摘要:

AbstractCallus cultures of carnation,Dianthus caryophyllusL. ev. G. J. Sim, were grown on a synthetic medium of half strength Murashige and Skoog salts, 3 % sucrose, 100 mg/l of myo‐inositol, 0.5 mg/l each of thiamin, HCl, pyridoxin, HCl and nicotinic acid and 10 g/l agar. Optimal concentrations of growth regulators were observed to be 3 × 10−6Mindoleacetic acid (JAA) combined with 3 × 10−6Mbenzylaminopurin (BAP) or 10−6M2,4‐dichlorophenoxy acetic acid (2,4‐D) alone. IAA + BAP caused a 100 fold increase in fresh weight over 4 weeks at 25°C. Addition of casein hydrolysate increased growth further.Cell suspension cultures worked best in media containing 2,4‐D in which they had a doubling time of about 2 days. Filtered suspensions were successfully plated on agar in petri dishes, but division was never observed in single cells. The cultures initiated roots at higher concentrations of IAA or NAA, but all attempts to induce formation of shoots or em‐bryoids gav

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03546.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractA very rapid increase in particulate cytochromecreductase activity during the very early stages of germination of lettuce is demonstrated. The increase in activity does not parallel water uptake or the increase in cytochrome oxidase activity. The increase is reversible on drying of imbibed seeds and is not inhibited by cyanide. It is concluded that the increase in activity is due to some kind of activation process and not tode novosynthesis of protein. Possible mechanisms of activation were investigated. It was not possible to simulate the activation processin vitro, in the isolated particulate fraction.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03547.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe average rate of rotation of circumnutating tendrils ofPisum sativumL. ev. Alaska, was 1.57 ± 0.29 mm/min. 53% of the tendrils rotated clockwise and 47% counterclockwise. Circumnutation is apparently dependent on the maintenance of sufficient turgor as it stopped when either the roots or all the shoot appendages except the terminal tendril were excised, but resumed when the aerial wounds were covered with petroleum jelly.Both circumnutation and contact coiling were similarly retarded when the plant was cut in the middle of the top inter‐node, or by the use of either juvenile or senescent organs.As the tendril circumnutated rapidly during the sweeping portion of its circuit, it was capable of coiling at only about 57% of the rate of which it could coil if stimulated during the relatively slow moving turn, Conversely, when the tendril was mechanically stimulated to coil, its rate of circumnutation decreased markedly and remained retarded as long as the tendril continued to coil.On the basis of these observations, it is concluded that contact coiling does not seem to be simply a modified form of circumnutation, but the two modes of movement might be related through a negative feedback syst

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03548.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe oxygen exchange obtained when isolated chloroplasts of wheat are irradiated, without the addition of a Hill oxidant, has been investigated. Depending on the wavelength, two types of oxygen exchange are obtained. In light absorbed by both photosystems an oxygen gush appears directly upon irradiation. This oxygen evolving reaction is soon replaced by an oxygen uptake which is present until the end of the irradiation period. In light absorbed mainly in photosystem I, no oxygen gush can be observed, instead an oxygen uptake appears directly upon irradiation. An oxygen evolving process can also be observed in irradiations performed with photo‐system I light, but this process appears after 10–15 seconds of irradiation. The influence of various external factors on the oxygen gush and the oxygen uptake,e.g.different wavelengths, light intensity, length of the dark periods between irradiations, was studied.The results show that the oxygen evolving reaction appearing upon irradiation with light absorbed by photosystem II and I, reflect the reduction of an oxidant, probably plasto‐quinone, in the electron transport chain between the two photosystems. The reoxidation of this oxidant can be brought about after irradiating with light absorbed in photosystem I, or by prolonging the dark period between irradiations, or through some unknown process connected to photosystem II.The oxygen uptake which consists of two components, one appearing directly upon irradiation and the other one appearing after about 10 seconds of irradiation, confirms earlier observations that oxygen can be reduced in photosystem I. The electrons for the oxygen uptake appearing directly upon irradiation, are obtained from the reduced intermediates in the electron transport chain between the two photosystems. The electrons for the other oxygen uptake process are obtained from a reductant in the chloroplasts with access to the carrier chain between the photosystems. Whether the two oxygen uptake reactions reflect two sites of interaction of oxygen with the electron transport chain or only one site is disc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03549.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe occurrence of growth regulators active in the Avena coleoptile straight‐growth test in sprouting buds and seedlings of Norway spruce (Picea abiesKarst.) was investigated.The acid ether fraction contained a growth stimulator, the Rf of which in isopropanol: ammonia: water was 0.2–0.4. This substance behaved as indole‐3‐acetic acid (IAA) in elec‐trophoresis, in chromatography in various solvent systems on paper and on a Sephadex column. It gave the colour typical of IAA when sprayed with Ehrlich reagent and its fluorescence characteristics corresponded to IAA. Acid ether‐soluble inhibitors showed most activity at Rf 0.4–0.7, but due to tailing they interfered with the determination of the stimulator at the Rf of IAA in the bioassay. They also masked the activity of other stimulators. Colour reactions were obtained with Ehrlich reagent in the inhibiting chromatogram zone. When eluates from this zone were tested in high dilutions or after gel filtration growth stimulation was obtained. The acid fraction of seedling shoots also contained a stimulator with Rf 0.7–0.8. In the neutral‐basic ether‐soluble fraction growth stimulation was obtained at Rf 0.5–0.7. The extracts also contained stimulatory substances insoluble in ether but soluble inn‐butanol and partly in ethyl acetate. When the butanol fraction was hydrolyzed in 1MNaOH a substance behaving as IAA when chrom

