Showing papers on "Zeatin published in 1976"
TL;DR: Changes in levels of abscisic acid (ABA) and cytokinin activity in the xylem sap of willow (Salix viminalis, L.) were followed throughout two growth cycles.
Abstract: Changes in levels of abscisic acid (ABA) and cytokinin activity in the xylem sap of willow ( Salix viminalis , L.) were followed throughout two growth cycles. Growth in spring was preceded by decreasing levels of ABA and an increase in cytokinin activity. The onset of dormancy was associated with low levels of cytokinins and high contents of ABA. A second peak of ABA was found in July which was not related to the dry weight of the sap. The main cytokinin activity in the sap was due to a zeatin riboside-like compound.
99 citations
TL;DR: In mature and aging leaves most of the cytokinin activity was due to slow moving compounds (paper chromatography) which could be hydrolysed by β-glucosidase, but after hydrolysis the active compounds co-chromatographed with zeatin andZeatin riboside respectively.
Abstract: During the course of the growing season Ginkgo biloba leaves undergo both quantitative and qualitative changes in their cytokinin content. In young expanding leaves the major cytokinins cochromatograph with zeatin and zeatin riboside. In mature and aging leaves most of the cytokinin activity was due to slow moving compounds (paper chromatography) which could be hydrolysed by β-glucosidase. After hydrolysis the active compounds co-chromatographed with zeatin and zeatin riboside respectively. This indicates that both zeatin glucoside and zeatin riboside glucoside are present in the mature leaves. It is suggested that these glucosides are formed when the xylem transported cytokinins are metabolized (inactivated) in the leaves.
82 citations
TL;DR: Leaf explants of tomato were cultured in vitro on Murashige and Skoog medium under controlled environmental conditions and large numbers of regenerated plantlets were transferred to pots and grown to mature plants.
72 citations
TL;DR: During the overall germination process in the light-requiring seeds of Chenopodium album L, two sites of hormonal action can be distinguished and a second site oformonal action is located during the progress of growth inside the covering structures.
Abstract: During the overall germination process in the light-requiring seeds of Chenopodium album L. two sites of hormonal action can be distinguished.
The start of visible growth is induced in darkness by the gibberellins 4 and 7 (GA4+7) or by ethylene. Added cytokinins are inactive although 8-14C-kinetin shows rapid penetration into the seed and rapid turnover. The induction of growth by GA4+7 and the uptake of 8-methylene-14C-GA3 are enhanced at lower pH values. Prolonged incubation in darkness results in a decreased responsiveness of the seeds towards GA4+7 and ethylene.
A second site of hormonal action is located during the progress of growth inside the covering structures. ABA inhibits radicle growth, while GA4+7, GA3, kinetin, zeatin and ethylene reduce the inhibition.
66 citations
TL;DR: Zeatin riboside was found to be the major translocational form of cytokinin in the xylem during early vegetative growth and decreased markedly in concentration during flower bud formation, so that, at anthesis, there was no appreciable difference in the zeatin and zeat in Riboside concentration in the root exudate.
Abstract: The zeatin and zeatin riboside content of tomato (Lycopersicon esculentum Mill.) root exudates were determined at different stages of development. Zeatin riboside was found to be the major translocational form of cytokinin in the xylem during early vegetative growth. During flower bud formation this cytokinin decreased markedly in concentration so that, at anthesis, there was no appreciable difference in the zeatin and zeatin riboside concentration in the root exudate.
65 citations
TL;DR: Morphogenesis in flax (Linum usitatissimum L `Redwing') was studied in hypocotyl sections taken 3-5 days after removal of the cotyledons and shoots and the sections were cultured on a Murashige and Skoog medium Zeatin and other cytokinins at 1-10 μM enhanced bud initiation and shoot development on the hypocrotyl explants.
Abstract: Morphogenesis in flax (Linum usitatissimum L `Redwing') was studied in hypocotyl sections taken 3-5 days after removal of the cotyledons and shoots and the sections were cultured on a Murashige and Skoog (1962) medium Zeatin and other cytokinins at 1-10 μM enhanced bud initiation and shoot development on the hypocotyl explants. Complete plants were obtained by culturing shoot tips in B5 medium at half strength and with 1 μM indoleacetic acid Plants were also obtained from callus derived from the hypocotyls. Methods for isolation of protoplasts from hypocotyls are described. When cultured, the protoplasts regenerated cell walls, divided, and formed callus. The callus differentiated with the formation of roots.
