Sap, cambial

Several groups have identified non-radioactive metabolic intermediates of lignification in cambial sap or sapwood extracts 54, 58 b, 68). The compounds detected agree well with the schemes for the biosynthesis of lignin precursors set forth in Figs. 1 and 2 and with the data described later for the third stretch of lignification. 

The three glucosides (IV-VI) are present in the cambial sap of spruce, V being by far the most abundant (49). Furthermore, spruce cambial sap contains very small amounts of coniferyl alcohol (I), coniferaldehyde (VII), the dilignols (XVII), (XIX), (XXII), and the trilignol (XXXVI) (19). Other lignols are present but in amounts too small for convenient identification. Extensive work has been done to examine the pathway of lignin formation in vivo and in vitro. 

Schmid, G. and Grisebach, H. (1982) Enzymic synthesis of lignin precursors purification and properties of UDP-glucose coniferyl alcohol glucosyltransferase from cambial sap of spruce (Picea abies L.). Eur.. Biochem., 123, 363-70. 

Prepn Pauly, Strassberger. Ber. 62, 2277 (1929) Freuden. berg. Schraube, Ber. 88, ]6 (1955). Isoln from lilac bark Freuden berg et at.. Ber. 84, 472 (1951) From various plants Plouvier. CompL Rend. 254,4)96 (1962) from cambial sap of spruce Freuden berg. Harkin, Phytochemistry 2, 189 (1963). 

At the same time, Wilhelm Haarmann in Holzminden (Germany) prepared vaniUin directly by oxidation of coniferin, which is a glucoside obtained from the cambial sap of various conifers (Fig. 3.35). [140]... 

Methyl ethers of several cyclitols occur as secondary substances in many higher plants. Attempts to use their occurrence for chemical taxonomy have been made (137). Sequoyitol (5-O-methyl-myo-inositol) is found in all families of gym-nosperms, and only in gymnosperms, although its distribution appears to be sporadic (137). It has been found in wood, bark, and cambial sap (114). D-Bornesitol (1-O-methyl-myo-inositol) is present in the latex of trees in the Apocynaceae family and in the wood of Sarcocephalus diderrichii (see 137). Dambonitol (1,3-di-O-methyl-myo-inositol) has been found in Gabon (Castilloa elastica) rubber latex (see 137). 

D-cA/ro-Inositol (D-inositol) was isolated from the heartwood of Pinus lamber-tiana (47) and detected in the cambial sap of Pinus sylvestris, Picea abies, and Abies alba (114). It will undoubtedly be found to be present in other coniferous saps and woods, especially those containing D-pinitol, when modern analytical techniques are used. 

D-Pinitol (lD-3-O-methyl-cA/ro-inositol) is the most widely distributed inositol ether. It has been found in six gymnosperm families and 13 angiosperm families (137). In gymnosperms, it is a component of the resin of Pinus lamber-tiana (see 137) the bark of Picea abies, Pinus nigra (71), Pinus halepensis, and Schinus molle (72) (where its content has been determined as a function of season) the cambial sap of Pinus silvestris, Picea abies, and Abies alba (114) and the wood of Pinus spp. (see 6, 137) and Sequoia sempervirens (153). It also occurs in various plant parts, including latex and wood Acacia mollissima), of angio-sperms (see 137). 

Quinic acid, a carboxylated tetrahydroxycyclohexane, is a secondary plant substance formed from dehydroquinic acid, an intermediate in the shikimic acid pathway, the metabolic pathway leading to aromatic compounds. It, therefore, is ubiquitous in living plant cells. It has been isolated from cinchona bark and detected in the cambial sap of conifers (114). 

Kretz A 1973 Sugars, cyclitols, and organic acids in the cambial sap of Pinus sylvestris L., Picea abies Karst., and Abies alba Mill. Planta (Berlin) 110 1-14... 

Stewart C M, Melvin J F, Ditchburne N, Tham S H, Zerdoner E 1973 The effect of season of growth on the chemical composition of cambial saps of Eucalyptus regnans trees. Oecologia 12 349-372... 

Terazawa M, Miyake M 1984 Phenolic compounds in living tissue of woods. II. Seasonal variations of phenolic glycosides in the cambial sap of woods. Mokuzai Gakkaishi 30 329-334... 

Franz M, Meier H 1969 Organic acids in the cambial sap of Larix decidua. Planta 85 202-208... 

Freudenberg K, Harkin J M 1963 The glycosides of cambial sap of spruce. Phytochemistry 2 189-193... 

There has been substantial discussion of the nature of the enzyme systems which catalyse the polymerisation process of lignification. Mason believes the enzyme to have a phraoldehydrogenase nature and Higuchi " has supported this conclusion, and among the enzymes of cambial sap in spruce wood, Freudenberg has demonstrated the presence of a plentiful supply of phenoldehydro-genase and some peroxidase activity. 

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