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1.
M. Kh. Chailakhyan V. Lozhnikova F. Seidlova J. Krekule N. Dudko V. Negretzky 《Planta》1989,178(2):143-146
Flowering of Chenopodium rubrum seedling plants was obtained in continuous light after application of fractions of a partially purified extract from leaves of flowering Maryland Mammoth tobacco (Nicotiana tabacum). The stage of flowal differentiation was dependent on the age of the Chenopodium plants used for the bioassay. Apices of plants treated with the extract at the age of four or seven days showed an advanced branching of the meristem or the beginning of formation of a terminal flower; treatment with the extract of plants 12 d old resulted in rapid formation of flower buds in all assay plants. Non-treated control plants kept in continuous light remained fully vegetative. The effects of the extract on flowering were associated with pronounced growth effects. Floral differentiation was preceeded by elongation of the shoot apex. Extension of all axial organs occurred, while growth of leaves, including leaf primordia, was inhibited. The pattern of growth after application of the flower-inducing substance(s) did not resemble the effects of the known phytohormones, but showed some similarities to growth changes resulting from photoperiodic induction of flowering. 相似文献
2.
Flowering was promoted in young plants of Chenopodium rubrumL. by application of growth inhibitors such as 5-fluorodeoxyuridine(FUDR) and (2-chloroethyl) trimethylammonium chloride (CCC),growth substances (indol-3yl-acetic acid, IAA), by the removalof roots and by drought. All the treatments were effective onlyduring the post-inductive period and at the threshold levelof photoperiodic induction. The response of plants was strictlytime-dependent. The experimental data indicate that the stimulationof flowering is usually accompanied by inhibition of leaf initiationand growth. The treatments probably produced variation in thequantitative expression of flowering by causing a shift in emphasisin the development of leaf and bud primordia at the shoot apex.The dynamic analysis of differentiation of the shoot apex indicatesa correlation between the morphological stage of the shoot apexand its responsiveness to the treatments. 相似文献
3.
21-day old plants ofChenopodium rubrum L. ecotype 374 were used. Organ relationships in the shoots were investigated by32P distribution, which indicated different organ correlations in plants grown in continuous light and in plants treated with
flower-inducing and non-inducing dark periods. Dark periods were associated with a low32P distribution in young leaves and a high one in axillary buds. In the following light period the high32P distribution in axillary buds continued whereas the32P distribution in the leaves on the main axis increased and was similar to that in plants grown in continuous light. The high32P distribution in axillary buds was brought about by both, flower-inducing and non-inducing dark treatments. Decapitation
resulted in a high32P distribution in buds, in continuous light an increased32P distribution was also found in leaves. These effects were not fully cancelled by IAA application.
The results are discussed with respect to an assumption that decrease of apical dominance represents a step in a sequence
of events leading to flowering. 相似文献
4.
Previous studies analyzed the importance of old leaves conservancy for wintergreen species plant growth only after early spring
old leaves elimination. However, carbon and nutrient resources for growth could have already been translocated from old leaves
to shoots during autumn. In this work, the effect of old leaves absence on the leaf mass per area (LMA, g m−2) and nutrient concentration of new spring leaves, shoot growth, and flowering was studied in Aristotelia chilensis, an Andean Patagonic woody wintergreen species of Argentina. Plants were studied after autumn defoliation (AD) or late winter
defoliation (WD) and results were compared to those of undamaged control plants (CO). The new leaves LMA and mineral nutrient
(N, P, K, and Mg) concentration values did not decrease in AD or WD compared to CO plants. Conversely, CO plants showed higher
flowering intensity and shoot lengthening compared to AD or WD plants. There were not remarkable differences regarding the
defoliation time, though non-flowering shoots grew in a lesser degree than the flowering shoots in WD plants. It was concluded
that A. chilensis old leaves cohort is an important source to shoot growth and flowering but their absence does not affect the new leaves structure
or nutritional status from early spring in either AD or in WD plants. New leaves formation probably is guaranteed by resources
(carbon and nutrients) previously stored in stems or even in the buds containing the preformed leaves since March, by the
end of summer. Provided the availability of complete resources for the new leaf flush independently of the old leaves A. chilensis would restore the carbon balance as soon as possible to resume the growth of heterotrophic tissues at normal rates. Endogenous
response to counterbalance the old leaves absence on non-flowering shoots was more effective when there was greater lag time
between defoliation and shoot growth resume. Flowering and non-flowering shoots compete for the available resources when A. chilensis have not yet expanded leaves and shoots supporting reproductive structures were stronger sinks compared to non-flowering
shoots in WD plants. 相似文献
5.