65 citations
TL;DR: A qualitative analysis of cytokinins and their distribution and site of production in mature vegetative plants of Xanthium, strumarium L., a species in which cytokinin levels are greatly influenced by photo period is concerned.
Abstract: Cytokinins from leaf laminae, buds, petioles, stems, roots, and root exudate of mature vege tative plants of Xanthium strumarium L. were extracted, fractionated, and partially character ized by means of column chromatography with Sephadex LH20. Two peaks of cytokinin activity with elution volumes corresponding to zeatin and zeatin riboside were detected, in varying concentrations, in all plant parts. A third cytokinin, detected only in petioles and in expanding and mature leaves, eluted off the Sephadex column before zeatin riboside. This cytokinin (peak 'a') was converted to zeatin or to a zeatin-like cytokinin following both acid hydrolysis and treatment with /3-glucosida.se. Peak 'a' was not detected in buds or in the young est developing leaves but was the predominant cytokinin present in half-expanded and more mature leaves. By contrast, the zeatin riboside-like peak (peak 'b') constituted the major cyto kinin in root exudate, apical buds, and the youngest developing leaves, while not greatly contributing to the cytokinin content of mature leaves. The detopped root system was shown to be capable of cytokinin production. The distri bution of cytokinins in the plant is discussed in relation to their probable origin in the root system. INTRODUCTION Cytokinins have been detected in a wide variety of plant tissues and several com pounds with cytokinin activity have now been fully characterized (e.g. Letham, Shannon, and McDonald, 1964; Koshimizu, Kusaki, and Mitsui, 1967 ; Dyson and Hall, 1972; Horgan, Hewett, Purse, and Wareing, 1973; Letham, 1973). However, there have been few investigations into the distribution of the different endogenous cytokinins within a single plant. Such information would be of considerable value with regard to a number of problems concerning the synthesis, movement, and role of these substances as regulators of plant growth and development. Previous studies comparing levels of cytokinins in various plant parts have indi cated fruits to be a major source of cytokinins while vegetative tissues contain much lower levels (e.g. Miller and Witham, 1964; Krasnuk, Witham, and Tegley, 1972). Consequently much work on cytokinin characterization has been concentrated on fruits. Nevertheless, vegetative tissues have not been entirely neglected and several reports have brought to light the existence of qualitative as well as quantitative 1 Present address : Department of Botany, University of Glasgow. This content downloaded from 157.55.39.116 on Sat, 11 Jun 2016 05:54:28 UTC All use subject to http://about.jstor.org/terms Henson and Wareing—Cytokinins in Xanthium 1269 differences in the content of cytokinins between, for example, leaves and xylem sap (Klâmbt, 1968; Hewett, 1973), roots and xylem sap (Yoshida, Oritani, andNishi, 1971 ; Yoshida and Oritani, 1972), and leaves and buds (Engelbrecht, 1971 ; Hewett, 1973; Hewett and Wareing, 1973a, b). The present paper is concerned mainly with a qualitative analysis of cytokinins and their distribution and site of production in mature vegetative plants of Xanthium, strumarium L., a species in which cytokinin levels are greatly influenced by photo period (Van Staden and Wareing, 1972). MATERIALS AND METHODS Plant material Plants of Xanthium strumarium were raised from seed and grown in a heated glasshouse under 18 h days as described previously (Henson and Wareing, 1974). Material for cytokinin extrac tion was harvested when the plants had developed 12 to 16 leaves. Root exudate (root pres sure sap) was obtained by detopping plants above the cotyledonary node. The exuding sap was collected over 24 h and frozen (—15 °C) prior to analysis. For purposes of identification leaves were numbered basipetally according to the procedure of Salisbury (1955) with leaf No. 1 being the first leaf with a midrib 1 -0 cm or more long. Extraction and partial purification of cytokinins Tissues were initially extracted, twice in 80% (v/v) aqueous methanol, using 10 ml g_1 fr. wt. The combined methanolic extracts were purified to give an n-butanol-soluble fraction by either of two methods, both of which gave very similar results. Method A involved reducing the methanolic solution to a small volume on a rotary film evaporator at 30 °C. The extract was then frozen, thawed, and centrifuged (20 000 g for 30 min) to remove chlorophyll, partitioned at pH 2-5 against ethyl acetate (three times), and then at pH 8-0 against water-saturated n-butanol (four times). The w-butanol fraction was