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Quality indicators for woodwind reed material
Nuclear Instruments and Methods in Physics Research B 150 (1999) 673±678
Quality indicators for woodwind reed material Stefan Glave a, Jan Pallon b,*, Chris Bornman c, Lars Olof Bj orn c, Rita Wallen d, b b b Jacob R astam , Per Kristiansson , Mikael Elfman , Klas Malmqvist b b
a Communal College of Music, Tobaksgatan 11, SE-271 41 Ystad, Sweden Department of Nuclear Physics, Lund Institute of Technology, Box 118, SE-221 00 Lund, Sweden c Department of Plant Physiology, Lund University, Box 117, SE-221 00 Lund, Sweden d Department of Zoology, Lund University, Helgonav agen 3, SE-223 62 Lund, Sweden
Abstract For the generation of sound, some woodwind musical instruments, e.g. oboe, bassoon, clarinet and saxophone, are provided with mouthpieces made from reeds. These reeds are the culms of Arundo donax, a tall, cane-like perennial grass. A general problem is that the material is of varying quality, yet externally dierences cannot be observed. Hence, large proportions of the prepared reeds are unusable. One hypothesis is that the changes in quality are correlated with dierences in the chemical and anatomical structure of the tissue. Therefore, a comparison of superior and inferior mouthpieces, used by professional musicians, was undertaken to determinate potential indicators of quality. Nuclear microprobe analysis of reeds was carried out and complemented by scanning electron and light microscopy. The elemental levels of Si, P, S, Cl, K and Ca were compared between good and poor mouthpieces using appropriate statistical tests. No statistically signi®cant dierences could be identi®ed. Microscopical observations showed that partial occlusion of vessels by tylose formation was associated with material deemed unusable. Ó 1999 Elsevier Science B.V. All rights reserved. Keywords: Arundo donax; Oboe; PIXE; Nuclear microprobe; Tyloses
1. Introduction Preparation of mouthpieces from raw material is a time-consuming and delicate task. On average, two hours of preparation is spent per reed. Only a small percentage of the woodwind reed material gives rise to high quality reeds, but it is not pos-
* Corresponding author. Fax: +46-46-222-4709; e-mail: [email protected]
sible to separate good from poor cane by visual examination. The question as to which properties distinguish good from poor quality woodwind reeds has thus attracted much interest. In particular, Veselack and Nisbet [1] and Casadonte [2] have studied the potential dierences in stem anatomy. Arundo donax, the natural source of woodwind reed, is a monocotyledonous plant and a member of the Poaceae, and therefore the diagnostic anatomical spatial arrangement and structure of its cells and tissues can be simply described in terms of those typical for a grass. Veselack and
0168-583X/99/$ ± see front matter Ó 1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 9 8 ) 0 1 0 2 5 - 8
674
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
Nisbet [1] have listed some cell and tissue characteristics that they consider may distinguish good reeds from those that are unusable. Here, we consider an additional characteristic, namely, the possible occlusion of the xylem vessels as a result of tylosis, the formation of which is often related to wounding or infection of plants by bacterial or fungal pathogens. One argument for the detailed elemental analysis using nuclear microprobe technique was data from a preliminary study (unpublished) that compared the soil and plant chemistry from different geographical locations, and showed large dierences in soil chemical composition which to some degree were re¯ected in the plant's composition. 2. Materials and methods In the investigation, reeds of Arundo donax L. were examined in cross-section with light microscopy, scanning electron microscopy (SEM) and particle induced X-ray emission (PIXE). Ten superior and nine inferior reeds were obtained from three experienced principal oboists. Samples of mouthpieces were prepared for light microscopy by in®ltrating the dry material with water for several hours before dehydration in an ethanol series and subsequent in®ltration with an embedment in Spurr's medium. Sections were cut 2 lm thick and stained with azure B/methylene blue. For nuclear microprobe analysis, the material was cut with a scalpel into 2 mm pieces. After irradiation, the samples were sputter-coated with gold/palladium (40/60) for SEM analysis. Using the Lund Nuclear Microprobe [3], each sample was scanned with a 5 lm beam for about 1 h using 2.5 MeV protons at a current of 0.5 nA. Each sample was scanned using a pattern of 64 ´ 128 pixels covering an area of about 300 ´ 570 lm2 . The X-rays were collected using a 30 mm2 Si(Li) detector (Kevex) having a 90 lm Be-foil as absorber. Data were collected on a CAMAC/ Mac-computer system equipped with KMAX (Sparrow) software [4].