Frideta Seidlová 《Biologia Plantarum》1977,19(5):387-390
Starch was determined by means of IKI reaction in shoot apices ofChenopodium rubrum plants induced to flowering by two short days and in non-induced plants. Small starch grains were already observed in the meristematic cells at an age of four days after sowing. Larger grains were found in the subapical region of the apex. Heterogeneity increases during further growth of the plants in induced, as well as in non-induced vegetative plants. Starch disappears from the cells potentially giving rise to axillary buds, while the number and size of starch grains increase in cells from which leaf primordia will be formed. This metabolic specifity of leaf and bud primordia is preserved during morphological differentiation and applies to vegetative, as well as to prefloral apices of photoperiodically induced plants. The amount of starch in the different regions of the apex is linked rather with organogenesis than with the quantitative growth in the apex. 相似文献
6.
Variation in flowering time of Arabidopsis thaliana was studied in an experiment with mutant lines. The pleiotropic effects of flowering time genes on morphology and reproductive yield were assessed under three levels of nutrient supply. At all nutrient levels flowering time and number of rosette leaves at flowering varied among mutant lines. The relationship between these two traits depended strongly on nutrient supply. A lower nutrient supply first led to an extension of the vegetative phase, while the mean number of leaves at flowering was hardly affected. A further reduction resulted in no further extension of the vegetative phase and, on average, plants started flowering with a lower leaf number. At low nutrients, early flowering affected the timing of production of siliques rather than the total output, whereas late flowering was favorable at high nutrients. This may explain the fact that many plant species flower at a relatively small size under poor conditions. Flowering time genes had pleiotropic effects on the leaf length, number of rosette and cauline leaves, and number of axillary flowering shoots of the main inflorescence. Silique production was positively correlated with the number of axillary shoots of the main inflorescence; the number of axillary primordia appeared to have a large impact on reproductive yield. 相似文献
7.
Five days of suitable continuous light induced flowering in the majority ofChenopodium murale L. ecotype 197 plants as early as at the phase of the first pair of leaves. At the time of initiation of the 2nd to 4th pairs
of leaves the capacity of plants to flower was reduced, the number of flowering plants being significantly lower under the
same inductive light treatment. The capacity to flower increased again at the phase of the 5th and the 6th pairs of leaves.
Inductive light treatment brought about a marked growth activation of organs present before induction, shoot apex elongation,
precocious formation of new leaves and activation of axillary meristems. The course of these changes in plants of different
age is demonstrated. The terminal flower developed during 5 short days following inductive light treatment. The paper shows
similarities and differences between long-daymutale L. ecotype 197 and short-day C.rubrum L. ecotype 374 grown under practically uniform conditions. 相似文献
8.
The growth changes of cotyledons, leaves, hypocotyls and roots due to photoperiodic induction in short day plantChenopodium rubrum were investigated in relation to flowering. Six-day old plants were induced by photoperiods with a different number of dark
hours. We found that the degree of inhibition which occurred during induction in the growth of leaves, cotyledons and roots
similarly as the stimulation of hypocotyl is proportional to the length of dark period. The photoperiods with 12, 16 and 20
dark hours bring about marked inhibition of growth and at the same time induce flowering in terminal and axillary meristems.
The inhibitory effect of critical period for flowering,i.e. 8 dark hours, is not apparent in all criteria used and even the flower differentiation is retarded. The photoperiods of 4
and 6 dark hours did not affect growth and were ineffective in inducing flowering even if their number has been increased.
The experiments with inductive photoperiod interrupted by light break have clearly shown that growth pattern characteristic
for induced plants can be evoked in purely vegetative ones. Such statement did not exclude the possible importance of growth
inhibition as a modifying factor of flower differentiation. We demonstrated that the early events of flower bud differentiation
are accompanied by stimulation of leaf growth. The evaluation of growth and development of axillary buds at different nodes
of insertion enabled us to quantify the photoperiodic effect and to detect the effects due to differences in dark period length
not exceeding 2 hours. 相似文献
9.
