filling had a negative effect on mean seed weight at harvest. We found that the decrease of seed number induced by the disease was proportional to aerial biomass production before the end of the period of seed production.     

Chromosome Location of Two RFLP Markers umc22 and umc122 Tightly Linked to the Ht1 Gene in Maize

A biotin-labeled in situ hybridization technique was used in order to physically map two RFLP markers-umc22 and umc122-tightly linked to the Htl gene on the chromosomes of maize ( Zea mays L. ). The results showed that both markers located on the chromosomes 2,7 and umc22 also hybridized with chromosome 4, which demonstrated that the two markers were a duplicated or triplicated sequence. The average detection rate of in situ hybridization was 17.46%. The percent distances of umc22 and umc122 from centromere on the chromosome 2 were 58.36 ± 3.19 and 61.02 ± 4.32 respectively, and on the chromosome 7 were 44.70 ± 2.11 and 45.19 ± 2.27 respectively, which indicates that there are no differences between genetic and physical distances of two markers umc22 and umc122. It was deduced that the gene Htl should also have its homeologous sequence between the hybridization sites of umc22 and umc122 on 7 L besides its location between the two hybridization sites.     

Bi-directional inflorescence development inArabidopsis thaliana: Acropetal initiation of flowers and basipetal initiation of paraclades

In this study we investigated Arabidopsis thaliana (L.) Heynh. inflorescence development by characterizing morphological changes at the shoot apex during the transition to flowering. Sixteen-hour photoperiods were used to synchronously induce flowering in vegetative plants grown for 30 d in non-inductive 8-h photoperiods. During the first inductive cycle, the shoot apical meristem ceased producing leaf primordia and began to produce flower primordia. The differentiation of paraclades (axillary flowering shoots), however, did not occur until after the initiation of multiple flower primordia from the shoot apical meristem. Paraclades were produced by the basipetal activation of buds from the axils of leaf primordia which had been initiated prior to photoperiodic induction. Concurrent with the activation of paraclades was the partial suppression of paraclade-associated leaf primordia, which became bract leaves. The suppression of bract-leaf primordia and the abrupt initiation of flower primordia during the first inductive photoperiod is indicative of a single phase change during the transition to flowering in photoperiodically induced Arabidopsis. Morphogenetic changes characteristic of the transition to flowering in plants grown continuously in 16-h photoperiods were qualitatively equivalent to the changes observed in plants which were photoperiodically induced after 30 d. These results suggest that Arabidopsis has only two phases of development, a vegetative phase and a reproductive phase; and that the production of flower primordia, the differentiation of paraclades from the axils of pre-existing leaf primordia and the elongation of internodes all occur during the reproductive phase.     

Comparative molecular and phytochemical investigation of Leontodon autumnalis (Asteraceae, Lactuceae) populations from Central Europe

Previous analyses of Leontodon autumnalis L. revealed the existence of two chemotypes. In the current study molecular and phytochemical methods were combined to investigate 24 Central European populations of L. autumnalis. The focus of this study was the correlation of molecular and phytochemical characters at the intraspecific level. DNA fingerprint profiles of 183 individuals were obtained by random amplified polymorphic DNA (RAPD) providing 77 molecular markers. Contents of phenolics and sesquiterpenoids of flowering heads and sub-aerial parts were quantified by HPLC-DAD analyses. HPLC results were evaluated by principal component analysis. Geographic distribution of the two detected chemotypes partially overlapped. Phylogenetic groupings displayed in an unrooted neighbor-joining tree calculated from the RAPD data matrix were correlated with the geographical origin of the plant material. However, genetic profiles neither correlated with the two chemotypes nor with the morphologically based subspecies of L. autumnalis recognized by some authors. The presented data imply that the morphotypes are of multiple origins or due to different ecological growing conditions rather than genetically determined and that phytochemical races are induced by a limited number of genetical differences, which might have occurred independently in different lineages of the L. autumnalis group.     