3. Results and discussion 3.1. Anatomical observations The stem of Arundo donax is upright, cylindrical and cane-like and, at maturity, made up of predominantly thick-walled parenchyma, sclerenchyma and xylary cells consisting of vessel elements and tracheids (Fig. 1). The cells that make up the epidermis are sclerenchymatous and many contain silica bodies. The largest proportion of the cells that comprise the epidermis, cortex and vascular tissue have secondary walls, as shown in Fig. 2 where the same section as in Fig. 1 is seen in polarized light. The cell walls consist of cellulose, hemicellulose and non-cellulosic polysaccharides and, except for the parenchyma cells, also lignin, as indicated by the blue-green stain imparted by azure B in Fig. 3. The cells are cemented to each other by a middle lamella of pectic substances. As shown in Figs. 3 and 4, which are light and scanning electron micrographs, respectively, of good quality material, the vessel elements (labelled X in Fig. 3) are devoid of occlusions. In contrast, vessel elements of poor specimens were often observed to contain occlusions (Fig. 5, arrows). Such occlusions are known as tyloses and are the remains of outgrowths, through the pit cavities of the xylem walls, by parenchyma cells adjacent to the vessel elements [5]. Tyloses ± or the process, tylosis ± may be induced in response to attack of the plant by pathogens or as a result of wounding. Therefore, control of disease and proper care in the mechanical handling of the reeds during and immediately after harvesting are factors that may prevent occlusion of the vessel elements, possibly resulting in reeds of superior quality. However, as these observations are preliminary, more de®nitive work, preferably including material sampled immediately before and after harvest, remains to be done. One of the features deemed by Veselack and Nisbet [1] to contribute to good reed quality, namely, ``twisted vascular bundles'', is apparent in Fig. 4 in which the two metaxylem poles of the vascular bundle on the right are oriented radially rather than tangentially with respect to the epidermis.
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
675
Fig. 1. Transverse section through part of a good quality mouthpiece from the stem of Arundo donax seen in ordinary light and showing the high degree of secondary wall formation in this tissue. Note the region below the epidermis of almost continuous scleri®ed ®bres. Magni®cation bars represent 50 lm in Figs. 1±3. Arrowheads indicate orientation towards the epidermis. Fig. 2. Transverse section through part of a good quality mouthpiece from the stem of Arundo donax seen in polarized light and showing the high degree of secondary wall formation in this tissue. Note the region below the epidermis of almost continuous scleri®ed ®bres. Magni®cation bars represent 50 lm in Figs. 1±3. Arrowheads indicate orientation towards the epidermis. Fig. 3. A vascular bundle from similar tissue as in Fig. 1 with metaphloem (P) and xylem vessels (X) surrounded by a band of thickwalled ®bres.
Fig. 4. Scanning electron micrograph of good quality tissue. Vessel elements are generally clear. Magni®cation bars represent 100 lm in Figs. 4 and 5.
Fig. 5. Scanning electron micrograph of poor quality tissue. Vessel elements of poor quality were often partially occluded with the desiccated remains of tyloses (arrow).
676
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
3.2. PIXE analysis Event data from the PIXE analysis were sorted into elemental maps and spectra. In the elemental
maps, showing the reed cross-section, the subepidermis and epidermis with its wax layer is easily identi®ed because of the high silicon content (Fig. 6). On the opposite side of the sample high levels
Fig. 6. Elemental maps of a good oboe reed. The epidermis is at the top of the image, and the vessels in the xylem can be seen as ``holes'' (marked X), while the metaphloem (see arrow) is rich in S, Cl, K and Ca. The high levels of most elements at the bottom of the images are artefacts from the edge of the sample and should be disregarded.