The effect of axillary bud age on the development and potentialfor growth of the bud into a shoot was studied in roses. Ageof the buds occupying a similar position on the plant variedfrom 'subtending leaf just unfolded' up to 1 year later. Withincreasing age of the axillary bud its dry mass, dry-matterpercentage and number of leaves, including leaf primordia, increased.The apical meristem of the axillary bud remained vegetativeas long as subjected to apical dominance, even for 1 year. The potential for growth of buds was studied either by pruningthe parent shoot above the bud, by grafting the bud or by culturingthe bud in vitro. When the correlative inhibition (i.e. dominationof the apical region over the axillary buds) was released, additionalleaves and eventually a flower formed. The number of additionalleaves decreased with increasing bud age and became more orless constant for axillary buds of shoots beyond the harvestablestage, while the total number of leaves preceding the flowerincreased. An increase in bud age was reflected in a greaternumber of scales, including transitional leaves, and in a greaternumber of non-elongated internodes of the subsequent shoot.Time until bud break slightly decreased with increasing budage; it was long, relatively, for 1 year old buds, when theysprouted attached to the parent shoot. Shoot length, mass andleaf area were not clearly affected by the age of the bud thatdeveloped into the shoot. With increasing bud age the numberof pith cells in the subsequent shoot increased, indicatinga greater potential diameter of the shoot. However, final diameterwas dependent on the assimilate supply after bud break. Axillarybuds obviously need a certain developmental stage to be ableto break. When released from correlative inhibition at an earlierstage, increased leaf initiation occurs before bud break.Copyright1994, 1999 Academic Press Age, axillary bud, cell number, cell size, pith, shoot growth, Rosa hybrida, rose 相似文献
10.
Indol-3yl acetic acid (104M) was applied to the plumulesof Chenopodium rubrum. Effects on the anatomical structure andthe growth pattern in the apical meristem, as well as DNA synthesisand nucleolus size were investigated. When auxin is applied before or during photoperiodic inductionit inhibits DNA synthesis and meristematic activity. The axillarymeristem (i.e. a group of cells in the axils of the leaf primordia)is most affected. A similar inhibition of the axillary meristemwas also observed in non-induced control plants grown in continuouslight. Auxin applied simultaneously with photoperiodic inductioncounteracts the reduction of apical dominance in the apex andthus inhibits the onset of floral differentiation. Auxin appliedfollowing induction inhibits the previously-formed buds andmakes possible a more complete development of the apical flower. The dual effect of IAA on flowering, inhibitory and stimulatory,manifests itself as a growth response at different stages ofthe changing shoot apex. 相似文献
11.
Martin P. N. Gent 《Journal of Plant Growth Regulation》1995,14(4):205-210
Field-grown large leaf Rhododendron and Kalmia latifolia were treated with one of three concentrations of paclobutrazol or uniconazol in April, June, or August in the second year from propagation. The elongation of stems was measured as was the number of flower buds initiated. Spray applications in April or June increased flowering at the lowest concentrations tested; 4 mg · L–1 paclobutrazol and 1.5 mg · L–1 uniconazol. Flowering was induced in cultivars that normally did not flower, and the number of flower buds per plant was increased in cultivars that normally flowered. All treatments that induced flowering also reduced stem elongation. Spray application in August failed to enhance flowering. At the concentrations tested, uniconazol was more effective than paclobutrazol in increasing the number of flower buds and reducing stem elongation of Rhododendron. For Kalmia, there was less response to the concentration of growth retardant, and the two chemicals enhanced flowering equally. 相似文献
12.
B. Vinterhalter T. Janković K. Šavikin R. Nikolić D. Vinterhalter 《Plant Cell, Tissue and Organ Culture》2008,94(3):329-335
Shoot cultures of Gentianella austriaca (A. & J. Kerner) Dostal established from seedling epicotyls were maintained on MS medium supplemented with 2.22 μM BA and
0.54 μM NAA. A characteristic feature of these cultures was precocious flowering, which appeared in all rapidly elongating
shoots. Flower development arrested shoot elongation and multiplication of shoot cultures. Continuous shoot propagation was
possible only by use of small axillary or adventitious buds as explants for subculturing. Flowering could not be suppressed
by GA3 addition or by cultivation in short-day conditions. The highest rooting percentage (47.3% with 7.83 roots per explant) was
achieved on media with 4.92 μM IBA. Shoot cultures contained the same types of secondary metabolites as plants from nature.
Xanthones were the major constituents, with DMB (demethylbellidifolin), DGL (demethylbellidifolin-8-O-glucoside) and BGL (bellidifolin-8-O-glucoside) present at roughly two times lower concentrations than in samples from nature. Secondary metabolite production
was strongly affected by the presence of BA in the medium. 相似文献
13.
