Structure of the Vessel-Parenchyma Pit Membrane in Some Species of Lauraceae

IAWA Bulletin n.s., Vol. 6 (1),1985 35

STRUCTURE OF THE VESSEL-PARENCHYMA PIT MEMBRANE IN SOME SPECIES OF LAURACEAE

Maria Agueda Castro Departamento de Ciencias Biol6gicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina

Summary Materials and Methods The structure of the vessel-parenchyma pit Fresh material of: Ocotea acutifolia (BAA membranes in the secondary xylem of seven 6656 & 6680); Cinnamomum camphora (BAA species of Lauraceae has been studied with 19097); C. glanduliferum (BAA 6759 & 2737) scanning electron microscopy (SEM). and Laurus nobilis (BAA 19096), was obtained In Cinnamomum camphora, C. glanduliferum, from the Botanical Garden of the Faculty of C. zeylanicum, Ocotea acutifolia and Phoebe Agronomy of Buenos Aires. Material of: Cinna porphyria the pit membrane of the parenchy momum zeylanicum (BAA 19100), Phoebe por ma cell side has numerous pectocellulosic, non phyria (BAA 19101) and Cryptocarya woodii lignified excrescences. In the case of Laurus no (BAA 19102) was obtained from the Buenos bilis and Cryptocarya woodii it is smooth. These Aires Municipal Botanical Garden. All the herba observations allow us to disregard the possibili rium material is preserved in the Gaspar Xuarez ty of artefacts on the membranes because such Herbarium (BAA). structures have definite characteristics and com Transverse, tangential and radial sections were position according to the microtests under made with a sliding microtome. Part of the sec taken. tions were prepared for SEM. Key words: Axial parenchyma, pit membrane, The identification of wall components was radial parenchyma, vessel. undertaken with ruthenium red, CIZnI 2 and the presence of lignin was tested with phloro Introduction glucinol-hydrochloric acid. The ornamentations In the present paper, the study of vessel of pit membrane are completely insoluble in parenchyma pit membranes in secondary xylem separate solutions of sodium hypochlorite, ace is continued in the following species: Phoebe tone and potassium hydroxide, the solvents porphyria (Griseb.) Mez; Ocotea acutifolia mentioned by Gale (1982). (Nees.) Mez; Cinnamomum zeylanicum Bl.; C. camphora (L.) Presl; C. glanduliferum Nees; Observations Cryptocarya woodii Engl. and Laurus nobilis When seen with SEM, pectocellulosic and L. non-lignified excrescences were observed on The presence of a cribiform structure, 'Sieb the surface of pit membrane on the parenchy tiipfelstruktur', in Lauraceae was mentioned by ma cell side only. This membrane presents a J anssonius (1934) as he observed with optical variable aspect in the different species: microscopy (OM) the wood of some Lauraceae. a. Membrane very ornamented with numerous Rich ter (1981) reported vestured pits in eight and more or less conspicuous excrescences in: genera. Cinnamomum glanduliferum (Fig. lA-F); This particular structure of the pit membrane C. camphora (Fig. I G-1); C. zeylanicum of the axial and radial parenchyma-vessel was (Fig. 2A-D); Phoebe porphyria (Fig. 2E) observed with OM and SEM in Nectandra falci and Ocotea acutifolia (Fig. 21, K). folia (Nees) Castigl. (Castro, 1982) and in b. Membrane slightly ornamented in: Cinnamo Persea americana Miller var. drymifolia (Cham. mum zeylanicum (Fig. 2B, C); Ocotea acuti & Schlecht.) Blake (Castro, 1984). folia (Fig. 2 I). The structure referred by Wheeler (1981) and c. Membrane smooth in: Cryptocarya woodii Gale (1982) are pit membrane incrustations or (Fig. 2G, H) and Laurus nobilis (Fig. 2L). artefacts. One exception is Phoebe porphyria (Fig. 2F), According to the results of the present paper which shows sometimes membranes without the observed features are strictly wall constit ornamentation but very convex, forming some uents. kind of plugs.

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Fig. !. Cinnamomum glanduliferum and C. camphora. SEM micrograph of the v-p pit membrane seen from the parenchyma cell side. - A-F. C. glanduliferum: A-D, aspect of the v-ax.p. pit mem brane; A & B, coalescent excrescences of the pit membrane (detail); C & D, isolated excrescences: C, detail, D, general aspect; E & F, aspect of the v-rd.p. pit membrane: more conspicuous ornamen tations with different aspect. - G- J. C. camphora: aspect of the v-ax.p. pit membrane: G, general aspect, H & J, detail. - ax.p.: axial parenchyma; p: parenchyma; rd.p.: radial parenchyma; v: vessel.

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Conclusions Acknowledgements The results published in two previous papers The author wishes to thank Dra. Elena Anci and those of the present study allow us to dis bor for her valuable guidance and the Conicet regard the possibility of the presence of arte for providing the use of the SEM. facts which are soluble deposits or protoplas mic remnants on the membrane because these References structures remained intact in various solvents. Castro, M. A. 1982. Estructura de la membrana The pit membrane ornamentations studied in de la puntuaci6n parenquima-vaso en Nec some species of Lauraceae may be interpreted tandra fa1cifolia (Lauraceae). Physis, Buenos as wall material added on the pit membrane of Aires, C 41 (100): 97-102. the axial and radial perivascular parenchyma - 1984. Estructura de la membrana de pun cells of xylem. It is necessary to stress that tuaci6n parenquima-vaso en Persea america these features are present on the pit membrane na var. drymifolia (Lauraceae). Darwiniana only on the side of living cells of xylem paren 25: 361-365. chyma and never have been observed on the Gale, R. 1982. Some pitfalls in wood identifica vessel element side. tion, with reference to Nothofagus. IAWA Although the pit membrane ornamentations Bull. n.s. 3: 179-184. are totally different from pit vestures, they could J anssonius, H. H. 1934. Mikrographie des Holzes be mistaken for vestures in the light microscope. der auf Java vorkommenden Baumarten 5: It would be interesting to know whether the 72-121. E. J. Brill, Leiden. reports of vestured pits in Lauraceae by J ans Richter, H.G. 1981. Anatomie des sekundiiren sonius (1934) and Richter (1981) are due to Xylems und der Rinde der Lauraceae. true vestures or to the type of pit membrane Parey, Hamburg, Berlin. ornamentations described in this paper. Wheeler, E. A. 1981. Intervascular pitting in The present study will be continued with ob Fraxinus americana L. IA WA Bull. n.s. 2: servations with the TEM to reveal the ultra 169-174. structure of the mentioned ornamentations.

- Fig. 2. SEM micrograph of the v-p pit membrane seen from the parenchyma cell side. - A-D. Cin namomum zeylanicum: A-C, ax.p.: A, general aspect, B & C, ornamentation with different aspect seen in other cells of the ax.p.; C, detail; D, ornamentation of the rd.p. pit membrane. - E & F. Phoebe porphyria: E, ax.p.: ornamented membrane; F, smooth and some convex pit membrane of the rd.p. - G, H, L, ax.p.: smooth pit membrane: G & H, Cryptocarya woodii; L, Laurus nobilis. - I-K. Ocotea acutifolia: I, J, two different aspects of the ornament of the ax.p. pit membrane; K, rd.p. pit membrane. - ax.p.: axial parenchyma; p: parenchyma; rd: ray; rd.p.: radial parenchyma; v: vessel.

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