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
of most elements are present. However, this is an artefact due to sample thickness and the X-ray detector ``looking at'' the edge of the sample and should be disregarded. The water conducting vessels (xylem) can be seen as ``holes'', while the nutrient transporting vessels (metaphloem) are rich in S, Cl, K and Ca. For each sample, a number of elemental pro®les across the reed were also determined. These pro®les consisted of 50±100 single data points, each representing the elemental concentrations of Si, P, S, Cl, K and Ca at dierent and speci®ed depths of the reed material. To facilitate comparison between dierent samples, each pro®le was divided into three zones. The ®rst zone, 170 lm thick, includes the protective wax layer, the epidermis and the subepidermal area of ®bres. This zone was dominated by silicon. The rest of the pro®le includes the cortex and was divided into two equal zones, each 200 lm thick. A striking observation was that for 7 out of 10 good reeds the silicon pro®le of the epidermal zone has a single maximum, while 7 out of 9 inferior reeds in addition also show a smaller secondary maximum immediately adjacent to the main peak, probably the epidermis. This second peak is on the average 20% of the main peak, however with rather large variations as indicated in Fig. 7.
677
Fig. 7. Normalised silicon pro®les across the wax layer, epidermis and subepidermis for a good and poor reed. Note the second peak in the case of the inferior reed. The height of this second peak varies for dierent reeds between a few percent of the main peak and up to 40% as indicated by the error bar.
3.3. Statistical evaluation of PIXE data Within each of the three zones in the pro®les, arithmetic means of the elements were calculated and used as estimates of the levels of the elements in each area. These estimates were used as single observations in the statistical analysis which was carried out in three separate steps: 1. Two-sample t-tests were used to identify any dierences among the chemical elements between good and poor reeds. All tests were made within each of the three zones giving a total of 6 ´ 3 18 comparisons. 2. As the two-sample t-test requires an approximately normally distributed sampling distribution, the Shapiro±Wilk test for normality was applied to all samples. Whenever this showed
evidence of non-normality, a non-parametric alternative would be preferable to the t-test. 3. The Mann±Whitney U-test was used only in those cases where the Shapiro±Wilk test showed evidence of non-normality. When applicable, the results of the t-test are always preferred as this test provides greater statistical signi®cance. The statistical signi®cance was assumed at p < 0.05. Most of the con®dence intervals were wide and in no case were any statistically signi®cant dierences found. An objection to the choice of data points in this study could be that the selection of data zones was coarse and ``mechanical'', not taking the detailed structures of the tissues into
678
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
particular consideration. A possible future approach might be to identify and isolate speci®c tissues and to limit comparisons to these regions, e.g. the epidermis, ®bre bands and the vascular bundles. 4. Conclusions The statistical tests in this study showed no evidence of dierences among the observed chemical elements between the poor and the good reeds, but more detailed studies with the nuclear microprobe on selected tissues might reveal further information. Preliminary observations showed the presence of tyloses in the vessel elements of inferior reeds. This partial occlusion of the xylem presumably aects the quality of the mouthpiece but its demonstration is time-consuming. Therefore, with a larger number of independent observations, e.g. using a greater number of reeds and speci®cally selected tissue regions, a multivariate analysis (e.g. discriminant analysis or logistic regression) might reveal possible interactions among the chemical elements that would help in identifying quality indicators of superior reeds.
Acknowledgements Thanks to Giovanni de Angeli, I Solisti Veneti, Giuseppe Falco, Teatro alla Scala, Sven Buller, Royal Danish Orchestra for providing oboe reeds and to Pietro Tonutti, Giovanna Capizzi, Padova University, J.-O. Mattsson, Petter Pilesj o, Nils Cronberg, B.O. Jonsson, Tommy Olsson, Erling Nilsson, Lars J onsson, Lund University for interest, encouragements and valuable discussions. References [1] M.S. Veselack, J.J. Nisbet, Abstract Proc. Indiana Acad. Sci. 89 (1980). [2] D.J. Casadonte, The clarinet reed: an introduction to its biology, chemistry, and physics. Doctoral Dissertation, UMI Dissertation Services, Ann Arbor, MI, USA, UMI No. 9612138, 1995, p. 466. [3] K.G. Malmqvist, G. Hylten, M. Hult, K. H akansson, J.M. Knox, N.P.-O. Larsson, C. Nilsson, J. Pallon, R. Scho®eld, E. Swietlicki, U.A.S. Tapper, C. Yang, Nucl. Instr. and Meth. B 77 (1993) 3. [4] M. Elfman, P. Kristiansson, K. Malmqvist, J. Pallon, A. Sj oland, R. Utui, C. Yang, Nucl. Instr. and Meth. B 130 (1997) 123. [5] K. Esau, Anatomy of Seed Plants, Wiley, New York, 1960, p. 135.
