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The combination of autoradiography and a filter paper 'sandwich' technique using wheat plants labelled with [SUP14]C has shown that roots of wheat exude two types of compounds, viz. (a) non-diffusible material released from the apices of both primary and lateral roots and (b) diffusible material released along the whole length of the roots. The high amount of non-diffusible material compared with diffusible material suggests that the former may be more significant than previously anticipated in relation to root functions and microorganisms in the rhizosphere. [ABSTRACT FROM AUTHOR]

The nitrogenous materials released by the blue-green phycobiont (Nostoc sp.) of five lichens have been examined by means of high voltage paper electrophoresis. They were found to be a mixture of substances with similar electrophoretic characteristics to the materials released by the same algae when grown in pure culture, and were largely peptide in nature. A more detailed study was made of the components released into their growth media by the three strains of Nostoc isolated from Peltigera aphthosa, P. canina and P. polydactyla. From about twelve compounds demonstrable by electrophoresis, the six most abundant were examined for their amino acid composition. The only finding strikingly different from existing data was a generally low level of serine. Molecular weight estimates by means of gel filtration indicated that most of the substances had molecular weights of approximately 1100, with substances with molecular weights of about 300 forming a smaller important group, although materials with a wide range of molecular weights were evidently present and low molecular weight material could also be important. [ABSTRACT FROM AUTHOR]

Autoradiographs of sections of explants treated distally with [14C]indolylacetic acid (IAA) for 48 hours showed that radioactivity was higher in the abscission zone than in the neighbouring distal and proximal zones at all stages of its development. Higher activity in the abscission zone compared with the distal zone (about 4 to 1) was confirmed by liquid scintillation counting and scanning of paper chromatograms of extracts. The chromatograms also showed that a large part of the activity from abscission zones was due to unchanged IAA. This was confirmed by showing that a large part of the radioactivity in the abscission zone could be removed by treating the explants with unlabelled IAA. [ABSTRACT FROM AUTHOR]

Techniques are described for the extraction, chemical detection, separation and purification of acidic, ether-soluble Ehrlich reactive substances present in young seedling roots of wheat. The value of DEAE cellulose chromatography as a purification step is demonstrated. The presence of at least four Ehrlich reactors whose properties point to their being indole compounds can be demonstrated by paper and thin-layer chromatography. The reactors detected did not coincide in their properties with any of the twenty-six natural and synthetic indole compounds (these included indol-3yl-acetic acid and its nitrile, indole acetaldehyde and indole aldehyde) available as reference compounds. To test the value of the isolation procedures adopted one of the reactors was purified as far as possible. Its chromatographic and chromogenic properties, its ultraviolet (uv) spectrum, its behaviour on gas chromatography, its hydrolysis and its activity in an auxin bioassay are described. [ABSTRACT FROM AUTHOR]

An inhibitor from Pinus radiata was separated using paper chromatography from an acidic ether fraction of a stem tissue extract. Using electrophoresis the inhibitory activity was resolved into two parts. One part remained at the origin. The second part behaved similarly to ABA, in electrophoresis and was investigated further. The inhibitor has similar properties to ABA in electrophoresis; TLC using a number of solvent systems; UV fluorescence spectra: UV absorption; ORD spectra and gas chromatography. Final proof of the identity of the natural inhibitor as ABA was obtained by gas chromatography-mass spectrometry. [ABSTRACT FROM AUTHOR]

There is an urgent need to examine the range of ecosystems that is currently protected in national parks and reserves, to point out those examples that are unprotected and to establish a rational programme of priorities for protecting as complete a series as possible. The International Biological Programme has pioneered the field of large-scale survey work for the collection of data of relevance to this need and has contributed to the development of information retrieval techniques for handling the data. The first part of the paper discusses the rationale of the development of the data base and its modus operandi. The system is illustrated by two examples of retrieval and analysis for specific enquiries; the distribution of four species of Pinus, and the occurrence of grazing, logging and burning in national parks and equivalent reserves in the United States. The second part of the paper deals with system design, details of programming for the data base, and retrieval strategy. It is intended as an independent section which may be skipped if the reader has no interest in the finer points of the data base itself. [ABSTRACT FROM AUTHOR]