1. A pseudomonad capable of utilizing the herbicide 4-chloro-2-methylphenoxyacetate as a sole carbon source was isolated from soil and cultured in liquid medium. 2. Analysis of induction patterns of 4-chloro-2-methylphenoxyacetate-grown cells suggests that 5-chloro-o-cresol and 5-chloro-3-methylcatechol are early intermediates in the oxidation of 4-chloro-2-methylphenoxyacetate. Cells were not adapted to oxidize 4-chloro-6-hydroxy-2-methylphenoxyacetate. 3. In culture, 4-chloro-2-methylphenoxyacetate rapidly disappeared and the chlorine in the molecule was quantitatively released as Cl(-) ion. 4. A lactone (gamma-carboxymethylene-alpha-methyl-Delta(alphabeta)-butenolide) was isolated from cultures and established as an intermediate. 5. The following metabolic pathway is suggested: 4-chloro-2-methylphenoxyacetate --> 5-chloro-o-cresol --> 5-chloro-3-methylcatechol --> cis-cis-gamma-chloro-alpha-methylmuconate --> gamma-carboxymethylene-alpha-methyl-Delta(alphabeta)-butenolide --> gamma-hydroxy-alpha-methylmuconate. 6. The tentative identification of 5-chloro-o-cresol, a gamma-chloro-alpha-methylmuconate and gamma-hydroxy-alpha-methylmuconate in culture extracts supports this scheme. However, the catechol was never observed to accumulate in cultures. 7. The detection of 4-chloro-6-hydroxy-2-methylphenoxyacetate, 2-methyl-phenoxyacetate, a dehalogenated cresol and oxalate in culture extracts is discussed in relation to the proposed metabolic pathway.

1. A cell-free system, prepared from Pseudomonas N.C.I.B. 9340 grown on 4-chloro-2-methylphenoxyacetate (MCPA) was shown to catalyse the reaction sequence: 5-chloro-3-methylcatechol --> cis-cis-gamma-chloro-alpha-methylmuconate --> gamma-carboxymethylene-alpha-methyl-Delta(alphabeta)-butenolide --> gamma-hydroxy-alpha-methylmuconate. 2. The activity of the three enzymes involved in these reactions was completely resolved and the lactonizing and delactonizing enzymes were separated. 3. This part of the metabolic pathway of 4-chloro-2-methylphenoxyacetate is thus confirmed for this bacterium. 4. The ring-fission oxygenase required Fe(2+) or Fe(3+) and reduced glutathione for activity; the lactonizing enzyme is stimulated by Mn(2+), Mg(2+), Co(2+) and Fe(2+); no cofactor requirement could be demonstrated for the delactonizing enzyme. 5. cis-cis-gamma-Chloro-alpha-methylmuconic acid was isolated and found to be somewhat unstable, readily lactonizing to gamma-carboxymethylene-alpha-methyl-Delta(alphabeta)-butenolide. 6. Enzymically the lactonization appears to be a single-step dehydrochlorinase reaction.

The long term metabolism of [ 14C]MCPA and ['4C]flamprop in wheat (Triticurn aestivum) straw was found to involve incorporation of radioactivity as residues that were insoluble in acetone+water (1+1 by volume). A chemical and an enzymic solubilisation procedure were critically evaluated in attempts to release these residues for further examination. The chemical procedure resulted in complete solubilisation of all the radioactivity of both compounds in association with more than one cell wall fraction. However, routine quantitative analysis was found to be difficult for some fractions. Furthermore, the extracts did not appear to be suitable for investigation of the nature of the binding with the plant constituents. None of the enzymes employed in the enzymic procedures released significant amounts of the residues insoluble in the aqueous acetone. Despite these problems, the residues of MCPA that were insoluble in aqueous acetone were found to contain both the parent MCPA and its major metabolite 4-chloro-a-hydroxy-o-tolyloxyacetic acid.

Stumm1azary. A procedure is described and evaluated for the analysis of ubiquinone, plastoquinone, tocopherols and vitamin K1 in Pisutm sativurin L. Vitamin K1 appears to be absent from the roots of this plant. While the pea seed contains only y-tocopherol, the root and shoot contain only a-tocopherol. During the greening of etiolated tissue, plastoquinone and vitamin K1 levels increase markedily while ubiquinone and a-tocopherol levels are tunaffected. On hoimogenization or damage to tissute, considerable losses of a-tocopherol occur in the pea plant.Vitamin E (tocopherols) and vitamin K1 have b)een shown to enhance the effects of atuxins in bioassays involving the elongation of pea stem sections (33). Other reports of physiological responses are summarized in the same paper. Vitamin E also has been found to have other physiological effects when applied to plants, e.g. stiimulation of flowering in s,trawberries (30); replacement of the vernalization requirement of winter rye (6); indtuction of flowering under non-inductive conditions (26, 217). Little is known, however, of the distribution, metabolism or ftunction of these compotunds in plants.The objective of this work was to devise an analytical procedture for vitamin K1 (K,) and the tocopherols (a-T, /3-T, etc.), to determine their distribution in the plant and the effect of enviroinment upon this. The chemically related compounds plastoqtlinone (PQ) and tlbiquiinone (UQ) were inclutded in the investigation. These ssubstances are known to function in photosynthesis and mitochondrial electron transport respectively. On largely theoretical grounds, functions also have been proposed for vitamin K and the tocopherols in reactions associated with electron transfer (2,21, 31).If such proposals are correct, some correlation would be expected between the distribution and levels of the functionally related compound;s.As analytical methods for the,se unstable compouinds mtust cope with relatively large losses during

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