then subject to paper or column chromatography using Sephadex LH20 prior to analysis for cytokinins. Cytokinin activity due to ribonucleotides was also estimated following incubation of the aqueous phase remaining after partitioning with the enzyme alkaline phosphatase (Sigma, from calf intestinal mucosa). The treated extract was then repartitioned against ra-butanol (Miller, 1965). Most such extracts yielded little activity and hence the results are presented only for the non-nucleotide cytokinins. With method B the methanolic extract was passed directly through a column of cation exchange resin (Zerolit 225, SRC 14, H+ form) at pH 2-5. After washing the column to remove anions and neutral substances (with two column volumes of 80% methanol and 10 column volumes of distilled water), the cations were eluted with two column volumes of 2 N NH4OH followed by 10 columns of 5 N NH4OH. The eluate was reduced to dryness and the residue redissolved in water and partitioned at pH 8-0 against water-saturated n-butanol (four times). The n-butanol fraction was then further purified as described above for method A. Paper chromatography was conducted using Whatman 3 MM paper and isopropanol: ammonia (0-88 s.g.) iwater (10:1:1, by vol.) as the developing solvent. Column chromatography on Sephadex LH20 (Armstrong, Burrows, Evans, and Skoog, 1969) was conducted using a 2-5 cm x 90-0 cm column eluted with 35% (v/v) aqueous ethanol at a flow rate of either 20 or 30 ml h-1. Bioassay Cytokinin activity was detected using the soybean callus bioassay of Miller (1968), with modifications as previously described (Henson and Wareing, 1974). RESULTS General distribution of cytokinins in the plant The distribution of cytokinins present in purified extracts of roots, root exudate, stems, petioles, leaf laminae, and axillary buds following fractionation on the This content downloaded from 157.55.39.116 on Sat, 11 Jun 2016 05:54:28 UTC All use subject to http://about.jstor.org/terms 1270 Henson and Wareing—Cytokinins in Xanthium
62 citations
TL;DR: Preliminary identification of cytokinins in root exudate has revealed the presence of compounds that cochromatograph with zeatin andZeatin riboside on Sephadex LH20 and kinetin to the growing medium increased the number of flowers produced by the seedlings.
Abstract: Ten days of phosphorus deficiency results in a decrease in the number of flowers that develop on the first truss of tomato plants. This effect on flower number is accompanied by a decrease in the cytokinin activity of the root exudate. The involvement of cytokinins in flower development is further implicated by the fact that application of kinetin to the growing medium increased the number of flowers produced by the seedlings. Preliminary identification of cytokinins in root exudate has revealed the presence of compounds that cochromatograph with zeatin and zeatin riboside on Sephadex LH20.
61 citations
TL;DR: Five cytokinin activities which induced soybean callus proliferation were detected in ethanol extracts of root nodules of the garden pea and the most active factors were identified as zeatin and its riboside on the basis of their mobility on thin layer chromatography in three solvent systems.
Abstract: Five cytokinin activities which induced soybean callus proliferation were detected in ethanol extracts of root nodules of the garden pea (Pisum sativum L., cv. Little Marvel). The most active factors among them were identified as zeatin and its riboside on the basis of their mobility on thin layer chromatography in three solvent systems. Smaller activities of zeatin ribotide, isopentenyladenine and its riboside were also detected. Cytokinin activity gradually decreased with the cultivation period, but no qualitative change in the active compounds was found.
56 citations
TL;DR: Honeydew and leaf extracts from Salix babylonica indicate that large quantities of cytokinin are present in the leaves and are transported through the phloem of this plant during late autumn.
Abstract: Honeydew and leaf extracts from Salix babylonica indicate that large quantities of cytokinin are present in the leaves and are transported through the phloem of this plant during late autumn The active compound in the extracts could be hydrolysed with β-glucosidase, whereafter it showed the same chromatographic behaviour as zeatin It is proposed that cytokinins in the leaves are converted to the glucoside and then redistributed to the rest of the plant organs where it is stored
53 citations
TL;DR: Cytokinin activity in extracts of nodules, roots, stems and leaves of Viciafaba L. was estimated using the soybean callus bioassay to estimate high levels of cytokinins while the amounts detected in roots and stems were much lower.