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03550.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractExcised shoots and potted plants ofColeus blumeiBenth, were subjected to different treatments with kinetin solutions. Control treatments were made with water. Free and bound auxin were extracted with ether. The acid fractions were purified by electrophoresis to remove all traces of kinetin, and were then analyzed with the Avena straight‐growth test.As compared with the controls, kinetin treatment increases the bound auxin, whereas the corresponding free auxin is unchanged. Also methanol extracts of treated stems contain more acid auxin than corresponding extracts of water‐treated stems. This indicates that on methanol extraction not only free auxin but also some bound auxin is obtained. The extracted auxin behaves like indoleacetic acid in paper chromatography with four different solvent systems, as well as in gel filtration through Sephadex.New formation or decreased breakdown of auxin seem the most likely explanations for the observed effects of kine

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03551.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractKinetin has a stimulating effect in the Avena straight‐growth test. The action of different concentrations of kinetin, 2.5 × 10−7, 2.5 × 10−6and 2.5 × 10−5M, in combination with different concentrations of IAA was studied in this test. It was shown that the effect of low IAA concentrations, 0.25 × 10−7and 1 × 10−7M, was strongly enhanced by the addition of all the kinetin concentrations investigated. The effect of the highest IAA concentrations, 25 × 10−7and 100 × 10−7M, on the other hand, was inhibited relatively strongly by the highest employed concentration of kinetin. The results are explained as due to a kinetin‐produced increase of auxin in the coleoptile segment, which in combination with low IAA concentrations can lead to a growth stimulation and with high IAA concentrations to a growth inhibition.Since kinetin in purification and chromatography of auxin can partly follow IAA, thereby affecting the quantitative yield, it is emphasized that, prior to the test, auxin extracts containing cytokinins should be freed from the latter by, for example, gel filtration

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03552.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractDifferent amounts of abscisic acid, 2.7 × 10−9− 5 × 10−8moles, were chromatographed in isopropanol: ammonia: water (100:14:6), firstly alone and secondly together with 5 × 10−8moles kinetin. The same amount of kinetin was also chromatographed alone. The chromatograms were tested biologically with the Avena straight‐growth test. Whereas a large part of the chromatograms of kinetin gives growth stimulation, the Rf region 0.4–0.6 of abscisic acid chromatograms is strongly growth‐inhibiting. The inhibition within this Rf region does not become less if abscisic acid and kinetin are chromato

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03553.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractUngerminated pumpkin (Cucurbita moschataPoir.) cotyledons contained 30 % of their dry weight as lipid and 26 % as protein, of which 93 % was globulin. There was a rapid degradation of these reserves 4 to 8 days after planting when the cotyledons had their maximum metabolic activity. About half of the mole percent of amino acids found in the globulin reserve was in arginine, glutamate, aspartate, and their amides. The cotyledons had a large soluble pool of arginine, glutamine, glutamate, and leucine. Most amino acids increased steadily in amount in the cotyledons during germination, except glutamine, ornithine, alanine, serine, glycine, and γ‐aminobutyrate and these appeared in large amounts in the translocation stream to the axis tissue. Little arginine or proline was translocated. By 10 days, when translocation had decreased, amino acids accumulated. Ornithine, γ‐aminobutyrate, and aspartate were rapidly utilized in the hypocotyl, while glutamine, glycine, and alanine accumulated there. Cysteine and methionine levels were low in the reserve, trans‐location stream and soluble fractions. γ‐Aminobutyrate‐U−14C injected into cotyledons or incubated with hypocotyls was utilized in a similar fashion. The label appeared in citric acid cycle acids and in the amino acids closely related to this cycle, but the bulk of the label appeared in CO2. The labeling pattern suggests that γ‐aminobutyrate was utilized via succinate, and thus entered the citric acid cycle. A close relationship between arginine, ornithine, glutamate, and γ‐aminobutyrate exists in the cotyledon with all but arginine being translocated rapidly to the axis tissue where these amino acids are

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03554.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe effect of coumarin, IAA, ethylene, kinetin and gibberellic acid on roots of maize and wheat was investigated. Sterile attached and detached roots and isolated elongation zones were used. In some experiments a semi‐sterile procedure was followed. The effects of the different regulators separately or in various combinations together with coumarin were studied on the root growth with regard to division, elongation and swelling of the cells. The ethylene production in isolated elongation zones was measured after treatment with coumarin, IAA, PCIB, kinetin, colchicine and dinitrophenol.The results show the following: 1) Each substance produces a specific morphologic pattern. 2) Changes in polarity were demonstrated for auxin‐induced swelling in cell divisions and cell expansion and for coumarin‐induced swelling in cell divisions. Other cell expansion in swollen parts was due to cylindric cells increasing in width while retaining their cylindric form. 3) Coumarin‐induced inhibition could not be counteracted by IAA, PCIB, carbon dioxide, kinetin, gibberellic acid or Cycocel. 4) The ethylene production in isolated elongation zones increases noticeably after kinetin treatment, less strongly after auxin treatment and least after coumarin treatment. The production of ethylene does not seem to be correlated with the morphogenetic effect of the different substances. 5) The isolated elongation zones reacted to a) IAA and kinetin with an increase in length in some cases and b) gibberellic acid with a reduction of their width. 6) The inhibitory effect of coumarin on the growth in length of the elongation zones was diminished by kinetin. The swelling produced by coumarin in these zones was reduced by gibberellic acid. The effects just mentioned of kinetin and gibberellic acid were considered as indirect ones. ‐ From the present findings it was concluded that concomitant effects of auxin, ethylene, cytokinins and gibberellins are not obligatory for coumarin to exert its morphogenetic effects on root growth. In discussing the results some pitfalls in studies of growth reactions after application of hormones to roots containing meristem were e

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03555.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY