International symposium Plant Growth Regulators June 18-22, 1984 Liblice, Czechoslovakia

Milan Kutáček

Biologia plantarum 1985, 27:81-82 | DOI: 10.1007/BF02902139

Book reviews

Jabmila Solárová, T. Herben, Libuše Pavlová, Kateřina Pánková, J. Tupý

Biologia plantarum 1985, 27:237-240 | DOI: 10.1007/BF02902168

The interaction of hormonal and environmental factors in leaf senescence

K. V. Thimann

Biologia plantarum 1985, 27:83 | DOI: 10.1007/BF02902140

The work concerns the senescence of isolated young leaves of oats (Avena sativa) floated on water or solutions. Senescence is rapid in darkness but slow in white light; the effect of light is not due to photosynthesis, but is paralleled by stomatal opening. Closure of the stomata by osmotic or chemical means makes senescence in light proceed as fast as in darkness, while opening the stomata in darkness by cytokinins, fusicoccin,etc., delays senescence to rates typical of light. The osmotic closure in light is mediated by abscisic acid, and since this also accumulates in darkness it appears as a major factor controlling senescence. Efflux...

Interaction of phytotropins with the NPA receptor

G. F. Katekak

Biologia plantarum 1985, 27:92 | DOI: 10.1007/BF02902141

The chemical and stereochemical properties of phytotropins are described in terms of a receptor model, based on their ability to bind to a receptor isolated from maize coleoptiles. Their root gravitropic properties are correlated with their ability to bind to the receptor. It is suggested that their ability to inhibit auxin transport, without more, may not be enough to explain their physiological effects.

Resolution of the subunit composition of a cytokinin-binding protein from wheat embryos

A. C. Brinegar, J. E. Fox

Biologia plantarum 1985, 27:100 | DOI: 10.1007/BF02902142

When the wheat germ cytokinin-binding protein (CBF-1) is isolated from excised wheat embryos only one group of polypeptides near 54 000 is observed as opposed to three polypeptide groups reported for CBF-1 from commercially milled wheat germ. The other two lower molecular mass polypeptide groups previously reported are probably proteolytic degradation products of the 54 000 species resulting from excessive heat or physical damage during milling. The CBF-1 polypeptide accumulates rapidly in the embryo after 20 days post-anthesis. A larger set of polypeptides near 66 000 - 68 000 appears during embryo development and also reacts with anti-CBF-1 serum....

Auxin binding site in tobacco cells

Helen M. Bailey, R. D. J. Barker, K. R. Libbenga, P. C. G. van der Linde, A. M. Mennes, M. C. Elliott

Biologia plantarum 1985, 27:105-109 | DOI: 10.1007/BF02902143

A specific, high affinity, IAA binding site was demonstrated in both a cytosolic fraction, and in isolated nuclei, fromNicotiana tabacum cv. Wisconsin No. 38 cells grown in suspension culture. The amount of the binding site detected in both these fractions changed during the culture cycle according to a strict pattern. The molecular mass of the binding site was estimated by gel filtration to be approximately 175 000 and it appears to be a protein. When partially purified by affinity chromatography and allowed to pre-incubate with IAA, the site had a significant stimulatory effect on total RNA synthesis, as measured by a cell-free assay system....

Genotype-specific soluble auxin-binding in etiolated pea epicotyls

H. -J. Jacobsen, Karin Hajek

Biologia plantarum 1985, 27:110-113 | DOI: 10.1007/BF02902144

Using different independent procedures for assaying soluble auxin-binding in etiolated pea epicotyls, wo could prove the reliability of the (XH₄)₂SO₄-pelleting assay both for crude cytosols as well as for specific protein fractions obtained after chromatofocusing. Three distinct genotypes (two parent lines, one tall recombinant) investigated so far exhibit characteristic differences with respect to soluble auxin-binding kinetics in their cytosols.

Auxin-binding site in wheat shoots: Interactions between indol-3-ylacetic acid and its halogenated derivatives

Eva Zažímalová, M. Kutáček

Biologia plantarum 1985, 27:114 | DOI: 10.1007/BF02902145

The specificity of IAA-binding site from the wheat shoots was investigated in an attempt to confirm its receptor function. Several monofluoro-, monochloro-, dichloro- and monobromo-substituted indol-3-ylacetic acids were allowed to displace¹⁴C-IAA from the binding site. Displacement abilities of these halogenated IAAs were closely related to there activities in wheat coleoptile straight growth biotest. This finding indirectly confirms thephysiological significance of this binding site.

