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Linear growth of wood-decomposing fungi on an agar medium was usually retarded, but in some cases enhanced by terpenoids in gaseous form. Increased dry matter production was demonstrated in some Coniophora, Peniophora, Stereum and Polyporus species exposed to the vapors of longifolene, limonene or a mixture of cuparene and thujopsene. The positive response to longifolene in some cases seemed to involve a more efficient utilization of the glucose in the medium. No stimulatory effect of terpenoids on dry matter production was obtained in liquid nutrient medium experiments.

The effects of several monoterpenes and the sesquiterpene longifolene on the vegetative growth of two mycorrhizal fungi, Boletus variegatus and Rhizopogon roseolus, were studied in petri plate experiments on an agar medium. The test substances are natural constituents of Pinus silvestris (Scots pine) roots. Vapors from 20 μl of all the test substances, upon a 5 day exposure inhibited the growth of both the mycorrhizal fungi 55% to 86%. The two fungi, however, differed in their tolerance to individual compounds. It is suggested that the terpenes and the sesquiterpenes play an important role in the development of the symbiotic condition in ectomycorrhizae by restricting the growth of the mycorrhizal fungi within the host root. [ABSTRACT FROM AUTHOR]

Carotenoid synthesis in the fruit of tomato mutants is under gene control. Since undifferentiated plant cells are presumably totipotent, the callus tissue should be able to produce the carotenoids typical of the genotype. The carotenoids of masses of callus derived from hypocotyls of the red ghost and tangerine tomatoes were extracted and characterized by means of column and thin layer chromatography, chemical and spectral properties. The red ghost callus contained predominntly phytoene and phytofluene; the tangerine callus had primarily ζ-carotene and prolycopene. Thus under our cultural conditions, carotenoids typical of the fruit rather than the leaf were produced, albeit in much reduced quantities. [ABSTRACT FROM AUTHOR]

1. The shift of the carotenoid absorption spectrum in chromatophores prepared from Rhodopseudomonas spheroides induced by different types of actinic illumination has been resolved into several distinct, kinetic phases. A saturating 20 ns pulse from a Q-switched ruby laser elicited a spectral change more rapid than the response time of the measuring apparatus (1 µs). A rapid change 10-20% greater than this was produced during a saturating 200 µs xenon flash. Additional slower phases (half-risetimes approximately 300 µs and 5 ms) could be distinguished after the xenon flash. Continuous illumination produced a rapid change of similar extent, to that produced by xenon flash but with a risetime limited by the light intensity, and an equally extensive slow change of half-risetime approximately 83 ms. During prolonged illumination the carotenoid shift decayed by about 50% with an approximate half-decay time of 30 s. 2. The effects of certain electron-transport inhibitors, uncoupling agents, ion-transporting antibiotics and permeant anions on these phases and upon the decay after illumination have been investigated. None of these agents markedly affected the rapid phase of the shift induced by flash illumination. The relation of this phase to membrane potential was indicated by the fact that its decay was stimulated during electrophoretic ion flux. These observations are consistent with the suggestion that the rapid phase of the carotenoid shift is in response to separation of charge across the chromatophore membrane, between reaction centre bacteriochlorophyll and the primary acceptor. The effects of these specific chemical modifiers on the slower phases of the carotenoid shift were complex. They are discussed in terms of a model in which these phases reflect the generation of a membrane potential as a result of electrogenic oxidation-reduction processes. Antimycin A partly in.hired electron flow through such an electrogenic site(s). Valinomyein delayed the formation of the membrane potential by catalysing an initial, electrophoretic K+ efflux. Uncoupling agents caused a partial but, permanent collapse of the electrical field. Permeant anions produced a slight, lowering of the steady-state electrical field by raising the membrane conductivity. 3. The contribution of the membrane potential to the high-energy state leading to ATP synthesis is discussed. [ABSTRACT FROM AUTHOR]

Tissue cultures of Nicotiana tabacuni were incubated anaerobically with [14C]-2,3-oxido-squalene and radioactive triterpenes were isolated by extraction, alcaline hydrolysis and chromatography. After acetylation and epoxidation, the radioactivity was found to be present in cycloartenol and 24-methylene-cycloartenol, but no radioactivity could be detected in lanosterol. [ABSTRACT FROM AUTHOR]