Quality indicators for woodwind reed material Stefan Glave a, Jan Pallon b,*, Chris Bornman c, Lars Olof Bj orn c, Rita Wallen d, b b b Jacob R astam , Per Kristiansson , Mikael Elfman , Klas Malmqvist b b
a Communal College of Music, Tobaksgatan 11, SE-271 41 Ystad, Sweden Department of Nuclear Physics, Lund Institute of Technology, Box 118, SE-221 00 Lund, Sweden c Department of Plant Physiology, Lund University, Box 117, SE-221 00 Lund, Sweden d Department of Zoology, Lund University, Helgonav agen 3, SE-223 62 Lund, Sweden
Abstract For the generation of sound, some woodwind musical instruments, e.g. oboe, bassoon, clarinet and saxophone, are provided with mouthpieces made from reeds. These reeds are the culms of Arundo donax, a tall, cane-like perennial grass. A general problem is that the material is of varying quality, yet externally dierences cannot be observed. Hence, large proportions of the prepared reeds are unusable. One hypothesis is that the changes in quality are correlated with dierences in the chemical and anatomical structure of the tissue. Therefore, a comparison of superior and inferior mouthpieces, used by professional musicians, was undertaken to determinate potential indicators of quality. Nuclear microprobe analysis of reeds was carried out and complemented by scanning electron and light microscopy. The elemental levels of Si, P, S, Cl, K and Ca were compared between good and poor mouthpieces using appropriate statistical tests. No statistically signi®cant dierences could be identi®ed. Microscopical observations showed that partial occlusion of vessels by tylose formation was associated with material deemed unusable. Ó 1999 Elsevier Science B.V. All rights reserved. Keywords: Arundo donax; Oboe; PIXE; Nuclear microprobe; Tyloses
1. Introduction Preparation of mouthpieces from raw material is a time-consuming and delicate task. On average, two hours of preparation is spent per reed. Only a small percentage of the woodwind reed material gives rise to high quality reeds, but it is not pos-
* Corresponding author. Fax: +46-46-222-4709; e-mail: [email protected]
sible to separate good from poor cane by visual examination. The question as to which properties distinguish good from poor quality woodwind reeds has thus attracted much interest. In particular, Veselack and Nisbet [1] and Casadonte [2] have studied the potential dierences in stem anatomy. Arundo donax, the natural source of woodwind reed, is a monocotyledonous plant and a member of the Poaceae, and therefore the diagnostic anatomical spatial arrangement and structure of its cells and tissues can be simply described in terms of those typical for a grass. Veselack and
0168-583X/99/$ ± see front matter Ó 1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 9 8 ) 0 1 0 2 5 - 8
674
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
Nisbet [1] have listed some cell and tissue characteristics that they consider may distinguish good reeds from those that are unusable. Here, we consider an additional characteristic, namely, the possible occlusion of the xylem vessels as a result of tylosis, the formation of which is often related to wounding or infection of plants by bacterial or fungal pathogens. One argument for the detailed elemental analysis using nuclear microprobe technique was data from a preliminary study (unpublished) that compared the soil and plant chemistry from different geographical locations, and showed large dierences in soil chemical composition which to some degree were re¯ected in the plant's composition. 2. Materials and methods In the investigation, reeds of Arundo donax L. were examined in cross-section with light microscopy, scanning electron microscopy (SEM) and particle induced X-ray emission (PIXE). Ten superior and nine inferior reeds were obtained from three experienced principal oboists. Samples of mouthpieces were prepared for light microscopy by in®ltrating the dry material with water for several hours before dehydration in an ethanol series and subsequent in®ltration with an embedment in Spurr's medium. Sections were cut 2 lm thick and stained with azure B/methylene blue. For nuclear microprobe analysis, the material was cut with a scalpel into 2 mm pieces. After irradiation, the samples were sputter-coated with gold/palladium (40/60) for SEM analysis. Using the Lund Nuclear Microprobe [3], each sample was scanned with a 5 lm beam for about 1 h using 2.5 MeV protons at a current of 0.5 nA. Each sample was scanned using a pattern of 64 ´ 128 pixels covering an area of about 300 ´ 570 lm2 . The X-rays were collected using a 30 mm2 Si(Li) detector (Kevex) having a 90 lm Be-foil as absorber. Data were collected on a CAMAC/ Mac-computer system equipped with KMAX (Sparrow) software [4].