Abscisic Acid and cutout in cotton

A decline in growth, flowering, and boll (fruit) retention is referred to as cutout in cotton (Gossypium hirsutum L.). Fruit load affects cutout, possibly through hormonal effects. Experiments were conducted to test the hypothesis that fruits are a source of abscisic acid (ABA) that moves into fruiting branches and growing points where it inhibits growth, flowering, and boll retention. Removal of the flower or young boll at the first node of fruiting branches did not decrease the ABA content of fruiting branches or the abscission zone at the second node. Effects on ABA content of the boll at the second node varied. In one field test, ABA content of bolls at the second node decreased with successive harvests as bolls were removed from first node positions of several fruiting branches. Thus, the effect was cumulative and was not limited to individual branches. Removal of the flower or boll at the first node increased boll retention at the second node. Removal of all flowers during the first 3 weeks of flowering delayed the decreases in growth, flowering, and boll retention that occurred as fruit load increased. But, the ABA content of fruiting branches and mainstem apices was not decreased by early defruiting and did not increase with increasing fruit load. The results do not support the hypothesis that fruits are a source of ABA that moves into fruiting branches and growing points where it then inhibits growth, flowering, and boll retention.     

Dioxin/polychlorinated biphenyl body burden, diabetes and endometriosis: findings in a population-based study in Belgium

Dioxins and polychlorinated biphenyls (PCBs) are persistent organic pollutants widely distributed in the food chain, which is the main source of human exposure. Their effects on human health at background exposure levels are still poorly understood. Recent epidemiological evidence suggests a possible association between these pollutants and diabetes. We report here the results of a population-based study in Belgium on 257 (142 women and 115 men) environmentally exposed subjects, including 10 cases of endometriosis and nine cases of diabetes. Seventeen 2,3,7,8-polychlorinated dibenzodioxins/dibenzofurans (PCDD/Fs or dioxins), four coplanar PCBs (International Union of Pure and Applied Chemistry [IUPAC] nos 77, 81, 126 and 169) and 12 PCB markers (IUPAC nos 3, 8, 28, 52, 101, 118, 138, 153, 180, 194, 206 and 209) were quantified in serum fat from fasting blood samples in order to estimate the body burden of these pollutants. Whilst no difference was found between women with endometriosis and their controls, diabetic patients had significantly increased serum levels of dioxins, coplanar PCBs and the 12 PCB markers. After adjustment for age and other covariates, serum total toxic equivalent activity (sum of PCDD/Fs and coplanar PCBs) and 12 PCB marker concentrations in diabetics were 62% (p=0.0005) and 39% (p=0.0067) higher, respectively, than in controls. The risk of diabetes was significantly increased in subjects in the top decile for adjusted concentrations of dioxins (odds ratio 5.1, 95% confidence interval [CI] 1.18-21.7), coplanar PCBs (odds ratio 13.3, 95% CI 3.31-53.2) or 12 PCB markers (odds ratio 7.6, 95% CI 1.58-36.3). These findings warrant further studies to assess the significance of the associations between diabetes and environmental exposure to polychlorinated pollutants.     

Dioxin/polychlorinated biphenyl body burden,diabetes and endometriosis: findings in a population-based study in Belgium

Dioxins and polychlorinated biphenyls (PCBs) are persistent organic pollutants widely distributed in the food chain, which is the main source of human exposure. Their effects on human health at background exposure levels are still poorly understood. Recent epidemiological evidence suggests a possible association between these pollutants and diabetes. We report here the results of a population-based study in Belgium on 257 (142 women and 115 men) environmentally exposed subjects, including 10 cases of endometriosis and nine cases of diabetes. Seventeen 2,3,7,8-polychlorinated dibenzodioxins/dibenzofurans (PCDD/Fs or dioxins), four coplanar PCBs (International Union of Pure and Applied Chemistry [IUPAC] nos 77, 81, 126 and 169) and 12 PCB markers (IUPAC nos 3, 8, 28, 52, 101, 118, 138, 153, 180, 194, 206 and 209) were quantified in serum fat from fasting blood samples in order to estimate the body burden of these pollutants. Whilst no difference was found between women with endometriosis and their controls, diabetic patients had significantly increased serum levels of dioxins, coplanar PCBs and the 12 PCB markers. After adjustment for age and other covariates, serum total toxic equivalent activity (sum of PCDD/Fs and coplanar PCBs) and 12 PCB marker concentrations in diabetics were 62% (p=0.0005) and 39% (p=0.0067) higher, respectively, than in controls. The risk of diabetes was significantly increased in subjects in the top decile for adjusted concentrations of dioxins (odds ratio 5.1, 95% confidence interval [CI] 1.18–21.7), coplanar PCBs (odds ratio 13.3, 95% CI 3.31–53.2) or 12 PCB markers (odds ratio 7.6, 95% CI 1.58–36.3). These findings warrant further studies to assess the significance of the associations between diabetes and environmental exposure to polychlorinated pollutants.     

