The effect of sucrose on the expression of the VvTFL1 and VFL genes during flower development in the “Xiangfei” grapevine

VFL and VvTFL1 genes expression patterns and the effects of sucrose on the expression of VFL and VvTFL1 genes in different organs of the “Xiangfei” grapevine (Vitis vinifera L.) were investigated. VvTFL1 gene expression was detected in the meristem of the apical bud and lateral bud, but was not detected during inflorescence differentiation and flower organ development. After sucrose treatment, VvTFL1 gene expression increased in the apical bud, but decreased in the lateral bud. These results suggested that the VvTFL1 gene might be mainly involved in the apical growth process of shoots, and exogenous sucrose had an effect on the VvTFL1 gene by increasing shoot apical meristem initiation of apical buds. The VFL gene was expressed primarily during inflorescence differentiation and early flower organ development, but it gradually reduced in later flower development. After sucrose treatment, VFL gene expression increased in the inflorescence and small or middle flower, but a little change was seen in the large flower. These results suggested that the VFL gene plays important roles in the initiation of inflorescence meristems and the morphological formation of flower organs. Exogenous sucrose had an effect on VFL gene expression at the early stage of flower development.     

Effect of light conditions on the development of the inflorescence in tomato

By growing tomato plants (Lycopersicon esculentum Mill.) in 4 different light regimes (2 photoperiods — 8 and 16 h — combined with 2 light intensities — 9,000 and 18,000 ergs cm^?2 s^?1, it was shown that increasing light integrals hastened flower initiation, greatly promoted the development of the inflorescence and increased the rates of leaf production and the growth of the stem. In similar light integrals, flower initiation was earlier and inflorescence development far better in short photoperiods than in long ones; the rates of leaf production were almost the same and stem growth was greater in long days.Transfer experiments from favourable to insufficient light conditions and inverse transfers at different times during the life of the plant indicated that light conditions were critical at the time of, and after, the macroscopic appearance of the inflorescence. At that stage, a transfer to low light conditions for 10 days induced complete abortion of the truss in our growth conditions. The effect of a transfer from insufficient to favourable light conditions was slower since at least 15 days in these latter conditions were required in order to achieve the development of the inflorescence.     

Anatomy of flower differentiation and abortion,in relation to the growth and development of hybrid tea-rose seedlings

From germination until anthesis or flower bud abortion, seedlings from ‘Sonia’ × ‘Hadley’ were grown in both a greenhouse (full daylight, 20° C) and a growth room (8 Wm^?2, 8 h, 20°C) of the IVT-phytotron. Plastochron was an external indication of the stage of flower differentiation. Flower differentiation in flowering and aborting seedlings ran parallel up to petal-segregation. Flower differentiation in aborting seedlings did not proceed beyond stamen formation. Early abortion, which also caused absence of the upper leaf, occurred without, later abortion with, an abscission zone in the flowerstalk.     

The effect of chlormequat chloride (CCC) application at the bolting stage on the flowering and seed production of lettuce plants previously treated with water or gibberellic acid (GA3)

Lettuce plants were sprayed with gibberellin (GA₃) or water at the rosette (8-leaf) stage and subsequently with water or CCC (500 or 1500 ppm) at the onset of bolting. GA₃ induced rapid bolting and increased seed yield, but seed stalks were longer and thinner than those that had been sprayed with water at the same stage. Treatment with CCC (500 ppm) at bolting decreased the flower stalk height of plants that had been sprayed with water at the rosette stage, but not that of GA₃ treated plants. CCC (500 ppm) increased the number of inflorescence branches per plant as well as seed yield in the autumn sown crop, but had no effect on the winter sown crop. When a higher concentration of CCC (1500 ppm) was applied at bolting, flower stalk height decreased, irrespective of whether the plants had been previously treated with GA₃ or not, and seed stalk diameter increased. However, 1500 ppm CCC reduced the number of inflorescence branches per plant and mean seed yield. It is concluded therefore that although the application of 500 ppm CCC at the onset of bolting may increase seed yield in the autumn sown crop, this treatment does not improve the seed stalk strength (e.g. increasing diameter or reducing height) of GA₃ treated plants. On the other hand, whereas a higher concentration of CCC (1500 ppm) improves seed stalk characteristics, it reduces seed yield.     