Cell wall modifications during auxin-induced cell extension in monocotyledonous and dicotyledonous plants

Yoshio Masuda

Biologia plantarum 1985, 27:119 | DOI: 10.1007/BF02902146

There are several differences between monocotyledonous and dicotyledonous plants. The sensitivity towards added galactose which inhibits auxin-induced coleoptile elongation but not stem elongation is one of the conspicuous differences between the two types of plants. InAvena coleoptile segments, galactose, probably as galactose-1-phosphate, inhibits the formation of UDP-glucose from glucose-l-phosphate. The inhibition of UDP-glucose formation due to galactose is not found inPisum epicotyl segments. InAvena UTP: α-D-glucose-1-phosphate uridyltransferase (EC 2.7.7.9) which catalyzes the reaction from glucose-1-phosphate to...

Influence of inhibitors of alternative respiration pathway and oxygen on growth and proton secretion

M. Böttger, H. -J. Soll, M. Bigdon

Biologia plantarum 1985, 27:125 | DOI: 10.1007/BF02902147

A possible involvement of the alternative oxidase pathway in proton translocation was investigated. Net H⁺ efflux- and elongation-rates were simultaneously and continuously measured by means of a pH-stat and an angular position transducer. Disulfiram, an inhibitor of the alternative path, reduces the IAA- and Fusicoccin-induced as well as endogenous proton secretion and growth. Fusicoccin-induced H⁺ secretion is very sensitive to reduced oxygen concentration values far apart from the K_m of cytochrome oxidase. The sensitivity of non stimulated proton secretion to reduction of oxygen concentration depends on the age of...

Cytokinin-controlled ribulose 1,5-bisphosphate carboxylase gene expression in pumpkin cotyledons

B. Parthier, S. Lerbs, J. Lehmann, R. Wollgiehn

Biologia plantarum 1985, 27:131 | DOI: 10.1007/BF02902149

Treatment of etiolated and excisedCucurbita cotyledons with exogenous cytokinin (benzyladenine) in darkness or light results in a marked stimulation of Rubisco activity, content of enzyme protein, and incorporation of labelled precursors into it, indicating cytokinin-stimulatedde novo synthesis of the enzyme. Cell-free translations of RNA in the wheat germ andE. coli systems show an increase in both large and small subunit mRNA amounts relative to the increase of total RNA under the influence of the phytohormone and light. This increase in the level of translatable RNA is confirmed by RNA hybridization with the Rubisco large subunit...

Phytohormones and pigments in albino mutants of cotton and pea

A. S. Polyakov, Ella M. Kof, S. A. Gostimskiï, Londa Sh. Kvarzhava, V. I. Kefeli

Biologia plantarum 1985, 27:139-144 | DOI: 10.1007/BF02902150

The contents of chlorophylls, carotenoids, flavonoids and phytohormones (IAA, ABA and other inhibitors) were determined in green and albino seedlings of cotton (Gossypium hirsutum L.) and pea (Pisum sativum L.) The growth of green and albino seedlings during 1 -2 weeks was similar. The green and albino seedlings do not differ remarkably in phytohormonal content and in the flavonoid concentration. In the etiolated seedlings of green and albino forms the content of flavonoids was rather decreased.

Auxin biosynthesis and its regulation on the molecular level

M. Kutáček

Biologia plantarum 1985, 27:145 | DOI: 10.1007/BF02902152

IAA synthesis proceeding by indol-3-ylpyruvate (IPyA) pathway seems to be regulated in two steps. In the first the L-trp conversion into IPyA is reduced by a low affinity of L-trp to the unspecific aminotransferase, by competition of L-trp with some aminoacids (e.g. L-asp) and indoles (e.g. indol-3-ylacetylaspartate). Simultaneously, a specific L-trp-dehydrogenase in dependence on the NAD(P)/NAD(P)H ratio regulates by its reversible effect the level of IPyA, connecting photosynthesis with growth. A second more "delicate" regulation of IAA level is carried out by the indol-3-ylacetaldehyde system. In pea plants two indol-3-ylacetaldehyde...

Tryptophan aminotransferase and tryptophan dehydrogenase activities in some cell compartments of spinach leaves: The effect of calcium ions on tryptophan dehydrogenase

Květa Vacková, Archana Mehta, M. Kutáček

Biologia plantarum 1985, 27:154 | DOI: 10.1007/BF02902153

The content of spinach-leaf cells was compartmented by differential centrifugation. Three fractions were obtained,i.e. chloroplasts, pellet of remaining organelles sedimenting at 97 000g and cytosol. Enzyme activities of L-tryptophan aminotransferase (TAT) as well as L-tryptophan dehydrogenase (TDH) were demonstrated in all cell fractions. The highest activities of both enzymes were found in the pellet of organelles followed by the enzyme activities in the chloroplasts. The cytosol had the lowest enzyme activities. Chloroplasts are characterized by a relatively higher TDH activity, organelles sedimenting at 97 000g were marked...