Abstract: SUMMARY Cytokinin activity in extracts of nodules, roots, stems and leaves of Viciafaba L. was estimated using the soybean callus bioassay. High levels of cytokinins were present in nodules and leaves while the amounts detected in roots and stems were much lower. Cytokinin levels in the root nodules were as much as twelve to thirteen times those detected in the roots. At least three kinds of cytokinins were present in the plant, two of which had similar chromatographic properties to the cytokinin zeatin and its riboside. The third cytokinin had properties which distinguished it from any of the known cytokinins. This peak was predominant in the leaves while the zeatin riboside-like peak was the main cytokinin detected in the root nodules and roots.
TL;DR: Correlations between seed number and fruit weight, and between seed distribution and fruit shape were established for Chinese gooseberry fruit as well as in terms of current theories on hormonal control of fruit growth.
Abstract: Correlations between seed number and fruit weight, and between seed distribution and fruit shape were established for Chinese gooseberry (Actinidia chinensis Planch) fruit Ovaries containing few seeds develop into small fruit, and various growth regulators, either alone or in combination, were applied to fruitlets containing few seeds in an attempt to increase fruit size In general, auxins (2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, β-naphthoxyacetie acid, indoleacetylaspartate), gibberellins (GA3, GA4–7), and cytokinins (6-benzylaminopurine, zeatin) when applied alone did not stimulate fruit development; nor did combinations of auxin + gibberellin, and gibberellin + cytokinin However, auxin (2,4-D or 2,4,5-T) + 6-benzylaminopurine and auxin + cytokinin + gibberellin markedly stimulated fruit growth especially when treated fruit contained over 200 seeds These results are discussed in terms of current theories on hormonal control of fruit growth
TL;DR: By means of chromatographic, mass spectrometric and enzymatic techniques, the major cytokinin in butanol extracts from the milk of Cocos nucifera fruits was identified as zeatin glucoside as discussed by the authors.
Abstract: By means of chromatographic, mass spectrometric and enzymatic techniques the major cytokinin in butanol extracts from the milk of Cocos nucifera fruits was identified as zeatin glucoside.
TL;DR: In anther cultures of Datura innoxia the addition of growth hormones, such as auxins, gibberellins, and cytokinins, to the culture medium enhanced the production of pollen embryoids.
Abstract: In anther cultures of Datura innoxia the addition of growth hormones, such as auxins, gibberellins, and cytokinins, to the culture medium enhanced the production of pollen embryoids. Cytokinins appeared to be the most effective and, among the four cytokinins tested, zeatin and kinetin gave the best results. Generally speaking, combinations of hormones did not improve the response over that of an individual hormone. The number of embryoids per anther varied in the same medium and did not strictly correlate with the percentage of respond ing anthers.
TL;DR: The cytokinins present in the spring sap of Acer pseudoplatanus L. were investigated and ribosyl-trans-zeatin, trans-zesatin and dihydrozeatin were isolated and identified by combined gas chromatography-mass spectrometry (GC-MS).
Abstract: The cytokinins present in the spring sap of Acer pseudoplatanus L. were investigated. Ribosyl-trans-zeatin, trans-zeatin and dihydrozeatin were isolated and identified by combined gas chromatography-mass spectrometry (GC-MS). A number of other cytokinin active fractions were observed. One of these was less polar than zeatin and did not behave as any known cytokinin. Two other fractions were more polar than ribosylzeatin and were unstable. A decomposition product of one of these was identified as ribosyl-trans-zeatin by GC-MS. The possible nature of the unstable compounds is discussed. Data on the changes in cytokinin activity of the various fractions during spring 1973 are presented and discussed.
TL;DR: Several compounds containing reduced nitrogen markedly increased the yields of cell-division compounds extractable from an A6 Vinca rosea L. crown gall tumor tissue and caused the appearance of a cytokinin not previously detected in this tissue.
Abstract: Several compounds containing reduced nitrogen markedly increased the yields of cell-division compounds extractable from an A6 Vinca rosea L. crown gall tumor tissue. Casein hydrolysate, several amino acids, and ammonium salts were effective. Both trans-zeatin and ribosyl-trans-zeatin were substantially increased in total amount per culture and in concentration. These two compounds have been identified by several criteria including mass spectra. The reduced nitrogen treatments also caused the appearance of a cytokinin not previously detected in this tissue; it has not yet been identified. The tumor tissue rapidly absorbed [8-14C]adenine from a liquid medium. Within 1 hour, the tissue converted some of the adenine to zeatin and ribosylzeatin, and greater degrees of conversion occurred in 2-, 4-, and 8-hour periods. The tissue grown on a medium containing ammonium chloride accumulated considerably greater quantities of the two cytokinins made from the labeled adenine during each incubation period.
