Acid-soluble phosphate esters were determined in extracts of plant material after a 24 h exposure of the roots of intact alfalfa plants to nutrient media labelled with³²P_i. Similar phosphate ester patterns were found in 2-, 3-, 8-, and 9-week-old plants with the exception of Gra-P which could be detected only in shoot extracts. However, phosphate ester levels differed in the shoots and roots. Whereas Fru-P₂, Glc-6-P, Fru-6-P, and adenine nucleotides were more abundant in the shoots, Grn-P and P-choline levels were higher in the roots. Certain differences in the levels of P-esters were also recorded between plants susceptible and resistant to bacterial wilt.

Abscisic acid, a potent growth inhibitor inhibits hypocotyl growth ofRaphanus sativus seedlings. Phenolic compounds,viz., trans-cinnamic acid, chlorogenic acid, ferulic acid, salicylic acid, tannic acid and quercetin when applied with ABA, antagonize ABA action and restore normal seedling growth.
Gibberellic acid promotes hypocotyl growth and on combined application with ABA, the ratio of their concentrations determines the course of the resultant growth. This interaction can be modulated by phenolic compounds. Phenolic compounds in low concentrations when present together with GA and ABA, favour GA-induced growth by antagonizing the inhibitory influence of ABA.
The inhibitory action of abscisic acid on a wide range of growth processes is so far known to be reversed only by growth promoting hormones,viz., IAA, GA and cytokinins. Antagonistic action of phenolic compounds towards ABA, and increasing the action of GA when present together with GA and ABA, establishes a dual role to this class of compounds; balancing the effect of both growth promoting and growth inhibiting hormones.

The contents of NADP⁺, NADPH, changes in the activity of glucose-6-phosphate dehydrogenase and some questions relating to its regulation in leaf tissues of tobacco plants infected with PVY were studied. The content of NADP⁺ and the total sum of pyridine nucleotides decreased after inoculation to 15 % and 30 %, respectively, whereas the content of NADPH increased up to the threefold control value. The contents of NADP⁺, NADPH and Σ(NADPH + NADP⁺) linearly correlated with the reproduction curve of PVY. The value of the reduction charge RC and the value of the ratio NADPH/NADP⁺ sharply increased after inoculation up to tenfold and eighteenfold values, respectively, of the healthy control.
The activity of glucose-6-phosphate dehydrogenase was markedly increased in virus-infected tissues during the entire experimental period both in crude homogenate and after its partial purification when compared with the values found in healthy control plants. The time courses of the activity curves of both crude and partially purified enzymes were coincident and correlated with the reproduction curve of PVY. The results indicate the involvement of coarse regulation of the activity of the enzyme by its content without the involvement of fine regulation by the ratio NADPH/NADP⁺ and RC.

Gibberellins A₃ and A₁₃ cause floral induction inImpatiens balsamina, a qualitative short day plant, under non-inductive 24-h photoperiods (continuous illumination). However, the influence of the two inductive factors,i.e. gibberellins and short days (8-h photoperiods) on the peroxidase enzyme system is different. The total peroxidase activity decreases under both inductive and non-inductive photoperiods, with or without gibberellin treatment. The electrophoretic pattern of isoperoxidases changes only in response to gibberellin treatment. Under 24-h photoperiods, treatment with gibberellins A₃ and A₁₃ causes the appearance in the stem of three additional isoenzymes of peroxidase (Rm 0.50, 0.71 and 0.76). These bands do not appear in the leaves, which are non-essential for gibberellin-caused floral induction in this plant. Under 8-h photoperiods also, gibberellins induce the appearance of new isoenzyme bandsi.e. two in the stem (Rm 0.50 and 0.76) and one in the leaves (Rm 0.05). These may be correlated with the synergistic increase in the number of floral buds in these plants in response to simultaneous exposure to two inductive factors.

InArabidopsis thaliana the relative measure of Darwinian fitness - the adaptive values of the two homozygotes related to the reference heterozygous genotype in one locus system were estimated on the original and on three changed genetic backgrounds. It was stated that the change of the genetic background with different gene-modifiers of the pleiotropic effect of a given gene on fitness may be important for the existence of mutations in populations, especially if we take into consideration not only the selection pressure against the homozygotes but also a certain real percentage of outcrossing. Special attention is paid to statistical elaboration of the experimental data.