Florogenesis of the Mediterranean geophyte Narcissus tazetta and temperature requirements for flower initiation and differentiation

Plant florogenesis is determined by the interaction between the genetics of the individual plant and environmental factors. Flower initiation and development of many studied plant species require low temperatures. However, some geophytes form flowers within the bulb during the summer quiescence period and do not require low temperatures for florogenesis. Narcissus tazetta was employed to study, in detail, the stages of flower development during the summer period, with special emphasis on the effect of temperature on inflorescence initiation. The sequence of morphological processes occurring during floral initiation and development was observed by SEM. During 3 years, the bulbs were subjected to different storage temperatures during the summer, and records were taken of the percentage of apical meristems that shifted from vegetative to reproductive development. Flowering and inflorescence quality were recorded after planting. It was concluded that, under natural conditions, the temperature increase in June, during the growth of the mother plant, leads to the transition of the apical meristem to the reproductive stage. Floral initiation and reproductive development in N. tazetta is promoted by high temperatures with an optimum of 25 °C. Sub- and supra-optimal temperatures (20 and 30 °C) delayed differentiation, while lower temperatures (12 °C) inhibited florogenesis completely.     

树莓花芽分化的观察

1991～1992年,对树莓花芽分化时期的形态特征及发育进程进行了定期观察。结果表明,树莓花芽分化始期为8月末,9月中下旬进入高峰期,约60～70d。形态特征是雏梢生长点向上隆起成半球状。10月上旬至翌年4月中旬,随初生髓部的伸展,半球状生长点(顶花序原基)向前推进,随后形成腋花序原基,即为花序原基分化期。随同冬芽萌发展叶,依次进入花蕾、萼片、花瓣、雄、雌蕊原基的芽外分化阶段,各期约7～15d。至5月中旬出现花药和胚珠原始体。此期距结果新梢的花序显露还有2～3d。基生枝下部花芽分化始期比中上部迟一个月,分化数量也有较大下降。     

Factors affecting the growth of in vitro cultured lateral buds from Phalaenopsis flower stalks

Phalaenopsis flower-stalk buds cultured in vitro show 3 modes of growth: dormant, vegetative and reproductive. The effects of bud position on the stalk, temperature, and benzyladenine (BA) on the mode of bud growth were examined.Flower stalks were cut into 1-node sections, each with 1 bud, and inserted into solid culture medium, top side up. Buds on the upper sections had a tendency to remain dormant regardless of temperature. Sprouting buds placed at 20°C or 25°C showed reproductive growth except for some on the basal sections which grew vegetatively. At 28°C, all buds developed vegetatively independent of their original position on the stalk. The buds on the sections taken from both stalks which had elongated at min 18°C and min 28°C were subcultured; the mode of growth of the cultured buds was not affected by the temperature during flower-stalk elongation but was affected by the subsequent culture temperature.Cultured buds which had remained dormant were stimulated to sprout by addition of BA to the medium. At 5 p.p.m. and above, all buds began to develop, but malformations developed on the leaves of the shoots. All factors considered, BA at 2.5 p.p.m. was found to be the optimum level. The further development of the buds released from dormancy by BA was also affected by the position on the flower stalk and by cultural temperature.     

金边瑞香花芽形态分化研究

 金边瑞香花芽由顶芽发育而成，花芽分化包括花序分化和小花分化两个过程，分为未分化、开始分化、花序原基分化、小花原基分化、花瓣分化、雄蕊分化和雌蕊分化7个时期，分化的顺序是向心的；分化的临界期为5月中旬，分化时期长达7个月，花芽分化既持续又表现出两个分化高峰，还受温度等因素的影响。     

Bulb and inflorescence development in Leucocoryne ixioides (Hook.) Lind.

Summary

Leucocoryne (Alliaceae) is a genus of bulbous plants with cut-flower potential. They are native to central Chile, which experiences a Mediterranean climate. The plants are ‘dormant’ during the heat of Summer (as bulbs, with no external leaf or root development). Leucocoryne plants ‘resume’ growth in Autumn, with the arrival of the rains and falling temperatures, and flower towards the end of their growth cycle, as temperatures rise again in Spring. Leaf and inflorescence initiation began during the Summer ‘dormant’ period and ended the following Spring. They emerged from the bulbs during the same growth cycle as they initiated. Leucocoryne bulbs consist of a series of sympodial units, each containing two leaves and a terminal inflorescence. The renewal meristem for each unit was initiated at the base of the inflorescence, in the axil of the younger leaf primordium. Leucocoryne bulbs were replaced each growing season. Secondary bulbs were initiated in the axils of the oldest, recently-initiated, leaves during late Spring.     

