Tulip Research Articles

Modern equations of diffractometry. Profile generation

It is possible to construct an integral which expresses the shape of diffraction spots exactly on the kinematical model, provided that phonon coupling and absorption are negligible. The integral is a function of two distributions describing quite generally the imperfections in the crystal and the beam. In the development, both the Ewald sphere and the diffraction plane are superseded by an infinitely extended quartic surface in reciprocal space reminiscent of an open tulip flower. The finite dual surface which would allow the calculation to be performed entirely in direct space is also described briefly. The method of linearizing the integral is given so that it can be used in the development and verification of profile-analysis algorithms for use with area-detector diffractometers and cameras, whether they be of the functional expansion or of the histogramming type. It is shown that in Gaussian approximation a single second-rank quantity dominates the shapes of every spot in a diffraction pattern, determining both the angular and spatial profiles simultaneously. This same approximation is the ideal zeroth-order expansion of a Weber–Hermite function profile analysis to be described in a later paper.

The effects of scale wounding of tulip bulbs on ethylene evolution, plant growth and flowering

Scale wounding significantly accelerated flowering of Tulipa gesneriana L. bulbs that had been stored for 3,6 and 9 weeks at 2°C for ‘Apeldoorn’ and for 3 and 6 weeks for ‘Oxford’. In addition, final scape length was significantly longer in plants produced from wounded bulbs after 3 and 9 weeks of precooling for ‘Apeldoorn’ and after 3 weeks for ‘Oxford’. Wounding increased ethylene production in all treatments of both cultivars. ‘Oxford’ produced significantly more ethylene than ‘Apeldoorn’, however, the increased ethylene production did not produce floral abortions.

Purification and herbicide metabolism studies on tulip (Tulipa gesneriana) cytochrome P450

AbstractMicrosomal cytochrome P450 from tulip bulbs was solubilized and purified to a specific content of 12.66 nmol mg protein−1. The cytochrome P450 was present as a mixture of two cytochrome P450 polypeptides in approximately equal proportions. Their molecular masses were 52.5 kD and 54.5 kD. Similarities between these proteins included cross‐reactivity with the same antibody. Activity of the purified sample was investigated in a reconstituted enzyme system using the herbicide 2,4‐D (2,4‐dichlorophenoxyacetic acid) as a substrate. A polar product of 2,4‐D was produced which co‐migrated on several chromatography systems with 2,4‐dichlorophenol.

Flower pigment composition in Tulipa

Flower pigment compositions of 43 accessions of Tulipa species, 6 species hybrids and 494 tulip cultivars were analysed with respect to the amount of carotenoids, and the anthocyanidins pelargonidin, cyanidin and delphinidin. After principal component analysis, the different pigment compositions appeared to be correlated with flower color. Hybrids were not intermediate between the parents in all cases. The variation found in T. gesneriana extends that of the whole rest of the genus. The biosynthetic pathway as described in Petunia, Anthirrinum and other genera can also be postulated for the genus Tulipa, but additive effects of multiple genes may be assumed, since several levels of concentration were found. Flavonoid synthesis has biological relevance in view of co-evolution with insect pollinators and male sterility.

The 4-methylene-glutamine: asparagine ratio in the shoot of tulip bulbs cv. ‘Apeldoorn’ as a criterion for dry storage duration at 5°C

Dry-stored tulip bulbs cultivar ‘Apeldoorn’ require a period of 12 weeks at 5°C to ensure satisfactory shoot elongation and flowering during subsequent growth at higher temperatures (17–20°C). To develop a test on this special precooling, changes in the free-amino-acid content of the shoots of bulbs dry-stored at 5°C during 15 weeks were studied. They were compared with changes occurring at 17°C. The 4-methylene-glutamine content per gram dry weight increased up to 15 weeks in both cooled and non-cooled bulbs, indicating the storage duration. The asparagine content per gram dry weight fluctuated around a constant level at 17°C storage, but decreased rapidly during the first weeks of the 5°C treatment. This level remained low during the rest of the cold period, indicating 5°C cooling. The ratio of the 4-methylene-glutamine content to the asparagine content increased considerably with the duration of the 5°C treatment, but to a much lesser extent at 17°C. This change was independent of the starting date of cooling. It is concluded that this ratio is a rough indicator for the duration of the special precooling.

