共查询到20条相似文献，搜索用时 31 毫秒
1.
F.A. Langton 《Scientia Horticulturae》1977,7(3):277-289
In a study of photoperiod response 30 early (summer)-flowering chrysanthemum cultivars from Britain and Japan reacted as quantitative short-day plants. Both flower bud initiation and development occurred more rapidly in short days (SD) as compared with long days (LD). The early-flowering cultivars differed from late-flowering chrysanthemums in that lateral flower buds, and often the terminal flower buds, develop to anthesis in LD. Internodes were shorter in SD and flowers had fewer florets. There was an increased number and proportion of disc florets in SD in all cultivars except one. Two cultivars, ‘Mezame’ and ‘Pennine Yellow’, closely approached day-neutrality.All cultivars produced fewer leaves in LD on upper lateral shoots than on main stems. Either the presence of the terminal flower bud induces earlier flowering of the upper lateral shoots, or the change which causes the terminal apical meristem to initiate a flower in LD influences the axillary meristem also.SD could be used to speed up the flowering of glasshouse-grown crops of early-flowering cultivars. The advantages and disadvantages which may be associated with treatment at different stages of growth are discussed. 相似文献
2.
CaM在梨花芽分化过程中的含量变化 总被引：8，自引：0，他引：8
以梨为试材，对成花过程中的短枝芽和叶所含钙调素（ＣａＭ）的含量进行了测定。（１）短枝芽的ＣａＭ含量在整个成花前后都明显高于新梢芽的含量，特别是在成花的发端期突然成倍增加，形成高峰；（２）短果枝叶的ＣａＭ与新梢叶有着相近的变化趋势，但在成花前后，短果枝叶的ＣａＭ含量明显高于新梢叶；（３）ＣａＡｃ处理可以使短枝芽所含ＣａＭ的峰值提前出现，ＴＦＰ处理可明显降低ＣａＭ含量和延迟其峰值到来。还就ＣａＭ在成花过程中的作用及与Ｃａ２＋的关系等问题进行了讨论。 相似文献
3.
T. L. Botwright R. C. Menary P. H. Brown 《The Journal of Horticultural Science and Biotechnology》2013,88(6):806-811
SummaryShoot morphogenesis in green tea was used to define key events in development which occur during rhythmic growth. These stages are: stage I, no shoot extension or leaf expansion with a maximum number of leaf primordia in the apical bud; stage II, maximum shoot extension and leaf expansion; stage III, cessation of shoot extension and leaf initiation; and stage IV, cessation of leaf expansion while leaf initiation in the apical bud recommences. The apical bud appears dormant during both stages III and IV. Leaf primordia initiated during stage IV expand to form the new shoot during stages I to III. The newly expanded leaves are harvested, forming the green tea crop. Photosynthetic capacity and the pattern of carbohydrate partitioning vary during shoot growth, as defined by the stages of development. Net photosynthesis of mature, fully expanded leaves was highest (18.0 ;C;mol C02 m–2s–1) during stage I, at the beginning shoot growth and lowest (13.2 μmol C02 m–2s–1) during stage III, at the cessation of shoot extension. Maximum starch reserves in leaves and internodes of 12.5% (dw) and 22% respectively were reached at the cessation of shoot extension, during stage III, and declined significantly to 0% and 9% respectively at the start of shoot growth during stage I. At the start of shoot growth, the major part of 14C label was partitioned to the bud, with the developing leaf primordia assumed to be the major sink organs as leaf initiation had ceased. Changes in sink activity with ontogeny are linked to changes in both photosynthesis and partitioning of assimilates during shoot growth and culminate in rhythmic growth of tea. 相似文献
4.
The appearance and development of buds on leaf cuttings of Begonia × hiemalis in long and short days
Bud initiation in leaf cuttings of Rieger begonia ‘Schwabenland Red’ was not affected by daylength. Approximately 30 buds per cutting were observed 13 weeks after insertion. Of these, an average of 8.2 developed into fully grown shoots in long days as opposed to 1.9 in short days. Competition between buds was apparent in both treatments, its effect being greatest on buds with fewer than 4 leaf primordia. 相似文献
5.
When grown in a glasshouse, flowering in Primula vulgaris ‘Aalsmeer Giant’ (yellow) and ‘Ducat’ (blue) was delayed with increasing temperature from approximately 12°C to 18°C. In addition, size of the first open flower and the number of flowering axillary shoots decreased, whereas the number of leaves and leaf area increased with the temperature increase. All temperature responses were greater in ‘Aalsmeer’ than in ‘Ducat’.When grown in growth rooms at 9°C, flowering in P. vulgaris ‘Aalsmeer Giant’ (yellow) was inhibited compared with 15°C. However, when 9 weeks of 15°C was applied to plants grown for 9 weeks at 9°C, the inhibition was overcome; longer periods of 15°C being no more effective. This indicates than an early stage of flower formation, probably the initiation, in Primula vulgaris is inhibited by 9°C, and not the further development of the buds towards open flowers. 相似文献
6.