Growth and photosynthesis of Oncidium ‘Goldiana’

SUMMARY

The growth and photosynthesis of Oncidium ‘Goldiana’, a popular tropical orchid for cut flower production, were studied. Four main developmental stages were identified: bud stage, plantlet stage, unsheathing stage and pseudobulb stage. Pseudobulb formation occurred during the unsheathing stage which was closely followed by the formation of an inflorescence. The pseudobulb is of the heteroblastic type (arising from a single node) and lacks stomata. It is a G, shade plant based on chlorophyll a/b ratio, C0₂ compensation point, post-illumination C0₂ outburst and light response curves. The formation of new sinks such as inflorescence and axillary bud have a significant effect on the rate of photosynthesis of certain leaves. The photosynthetic rates of leaves L₂ and L₃ increased during the development of the axillary bud and inflorescence respectively. Pseudobulbs have high water content and contain chlorophyll but show no sign of gas exchange in light and dark. However, fixation of C0₂ is possible in light with partial removal of the underlying cuticle.     

寒地草莓植物学特性与花芽分化的关系

通过对不同质量的草莓苗的花芽分化研究,表明草莓苗的质量对草莓的花芽分化有影响,各品种草莓4片叶、5片叶、6片叶植株花芽分化进程相似,都早于3片叶植株3d。到雌蕊分化开始时,5片叶和6片叶草莓的花芽分化进程较4片叶和3片叶的提早3～9d。定植时新茎粗度在0．84cm以上的草莓植株,花芽分化时期和进程差异小,新茎粗度在0．65cm以下的植株花芽分化进程慢。     

Competition for water between inflorescences and leaves in cut flowering stems of Grevillea ‘Crimson Yul-lo’

Summary

Grevillea cv. ‘Crimson Yul-lo’ has large bright red terminal inflorescences on leafy stems and has recognised commercial potential as a cut flower crop. A major limitation is its relatively short vase-life, often terminated by early wilting of the inflorescence despite apparently turgid leaves. An investigation of the water relations of cut Grevillea ‘Crimson Yul-lo’ stems revealed that the water potential of inflorescences on intact stems in vases was significantly higher (i.e., less negative) than that of leaves from day-0 to day-3 of vase-life. Thereafter, the water potential of inflorescences declined more rapidly than that of leaves, accompanied by visible wilting of the tepals and styles of individual florets. Removal of leaves from the stems reduced both water uptake and water loss, and delayed the onset of a negative water balance in the inflorescence. Bagging of entire stems, leaves only, or inflorescences only, with micro-perforated plastic film to reduce transpiration, reducing leaf number to reduce leaf area, or supplying abscisic acid to reduce leaf stomatal aperture, all aided relative fresh weight retention by stems and extended vase-life. Four or six leaves on a stem caused greater loss in inflorescence water content than zero or two leaves. Considered collectively, these findings show that competition for water between the inflorescence and the leaves in cut Grevillea ‘Crimson Yul-lo’ stems contributes to the onset of inflorescence wilting and their short vase-life.     

Plant carbohydrate partitioning of Lachenalia cv. Ronina during bulb production

Carbohydrate partitioning was investigated in different plant organs of Lachenalia cv. Ronina during bulb production under a low temperature regime. At 4-week intervals, data were collected on bulb, roots, leaves, inflorescence and carbohydrate composition. The roots and especially the bulb were found to be the main starch sinks of the plant, whilst the leaves and the inflorescence were the main source for soluble sugars. Changes in the starch concentration closely followed dry weight changes in the bulb during the growing season. When bulbs were initially exposed to a low temperature, starch was converted to soluble sugars, but thereafter sugars were low, indicating continued export and conversion to starch. Low sugar levels in the leaves and high levels in the inflorescence, with continuous starch increase in the bulb and roots, probably indicate that the inflorescence, but especially the leaves, produced ample photosynthates during the growing season.     

Juvenile Phase and Flower Initiation in Brilliant Stocks (Matthiola Inc Ana R.Br.)

The effect of temperature and day-length on growth and flowering of the Scandinavian Brilliant-type stock (Mattkiola incana R. Br.) has been studied. Flower differentiation and development were examined.

Flower initiation was favoured by low temperature and long days, but a temperature as high as 20° C. (68 °F.) did not prevent flowering even under short-day (9 hours) conditions. A close interaction between temperature and day-length was observed.

High temperature was favourable for further development of the flowers, but abnormal flowers were developed if the plants were removed to high temperature before the first flower primordium was visible under the microscope.

Flower initiation was associated with accelerated stem elongation. Therefore, optimal temperature conditions for stem elongation changed with the developmental stages of the plants.

The plants responded to a low-temperature treatment as early as 12 days after germination, at which stage they had only two small leaves in addition'to the cotyledons. The Brilliant stocks have evidently a much shorter juvenile phase than that previously described for the Column type. This might be the main reason why the Brilliant stocks flower very early.

In single-flowered plants the differentiation of floral organs took place in the following sequence: sepals, stamens, carpels, petals. In this respect the stock showed a similar behaviour to that previously described for certain other cruciferous genera.

