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A protocol for obtaining bulbs via in vitro organogenesis was developed for tarda tulip ( Tulipa tarda Stapf). Scale explants were obtained from bulbs formed at the base of seedlings or from adventitious bulbs that developed from callus tissue forming on stolons or on germinating seeds. Some explants were subjected to chilling at 5°C for 12 wk. The culture media contained 3 or 6% sucrose and was supplemented with either no growth regulators, either 0.5 μM 6-benzyl-aminopurine (BAP) or 18.9 or 94.6 μM abscisic acid (ABA). Cultures were maintained in the dark at 20°C. Callus tissue developed mainly on media without growth regulators or with BAP. Callus was formed from up to 96% of explants derived from non-chilled adventitious bulbs that were treated with 3% sucrose and 0.5 μM BAP. Less callus was formed from chilled explants compared with non-chilled explants. Newly formed adventitious bulbs appeared on the explants via direct and indirect organogenesis. The media with BAP promoted the formation of adventitious bulbs at a rate of 56-92% from non-chilled explants, whereas a maximum rate of 36% was observed from chilled explants. ABA inhibited the induction of adventitious bulbs and callus. The adventitious bulbs obtained in these experiments contained a meristem, which was evidence that they had developed properly. [ABSTRACT FROM AUTHOR]

Probe electrospray ionization (PESI) is a recently developed ESI-based ionization technique which generates electrospray from the tip of a solid needle. In this study, we have applied PESI interfaced with a time of flight mass spectrometer (TOF-MS) for direct profiling of phytochemicals in a section of a tulip bulb in different regions, including basal plate, outer and inner rims of scale, flower bud and foliage leaves. Different parts of tulip petals and leaves have also been investigated. Carbohydrates, amino acids and other phytochemicals were detected. A series of in vivo PESI-MS experiments were carried out on the second outermost scales of four living tulip bulbs to monitoring the change of carbohydrate content during the first week of initial growth. The breakdown of carbohydrates was observed which was in accordance with previous reports achieved by other techniques. This study has indicated that PESI-MS can be used for rapid and direct analysis of phytochemicals in living biological systems with advantages of low sample consumption and little sample preparation. Therefore, PESI-MS can be a new choice for direct analysis/profiling of bioactive compounds or monitoring metabolic changes in living biological systems. [Copyright &y& Elsevier]

Time-course of ABA, cytokinins, monosaccharides (MS), and water-soluble polysaccharides (WSP) contents were followed during cold dormancy period in the bulbs of tulip ( Tulipa bifloriformis Vved.) that stayed over winter in the open ground or were cold-forced into bloom in a greenhouse. In both cases, the level of monosaccharides and water-soluble polysaccharides in the storage scale tissues increased, whereas the MS/WSP ratio in the bulbs planted in the open remained essentially the same and in case of forcing treatment decreased almost fivefold. In the apical bud tissues, the level of monosaccharides also rose in both cases, but the MS/WSP ratio in the open was greater throughout the whole experiment. The level of cytokinins in the apical bud tissues in the open was higher than in the forcing case, although the changes in their total content were identical following both treatments. Following the forcing treatment, the contents of free and bound ABA in the apical bud tissues increased reaching their peaks by the end of cold period. In the open, there were two peaks of free ABA: in October (when early frosts occurred) and in March (at the end of the wintering period). The winter forcing treatment resulted in rapid depletion of energy and plastic resources in T. bifloriformis and the death of 20% of embryonic flower buds (in the open, all flower buds survived). Nevertheless, plant adaptation potential ensured the development of generative shoots with 4–5 normal flowers, which makes it possible to use this species of multiflorous tulip for winter forcing in a greenhouse. [ABSTRACT FROM AUTHOR]

Triploid tulips have agronomically desirable traits such as vigorous growth and large flower size, but only a portion of all cultivated tulips is triploid. To apply 2 n pollen to polyploid breeding of tulips, the polyploidizing agent, nitrous oxide gas (N2O), was applied to bulbs. In tulips, meiosis in anthers occurs inside the bulbs from mid- to late-October. When meiosis in anthers (excised from bulbs) reached metaphase I, we treated other bulbs of the same clones with N2O for 24–48 h. Most of the treated plants produced pollen grains with a wide-ranging or bimodal size distribution, indicating a mixture of n, 2 n and aneuploid pollen grains. The use of pollen containing a relatively high proportion of giant pollen grains tended to yield larger numbers of triploids in the progeny. The number of giant pollen grains could be increased when N2O-treated pollen grains were suspended in 10% sucrose and then sieved through a nylon mesh. Very few polyploids were observed in some cross combinations, even those involving pollen with a relatively high proportion of giant grains. Even so, this low polyploid yield most likely is due to a triploid block, because the capsules obtained in the crosses of the diploid×N2O-treated plants contained some abnormal seeds, which were mostly triploid. Embryo culture was useful in rescuing abnormal embryos. The present study reveals that 2 n pollen can be produced at high frequency using N2O during tulip breeding. [ABSTRACT FROM AUTHOR]

Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract predatory mites (Neoseiulus cucumeris). Since our aim was to demonstrate such odours and not their relevance under soil conditions, the experiments were carried out using a classic Y-tube olfactometer in which the predators moved on a Y-shaped wire in open air. We found that food deprived female predators can discriminate between odours from infested bulbs and odours from uninfested bulbs or artificially wounded bulbs. No significant difference in attractiveness to predators was found between clean bulbs and bulbs either wounded 30 min or 3 h before the experiment. These results indicate that it may not be simply the wounding of the bulbs, but rather the feeding by rust mites, which causes the bulb to release odours that attract N. cucumeris. Since bulbs are belowground plant structures, the olfactometer results demonstrate the potential for odour mediated interactions in the soil. However, their importance in the actual soil medium remains to be demonstrated. [ABSTRACT FROM AUTHOR]

Examines the effect of cold treatment on the development of tulip bulbs. Rate of internode elongation at different low temperatures; Gradual auxin response enhancement; Sensitivity to auxin by internodes in the presence of gibberellic acid; Low temperature sensing by a change in the response to auxin.