SummaryThe apical meristem of cv. Nocellara Etnea buds is described in the course of its anatomical progression, from July until bud break, the following spring. Differences in the apex of potentially vegetative and flower buds are already visible in the summer. In leaf buds the apex is a round dome, with two buttresses determined by leaf primordia. The cells of the outer layers are arranged in concentric rings, distinguished by different conditions of the nucleic acids. In flower buds the apical dome is less prominent, and the outer cell layers are histologically quite uniform. These characteristics remain unchanged in flower buds, and are little modified in leaf buds, until December; in January flower bud differentiation becomes more active, and both bud types start developing with increasing intensity. Our observations postulate a very early anatomical separation of the two bud types, on which further environmental factors might determine the final differentiation process. 相似文献
7.
《International Journal of Fruit Science》2013,13(1):51-58
Abstract The development of Fragaria xananassa Duch. cv. Elsanta was analyzed during summer and fall in order to define the sequence of growth alteration and dormancy with regard to inflorescence initiation. The leaf growth as well as the initiation of the inflorescence buds were followed in the fall by conditions imposed in a climate chamber, with plants then being transfered to conditions favorable for growth. Results pointed to clear changes in leaf growth characteristics over the late summer-early fall (September-October) period while the leaf emergence rate remained constant up to mid-October when it stopped. The first sign of inflorescence initiation started in early October, and the differentiation of the terminal flower reached the stamen initiation stage within 2 weeks. From early November, the terminal flower had initiated the carpel primordia and no further differentiation was detected later on. The plant growth potential, expressed by the size, at full growth, of the leaf or inflorescence axis emerging from the terminal bud, decreased progressively from early September and reached a minimum between October and November. By mid-December, the growth capacity of the plant was restored to a situation similar to that described for early September. 相似文献
8.
D. G. Hill-Cottingham R. R. Williams 《The Journal of Horticultural Science and Biotechnology》2013,88(4):319-338
Fertilizer nitrogen was applied to pot-grown trees during the year of initial scion growth either as “spring N”, “summer N” or “autumn N”, while other trees were left untreated—“minus N”. Tree performance was followed until fruit set the following summer.At regular intervals whole trees were sampled, divided into as many as seven different parts, which were separately weighed, dried and analysed for total nitrogen. Specimens were also taken for histological examination of flower bud development.The large amount of fertilizer given as “spring N” resulted in extensive root damage from which the trees did not recover fully; nevertheless they produced large, vigorous scions. After “spring N” and “summer N” at lower dosages the total N content of all parts increased substantially and rapidly. “Autumn N” was absorbed more slowly and remained largely in the roots during the winter, when a considerable amount of root growth took place.Flowers were initiated in late July or early August on all trees except those given “spring N”, on which flower primordia were not initiated until September. The development of flower buds was accelerated during September on “summer N” trees compared with those left untreated. From the end of November until the end of March no further differentiation took place on “minus N” or “spring N” trees, but it continued on the other treatments, especially following “autumn N”.“Summer N” and “autumn N” trees were 4–5 days in advance of the others in flowering. “Summer N” trees had large flowers and large green primary leaves, whereas those on “autumn N” trees were smaller and the leaves were initially pale, though turning dark green during blossoming.When the blossoms were self-pollinated under controlled conditions virtually no fruit was set on “minus N” and “spring N” trees, but “summer N” gave an appreciable set and “autumn N” a heavy set. Only the “summer N” and ”autumn N” flowers had ovules that remained viable six days after anthesis, which was the minimum period found necessary for the pollen tubes to effect fertilization.It is suggested that fertilizer nitrogen stimulates the synthesis of a kinin-like factor in the roots and that the difference in response to applications at different times of year depends upon the stage of development of the flower buds when this factor reaches them. 相似文献
9.
N.Torkel Welander 《Scientia Horticulturae》1984,23(4):371-377
In vegetatively propagated Pelargonium × hortorum plants, formation of axillary shoots and initiation of inflorescences and leaves were promoted by an increase in quantum flux density, whereas application of GA3 had a negative effect. Application of CCC caused an increase in number of axillary shoots and consequently an increase in number of inflorescences and leaves per plant.Dry weight increase was promoted by an increase in quantum flux density, unaffected by GA3 treatment, but inhibited by CCC treatment. Moreover, continuous removal of the oldest leaves reduced the number of inflorescences, leaves, axillary shoots and dry weight. The changes in inflorescence and leaf initiation could not be definitely correlated to the changes in dry weight increase. 相似文献
10.
11.