The role of induced mutation in conversion of photoperiod dependence in cotton

Wild cotton germplasm resources are largely underutilized because of photoperiod-dependent flowering of "exotic" cottons. The objectives of this work were to explore the genome-wide effect of induced mutation in photoperiod-converted induced cotton mutants, estimating the genetic change between mutant and wild-type cottons using simple sequence repeats (SSRs) as well as understand the pattern of SSR mutation in induced mutagenesis. Three groups of photoperiod-converted radiomutants ((32)P) including their wild-type parental lines, A- and D-genome diploids, and typically grown cotton cultivars were screened with 250 cotton SSR primer pairs. Forty SSRs revealed the same SSR mutation profile in, at least, 2 independent mutant lines that were different from the original wild types. Induced mutagenesis both increased and decreased the allele sizes of SSRs in mutants with the higher mutation rate in SSRs containing dinucleotide motifs. Genetic distance obtained based on 141 informative SSR alleles ranged from 0.09 to 0.60 in all studied cotton genotypes. Genetic distance within all photoperiod-converted induced mutants was in a 0.09-0.25 range. The genetic distance among photoperiod-converted mutants and their originals ranged from 0.28 to 0.50, revealing significant modification of mutants from their original wild types. Typical Gossypium hirsutum cultivar, Namangan-77, revealed mutational pattern similar to induced radiomutants in 40 mutated SSR loci, implying possible pressure to these SSR loci not only in radiomutagenesis but also during common breeding process. Outcomes of the research should be useful in understanding the photoperiod-related mutations, and markers might help in mapping photoperiodic flowering genes in cotton.     

成年斑马鱼脊髓损伤修复中脑gdnf和nos基因的表达

成年斑马鱼(Danio rerio)具有很强的脊髓损伤后自主修复的能力, 但目前其机制不明。为了研究斑马鱼中脑组织对脊髓再生的影响, 文章应用成年斑马鱼脊髓损伤模型, 采用实时定量PCR方法和原位杂交技术, 检测了斑马鱼脑中胶质细胞源性神经营养因子(gdnf)和一氧化氮合酶(nos)基因在脊髓损伤后4 h、12 h、6 d、11 d的表达情况, 展示了这两种基因在斑马鱼脑内不同核团的动态表达变化。结果显示, 成年斑马鱼脊髓损伤后, 神经营养因子gdnf基因在损伤急性期(4 h、12 h)和神经修复期(6 d、11 d)于斑马鱼脑内呈现显著性升高(P<0.05),而一氧化氮合酶基因nos的表达于损伤急性期显著性升高 (P<0.05), 随后下降, 并在修复期 (11 d)显著降低(P<0.05)。这表明, 脊髓损伤后, 高表达gdnf基因同时低表达nos基因的脑环境给脊髓损伤提供了良好的神经再生微环境, 从而可能促进轴突的再生长及运动能力的恢复。     

Flowering induced by 5-azacytidine, a DNA demethylating reagent in a short-day plant, Perilla frutescens var. crispa

Treatment with 5-azacytidine, a DNA demethylating reagent, induced flowering in Perilla frutescens (L.) Britton var. crispa (Thunb. ex Murray) Decne. ex L. H. Bailey, an absolute short-day plant under long days. The 5-azacytidine treatment induced slight suppression of vegetative growth but had no obvious effect on any other phenotypes. The Southern hybridization analysis of the genomic DNA isolated from the leaves of 5-azacytidine-treated plants and digested with restriction enzyme, methylation-insensitive Msp I or methylation-sensitive Hpa II with P. frutescens 25S-18S rDNA intergenic spacer probe indicated that the 5-azacytidine treatment caused demethylation of the genomic DNA. The 5-azacytidine-induced flowering was delayed as compared with the short day-induced flowering. Flowers were formed even at the lower nodes which had not been directly treated with 5-azacytidine. The results suggest that DNA demethylation induced flowering by inducing the production of a transmissible flowering stimulus in P. frutescens .     