TL;DR: The cytokinin-active nucleosides from the tRNA of Agrobacterium tumefaciens, the causative organism of plant crown gall disease, were examined and it was found that some prokaryotes have acquired the ability to hydroxylate the isoprenoid side chain and that zeatin and its derivatives are not restricted to plants.
Abstract: THE cytokinin-active N-6-isoprenoid-substituted purine nucleosides have wide distribution as minor components of the tRNA of animals, bacteria and plants. Skoog, Hall and others (refs in ref. 1) have shown that there are three classes of cytokinin nucleosides, and that one member of each predominates in the tRNA of organisms from each kingdom. Thus, animal tRNA contains 6-(3-methylbut-2-enylamino)-9-β-D-ribofuranosyl purine2 (iPA); whereas in bacterial tRNA, the purine ring is thiomethylated and the predominant cytokinin-active nucleoside is 6-(3-methylbut-2-enylamino)-2-methylthio-9-β-D-ribofuranosyl purine3 (ms-iPA). In plants, the isoprenoid side chain is hydroxylated and the predominant cytokinin-active nucleoside is 6-(4-hydroxy-3-methylbut-2-enylamino)-9-β-D-ribofuranosyl purine4 (zeatin riboside, ZR). Minor amounts of 2-methylthio zeatin riboside (ms-ZR) are also present5. But the distribution of these nucleosides may not be quite so clearcut. The plant pathogenic prokaryote Corynebacterium fascians has been shown6 to release cis-zeatin into the culture medium. Other evidence7 suggests that Pseudomonas aeruginosa tRNA contains ms-ZR. It may be that some prokaryotes have acquired the ability to hydroxylate the isoprenoid side chain and that zeatin and its derivatives are not restricted to plants. We have now examined the cytokinin-active nucleosides from the tRNA of Agrobacterium tumefaciens, the causative organism of plant crown gall disease. Besides the expected ms-iPA and small amount of iPA, trans-ZR was present in significant amounts.
TL;DR: Quantitative trace-enrichment of cytokinins from a plant source (xylem sap from the Douglasfir, Pseudotsuga menziesii (Mirb.) Franco) has been achieved by adsorption onto octadecyl-silica columns followed by elution with ethanol.
Abstract: Quantitative trace-enrichment of cytokinins from a plant source (xylem sap from the Douglasfir, Pseudotsuga menziesii (Mirb.) Franco) has been achieved by adsorption onto octadecyl-silica columns followed by elution with ethanol. Adsorption is rapid and efficient and allows complete recovery of cytokinins at the nanomolar level. Douglas-fir sap contains at least four compounds having cytokinin activity, one of which co-elutes with zeatin and another with ribosylzeatin.
TL;DR: Callus tissue that was more than 2 years old and had been used in 30 transfers still had the capacity to produce normal shoots and roots and pointed to a high endogenous auxin level in the original stem explants of L. peruvianum.
TL;DR: A modified soybean (Glycine max) tissue culture bioassay for cytokinins should prove to have several advantages over the conventional soybean callus bioassays including convenience, lower variability between tissue samples, and improved resolution.
Abstract: This paper describes a modified soybean (Glycine max) tissue culture bioassay for cytokinins. Soybean hypocotyls were grown under sterile conditions and sliced into 1-mm sections. Sections were cultured for 5,9,13, or 22 days on a callus medium with zeatin or other cytokinins. The fresh weight of sections increased with the cytokinin concentration from 0.0005 to 1 mum zeatin; 2-fold concentration differences were readily distinguishable at 9 days. The assay should prove to have several advantages over the conventional soybean callus bioassay including convenience, lower variability between tissue samples, and improved resolution. Its specificity is comparable to that of the soybean callus bioassay.
TL;DR: 6-(o-hydroxybenzyl)aminopurine (hyd-BA) and its naturally occurring riboside inhibited germination under normally inductive conditions and all the cytokinins examined were more active in promoting germination of lettuce than celery seeds.
Abstract: The naturally occurring cytokinins, zeatin, zeatin riboside and dihydrozeatin did not promote the germination of celery (Apium graveolens L.) seeds and 6-Δ2-isopentenyladenine (2iPA) and its riboside were only moderately active. Of the synthetic cytokinins, kinetin, kinetin riboside, and the disubstituted urea, N-phenyl-N′-pyridyl urea (NC5392) were moderately active, and 6-benzyl-aminopurine (BA) and its derivatives BA riboside and 6-benzyl-amino-9(tetrahydropyran-2yl)purine (SD8339) were the most active cytokinins tested. 6-(o-hydroxybenzyl)aminopurine (hyd-BA) and its naturally occurring riboside inhibited germination under normally inductive conditions.