Temperature dependent redistribution of organic nitrogen during ‘dry' storage of tulip bulbs cv. Apeldoorn

Tulip bulbs cv. Apeldoorn are dry stored at 5°C for 12 weeks to ensure subsequent optimal flowering when planted in the greenhouse at higher temperatures of 17–20°C. Both temperature and duration of the cold treatment determine the subsequent rate of the shoot elongation, the time until anthesis and the flower size, pigmentation and water content. In search for cold‐specific physiological changes, possibly related to the development of the potential of proper flowering (flowering preparation), we studied the redistribution of organic nitrogen in both cooled (5°C) and non‐cooled (17°C) bulbs.During 12 weeks of dry storage, the total protein‐ and free amino acid‐nitrogen content decreased in the scales, whereas the opposite was found in the basal plate (with root primordia) and the shoot. In the shoot, this occurred significantly more at 17°C than at 5°C. At the same time, there was a tissue‐specific change in the free amino acid composition in both cooled and non‐cooled bulbs. Changes specific for the 5°C treatment were only found for the alanine content, in both the basal plate (with root primordia) and the shoot, and for the proline, asparagine, threonine, glycine and isoleucine content, in the shoot only. These changes are, for the greater part, completed within the first 6–8 weeks of dry storage. Bulbs stored for such a short period of time at 5°C still show flowering disorders. Thus, flowering preparation is only partly accompanied by changes in free amino acid contents.

Temperature dependent redistribution of organic nitrogen during 'dry' storage of tulip bulbs cv. Apeldoorn

Temperature dependent redistribution of organic nitrogen during 'dry' storage of tulip bulbs cv. Apeldoorn

Detection of tobacco rattle virus by ELISA and test plants in main sprouts of tulip bulbs during storage at different temperatures

The detectability of tobacco rattle virus (TRV) in the main sprouts of primarily and secondarily infected tulip bulbs of cv. Apeldoorn stored at different temperatures from the lifting in July up to February is described. Detection by ELISA was not affected by the size of the main sprout, nor by the size of the bulbs. The rates of TRV-infected bulbs found by ELISA were highest during storage at 13, 9 or 5°C continuously, and when temperatures were lowered from 20 or 17°C to 5°C in October. The percentages detected via test plants, but undetectable by ELISA were also lowest at these temperatures. The unfavourable effect of continuous storage at 20, 17, or 2°C as expressed in low ELISA absorbances not significantly different from the mean value of healthy bulbs, was largely overcome during long storage by the change of temperature down to 5°C from 20 and 17°C or upwards from 2°C. The reverse from 5°C upwards to 17 and 20°C affected the detectability by ELISA unfavourably. The rate of detection via test plants in the main sprout and in the small sprouts from different positions in bulbs was only possible at low percentages. The effect of some factors, like different temperatures during storage, detectability of different TRV serotypes, interference of irregular occurrence of TRV in the removed scale and basal-plate tissue with the main sprout, and variable recurrence of TRV in progeny bulbs, is discussed in view of its impact on routine testing of bulbs during storage.

Role of Cytochrome P450 in Tulip Bulb Probed by Substrate‐Binding Studies

AbstractMicrosomal fractions from dormant and wounded (sliced, aged) tulip bulbs showed a Soret peak at 448 nm in the carbon monoxide difference spectrum of dithionite‐treated membranes characteristic of cytochrome P450. Wounding and ageing induced a seven‐fold increase in P450 content. The enzyme‐substrate binding spectra and substrate affinity constants found under different conditions implied different forms of cytochrome P450. Of the several xenobiotics examined, two of them, benzo[a]pyrene and the herbicide 2,4‐dichlorophenoxyacetic acid, were inferred to be substrates from the production of P450 substrate‐binding spectra and varied substrate affinity constants were observed using the different microsomal preparations. In the wounded tissue, geraniol binding was also observed, which may reflect the endogenous function of the P450, possibly as part of a defence mechanism.

Mitogenic Activity of Tulipa gesneriana Lectins on Mouse and Human Lymphocytes.

Tulipa gesneriana lectin-erythrocyte (TGL-E) which agglutinates mouse erythrocytes showed a potent mitogenic activity on mouse spleen cells and human peripheral blood lymphocytes, however, TGL-E had only slight mitogenic activity on mouse thymus cells. Its subunit alpha with a molecular weight (MW) of about 26,000 showed a potent mitogenic activity as did that of native lectin, but subunit beta with a MW of about 14,000 showed no activity, indicating that the mitogenic activity of TGL-E originates from subunit alpha. TGL-E stimulated T cell enriched spleen cells which passed through a nylon column, but not spleen cells from a nude mouse or spleen cells treated with anti-Thy 1.2 antibody and complement. Thus, TGL-E stimulates only mouse T cells but not B cells. The other lectin in tulip bulbs, Tulipa gesneriana lectin-yeast showed no mitogenic activity on mouse spleen, thymus cells or human paripheral blood lymphocytes.

Further studies on the use of free amino acids in anthers from tulip bulbs cultivar ‘Apeldoorn’ as indicators about cold treatment at 5°C

Twenty-one free amino acids were estimated in freeze-dried anthers from tulip bulbs cooled at 5°C for 12 weeks and subsequently kept at 17°C for 1 week (transport simulation (TS)), and from a control batch kept at 17°C. By comparing the patterns of changes of these amino acids in controlled laboratory trials with the contents in anthers from nine batches of special precooled (12 weeks at 5°C) bulbs from different regions of The Netherlands (“practical samples”), we deduced the following. (1) Arginine, asparagine, glycine, histidine, lysine and tryptophan contents lower than 108, 6, 3, 4, 5 and 3 mmol kg −1, respectively, indicated bulbs that had been precooled. (2) An aspartic acid content lower than 7 mmol kg −1 indicated that cold treatment had lasted for at least 10 weeks. (3) Only aspartic acid constitutes a criterion for duration of treatment.

STRUCTURE AND APPLICATIONS OF A PRODUCTION MODEL IN TULIP BULB CULTURE

STRUCTURE AND APPLICATIONS OF A PRODUCTION MODEL IN TULIP BULB CULTURE

THE DEVELOPMENT OF FLOWERING ASSAYS FOR COLD-TREATED TULIP BULBS

THE DEVELOPMENT OF FLOWERING ASSAYS FOR COLD-TREATED TULIP BULBS

Diffuse reflectance of flower bulbs

Using a spectrophotometer, the diffuse reflection of tulip (Tulipa L.) and lily (Lilium L.) bulbs were measured. The tulips were measured over a range of wavelengths between 350 and 1480 nm, and the lilies over the range 350 to 1350 nm. The tulip group contained healthy clean bulbs and bulbs infected with Fusarium, while the lily group contained sound, healthy bulbs and some damaged by mechanical harvesting. Both groups were analysed to identify wavelengths that might be capable of discriminating between the sound and defective bulbs. Results for the tulip bulbs indicated that there were no wavelengths where the reflectance means of the clean and diseased bulb groups were significantly different at the 90% level. Discrimination was possible between the damaged and undamaged lily bulbs over a range of wavelengths from 650 to 950 nm.

Studies on the cytochrome P-450 of avocado (Persa americana) mesocarp microsomal fraction

1. Because of the low concentration of cytochrome P-450 in avocado fruit, microsomal fractions were prepared using polyethylene glycol aggregation and low-speed centrifugation, thus avoiding the need for high-speed centrifugation of large volumes of post-mitochondrial supernatant. Recoveries of cytochrome P-450 by this means (0.29 nmol/g tissue) were similar to those after the usual high-speed centrifugation preparation (0.26 nmol/g). The cytochrome P-450 content of tulip bulb (0.30 nmol/g) was similar to that of avocado, but both plant tissues had much lower P-450 contents than did rat liver (13.0 nmol/g). 2. Spectral studies indicate that cytochrome P-450 of avocado mesocarp microsomal fraction binds fewer substrates than does the rat liver enzyme system. Type I binding spectra are given by fatty acids (C7-C14), aryl hydrocarbons (C7-C12), p-chloro-N-methylaniline and N,N-dimethylaniline. Type II binding is seen with inhibitors of mammalian cytochrome P-450 such as metyrapone, and with the imidazole antifungal agents such as clotrimazole. 3. These binding spectra provide a rapid method for identifying possible substrates and inhibitors of avocado cytochrome P-450, and also provide information concerning the nature of the active site of avocado cytochrome P-450. 4. Avocado cytochrome P-450 catalysed the N-demethylation of N,N-dimethylaniline (17.1 nmol/min per nmol P-450) and p-chloro-N-methylaniline (13.1 nmol/min per nmol P-450), and the hydroxylation of lauric (dodecanoic) acid (1.1 nmol/min per nmol P-450).

Changes in the contents of four free amino acids in anthers from tulip bulbs cultivar ‘Apeldoorn’, stored at 5 or 17°C, as criteria related to cold treatment

Asparagine, aspartic acid, glutamic acid and glutamine were estimated in freeze-dried anthers from tulip bulbs precooled at 5°C for 12 weeks and subsequently at 17°C for 1 week (transport simulation), and from a control batch kept at 17°C. Based on the patterns of changes of these 4 free amino acids, we deduced the following: (1) the asparagine content could be an indicator of cold treatment: it was less than 7 mmol kg −1 for cold-stored bulbs and higher than 15 mmol kg −1 for the control; (2) an aspartic acid content of 3–6 mmol kg −1 could indicate that cold treatment had lasted for at least 11 weeks. These criteria apply to laboratory-scale tests; (3) the contents of glutamine and glutamic acid cannot be used as criteria of cold treatment because they are similar in treated and control bulbs during 1 week of transport simulation.

