Production of embryos on the stem ofRanunculus sceleratus L.

Résumé Les embryoïdes se développant à partir du bourgeon de calle deRanunculus sceleratus deviennent des plantules. Ces plantules produisent des embryons surnuméraires à l'extrémité radiculaire ainsi que tout le long de la surface de la tige. Les études anatomiques révèlent que ces embryons sont d'origine épidermique. C'est une nouvelle preuve de la totipotence des cellules.     

Antifungal properties of taxol and various analogues

The antimitotic agent taxol was tested for toxicity towards fungi from different taxonomic groups and found to be particularly active against oomycete fungi. In germinating zoospore cysts of the oomycetePhytophthora capsici the mechanism of action of taxol was shown to involve inhibition of mitosis, presumably resulting from an effect on microtubules. Various taxol analogues with deleted A-ring C-13 side chain substituents were tested for toxicity towardsP. capsici andAphanomyces cochlioides to provide insight into structural features required for activity. The importance of the side chain was shown by the much lower activity as compared to taxol of analogues lacking all or part of the side chain. The effect of stereochemistry at the C-2 position on fungitoxicity towards oomycetes was similar to that reported previously on mammalian microtubule assembly.     

Antifungal properties of taxol and various analogues.

The antimitotic agent taxol was tested for toxicity towards fungi from different taxonomic groups and found to be particularly active against oomycete fungi. In germinating zoospore cysts of the oomycete Phytophthora capsici the mechanism of action of taxol was shown to involve inhibition of mitosis, presumably resulting from an effect on microtubules. Various taxol analogues with deleted A-ring C-13 side chain substituents were tested for toxicity towards P. capsici and Aphanomyces cochlioides to provide insight into structural features required for activity. The importance of the side chain was shown by the much lower activity as compared to taxol of analogues lacking all or part of the side chain. The effect of stereochemistry at the C-2' position on fungitoxicity towards oomycetes was similar to that reported previously on mammalian microtubule assembly.     

Course of cation accumulation by leaf tissue inPhaseolus vulgaris L.

Résumé On a suivi l'absorption du cation dans les disques de feuille de différentes grandeurs. Le taux d'absorption par les cellules dans les disques est régi par le taux de diffusion à travers la cuticule à la surface et à travers la circonférence de section où sont exposés la cellule et l'espace intercellulaire. La lumière augmente la diffusion ainsi que l'absorption des ions.     

Effect ofLantana camara L. extract on fern spore germination

Summary Extracts of root, stem, leaf and inflorescence ofLantana camara Linn., (Verbenaceae) inhibited exine bursting, rhizoid initiation and protonemal initiation of spores of the fernCyclosorus dentatus (Forsk.) Ching. The leaf extract was found to be qualitatively and quantitatively most potent in its inhibitory effect. Attention is drawn to the fact that further spread ofLantana camara at Mt. Abu, Rajasthan, India may lead to the complete destruction, of the sizeable pteridophytic component in this locality, the richest vegetationally in Rajasthan.     

Phytochrome involvement in the control of leaf shape ofTaraxacum officinale L.

Resumen Sobre la base del efecto de irradiaciones de baja energía con luz rojo lejana, y la reversión del mismo por la luz roja, se postula la participación del fitocromo en el control de la forma de la hoja deTaraxacum officinale.

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This work was supported by a research grant from the CNICT.     

Reduction in bean common mosaic virus (BCMV) infectivity vis-a-vis crude leaf extract of some higher plants

Summary Crude leaf extracts of 17 plants were tested for their antiviral activity against BCMV. An extract ofAzadirachta indica A. Juss. was found to be most potent in reducing the infectivity of the virus.Authors are thankful to Dr R. D. Joshi for his valuable guidance and Prof. S. N. Mathur for providing lab facilities. Financial assistance by U. G. C. and C. S. I. R. is gratefully acknowledged.     

Keto acids and free amino acids during leaf growth in Bauhinia purpurea L

Summary The biosynthesis of keto acids and free amino acids was studied during the growth of Bauhinia purpurea leaves. -KGA, OAA, pyruvic acid and PEP are the important keto acids observed at various stages. The first 2 metabolites show a progressive increase and PEP OAA pathway is very active during the process of growth.     

Phytotoxic effects of cadmium in leaf segments ofAvena sativa L., and the protective role of calcium

Cellular and Molecular Life Sciences - It is shown that ethylene production can be stimulated in peeled oat leaf segments in the dark by cadmiun at concentrations below 0.01 mM, and that...     

A queen bee extract (Apis mellifera L.) (Hymenoptera) reduces the fecundity ofTenebrio molitor L. (Coleoptera)

Summary 3 different doses of crude queen bee extract were administered to pairs of adultTenebrio molitor L.; the extract exerted an inhibitory action on fecundity, but did not induce complete sterility of the females.     

Chemical defence in the larvae of the leaf beetleGonioctena viminalis L. (Coleoptera: Chrysomelidae)

Summary The leaf beetle larva ofGonioctena (Phytodecta) viminalis L. has been shown to produce five volatile constituents within its paired abdominal defensive gland reservoirs. It is the first time that these compounds have been reported to occur in coleopteran defensive glands (linalool, phenylethanol) and Chrysomelidae larvae (6-methyl-5-hepten-2-one, 6-methyl-5-hepten-2-ol, 2-hexenal). In addition to the gross morphology of theGonioctena gland and its discharge behavior, the natural products found are discussed in terms of chemotaxonomy.     

Antifungal substances found in leaves of Eucalyptus species

Summary Antifungal substances were detected in leaves of 11 out of 27 Eucalyptus species examined. It was shown that antifungal substances found in the Eucalyptus species examined consist of from 1 to 4 different components.Acknowledgment. Gratitude is extended to Dr D. Mossop, Department of Plant Pathology, Waite Agricultural Research Institute, South Australia, Australia, for reading the draft.     

Antifungal activity of some constituents ofMurraya koenigii spreng

Zusammenfassung Es wird über die antifungale Wirksamkeit der Murrayanine, Girinimbine und Mahanimbine, drei ausMurraya koenigii Spreng. isolierte Carbazolderivate, berichtet.