Michael G. Mullins 《The Journal of Horticultural Science and Biotechnology》2013,88(3):237-247
A distinctive seasonal pattern in the outgrowth of shoots was observed in upright maiden apple trees. Until midsummer, extension shoot growth was confined to the apical region of the trunk. After midsummer, vigorous shoots grew from the basal region of the trunk, and the production of these shoots coincided with a decline in growth rates of shoots in the apical region. A similar pattern of shoot growth was evident in trees grown in horizontal and inverted positions but was modified by the effects of gravity, viz. growth curvatures, effects on the symmetry of shoot production about the axis, and changes in the vigour of shoots in the apical and basal regions of the trunk. Growing trees in horizontal and inverted positions caused a reduction in terminal extension growth, but did not reduce the total amount of shoot growth compared with vertically-grown trees. Changing the orientation of the trunk caused differences in the pattern of axillary flower bud formation, but had no detectable effect on the total numbers of flower buds initiated. 相似文献
12.
T. G. Thorp D. Aspinall Margaret Sedgley 《The Journal of Horticultural Science and Biotechnology》2013,88(5):645-651
Floral bud development, early fruit set, bud size, leaf nitrogen and shoot starch content were recorded in spring, summer and autumn shoots of ‘Hass’ avocado (Persea americana Mill.). Floral initiation occurred in late autumn, but only in buds on terminal shoots (the last-formed shoot module on a terminal or axillary growth axis). In branching systems with three growth flushes, more flowers were produced and more fruit set on autumn and summer, than on spring flush terminal shoots. Floral development and leaf nitrogen accumulation occurred later in autumn than in summer shoots, but leaf numbers, dry and fresh weights, starch content of wood, mean floral status at anthesis and anthesis date were similar. The results suggest that nitrogen and starch were present in excess during floral development, and that shoot age did not influence the ability of a shoot to flower and set fruit, provided the shoot had sufficient vigour to produce new shoot growth in spring. 相似文献
13.
SUMMARYThe possibility of using water stress during floral initiation and development, to synchronize flowering in potted coffee trees of cvs Catuai Rojo and Mundo Novo was investigated. Moderate and severe cyclic and constant water stress had little effect on vegetative growth during floral initiation. However, upon rewatering, shoot growth was significantly greater in plants where leaf water potential [¨,] had declined to -2.5 MPa compared with plants where ¨, was maintained above -0.5 MPa. The period of floral initiation was not influenced by water stress and occurred only under short days (<12 h). In contrast, a y, of -2.5 MPa significantly reduced the number of inflorescences compared with plants maintained at a ¨| of -0.5 or -1.5 MPa. This reduction was associated with leaf drop in stressed plants. Therefore, regular irrigation during the period of floral initiation is recommended. Water stress (¨, of -1.5 or -2.5 MPa compared with -0.5 MPa) accelerated floral development with no deleterious effects on floral differentiation. Once flower buds are fully differentiated they enter dormancy and reach anthesis only if trees are stressed and rewa-tered. Flower buds remain dormant if trees are watered regularly or a constant water stress provided. A constant period of water stress in the late stages of floral development after floral initiation is complete provides a means of increasing the proportion of fully differentiated dormant flower buds (mature buds). This could represent a practical method to achieve synchronized flowering in field conditions where there is irrigation and a reliable dry season in the late stages of floral development. 相似文献
14.
O. M. Heide 《The Journal of Horticultural Science and Biotechnology》2013,88(4):267-284
The effect of plant age, temperature and day-length on flower initiation and development in “ K. & M. Super ” freesias has been studied.The flowering response decreased with increasing temperature and the critical temperature for flower initiation was found to be about 21°C. An interaction of plant age, temperature, and duration of treatment was present. Short days (9 hrs.) slightly stimulated flower initiation in“ Yellow K. & M. Super” but delayed it in “ Blue K. & M. Super” freesias. Short-day treatment in the open during the summer had no significant effect, whereas shading markedly hastened flowering.Flowering could be initiated at an early stage, but older plants were more responsive, especially those of “Blue K. & M. Super”. Optimum temperatures for flower initiation were 12-15°C., applied for 6-9 weeks after the plants had formed about seven visible leaves.Abnormal inflorescences in freesias, recognized by enlarged bracts and irregular spacing of the florets (so-called “gladiolus-like flowers”), appeared to result from incomplete flower initiation. In extreme cases flower stalks without any flowers were formed. In order to avoid such abnormal flowering it was important that the first floret in the inflorescence should have reached a certain stage (P2) of development before low-temperature treatment was discontinued. 相似文献
15.
16.