A binary vector system inA. tumefaciens for the introduction of foreign genes into the plant genome was developed. The first component is the Ri plasmid and the second component is a small vector plasmid, replicating inAgrobacterium, which carries the 25 bp terminal sequence of the Ti plasmid, theNos gene as the selectable marker and neighbouring sequences of the Ti plasmid. Functions necessary for integration are providedin trans by the virulence region of the Ri plasmid. Transformed cells are selected on the basis of hairy root tumor proliferation and agropine synthesis. They also showNos activity coded by the gene on the small part of Ti T-DNA.

On the basis of proportionality between flow and its conjugated force a mathematical model for volume, current and osmotic flows was designed and a method for the experimental measurement of flows, the transbarrier (trans-segmental) potential and the rate of flow was devised.
The results obtained experimentally as well as using the mathematical model indicate that the plant root is differentiated not only according to localization, but also according to the conductivity, permeability and selectivity of these tissues.

XAD-4 resin was used to isolate cytokinins present in Baltic sea water. Four compounds were tentatively identified as 6-(3-methylbut-2-enylamino) purine and zeatin, and their ribosides.

An analysis of axillary meristem (axillary bud) localization of radish (Raphanus sativus L. cv. Tetra-Iłówiecka) was undertaken on vernalized (flowering) and unvernalized (vegetative) plants. It has been shown that the localization of these meristems can be different on successive nodes of the same plant and is connected with the development stages of the plants. The axillary meristems can arise on the stem as well as in the leaf axil or on the base of the subtending leaf. The localization of axillary meristems has been discussed in relation to growth directions and growth correlations inside the meristematic region of the shoot apex.

The protoplasts of the moss Anoectangium thomsonii, isolated from protonemal cells underwent divisions in 48-72 hours on modified MS medium enriched with growth regulators, 2,4-D and kinetin, 10 % sucrose and coconut water (5 %). Subculture of protoplast derived cells in a medium of relatively low osmotic potential (5 % sucrose) produced dark green calli which could be maintained completely undifferentiated.

Certain cultivars ofMalus growing at Geneva, New York, USA, begin growth and bloom 2 -3 weeks later than commercial cultivars of apple. Our research suggests that these late bloomers bloom late because they have a very high chilling requirement for bud burst. The chilling requirement interacts with the heat requirement for bud burst in such a way as to result in delayed bud burst and bloom. Abscisic acid (ABA) decreases in the terminal buds of both early and late bloomers during the chilling period, but it decreases more rapidly in the early bloomers. It has not been determined if ABA plays a role in controlling bloom date.

Glass microelectrodes filled with antimony were constructed, the electrical potential of which linearly depends on pH and is not influenced by light. Recording at the surface and in the cytosol (the latter corrected for the transient response of the membrane potential measured with a conventional electrode) showed both intra- and extracellular alkalization brought about by irradiating the algaPithophora pragensis. DIURON (DCMU, 3-(3,4-dichlorophenyl)-1,1-dimethylurea) in the concentration 10^-4M almost entirely abolished the photoeffect.

Virus particles of isometric shape with a diameter of 26 nm were found in the sieve tubes and accompanying phloem cells in ultrathin sections prepared from the nerves of white mustard (Sinapis alba L.) leaves and roots infected with the beet mild yellowing virus (BMYV). BMYV particles were much more frequent in the roots ofSinapis alba plants. Isometric particles were not found in the leaves and roots of healthy mustard plants.

A haemagglutinating material was isolated and purified from the phosphate buffered saline extract of the seeds of the jack fruit using an immobilized N-aeetyl-D-galactosamine column. This material was composed of two iso-lectins of molecular masses 11 500 and 15 000. The lectins agglutinated native washed red blood cells of the human A, B and 0 groups and sheep, rabbit and mouse erythrocytes. The lectins were found to be composed of single polypeptide chains and they contained no covalently linked sugars. The lower molecular mass material was present in considerably greater quantity than the higher molecular mass component. On isoelectric focussing on PAG the lectins gave a spread of components with calculated pI between 6.0 and 8.3.