Dual effect of light on flowering and sprouting of rose shoots 总被引:1,自引:0,他引:1
Shade, caused by a dense leaf canopy in the light conditions of a normal greenhouse, reduced sprouting of the third axillary bud (from the top) on decapitated rose branches ( Rosa hybrida cv. Marimba) in comparison to less shaded buds on branches protruding above the canopy and sparsely spaced. Flowering of the third young shoot on shaded branches bearing 3 lateral shoots was totally inhibited. Mixed fluorescent and incandescent light in a growth chamber reduced sprouting of the third bud on decapitated rose branches in comparison to decapitated branches on rose plants held in fluorescent light of similar photon flux density. This was attributed to the higher R:FR ratio in fluorescent vs mixed light that reached the third bud, and in exposed vs shaded branches. Flowering of the third shoot was promoted by several factors: high photon flux density, 0.5 m M gibberellic acid (GA) or 0.2 m M benzyladenine (BA). BA was the most effective treatment. Treatments promoting flowering of the third shoot did not reduce growth or flowering of the upper shoots. However, spraying the uppermost shoot with BA suppressed the growth of the shoots below. It is concluded that light affects flowering in two ways. The effect on bud sprouting is related mainly to R:FR ratios, while the effect on flower development is related mainly to photon flux density. Cytokinins may substitute for the light effect on flower development. 相似文献
14.
The development of axillary buds, terminal buds, and the shoots extended from them was studied inHydrangea macrophylla. The upper and lower parts in a nonflower-bearing shoot are discernible; the preformed part of a shoot develops into the
lower part and the neoformed part into the upper part (Zhou and Hare, 1988). These two part are formed by the different degrees
of internode elongation at early and late phases during a growth season, respectively. Leaf pairs in the neoformed part of
the shoot are initiated successively with a plastochron of 5–20 days after the bud burst in spring. The upper axillary buds
are initiated at approximately the same intervals as those of leaf pairs, but 10–30 days later than their subtending leaves.
Changes in numbers of leaf pairs and in lengths of successive axillary buds show a pattern similar to the changes in internode
lengths of the shoot at the mature stage. The uppermost axillary buds of the flower-bearing shoot often begin extending into
new lateral shoots when the flowering phase has ended. The secondary buds in terminal and lower axillary buds are initiated
and developed in succession during the late phase of the growth season. Internode elongation seems to be important in determining
the degrees of development of the axillary buds. Pattern of shoot elongation is suggested to be relatively primitive. Significances
of apical dominance and environmental conditions to shoot development are discussed. 相似文献
15.
Summary Protocols for both axillary bud proliferation and shoot organogenesis of Euphorbia pulchurrima Winter RoseTM were developed using terminal buds and leaf tissues. Greenhouse-grown terminal buds were placed on Murashige-Skoog (MS) basal
medium supplemented with various concentrations of either benzlyaminopurine (BA) or thidiazuron (TDZ). Explants produced the
greatest number of axillary buds on media containing between 2.2 and 8.8 μM BA. The number of explants that produced axillary buds increased with increasing BA concentration. TDZ at concentrations
between 2.3 and 23.0 μM caused hyperhydricity of shoots and were not effective in promoting shoot proliferation. The most calluses and shoots were
produced from leaf midvein sections from in vitro grown plants placed on the medium containing 8.8–13.3 μM BA and 17.1 μM indole-3-acetic acid (IAA) for 1 mo. before transferring to the medium containing only BA. Adventitious buds were produced
only from red-pigmented callus, and explants that produced callus continued to produce adventitious shoots in the presence
of IAA. Five-mo.-old shoots derived from shoot culture or organogenesis rooted readily in artificial soil with or without
treatment with indolebutyric acid, and were acclimatized in the greenhouse. 相似文献
16.
The objective was to determine whether the protein of
rolB affects shoot formation and whether this
potential relationship depends on the developmental stages of the plant
and/or on the culture conditions. Thin cell layers (TCL) and leaf explants
were excised from tobacco plants in the vegetative and flowering stages and
cultured under various hormonal conditions. In TCLs of vegetative-stage
plants, the expression of rolB enhanced the formation
of the shoot buds under hormone-free conditions and with specific
concentrations of auxin and/or cytokinin. Histological examination showed
that the induction of the shoot meristemoids was particularly enhanced by
rolB protein and that meristemoid growth was
accelerated. In leaf explants from vegetative-stage plants, the expression
of rolB increased the formation of shoot buds in the
presence of 1 M IAA plus 1 or 10 M cytokinin. With BA alone, at a 0.1 M concentration, shoot formation occurred in the
transgenic explants only, whereas with concentrations ranging from 0.5 to
10 M, it was higher in these explants than in
controls.RolB protein enhanced the formation of shoot
buds in TCLs from flowering plants under all hormonal conditions. In the
presence of 1 M IAA and kinetin, the protein also increased the
flowering response. In leaf explants from flowering plants, the expression
of rolB increased the number of shoot buds in the
presence of 1 M IAA with 10 M BA.In conclusion,
rolB protein promotes shoot formation; it seems to
have a positive interaction with cytokinin and an effect on the induction
of the meristematic condition. 相似文献
17.