Leaves of tulip plants were treated with [SUP14]CO[SUB2] on three occasions during flowering, one week apart--at the bud stage, at early flowering and when flowers were fully opened. The amount of [SUP14]C fixation was examined 5 min after a pulse application of [SUP14]CO[SUB2] and the organic carbon and [SUP14]C contents of various organs were examined 24 h later. Total carbon in the mother-bulb scales fell over 14 days to only 40% of the initial value, whilst that of all new organs increased by 71%. A negligible amount of [SUP14]C was recovered from scales or from roots. The [SUP14]C recovered from the flower and stem accounted for 83% of [SUP14]C exported from leaves at the early flowering stage. The total carbon content of the daughter bulbs increased uniformly with time but the [SUP14]C recovered from the daughter bulbs was initially small but increased to 59% of the exported [SUP14]C when the flower was fully opened. The imported [SUP14]C in flower and stem was mainly recovered from the soluble and residual (non-starch, insoluble) fractions, whilst that in daughter bulbs was from the soluble and starch fractions. The amount of [SUP14]C lost by respiration fell from 20% to 10% of initial [SUP14]C uptake over the 3-week period. [ABSTRACT FROM AUTHOR]

The organic carbon content and the amount and identity of [SUP14]C-labelled compounds derived from the [SUP14]C-leaf assimilates fixed in the previous season were examined in various organs of tulip bulbs at replanting, on transfer to the glasshouse and at anthesis. Differences in the partition of reserves to various organs were related to the timing of their development and growth, their sink strengths and to their position relative to source organs (initially the bulb scales, later also the leaves). Leaves and roots were the major sinks which received 75% of the [SUP14]C-reserves exported from the scales in the first three months at low temperature (the first period). After 21 days at 18°C up to anthesis (the second period), the new leaves were a further source of carbon for the continued growth of the flower, stem and daughter bulbs. Daughter bulbs appeared to be the only organs still receiving carbon from the scales during the second period, and this was stored mainly as starch. A high rate of respiratory loss of carbon by the whole tulip plant, and particularly by the scales, was indicated in the second period. [ABSTRACT FROM AUTHOR]

The involvement of gibberellins (Gas) in the regulation of floral stalk elongation and flower development has been studied in tulip. The biological activity of GA4 and GA9, both endogenous in tulip bulb sprouts, and GA1, was tested in vitro on sprouts of cooled and non-cooled tulip bulbs (Tulipa gesneriana L. cv. Apeldoom), in the presence or absence of the GA biosynthesis inhibitor paclobutrazol. At early starting dates of incubation, floral stalks from both cooled and non-cooled bulbs hardly showed any elongation in the absence of exogenous GA. Paclobutrazol had no effect on floral stalk elongation, and the response to Gas of sprouts from cooled bulbs was greater than that of sprouts from non-cooled bulbs. At later starts of incubation, considerable floral stalk elongation occurred without GA application. Paclobutrazol inhibited this floral stalk elongation, and the growth of sprouts from both cooled and non-cooled bulbs was stimulated by GA application. The effect of paclobutrazol was reversed by simultaneous application of GA4 or GA9. Application of GA with and without paclobutrazol resulted in the same elongation of the floral stalk, indicating the absence of substantial side effects of the inhibitor. The isolated sprouts did not develop a full-grown flower without the addition of GA. GA4 was more effective than GA9 in stimulating this flower development. The results demonstrate that both sprouts from cooled and non-cooled bulbs are responsive to exogenous Gas in vitro, and may be a site of GA biosynthesis. [ABSTRACT FROM AUTHOR]

In 1974 a severe outbreak of grey bulb rot (Rhizoctonia tuliparum Whetzel & Arthur) occurred on tulips in Lincolnshire in a field not planted with a highly susceptible crop for six years. A long-term experiment on the survival of R. tuliparum showed that about 10 per cent of sclerotia can remain viable for at least 10 years. Where severe outbreaks of disease have occurred, longer intervals between susceptible crops are suggested. [ABSTRACT FROM AUTHOR]

Though it is always mentioned first among the list of obvious manias, no serious effort has ever been expended to investigate the market fundamentals that might have driven the tulip speculation. This paper compiles time series on individual tulip prices and examines market fundamentals potentially driving prices. Most of the "tulipmania" was not obvious madness. High but rapidly depreciating prices for rare bulbs is a typical pattern in the flower bulb industry. Only the last month of the speculation, during which common bulb prices increased rapidly and crashed, remains as a potential bubble. [ABSTRACT FROM AUTHOR]

Examines effects of planting density on bulb yield in Tulips. Effect of planting density on lifted bulb weight and grades of bulbs lifted; Dependency of predictions for optimum planting densities on the weather forecasting for the next season; Influence of planting density on leaf area per plant.

This article focuses on the results of trials on soil transmission of tobacco necrosis viruses in tulips. In the first year of the trials, infected Zimmerman bulbs from the boxes that failed on forcing in 1949 and 1950, and also healthy Zimmerman from another source, were each boxed, in duplicate. After boxing, the bulbs were kept under straw outdoors in the normal way and they were forced in February at 60 to 65 degrees Fahrenheit. There were no diseased shoots in all the boxes with healthy bulbs. In all the boxes with infected bulbs, all the shoots which came up were diseased, and many failed to throw up any shoot at all.