60Co-γ辐射对切花菊试管苗的诱变效应 总被引：1，自引：0，他引：1
以‘神马’和‘长紫’两个切花菊品种的生根试管苗为试材,用60Co-γ射线进行辐射,设0（对照）、10、15和20 Gy等4个剂量处理,处理后以茎段和叶片为外植体进行离体培养,分析辐射对腋芽发生率、愈伤组织诱导率和分化率的影响,统计M1代田间主要性状及变异情况。结果表明：γ射线对试管苗茎段和叶片的愈伤组织诱导及分化有明显抑制作用,随着辐射剂量的增加抑制作用加强。不同品种、不同外植体对辐射的敏感程度都存在差异。茎段较叶片更适合做辐射后组培的外植体。‘长紫’M1代株高降低,花径减小;而‘神马’在株高和花径出现略微增加的趋势。茎段和叶片的再生植株田间主要性状的变异程度大于腋芽的再生植株。‘长紫’在花色和瓣形上的变异率高于‘神马’。 相似文献
17.
A positive correlation existed between the development of shoot and root systems of ‘Mirandy’ roses. Scions bench-chip-budded below rootstock lateral shoots were inhibited by apical dominance. Inhibition of scion apices was overcome by pruning the top of each rootstock above the graft. Rootstock axillary buds were necessary for adequate initial root-system establishment, but should be eliminated early in the growth cycle to maximize scion development of rose bushes and reduce field production time. 相似文献
18.
B.M.M. Mansour 《Scientia Horticulturae》1975,3(2):129-135
Hibiscus sabdariffa L. was found to show an ambiphotoperiodic reaction, flowering both in short days and in extremely long days, but remaining vegetative (at least at 21–25° C) in a 16 h day. Flowering had a dual effect on growth. When floral induction was strong, lateral buds developed into flowers and the number of branches was proportionally reduced. The first stage of floral induction, however, was accompanied by a decrease of apical dominance. Plants shifted to long days after only a short stay at an inductive daylength, and plants moved to short days after a prolonged stay in long days, formed many more branches and a much greater vegetative mass than plants grown in continuous short days or long days.Plants were already sensitive to daylength in the cotyledon stage. Floral induction was not carried over from short days into long days. After marginal induction, floral buds reverted to vegetative shoots, or aborted and were replaced by a shoot from the axil of a bract.In short days, seedlings form shallowly three-lobed leaves until the generative stage, when only entire leaves are formed. In long days, the leaves are deeply five-lobed, also when the plant flowers. 相似文献
19.
The effects of pinching and lateral bud removal (deshooting) on the development of structural shoots, the number of flowers, and the average flower stem length in young rose plants were examined, using the cultivars ‘Baccara’, ‘Sonia’ and ‘Belinda’. The effect of deshooting on flower yield varied with each cultivar. It did not affect the number of ‘Baccara’ flowers, but increased ‘Sonia’ and ‘Belinda’ flower production by 50% and 75%, respectively. Leaving flowers to bloom out on plants before the start of commercial harvest resulted in a decrease in the length of the flower stems and also reduced the beneficial effect of deshooting on flower yield. Deshooting enhanced structural shoot formation (“bottom breaks”). Pinching flower buds of structural shoots increased the number of ‘Baccara’ flowers in comparison with pruning these shoots to 40–60 cm, as in common practice. Deshooting of the structural shoots of ‘Sonia’ and ‘Belinda’ increased the number of flowers in both cultivars. 相似文献
20.
A. Beryl Beakbane W. S. Rogers 《The Journal of Horticultural Science and Biotechnology》2013,88(2):99-110
Young clonal cacao trees have been grown under controlled soil moisture conditions for 20 months in a glasshouse. Weighable soil containers were used, and water was added to restore the soil to field capacity each time the total available water, which was about 40 lb. for each plant, had been depleted to 85% (wet treatment), 50% (medium treatment) or 15% (dry treatment). Plants were either given one of these treatments for the whole experiment, or one treatment was given during the natural dry seasons and another during the natural wet seasons.Plants given a dry treatment at any time lost their apical dominance and flushed vigorously about 10 days after each watering, though many flushes subsequently withered. The other plants flushed normally, except that the continuously wet plants ceased to flush towards the end of the experiment. The mean expanded area of each leaf was greatest during wet and least during dry periods, and plants which had suffered the least soil moisture deficit throughout growth had the greatest net leaf area and dry weight accumulation. There was little difference in the rate of transpiration per unit leaf area between plants during periods of high compared to medium soil moisture, but the rate was less during dry periods. Dry weight increases both per unit of water transpired and per unit of net leaf area were greatest in the wettest plants.There was little difference between the effects of the wet and the medium treatments on flower production or setting or on cherelle wilt, though ultimately slightly more pods ripened on the wet plants. Plants in a dry period developed few flowers, but initiation was apparently stimulated, for in a subsequent wet or medium period flowering was exceptionally heavy ; setting was poor and cherelle wilt high, however.It is concluded that irrigation on a greater scale than is practised at present is likely to be beneficial to the growth and yield of cacao. 相似文献