The Effects of Temperature and Light Integral on the Phases of Photoperiod Sensitivity inPetuniaxhybrida

Flowering in petunias is hastened by long days, but little isknown about when the plants are most sensitive to photoperiod,or how light integral or temperature affect such phases of sensitivity.The effects of these factors on time to flowering was investigatedusing reciprocal transfer experiments between long (16 h d^-1)and short days (8 h d^-1). The effect of light integral on thephases of photoperiod sensitivity was examined using two sowingdates and a shading treatment (53% transmission). The effectsof temperature were investigated by conducting reciprocal transferexperiments in glasshouse compartments at five temperature regimes(means of 13.7, 19.2, 22.3, 25.0 and 28.7 °C). The lengthof the photoperiod-insensitive juvenile phase of development,when flowering cannot be induced by any environmental stimulus,was sensitive to light integral; low light integrals prolongedthis phase, from 23 d at 2.6 MJ m^-2d^-1to 36 d at 1.6 MJ m^-2d^-1(totalsolar radiation). The length of this development phase was shortest(12.5 d) at 21 °C; it was longer under cooler (21 d at 13.5°C) and warmer temperatures (17.6 d at 28.3 °C). Afterthis phase, time to flowering was influenced greatly by photoperiod,with long days hastening flowering by between 28 and 137 d,compared with short days. Plants also showed some sensitivityto both temperature and light integral during this phase, butthe duration of the final phase of flower development, duringwhich plants were photoperiod-insensitive, was dependent primarilyon the temperature at which the plants were grown; at 14.5 °C,33.9 d were required to complete this phase compared with 11.4d at 25.5 °C. The experimental approach gave valuable informationon the phases of sensitivity to photothermal environment duringthe flowering process, and could provide the basis of a morephysiologically-based quantitative model of flowering than hashitherto been attempted. The information is also useful in thescheduling of lighting and temperature treatments to give optimalflowering times of high quality plants.Copyright 1999 Annalsof Botany Company Petunia,Petuniaxhybrida, juvenility, flowering, photoperiod, temperature, light integral, reciprocal transfer.     

Evaluation of miR-122 level in the plasma of chronically HCV infected patients

MicroRNAs (miRNAs) are small non-coding RNA molecules, which have an important function in regulating RNA stability and gene expression. They also can circulate in a cell-free form in the blood thatmakes them potential disease markers. The liver contains various classes of miRNAs in which miR-122 accounts for about 70% of all miRNAs and it has been proved that its level increases in case of liver damage. Here, we investigated plasma levels of miR-122 as a useful disease parameter in patients with chronic hepatitis C (CHC) infection. Thirty five hemophilia and thalassemia patients with CHC were studied. The total RNA was extracted from plasma samples, and miR-122 levels were measured by qPCR and then compared with the specific liver markers. The plasma levels of alanine transaminase (ALT) and aspartate transaminase(AST) were correlated with plasma miR-122 level in CHC patients, and the level of circulating miR-122 in healthy individual groups were rarely lower than those of patients with CHC. In our study, miR-122 levels correlated well with markers of liver inflammatory activity. Plasma miR-122 can be assumed to be another marker in liver similar to the currently used specific markers such as ALT and AST for evaluation of liver damage in hepatitis C virus (HCV) infected patients. Moreover, the correlation between miR-122 and ALT was shown to be higher than between miR-122 and AST.     

The Effect of Fruit Shading on Yield in Pisum sativum L.