3. Results and discussion 3.1. Anatomical observations The stem of Arundo donax is upright, cylindrical and cane-like and, at maturity, made up of predominantly thick-walled parenchyma, sclerenchyma and xylary cells consisting of vessel elements and tracheids (Fig. 1). The cells that make up the epidermis are sclerenchymatous and many contain silica bodies. The largest proportion of the cells that comprise the epidermis, cortex and vascular tissue have secondary walls, as shown in Fig. 2 where the same section as in Fig. 1 is seen in polarized light. The cell walls consist of cellulose, hemicellulose and non-cellulosic polysaccharides and, except for the parenchyma cells, also lignin, as indicated by the blue-green stain imparted by azure B in Fig. 3. The cells are cemented to each other by a middle lamella of pectic substances. As shown in Figs. 3 and 4, which are light and scanning electron micrographs, respectively, of good quality material, the vessel elements (labelled X in Fig. 3) are devoid of occlusions. In contrast, vessel elements of poor specimens were often observed to contain occlusions (Fig. 5, arrows). Such occlusions are known as tyloses and are the remains of outgrowths, through the pit cavities of the xylem walls, by parenchyma cells adjacent to the vessel elements [5]. Tyloses ± or the process, tylosis ± may be induced in response to attack of the plant by pathogens or as a result of wounding. Therefore, control of disease and proper care in the mechanical handling of the reeds during and immediately after harvesting are factors that may prevent occlusion of the vessel elements, possibly resulting in reeds of superior quality. However, as these observations are preliminary, more de®nitive work, preferably including material sampled immediately before and after harvest, remains to be done. One of the features deemed by Veselack and Nisbet [1] to contribute to good reed quality, namely, ``twisted vascular bundles'', is apparent in Fig. 4 in which the two metaxylem poles of the vascular bundle on the right are oriented radially rather than tangentially with respect to the epidermis.
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
675
Fig. 1. Transverse section through part of a good quality mouthpiece from the stem of Arundo donax seen in ordinary light and showing the high degree of secondary wall formation in this tissue. Note the region below the epidermis of almost continuous scleri®ed ®bres. Magni®cation bars represent 50 lm in Figs. 1±3. Arrowheads indicate orientation towards the epidermis. Fig. 2. Transverse section through part of a good quality mouthpiece from the stem of Arundo donax seen in polarized light and showing the high degree of secondary wall formation in this tissue. Note the region below the epidermis of almost continuous scleri®ed ®bres. Magni®cation bars represent 50 lm in Figs. 1±3. Arrowheads indicate orientation towards the epidermis. Fig. 3. A vascular bundle from similar tissue as in Fig. 1 with metaphloem (P) and xylem vessels (X) surrounded by a band of thickwalled ®bres.
Fig. 4. Scanning electron micrograph of good quality tissue. Vessel elements are generally clear. Magni®cation bars represent 100 lm in Figs. 4 and 5.
Fig. 5. Scanning electron micrograph of poor quality tissue. Vessel elements of poor quality were often partially occluded with the desiccated remains of tyloses (arrow).
676
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
3.2. PIXE analysis Event data from the PIXE analysis were sorted into elemental maps and spectra. In the elemental
maps, showing the reed cross-section, the subepidermis and epidermis with its wax layer is easily identi®ed because of the high silicon content (Fig. 6). On the opposite side of the sample high levels
Fig. 6. Elemental maps of a good oboe reed. The epidermis is at the top of the image, and the vessels in the xylem can be seen as ``holes'' (marked X), while the metaphloem (see arrow) is rich in S, Cl, K and Ca. The high levels of most elements at the bottom of the images are artefacts from the edge of the sample and should be disregarded.
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
of most elements are present. However, this is an artefact due to sample thickness and the X-ray detector ``looking at'' the edge of the sample and should be disregarded. The water conducting vessels (xylem) can be seen as ``holes'', while the nutrient transporting vessels (metaphloem) are rich in S, Cl, K and Ca. For each sample, a number of elemental pro®les across the reed were also determined. These pro®les consisted of 50±100 single data points, each representing the elemental concentrations of Si, P, S, Cl, K and Ca at dierent and speci®ed depths of the reed material. To facilitate comparison between dierent samples, each pro®le was divided into three zones. The ®rst zone, 170 lm thick, includes the protective wax layer, the epidermis and the subepidermal area of ®bres. This zone was dominated by silicon. The rest of the pro®le includes the cortex and was divided into two equal zones, each 200 lm thick. A striking observation was that for 7 out of 10 good reeds the silicon pro®le of the epidermal zone has a single maximum, while 7 out of 9 inferior reeds in addition also show a smaller secondary maximum immediately adjacent to the main peak, probably the epidermis. This second peak is on the average 20% of the main peak, however with rather large variations as indicated in Fig. 7.