Isolation and characterization of 5-lipoxygenase from tulip bulbs

An unique membrane bound lipoxygenase was isolated and purified from purple star tulip bulbs with a specific activity of 5.2 mu moles O2 consumed.min-1.mg-1 protein. The purified tulip enzyme exhibits regiospecificity for O2 insertion at C-5 of the arachidonic acid molecule. Identification of the reaction product was confirmed as 5-hydroperoxyeicosatetraenoic acid by analytical criteria which included: cochromatography with the authentic compound, as well as mass spectral and 1H-NMR analysis. Thus, the enzyme from tulip bulbs appears to be different from the cytosolic lipoxygenase from potato tubers, which exhibits non-regiospecificity in terms of O2 incorporation. However, the purified tulip lipoxygenase showed a strong immunological crossreactivity with antiserum raised against the purified potato lipoxygenase, indicating close immunological relationship with the other plant lipoxygenases.

Occurrence of 4-methyleneglutamine and 2-oxo-4-methyl-3-pentene-1,5-dioic acid in leaves and stem of tulip plants

Abstract The presence of 4-MeGln in the tulip plant was discovered by ZACHARIUS et al. (1954), and it was found that this amide generally occurred in the leaves of almost all the species of genus Tulipa (FOWDEN and STEWARD 1957a). The 4-MeGln compound has been detected in every part of the tulip plant, i.e., bulb scales, roots, basal plate, young shoots, leaves, stern, and flower (FOWDEN and STEWARD 1957a, b; OHYAMA 1986; OHYAMA et al. 1985, 1988a, b; ZACHARIUS et al. 1954, 1957). Especially 4-MeGln was found to be a major soluble N constituent in the leaves and stem of tulip of the flowering stage (OHYAMA et al. 1985; OHYAMA 1986).

Effect of cold storage treatment for forcing bulbs on the C and N metabolism of tulip plants

Abstract The changes in the carbohydrate and N constituents in tulip bulb scales were investigated in relation to the physiological role of cold treatment for forcing cultivation, by comparing the plants subjected or not subjected to the conventional cold storage treatment. When the bulbs subjected to cold storage were cultivated in a greenhouse, they grew rapidly and flowering occurred normally in early December, whereas without cold storage the growth of the shoots was markedly depressed, they exhibited a rosette form, and flowering occurred in the middle of January. Regarding the changes in the carbohydrate content in the scales of bulbs subjected to the cold treatment, starch degradation occurred rapidly after the onset of the treatment. Based on the morphological observations, small starch granules with a spherical shape disappeared initially, and subsequently the amount of the large granules with a lenticular shape decreased. Along with the starch degradation, there was a considerable accumulation o...

Detection of tobacco rattle virus in different parts of tulip by ELISA and cDNA hybridisation assays

Different parts of tulips cv. Apeldoorn were assayed for the presence of tobacco rattle virus (TRV) by means of ELISA, cDNA hybridisation and immuno-electron microscopy. Assays were periodically performed during the growing season and upon storage of the bulbs, During the growing season in the field the relative TRV concentrations detected by ELISA and cDNA were highest mainly in the basal stem-parts and basal leaf-parts, respectively. When, during storage, infected bulbs were divided into a number of sections, TRV could be detected only in some of the sections, irrespective of the test used. However, nearly all sprouts of infected bulbs, stored at 5°C for 7 months, appeared to contain detectable amounts of TRV upon testing with ELISA and cDNA. Thus, testing of sprouts may offer a possibility to develop a routine test for TRV in tulip bulbs in due course. Verschillende delen van tulp cv. Apeldoorn werden getoetst op de aanwezigheid van tabaksratelvirus (TRV) met behulp van ELISA, cDNA-hybridisatie en immuno-elektronemicroscopie. Tijdens het groeiseizoen en de bewaring van de bollen werden regelmatig toetsingen uitgevoerd. Gedurende het groeiseizoen op het veld werden de relatief hoogste TRV concentraties voornamelijk gevonden in het basale deel van de stengel en het okselgedeelte van het blad met respectievelijk ELISA en cDNA-hybridisatie. TRV bleek gelokaliseerd aanwezig te zijn in een of meer stukjes van een gedeelde bol, onafhankelijk van de gebruikte toetsmethode. Bijna alle spruiten van geinfecteerde bollen die gedurende 7 maanden bij 5°C bewaard waren, bleken bij het toetsen met behulp van ELISA en cDNA aantoonbare hoeveelheden van TRV te bevatten. Het toetsen van spruiten biedt de mogelijkheid te zijner tijd een routinetoets voor TRV in tulpebollen te ontwikkelen.