Fruits of Pisum sativum L. cv. Feltham First which initiatesonly one flower per flowering node, were selectively shadedunder varying levels of defoliation. The purpose of the experimentswas to ascertain whether the foliage could compensate for lossof the fruit's contribution to its own growth. There was evidenceof this, but fruit and seed weight per fruit and per plant werereduced by fruit shading at all levels of defoliation. The lossin yield due to shading suggested that the contribution fromthe fruit was at least 12 per cent. The number of seeds whichdeveloped to maturity was the yield component most affectedby treatment. There was no evidence to suggest that shadinghad a different quantitative effect on final weight at differentnodes, but it did increase flower abscission at the first foweringnode in an experiment done at low radiant exposure. In an experimentat higher radiant exposure, very few flowers abscised at theearlier nodes, but leaflet removal reduced final fruit yieldat the first flowering node to a greater degree than at thesecond. These differential responses could contribute to variabilityof seed size in a crop of vining peas. Pisum sativum, pea, fruit, pod, light, shading, photosynthesis, yield     

Protracted protection to Plasmodium berghei malaria is linked to functionally and phenotypically heterogeneous liver memory CD8+ T cells

We previously demonstrated that protection induced by radiation-attenuated (gamma) Plasmodium berghei sporozoites is linked to MHC class I-restricted CD8(+) T cells specific for exoerythrocytic-stage Ags, and that activated intrahepatic memory CD8(+) T cells are associated with protracted protection. In this study, we further investigated intrahepatic memory CD8(+) T cells to elucidate mechanisms required for their maintenance. Using phenotypic markers indicative of activation (CD44, CD45RB), migration (CD62L), and IFN-gamma production, we identified two subsets of intrahepatic memory CD8(+) T cells: the CD44(high)CD45RB(low)CD62L(low)CD122(low) phenotype, representing the dominant effector memory set, and the CD44(high)CD45RB(high)CD62L(low/high)CD122(high) phenotype, representing the central memory set. Only the effector memory CD8(+) T cells responded swiftly to sporozoite challenge by producing sustained IFN-gamma; the central memory T cells responded with delay, and the IFN-gamma reactivity was short-lived. In addition, the subsets of liver memory CD8(+) T cells segregated according to the expression of CD122 (IL-15R) in that only the central memory CD8(+) T cells were CD122(high), whereas the effector memory CD8(+) T cells were CD122(low). Moreover, the effector memory CD8(+) T cells declined as protection waned in mice treated with primaquine, a drug that interferes with the formation of liver-stage Ags. We propose that protracted protection induced by P. berghei radiation-attenuated sporozoites depends in part on a network of interactive liver memory CD8(+) T cell subsets, each representing a different phase of activation or differentiation, and the balance of which is profoundly affected by the repository of liver-stage Ag and IL-15.     

Genetic mapping of <Emphasis Type="Italic">Eef1</Emphasis>, a major effect QTL for early flowering in <Emphasis Type="Italic">Eucalyptus grandis</Emphasis>

An early flowering mutant plant of Eucalyptus grandis with normal vegetative growth was found in a nursery in northern Brazil. This mutant plant flowers at approximately 90 days from germination. A cross between a wild-type (normal flowering) tree and the mutant was carried out, generating a progeny of 88 individuals where early flowering segregated in an approximate 1:1 ratio. A genome scan with 100 microsatellite markers distributed across the genome was carried out using bulk segregant analysis (BSA) on two contrasting bulks of 15 plants each. Linkages (LOD>3.0) with a major effect early flowering quantitative trait locus (QTL) were detected and confirmed by a full scale cosegregation analysis for markers EMBRA27, EMBRA60, EMBRA164, EMBRA158, EMBRA91, and EMBRA65. A localized linkage map involving the six loci and the early flowering QTL named Eucalyptus early flowering 1 (Eef1) was constructed belonging to linkage group #2 in the existing microsatellite reference map. The Eef1 locus was mapped between markers EMBRA27 and EMBRA164, with distances of 21.8 and 6.4 cM, respectively. In introgression experiments, these two markers could be successfully used with an expected precision of 98% to select plants carrying the Eef1 mutant allele, assuming no recombination interference in the genomic segment. Early flowering could be a very useful trait both in breeding as well as experimental genetics of Eucalyptus.     