677
Fig. 7. Normalised silicon pro®les across the wax layer, epidermis and subepidermis for a good and poor reed. Note the second peak in the case of the inferior reed. The height of this second peak varies for dierent reeds between a few percent of the main peak and up to 40% as indicated by the error bar.
3.3. Statistical evaluation of PIXE data Within each of the three zones in the pro®les, arithmetic means of the elements were calculated and used as estimates of the levels of the elements in each area. These estimates were used as single observations in the statistical analysis which was carried out in three separate steps: 1. Two-sample t-tests were used to identify any dierences among the chemical elements between good and poor reeds. All tests were made within each of the three zones giving a total of 6 ´ 3 18 comparisons. 2. As the two-sample t-test requires an approximately normally distributed sampling distribution, the Shapiro±Wilk test for normality was applied to all samples. Whenever this showed
evidence of non-normality, a non-parametric alternative would be preferable to the t-test. 3. The Mann±Whitney U-test was used only in those cases where the Shapiro±Wilk test showed evidence of non-normality. When applicable, the results of the t-test are always preferred as this test provides greater statistical signi®cance. The statistical signi®cance was assumed at p < 0.05. Most of the con®dence intervals were wide and in no case were any statistically signi®cant dierences found. An objection to the choice of data points in this study could be that the selection of data zones was coarse and ``mechanical'', not taking the detailed structures of the tissues into
678
S. Glave et al. / Nucl. Instr. and Meth. in Phys. Res. B 150 (1999) 673±678
particular consideration. A possible future approach might be to identify and isolate speci®c tissues and to limit comparisons to these regions, e.g. the epidermis, ®bre bands and the vascular bundles. 4. Conclusions The statistical tests in this study showed no evidence of dierences among the observed chemical elements between the poor and the good reeds, but more detailed studies with the nuclear microprobe on selected tissues might reveal further information. Preliminary observations showed the presence of tyloses in the vessel elements of inferior reeds. This partial occlusion of the xylem presumably aects the quality of the mouthpiece but its demonstration is time-consuming. Therefore, with a larger number of independent observations, e.g. using a greater number of reeds and speci®cally selected tissue regions, a multivariate analysis (e.g. discriminant analysis or logistic regression) might reveal possible interactions among the chemical elements that would help in identifying quality indicators of superior reeds.
Acknowledgements Thanks to Giovanni de Angeli, I Solisti Veneti, Giuseppe Falco, Teatro alla Scala, Sven Buller, Royal Danish Orchestra for providing oboe reeds and to Pietro Tonutti, Giovanna Capizzi, Padova University, J.-O. Mattsson, Petter Pilesj o, Nils Cronberg, B.O. Jonsson, Tommy Olsson, Erling Nilsson, Lars J onsson, Lund University for interest, encouragements and valuable discussions. References [1] M.S. Veselack, J.J. Nisbet, Abstract Proc. Indiana Acad. Sci. 89 (1980). [2] D.J. Casadonte, The clarinet reed: an introduction to its biology, chemistry, and physics. Doctoral Dissertation, UMI Dissertation Services, Ann Arbor, MI, USA, UMI No. 9612138, 1995, p. 466. [3] K.G. Malmqvist, G. Hylten, M. Hult, K. H akansson, J.M. Knox, N.P.-O. Larsson, C. Nilsson, J. Pallon, R. Scho®eld, E. Swietlicki, U.A.S. Tapper, C. Yang, Nucl. Instr. and Meth. B 77 (1993) 3. [4] M. Elfman, P. Kristiansson, K. Malmqvist, J. Pallon, A. Sj oland, R. Utui, C. Yang, Nucl. Instr. and Meth. B 130 (1997) 123. [5] K. Esau, Anatomy of Seed Plants, Wiley, New York, 1960, p. 135.