All the cytokinins examined were more active in promoting germination of lettuce (Lactuca sativa L.) than celery seeds. BA, BA riboside and SD8339 were again the most active cytokinins. In contrast to the results with celery, zeatin and zeatin riboside were highly active. The other cytokinins also showed high activity with the exception of dihydrozeatin, hyd-BA and hyd-BA riboside which were less active. Cytokinin ribosides were less active than the corresponding free bases during the early period of the lettuce seed incubation but total germination after 90 h was similar.
01 Jan 1976
TL;DR: In anther cultures of Datura innoxia the addition of growth hormones, such as auxins, gibberellins, and cytokinins, to the culture medium enhanced the production of pollen embryoids as discussed by the authors.
Abstract: In anther cultures of Datura innoxia the addition of growth hormones, such as auxins, gibberellins, and cytokinins, to the culture medium enhanced the production of pollen embryoids. Cytokinins appeared to be the most effective and, among the four cytokinins tested, zeatin and kinetin gave the best results. Generally speaking, combinations of hormones did not improve the response over that of an individual hormone. The number of embryoids per anther varied in the same medium and did not strictly correlate with the percentage of respond ing anthers.
TL;DR: Findings do not support the suggestion that zeatin-riboside is the major translocational form of cytokinin in the xylem, and Qualitative changes during maturation and development of the plants can however not be eliminated.
TL;DR: Substances that coeluted withZeatin and zeatin riboside were extracted from soils supporting plants growing in symbiotic association with microorganisms.
Abstract: Substances that coeluted with zeatin and zeatin riboside were extracted from soils supporting plants growing in symbiotic association with microorganisms.
TL;DR: In this paper, the principal cytokinins in the root exudate of young tomato plants were identified as Zeatin and zeatin riboside by means of Sephadex LH-20 fractionation and mass spectrometry.
TL;DR: Eight species of mosses studied were divided into two groups on the basis of their developmental responses to ribosyl-trans-zeatin and Agro-bacterium tumefaciens B(6), and characteristics of protonemal growth common to each of these two groups are described.
Abstract: Eight species of mosses studied were divided into two groups on the basis of their developmental responses to ribosyl-trans-zeatin and Agro-bacterium tumefaciens B6. All eight produced either gametophores or callus on the protonema in response to 6-(γ,γ-dimethylallylamino) purine and trans-zeatin. Three which produced normal gametophores with A. tumefaciens yielded callus or abnormal gametophores with ribosyl-trans-zeatin. Ribosyl-trans-zeatin and A. tumefaciens were relatively ineffective on five other mosses. Characteristics of protonemal growth common to each of these two groups are described.
01 Jan 1976
TL;DR: The involvement of cytokinins in flower development is further implicated by the fact that application of kinetin to the growing medium increased the number of flowers produced by the seedlings as mentioned in this paper.
Abstract: Ten days of phosphorus deficiency results in a decrease in the number of flowers that develop on the fist truss of tomato plants. This effect on flower number is accompanied by a decrease in the cytokinin activity of the root exudate. The involvement of cytokinins in flower development is further implicated by the fact that application of kinetin to the growing medium increased the number of flowers produced by the seedlings. Preliminary identification of cytokinins in root exudate has revealed the presence of compounds that cochromatograph with zeatin and zeatin riboside on Sephadex LH20.
TL;DR: Caution should be exercised when expansion of radish cotyledons is employed as a cytokinin assay if NaCl or KCl are present in varying quantities; the interaction between cytokinins and NaCl appeared to be additive.
TL;DR: The cytokinin has been identified as ribosyl-cis-zeatin, 6-(4-hydroxy-3-methyl-Cis-2-butenylamino) -9-beta-d-ribofuranosylpurine, which accounts for approximately 7% of the total cytokinIn activity in acid hydrolysates of pea tRNA.
Abstract: tRNA6Leu in Pisum sativum seed has been purified. This tRNA species contains a cytokinin-active nucleoside and accounts for approximately 7% of the total cytokinin activity in acid hydrolysates of pea tRNA. The cytokinin has been identified as ribosyl-cis-zeatin, 6-(4-hydroxy-3-methyl-cis-2-butenylamino) -9-β-d-ribofuranosylpurine.