Changes in RNA levels in the shoot apex of Silene during the transition to flowering

Changes in RNA concentration in the shoot apical meristem during induction and the transition to flowering were measured histochemically in Silene coeli-rosa (L.) Godron, a long-day plant. In the apices of plants induced by 7 long days the RNA concentration increased to about 25 per cent higher than in non-induced plants. Three long days did not induce flowering but resulted in a transient rise in RNA concentration. When plants were given long days interrupted by varying numbers of short days successful induction was accompanied by a sustained increase in RNA concentration but those treatments which were not inductive gave only transient increases in RNA. Gibberellic acid had no effect on induction or apical growth rates but increased the RNA concentration by 50 per cent or more in both induced and non-induced plants. Plants induced to flower at 13° C had the same RNA concentration and growth rate at the apex as in non-induced plants at 20° C. Since changes in RNA concentration in the apex could occur without changes in growth rate and without flowering, and induction could occur without a change in RNA concentration or growth rate, it is suggested that the increase in RNA and growth rate which normally occur at the transition to flowering might not be essential for the formation of a flower but may be more closely related to the rapid growth associated with the formation of the inflorescence.Abbreviations LD long day - SD short-day     

黄瓜核心种质遗传多样性的苗期和初花期形态标记分析

对92份黄瓜核心种质进行苗期和初花期形态学标记分析,以评价供试核心种质资源的遗传多样性水平。结果表明:供试黄瓜核心种质的苗期和初花期性状存在明显的遗传变异,不同种质间各性状的平均变异系数为31.0%,其中第一雌花节位的变异系数最大,为59.4%;始花期最小,为14.2%。聚类分析表明,在Pearson相关系数为6.5时,把92份黄瓜核心种质划分为3大类群;Pearson相关系数为3.5时,把92份黄瓜核心种质划分为8个类群。本研究结果丰富了黄瓜种质资源的评价体系,为今后优异基因资源的挖掘与利用提供了科学参考。     

Induction of nopaline synthase promoter activity by H2O2 has no direct correlation with salicylic acid.

Transgenic tobacco (Nicotiana tabacum L.) plants carrying a fusion between the nopaline synthase (nos) promoter and chloramphenicol acetyltransferase (CAT) reporter gene (caf) were tested for their response to treatment with H2O2. The nos promoter-driven CAT activity increased significantly by addition of H2O2, reaching the maximum level at 15 mM. Kinetic analysis for CAT activity showed that induction by H2O2 was similar to that of methyl jasmonate (MJ), but was much slower than induction by salicylic acid (SA). Time-course experiments for mRNA level also revealed that the response to H2O2 treatment was similar to that of MJ. The nos promoter displayed a rapid and transient induction of mRNA with SA treatment, with the maximum levels occurring at 3 h, whereas the levels induced by H2O2 or MJ treatment increased continuously during the 11-h experimental period. The antioxidants N-acetyl-L-cysteine and catechol did not alter the SA effect. The responses of the nos promoter to H2O2, MJ, and wounding were significantly reduced by deletions of the CAAT box region and the sequence between -112 and -101. However, these deletions did not significantly alter the SA response. This suggests that H2O2 may have a different mechanism from that of SA for inducing nos promotor activity.     

Axillary bud flowering after apical decapitation in Pharbitis in relation to photoinduction

The flowering response of axillary buds of seedlings of Pharbitis nil Choisy, cv. Violet, was examined in relation to the timing of apical bud removal (plumule including the first leaf or second leaf) before or after a flower-inductive 16-h dark period. When the apical bud was removed well before the dark period, flower buds formed on the axillary shoots that subsequently developed, but when removed just before, or after, the dark period, different results were observed depending on the timing of the apical bud removal and plant age. In the case of 8-day-old seedlings, fewer flower buds formed on the axillary shoots developing from the cotyledonary node when plumules were removed 20 to 0 h before the dark period. When the apical bud was removed after the dark period, no flower buds formed. Using 14-day-old seedlings a similar reduction of flowering response was observed on the axillary shoots developing from the first leaf node when the apical bud was removed just after the dark period. To further elucidate the relationship between apical dominance and flowering, kinetin or IAA was applied to axillary buds or the cut site where the apical bud was located. Both chemicals influenced flowering, probably by modulating apical dominance which normally forces axillary buds to be dormant.