The results of the experiments are discussed in the light of previous studies concerning low-temperature effects, vernalization and related phenomena, on flowering. It is concluded that no true vernalization process is involved. The facts that the initiation took place immediately after exposure to low temperature, and that removal to high temperature caused abnormal flower development unless differentiation had reached a certain stage, form the main basis for this conclusion.     

Increasing Flower Number in Single-Truss Tomatoes

Flower number in the first truss (inflorescence) of glasshouse tomatoes was increased by growing the seedlings at low temperatures shortly after pricking off. The optimal timing for this treatment varied by only a few days over most of the year. The longest chilling duration (14 days) was most effective, possibly because of variability between plants. In summer flower number could be doubled, but in winter only 30% to 40% increases were obtained. Chilling delayed anthesis by up to ten days, the delay being proportional to the duration of chilling.

Day/night temperatures of either 10°/10° C. or 16°/4° C. during chilling had similar effects on flowering, and resulted in similar delays to growth and anthesis.

The mechanism by which chilling may increase flower number and the distinctions between this process and vernalization are discussed.     

依据显微结构及光合特性探讨蝴蝶兰花芽分化的时期

以蝴蝶兰‘大辣椒’为试验材料,对花芽分化进程及期间光合特性和碳水化合物、可溶性蛋白及激素含量的变化进行研究。结果表明：花芽长度为0、2、4、8、16和24 cm时,分别处于花芽分化初始期、花序原基分化期、花原基分化期、萼片原基分化期和花瓣原基分化期（16和24 cm）。蝴蝶兰叶片的净CO2吸收速率在花芽发育前期（0 ~ 4 cm）没有显著变化,花芽8 cm时显著降低。花芽中的碳水化合物和可溶性蛋白的含量显著高于叶片,碳水化合物在花芽长度为4 cm时达到稳定水平,可溶性蛋白含量在花芽8 cm时达到叶片与花芽的平衡;赤霉素（GA）的含量在花芽2 cm时达到最大值,生长素（IAA）含量在花芽4 cm时显著升高,玉米素（ZT）含量在花芽8 cm时显著降低,而ABA含量在花芽发育的过程中并没有显著变化。由此可知,当蝴蝶兰花芽开始分化萼片原基（8 cm）时,光合生理及生化物质基本达到一个相对稳定的水平,此阶段的蝴蝶兰花芽已彻底完成成花分化。     

Inflorescence architecture of olive

The influence of flower position on the inflorescence on opening day, gender, and petal persistence was studied in three olive cultivars: Manzanillo, Mission, and Frantoio. In each cultivar, 45 inflorescences were checked every morning from flower opening to petal fall. Perfect flowers opened mainly in the beginning of the flower opening period, and staminate flowers opened later. Flower position on the inflorescence had a highly significant effect on the opening day in all cultivars. Terminal flowers and the flowers located on the primary branches opened earlier than the flowers located on the secondary branches. Flower position had also a highly significant effect on gender in Manzanillo and Mission. In Manzanillo, the secondary branches had fewer perfect flowers than the primary branches. In Mission, the secondary branches had no perfect flowers at all. Among the primary branches, the branch arising immediately next to the terminal flower had the latest flowers to open and the lowest percent of perfect flowers. In Manzanillo, perfect flowers had significantly longer petal persistence than staminate flowers. To study flower competition within the inflorescence, the distal half of 120 inflorescences, on which the flowers tend to be perfect, in three trees of Manzanillo were removed about 1 month before full bloom. There was a highly significant effect on the percent of perfect flowers that opened on the proximal half. Flower competition may be a reason for pistil abortion in flowers located on secondary branches.     

Characteristics of Dormancy of June-Bearing Strawberry(Fragaria Xananassa Duch. cv. Elsanta)

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.     

The effect of temperature and light on flower development in Pelargonium × domesticum

Factors influencing the number of flowers produced in Pelargonium × domesticum cultivar ‘Lavender Grand Slam’, and their rate of development after the plants had been given a period of low-temperature flower induction, were studied.Under short days progressive abortion reduced flower numbers as the temperature regime during the forcing-period was increased. Under long days this effect was less marked and the high-temperature regime advanced flowering by over a month. When long days and high temperatures were used for forcing, it was necessary to maintain a high light intensity, 335 J/cm²/day giving the best results in terms of earliness of flowering and the number of flowers produced. At lower irradiance there was some risk of flower abortion, particularly in the first inflorescence.     

小苍兰新品种‘上农红台阁’

 小苍兰新品种‘上农红台阁’是采用辐射诱变和单株选择法培育而成。花深红色，花蕊金黄色，具芳香，为半重瓣花。主花梗平均高54.1 cm，主花序小花数9 ~ 11，主花序基部第一朵花平均花径4.95 cm。