Determination of Structure and Composition of Suberin from the Roots of Carrot, Parsnip, Rutabaga, Turnip, Red Beet, and Sweet Potato by Combined Gas-Liquid Chromatography and Mass Spectrometry

Abstract

Suberin from the roots of carrots (Daucus carota), parsnip (Pastinaca sativa), rutabaga (Brassica napobrassica), turnip (Brassica rapa), red beet (Beta vulgaris), and sweet potato (Ipomoea batatas) was isolated by a combination of chemical and enzvmatic techniques. Finely powdered suberin was depolymerized with 14% BFs in methanol, and soluble monomers (20-50% of suberin) were fractionated into phenolic (< 10 % ) and aliphatic (13-35%) fractions. The aliphatic fractions consisted mainly of w-hydroxyacids (29-43%), dicarboxylic acids (16-27%), fatty acids (4-18%), and fatty alcohols (3-6%). Each fraction was subjected to combined gas-liquid chromatography and mass spectrometry. Among the fatty acids very long chain acids (>C2o) were the dominant components in all six plants. In the alcohol fraction C18, C20, C2, and C24 saturated primary alcohols were the major components. C16 and Ci8 dicarboxylic acids were the major dicarboxylic acids of the suberin of all six plants and in all cases octadec-9-ene-1,18-dioic acid was the major component except in rutabaga where hexadecane-1 ,16-dioic acid was the major dicarboxylic acid. The composition of the w-hydroxyacid fraction was quite similar to that of the dicarboxylic acids; 18-hydroxy-octadec-9-enoic acid was the major component in all plants except rutabaga, where equal quantities of 16-hydroxyhexadecanoic acid and 18-hydroxvoctadec-9-enoic acid (42% each) were found. Compounds which would be derived from 18-hydroxyoctadec-9-enoic acid and octadec-9-ene-1, 18-dioic acid by epoxidation, and epoxidation followed by hydration of the epoxide, were also detected in most of the suberin samples. The monomer composition of the six plants showed general similarities but quite clear taxonomic differences.A polymeric material derived from lipids constitutes the structural component of the outer layer of plants, whereas pro-

Suberin Production by Isolated Tomato Fruit Protoplasts

“…The difunctional molecules of the mlw might be exceptional in that chain lengths below C, 6 have not previously been reported (7). Unsaturated C,, was the major group (32.8%) of dicarboxylic acids in the present study; an observation similar to reports on wounded periderms of carrot, rutabaga, and sweet potato (10), and tomato wound periderm in particular (3). The C20 group predominated in w-OH.…”

13C Nuclear Magnetic Resonance Study of Suberized Potato Cell Wall

“…Solution-state NMR and other physical evidence (7)(8)(9) (10,11,18,22); it also suggests that the aromatic domains of all three materials originate from deamination of L-phenylalanine (6, 1 1).…”

“…Prior GC-MS analysis identified the major soluble products as unsaturated fatty-acid dimethyl esters and/or c-hydroxy fatty-acid methyl esters (9). These [9].) At least 25% ofthe suberized cell wall is resistant to the transesterification treatment, and this residue has been found to be rich in aromatic functionalities (18).…”

“…Figure 1 is the solution-state '3C NMR spectrum of the aliphatic monomers that result from transesterification of suberized potato cell wall with BF3/CH30H. Prior GC-MS analysis identified the major soluble products as unsaturated fatty-acid dimethyl esters and/or c-hydroxy fatty-acid methyl esters (9). These [9].)…”

Revegetação de cava de extração de argila com Acacia mangium: II - caracterização química da humina

“…A purificação foi realizada com uma mistura (1:1) de HCl e HF 1 % durante 12 h à temperatura ambiente, para posterior extração com metanol e Kolattukudy et al (1975). A subfração aromática foi acidificada e extraída com éter etílico.…”