The structure of shoots, in particular of winter buds, ofHydrangea macrophylla was examined. The non-flower-bearing shoot is usually composed of a lower and an upper part, between which a boundary is
discernible by means of a distinctly short internode. This internode is the lowermost of the upper part, and it is usually
shorter than the internodes immediately above and below, although the internodes tend to shorten successively from the proximal
to the distal part of the shoot. Variations exist in the following characters among the terminal bud, the axillary bud on
the lower part of the shoot and the axillary bud on the upper part: (1) length of bud; (2) character of the outermost pair
of leaf primordia; (3) degree of development of secondary buds in the winter bud; and (4) the number of leaf primordia. Usually,
the terminal bud contains several pairs of foliage leaf primordia with a primordial inflorescence at the terminal of the bud,
but the axiallary bud contains only the primordia of foliage leaves in addition to a pair of bud scales. 相似文献
18.
Zofia Michno-Zatorska Jana Opatrná J. Krekule M. Michniewicz Teresa Szcesniak 《Biologia Plantarum》1989,31(5):376-380
Axillary meristems of short day plantChenopodium rubrum are localized as caulinar, foliar or axillar. The localization of axillary meristems and axillary buds of 14 day old plants
varied in similar pattern as in other plant species so far investigated: after several nodes with foliar axillary meristems
the caulinar ones were produced. However, unlike in other species, in C.rubrum a very high percentage of caulinar meristem is produced also on the first node. In this case, like in the case of its later
differentiation at higher nodes, the formation of caulinar meristem is confined also to the vegetative state. It was found
that the caulinary position coincides with higher responsiveness to photoperiodic induction. The developmental significance
of such behaviour is discussed. 相似文献
19.
Frideta Seidlová 《Biologia Plantarum》1985,27(4-5):350-359
Reorganization of growth in the shoot apex ofChenopodium rubrum during transition to flowering is described. Growth and morphogenic changes — a rise in cell division rate, changes in leaf
and bud formation and changes in directions of cellular growth — are viewed from the aspect of a possible role of growth hormones
in controlling these changes. Growth and morphogenic effects of exogenous growth regulators in the shoot apex ofChenopodium are summarized and their floral effects explained in terms of changing apical growth correlations. New evidence concerning
the timing of increased cell division rate and showing the limited requirement of axillary cell division and a shift to more
vertical direction of growth in the apex in the floral developmental pathway was obtained in experiments with kinetin application
and by surgical treatments. 相似文献
20.
Effect of Assimilate Supply on Development and Growth Potential of Axillary Buds in Roses 总被引:1,自引:0,他引:1
The effect of assimilate supply on axillary bud developmentand subsequent shoot growth was investigated in roses. Differencesin assimilate supply were imposed by differential defoliation.Fresh and dry mass of axillary buds increased with increasedassimilate supply. The growth potential of buds was studiedeither by pruning the parent shoot above the bud, by graftingthe bud or by culturing the bud in vitro. Time until bud breakwas not clearly affected by assimilate supply during bud development,Increase in assimilate supply slightly increased the numberof leaves and leaf primordia in the bud; the number of leavespreceding the flower on the shoot grown from the axillary budsubstantially increased. No difference was found in the numberof leaves preceding the flower on shoots grown from buds attachedto the parent shoot and those from buds grafted on a cutting,indicating that at the moment of release from inhibition thebud meristem became determined to produce a specific numberof leaves and to develop into a flower. Assimilate supply duringaxillary bud development increased the number of pith cells,but the final size of the pith in the subsequent shoot was largelydetermined by cell enlargement, which was dependent on assimilatesupply during shoot growth. Shoot growth after release frominhibition was affected by assimilate supply during axillarybud development only when buds sprouted attached to the parentshoot, indicating that shoot growth is, to a major extent, dependenton the assimilate supply available while growth is taking place.Copyright1994, 1999 Academic Press Assimilate supply, axillary bud, cell number, cell size, defoliation, development, growth potential, meristem programming, pith, Rosa hybrida, rose, shoot growth 相似文献