Auxin formation by rhizosphere bacteria as a factor of root growth

Z. Přikryl, V. Vančura, M. Wurst

Biologia plantarum 1985, 27:159-163 | DOI: 10.1007/BF02902155

Bacteria of the speciesPseudomonas putida andPseudomonas fluorescens isolated from the rhizosphere of maize and bean plants produce indol-3-ylacetic acid and some other auxins when grown in suspension cultures. IAM and ILA were also found besides IAA and its degradation product IAH by means of HPLC and MS methods. This finding indicates the involvement of two different metabolic pathways in IAA synthesis in bacteria. The amounts found varied between 1.6 and 3.3 μg IAA per ml of media which corresponded to 100-200 μg per gram of bacterial dry mass. The effect of IAA production by rhizosphere bacteria on IAA level in the plant is discussed.

Gibberellin metabolism: Objectives and methodology

J. MacMillan

Biologia plantarum 1985, 27:164 | DOI: 10.1007/BF02902156

The objectives and methodology of metabolic studies of the gibberellins are discussed with particular reference to the rôle of gibberellins in the promotion of stem elongation in gibberellin-responding dwarf mutants of pea.

Gibberellin A₁ dwarfism and shoot elongation in higher plants

B. O. Phinney

Biologia plantarum 1985, 27:172 | DOI: 10.1007/BF02902157

Evidence is presented to support the generalization that gibberellin A₁ is the main 'gibberellin hormone' that is activeper se in the control of elongation growth in higher plants. The evidence is based on a combination of chemical and genetic studies using single gene mutants of maize, pea and rice.

Cytokinin metabolism and the control of cytokinin activity

B. A. McGaw, R. Hobgan

Biologia plantarum 1985, 27:180 | DOI: 10.1007/BF02902158

The roles of the different cytokinin structures are discussed in relation to our knowledge of their biological activities, endogenous occurrence and metabolism.

Cytokinins in maturing and germinatingLupinus luteus L. seeds

J. S. Knypl, D. S. Letham, L. M. S. Palni

Biologia plantarum 1985, 27:188-194 | DOI: 10.1007/BF02902159

³H-labelled zeatin riboside (ZR) was applied to pod walls of intactLupinus luteus L. plants. Metabolites present in mature, dry seeds were zeatin nucleotide (ZNT), zeatin riboside (ZR) and zeatin (Z), zeatin O-glucosides and lupinic acid (LA), and the corresponding dihydro-derivatives of the cytokinins listed. Endogenous cytokinins were rapidly metabolised in germinating seeds. In seeds labelled with [³H]ZR for 90 min following a 2 h period of imbibition in water, ZR was actively converted to ZNT and dihydro-ZNT but the prevailing CTK was Z in cotyledons and ZR in embryo axes (EA); later LA and dihydro-LA, and O-glucoside...

Cytokinin biosynthesis in plant tumour tissues

L. M. S. Palni, S. A. B. Tay, S. K. Nandi, D. J. Pianca, G. J. M. de Klerk, O. C. Wong, D. S. Letham, J. K. MacLeod

Biologia plantarum 1985, 27:195-203 | DOI: 10.1007/BF02902160

A range of endogenous cytokinins have been identified inDatura crown-gall tissue by GC-MS. Incorporation of [³H]adenine into zeatin riboside, zeatin and its nucleotide(s) is also shown. Metabolism studies usingcis- andtrans-isomers of zeatin riboside indicate that interconversion of the two isomers does not occur in this tissue. Data on the identity of major endogenous cytokinins in a genetic tumour line of tobacco is also provided.

Oligopeptides as plant growth regulators

D. Klämbt

Biologia plantarum 1985, 27:204-208 | DOI: 10.1007/BF02902161

It is generally accepted that plant growth and development are regulated by the known plant hormones. Some objections to the functions of auxins and cytokinins in the induction of shoot and root primordia are reported. Instead of them oligopeptides of special amino acid sequences could be the endogenous signals. There exist structure relationships between auxins and parts of the α-helical oligopeptides of defined amino acid sequences. The same is true for cytokinins.
The most difficult part of this hypothesis is its verification. Using protonemata ofFunaria hygrometrica bud induction by various oligopeptides was investigated. The most...