The content of ATP, ADP, AMP, P_i, the activity of the enzymes involved in the glycolytic pathway, some problems of their regulation by adenine nucleotides and some basic problems connected with tissue energy balance were studied in tobacco plants infected with the potato virus Y (PVY). The contents of ATP and ΣAdN were increased in virus-infected tissues when compared with healthy tissues and correlated with the PVY reproduction curve. ADP and AMP contents decreased just after the inoculation and increased at the end of the experimental period, P_i content was not influenced by the infection.
The activities of the key enzymes of the glycolytic pathway (6-phosphofructokinase, hexosediphosphatase, and pyruvate kinase), determined both in crude homogenates and after partial purification, did not differ during the entire experimental period from the values found in healthy control tissues, similarly as the activities of glucosephosphate isomerase, glyceraldehydephosphate dehydrogenase, phosphoglyceromutase and enolase observed in crude homogenates. The unchanging AEC value in virus-infected tissues simultaneously indicated that no change in the rate of the glycolytic pathway occurred even under "invivo" conditions at the period of the acute stage of infection.

The rice is important in plant science for its ability to germinate and grow with restricted or without oxygen availability. In this work we have investigated the variation of growth substances when anoxia was imposed to rice seedlings previously grown in air. An increase, in all the organs of a seedling and in particular in the fraction released in the medium, was observed for ABA (abscisic acid), PA (phaseic acid) and DPA (dihydrophaseic acid) quantities.Vice versa a reduction of total IAA (indol-3-ylacetic acid) was observed in seedlings. This was accompanied by its accumulation in roots. IAA was poorly released in aerobic conditions and anoxia has not changed this pattern.

Isolated uninucleate microspores of tomato,Lycopersicon esculentum Mill, were cultured in defined, liquid nutritive media. The microspores developed to haploid embryoids with or without an attached suspensor or into calli with compactly or loosely arranged cells.

Diphenylamine (DPA), 2-hydroxybiphenyl (OHBP) and 9-fluorenone (9-F), known inhibitors of carotenoids (car) synthesis, altered the pattern of incorporation of 2-¹⁴C-mevalonate into car in ripening fruits ofCapsicum annuum. OHBP was the most powerful inhibitor of the whole process of biosynthesis, followed by DPA and 9-F. The most sensitive step was the dehydrogenation of phytofluene. Cyclization of β-carotene and isomerizations yielding the structure of hydroxy-cyclopentane were also affected, although to a lesser extent.

The effect of phosphorus deficiency on acid phosphatase activity in the apical, middle and basal parts of the root of maize plants was followed. The supernatant obtained by centrifuging the homogenate of plant tissue at 1500 ×g was further centrifuged at 18 000 ×g, the sediment being marked as fraction II and the supernatant as fraction III. The results obtained document the fact that acid phosphatase activity of the two fractions of all analyzed root segments was higher in plants cultured in nutrient medium without phosphate than in those containing phosphorus in nutrient medium. In most cases this difference was significant to highly significant. The results of experiments proved unambiguously a higher enzymatic activity in all root segments in fraction III than in fraction II. In fraction III the highest acid phosphatase activity was found in the apical part, in fraction II in the basal part of the root.

The level of gibberellin-like substances was determined in the cotyledons and axis of developing seedlings of dwarf (Little Marvel) and normal (Tall Telephone) cultivars of pea (Pisum sativum L.). The effect of cotyledon removal with GA₃ application on growth was also examined. Greater levels of gibberellin-like substances were observed in the cotyledons of the normal cultivar than the dwarf. This was particularly evident in the cotyledons during the early stages of seedling growth. Subsequently there was a decline in GA levels in the cotyledons. This was coincidental with a rise in GA content in the axis with markedly greater levels in the normal than the dwarf cultivar.
Decotyledonated dwarf and normal plants supplied with GA were much taller than the decotyledonated controls. This observation along with those of the gibberellin levels in the cotyledons and axis, provided circumstantial evidence that there may be translocation of gibberellins from the cotyledons to the axis.

This paper describes the differentiation of karyotypically stable callus strains ofCrepis capillaris (with modal chromosome numbers 7, 8 -11 and ≧ 12, in particular) during 12 years' subculturing on an identical M-S medium with supplements, including 2,4-D (1 mg 1^-1) and adenine (1 mg 1^-1). The possible modes and factors of karyotypic adaptationin vitro are discussed.

Two phases of radish ontogenesis (I-when the plant had produced 3 -5 nodes and II-when the plant had produced 8 -10 nodes) were established on the basis of axillary, meristem localization. Flowering of the plants in response to GA treatment depends on the phases in which they were treated and on growth correlations in the apical meristem. The results obtained suggest that the reaction ofRaphanus sativus (LDP) to GA treatment is parallel to that ofChenopodium rubrum (SDP), and that the response of radish plants also depends on changes in growth correlations in the shoot apical meristem at the time of treatment.