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Three complexes between phenols and amines (phenolamides) have been found in Cichorium intybus L., a plant with an absolute requirement of vernalisation followed by long days for flowering. Upon hydrolysis, these complexes (A, B and C) liberate aromatic amines whose exact identification is in progress, but which are closely related to dopamine, tyramine and serotonin, respectively. In a first series of experiments, phenolamides were studied in the buds of plants grown in the greenhouse under varying conditions. Only buds from plants which flower in long days contained large amounts of these compounds. Much smaller amounts were found in buds at the end of vernalisation (at 2-4°C) before long-day treatment as well as in buds kept in the vegetative state after vernalisation by being grown in short days (8 h light) or in total darkness. In a second series of experiments, phenolamides were studied in bud-forming calli induced in vitro on explains of tuberised root. After sixteen days of culture in continuous light, large quantities of phenolamide were found in the buds and calli of the upper part of the explant, whale the lower part which never produces buds contained much less. Buds formed under continuous light produce inflorescences m approximate]y one month. Various other culture conditions make it possible to maintain the explants in the vegetative state. This can be obtained by short-day conditions, or otherwise under continuous illumination by decreasing the sugar or increasing the NAA levels in the medium. After 13 days of culture, the phenolamide levels were much lower under all of these conditions, than under conditions favourable to floral induction. Compound C is absent or present in trace amounts in vegetative buds. The significance of the differences observed between floral and vegetative buds is supported by the sensitivity of the analytical techniques used. The accumulation of phenolamides in tissues of Cichorium intybus appears to be closely linked to floral induction. Under continuous light it begins very early in young buds and even in the calli that bear these buds. [ABSTRACT FROM AUTHOR]

3H-IAA was applied to the tips of intact wheat coleoptiles (Triticum sativum L., var. Capitole) for 30, 60 or 120 min. The quantity of label per segment (1.5 mm), determined by liquid scintillation counting, was a decreasing exponential function of distance from the source of radioactivity. Chromatographic analysis showed that 3H-IAA was transported more rapidly than its tritiated metabolites. Autoradiographs of semi-thin sections were performed after application of 3H-IAA during 2 h and after treatment by DCC [1- (3-dimethyl-aminopropyl)-3-ethylcarbodiimide hydrochloride]. The quantity of label per tissue and per cell was determined at 1.5, 3.0 and 4.5 mm from the tip. Tritiated IAA was estimated to account for 70 to 100% of the label, depending on the distance from the tip. The amount of auxin transported basipetally was greatest in the parenchyma, with lesser amounts transported in the inner and outer epidermis. Tissues of the vascular bundles did not contain more than 10% of total radioactivity of the coleoptile sections. The rate of auxin transport was greater in xylem and parenchyma than in epidermis and bundle sheath. Movement was very slow in procambium and phloem. In parenchyma and epidermis the quantity of label per cell as a function of distance from the tip agreed with the model of exponential regression. These results support the theory of polar diffusion of auxin. [ABSTRACT FROM AUTHOR]

Two methods of fixation of 3H‐IAA on macromolecules were studied in order to obtain autoradiographs of semi‐thin sections after a routine treatment for electron microscopy. Glutaraldehyde and DCC [1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride] could be used to obtain in vitro fixation of auxin on proteins. However, the rate of reaction with DCC was greater, so that the method using this compound is preferable. A cytological study was performed on wheat coleoptiles (Triticum sativum L., var. Capitole) after application of 3H‐IAA to their tips. Almost no radioactivity was found in the phloem elements while the procambium and the vessels were intensively labelled. In parenchyma cells, cell walls, nuclei and intercellular spaces contained a large amount of 3H‐IAA. These results are consistent with the hypothesis that auxin is transported, from cell to cell, via the apoplast. The extraction of auxin by methanol before cytological fixation indicates that this hormone is not bound (by a covalent binding) to cellular structures, except perhaps in the secondary wall of vessels. [ABSTRACT FROM AUTHOR]

The study of the sensitiveness of 16 varieties or lines of Triticinae against two races of Pseudocercosporella herpotrichoides shows that, whatever the strain used, the importance of the attacks is much less serious on seedlings of Ae. ventricosa no. 11, Ae. squarrosa no. 15, Ae. squarrosa no. 33 and Roazon. Roazon was the least sensitive among the Triticum. It is obvious that Ae. ventricosa is the most resistant one in all varieties or lines used. [ABSTRACT FROM AUTHOR]

The microscopic observations reveal important histological differences between the sensitive or resistant varieties. The disease rapidly affect the whole of the first three leaf-sheath tissues in the "Etoile de Choisy" variety; in the "Roazon" variety, it only affects the first two sheaths. The inter- or intracellular mycelia can be observed both under the form of filaments more or less dilated or under the form of dense segments in the sensitive variety. However in the resistant variety, only short segments can be observed. The tissues of those two varieties are gradually destroyed when they are in contact with P. herpotrichoides hyphae, whereas the hyphae remain undamaged. In "Etoile de Choisy" the hyphae develop in great quantity whereas in "Roazon," the development remains limited. In the variety Ae. ventricosa no. 11, which is very resistant, the parasite rarely penetrates into the more external cell layers of the first leaf sheath, those invaded host cells are destroyed by the mycelium but, at the same time, the mycelian hyphae degenerate and dilate. Thus, the Ae. ventricosa no. 11 tissues seem to be the seat of a strong fungic toxic reaction. [ABSTRACT FROM AUTHOR]