Sensitized bean first internode bioassay for auxins and brassinosteroids

M. Strnad, M. Kamínek

Biologia plantarum 1985, 27:209 | DOI: 10.1007/BF02902162

The bean first internode bioassay ofMeudt andBennett (Physiol. Plant.44: 422-428, 1978) is based on the curvature of bean internode sections after unilateral application of test material near to their base. The test was also used for estimation of biological activity of brassinosteroids which enhance the effect of auxin. Sensitivity of the assay to both IAA and 24-epibrassinolide was increased 1000 and 100 times, respectively, when internode sections were incubated in morphologically inversed position. Under these conditions test material was applied to the young auxin-sensitive morphologically apical internode tissues and auxin was basipetally...

Control of growth by auxin and its specific neutral inhibitor

R. M. Muir

Biologia plantarum 1985, 27:216 | DOI: 10.1007/BF02902163

Evidence for the existence of a neutral inhibitor specific for auxin has been in the literature for 45 years. The inhibitor is demonstrable by its effect in causing positive curvature of theAvena coleoptile. The growth of the mesocotyl of oat and corn seedlings in darkness and its inhibition by light are determined by the neutral inhibitor as is the phototropic response of the sunflower stem. Production of the inhibitor is promoted by red and fluorescent light. Irradiance at 730 nm promotes auxin production while irradiance at 660 nm promotes production of the inhibitor. The positive curvature induced by 2,3,5-triiodobenzoic acid can be used...

Effects of TIBA on meristematic activity and starch metabolism inRiella helicophylla (Bory et Mont.) Mont.

Luise Stange

Biologia plantarum 1985, 27:221 | DOI: 10.1007/BF02902165

The auxin transport inhibitor TIBA strongly influences meristem structure and activity in the unistratose gemmaling ofRiella. The gradient of cell cycle duration, essential for normal morphogenesis, is abolished and the cell cycle is reversibly arrested during exposure to light. At the same time starch accumulation in the light is inhibited. Possibly, these effects are the consequencc of the inactivation of sulfhydryl-containing proteins by TIBA.

Possible explanation of IAA-stimulated transport of¹⁴C-ABA in long pea (Pisum sativum L.) epicotyl segments

V. Borkovec, S. Procházka

Biologia plantarum 1985, 27:226-230 | DOI: 10.1007/BF02902166

Effects of 2,3,5-triiodobenzoic acid (TIBA) and age of etiolated pea epicotyl segments on the indol-3-ylacetic acid (IAA) stimulated transport of¹⁴C-abscisic acid (ABA) was studied. In spite of a slight decrease of IAA transport after the application of TIBA, the IAA stimulation of¹⁴C-ABA transport did not change. In segments excised from epicotyls of different age,³H-IAA transport was identical and the induction of prolongation growth by IAA in segments from the upper part of the epicotyl was observed. The IAA ap{ie226-01}ation to the growing segments was connected with intensive attraction of¹⁴C-ABA to...

In vitro glucosylation of gibberellins

G. Sembdner, H. -D. Knöfel, Evelin Schwarzkopf, H. W. Liebisch

Biologia plantarum 1985, 27:231-236 | DOI: 10.1007/BF02902167

In maturing fruits ofPhaseolus coccineus a soluble glucosyltransferase activity occurs which converts gibberellins into their O-glucosides. The enzyme glucosylates GA₃ and structurally closely related gibberellins (GA₇ and GA₃₀) to their 3-O-glucosides by transfer of glucose preferentially from UDP-glucose.
From cell suspension cultures ofLycopersicon peruvianum cytosolic glucosyltransferases were isolated which in the presence of UDP-glucose converted GA₇ and GA₉ to the corresponding glucosyl esters. In both cases numerous other gibberellins failed to serve as substrates. Thus,...

Cooke, M., Dennis, A. J.: Polynuclear aromatic hydrocarbons: formation, metabolism and measurement

Kateřina Pánková

Biologia plantarum 1985, 27:130 | DOI: 10.1007/BF02902148

Bors, W., Saran, M., Tait, D. (ed.):Oxygen radicals in chemistry and biology

T. Gichner

Biologia plantarum 1985, 27:144 | DOI: 10.1007/BF02902151

Magee, P. S., Kohn, G. K., Menn J. J.: Pesticide synthesis through rational approaches

T. Gichner

Biologia plantarum 1985, 27:158 | DOI: 10.1007/BF02902154

Briggs, W. R., Jones, R. L., Walbot, V. (ed.): Annual review of plant physiology

Z. Šesták

Biologia plantarum 1985, 27:220 | DOI: 10.1007/BF02902164