Chemical Composition of Woods of 37 Woody Species of Tamaulipan Thorn Scrub, Northeast Mexico: A Case Study

HUMBERTO GONZALEZ RODRIGUEZ1', RATIKANTA MAITI1,

NATALYA S. IVANOVA2, and CH. ARUNA KUMARI3

  • 1Universidad Autonoma de Nuevo Leon, Facultad de Ciencias Forestales, Carr. Nac. No. 85 Km. 45, Linares, Nuevo Leon 67700, Mexico
  • 2 Russian Academy of Science, Botanical Garden of Ural Branch, 202a, 8-March street, Yekaterinburg 620144, Russia
  • 3Crop Physiology, Professor Jaya Shankar Telangana State Agricultural University, Agricultural College, Polasa, Jagtial 505529, India

'Corresponding author. E-mail: This email address is being protected from spam bots, you need Javascript enabled to view it

ABSTRACT

The present study was directed to determine the chemical composition of 37 woody trees at Linares, of Tamaulipas Thom Scrub, Northeast Mexico.

The results show large variability among the species in wood chemical composition, such as neutral detergent fiber (NDF), digestible detergent fiber (ADF), lignin, cellulose, hemicellulose. In these aspects, maximum of amount NDF (94.8%) is observed in Celtis pallida, Parkinsonia aculeata, and Guaiacum angustifolium. High amount of ADF was found in three species: Celtis pallida, Parkinsonia aculeata, Lantana macropoda. With respect to lignin, Sideroxylon celastrina, Ebenopsis ebano, Ehretia anacua, Amyris texana, LeucophyUum frutescens, Cordia boissieri, and Condalia hookeri have high lignin content (over 24%). On the other hand, maximum of cellulose was observed in Parkinsonia aculeata, Celtis pallida, and Lantana macropoda have also high levels of cellulose.

Similarly, maximum amount of cellulose was observed in Bernardia myricifolia. Close to the maximum content of hemicellulose was revealed in Celtis laevigata. With respect to fiber, maximum of fiber is observed in Celtis pallida. Close to the maximum content of fiber was found in Parkin- sottia aculeata and Guaiacum angustifolium. The variations in chemical compositions could be related to quality determination and utility of timbers of different woody species.

INTRODUCTION

Wood is a hard tissue below the bark of a tree. It is of high commercial importance in wood industry. It is used for several domestic uses and also in the manufacture of furniture. Wood quality depends on anatomical structure and chemical composition. Various authors have reported the chemical composition of wood and its relation to wood quality and utilization (Petterson et al., 1984). These studies analyze chemical composition of wood, its methods, structure, hemicellulose components, and the degree of polymerization of carbohydrates. Woods were collected from different countries and analyzed for sugar compositions, such as glucan, galactan, arabinan, and mannan; besides uronic anhydride, aceyle, lignin, were analyzed.

Wood is composed mainly of cellulose, hemicellulose, lignin, and other extractable materials mentioned below. The lignin is present in the cell wall of wood (20-30%). It is cemented in the cell wall of wood, confers rigidity of the same and acts as an obstacle against the degradation of enzymes of the cell wall.

In wood, it is always associated to cellulose but do not occur the same in other cellulosic materials, so that the cellulose may be found practically in a pure condition, for example, in cotton (Ortuno, 1998). Lignin is a tridimensional aromatic polymer in which phenylpropane units are repeated with different types of bonds (ether or C-C) between the monomers. A review was undertaken by Guadalupe Berecenas Pazos and Raymundo Sotelo on the importance of lignin contraction.

On the basis of literature, it is confirmed that the shrinkage of wood can be partially attributed to the content of lignin in the wood. It was assessed that temperate hard wood obtained both from Mexico and the United States had a higher shrinkage capacity than tropical woods.

Specific gravity is found to be the most important variable; however, the influence of lignin is also significant. They remarkedly suggested that it is necessary to cany out experimental studies on the effect of these variables on dimensional changes, along with other important traits such as extractives and ray volume. All the plants and especially woody species are constituted by majority the components like С, H, O, and N and also contain small quantities of Ca, K, and Mg. The elements С, H, and О are combined to form organic components of wood, such as cellulose, hemicellulose, and Ugnin, as well as pectins (Ortuno, 1998). The components of the cell wall are lignin and the polysaccharides constituted by cellulose and hemicellulose. Cellulose is the main constituent of the cell wall of all higher plants with the majority of wood fibers (40-45%).

This is constituted by D-glucose in form of pyranose linked together by 1-4 glycosidic bonds with the formation of cellobiose residues. The hemicellulose is associated with cellulose in the cell wall. This is formed by pentose and hexose distinct from glucose (mannose, xylose, glucose, galactose, and arabinose), linked together with a polymerization grade from 100 to 200. The chemical structure and composition vary according to species.

Similarly, all the hemicelluloses are insoluble in H,0 but can be dissolved in strong alkalis and easily hydrolyzed by acids. Its amorphic structure and low molecular weight confer greater solubility and susceptibility to hydrolysis than cellulose (Ortuno, 1998). The cellulosic fraction—cellulose and hemicellulose—of wood may be separated in its components, depending on its solubility in NaOH at 17.5%, according to their grade of polymerization (Ortuno, 1998). The pectins or pectic substances are also the hydrates of carbon, form cell wall of young cells.

It is difficult to separate lignin of wood; besides it alters with the method of extraction. The molecular weight of the separated product may vary between 1000 and 20,000 g/mol (Lu and John, 2010). Owing to the high content of this aromatic and phenolic compounds, the lignins shows dark color and are easily oxidized, are relatively stable in aqueous acidic minerals, but are soluble in aqueous bases and hot bisulfite.

The wood also contains a series of extractable compounds of varied chemical compositions, such as gums, resins, fats, alkaloids, and also tannins. Tannins can be extracted from woods, which can be extracted from wood by cold or hot water or with organic solvents, including alcohol, benzene, acetone, or ether. The proportion of these substances is from 1% to 10%, whereas some tropical species may contain up to 20% of the same. The inorganic compounds are not soluble in the mentioned solvents but sometimes are included among the extracts (Ortuno, 1998).

Berland and Holmbom (2004) investigated the pattern of distribution of wood components along a radial cross-section of the stem using microscale analytical technique. The results reveal that heartwood had more lignin but less cellulose than sapwood. The total content of hemicellulose was similar along the radial direction.

There were significant differences in the distribution of sugars units in hemicellulose. Latewood contained galactoglucomannan in earlywood but less pectin. Jones et al. (2006) used diffuse reflectance near infrared spectroscopy for nondestructive estimation of wood’s chemical composition from wood strips. Besides, they estimated cellulose, hemicellulose, lignin, arabinan, galactan, mannan, and xylan by using standard analytical chemistry methods.

Sriraam et al. (2012) reported the average chemical contents of wood mentioned below. Elements share, % of dry matter weight, carbon 45-50%, hydrogen 6.0-6.5% oxygen 38-42%, nitrogen 0.1-0.5%. Sulfur max 0.05. They observed large variations of cellulose, hemicellulose, lignin, and total extractives among scot pine, spruce, eucalyptus, silver birch.

A study has been undertaken by Memet Baharloglu et al. (2013) to determine the effects of the anatomical and chemical composition of wood on the quality of particleboard containing woods of different species. They concluded that anatomical and chemical composition of wood species determine physical properties of particleboard that are related to the length and number of cells and fibers. Panels containing more of pinewood gave higher mechanical strength and lowest thickness values and there were significant differences in physical and mechanical properties among particle boards that were related to length, thickness, and the number of cells and fibers.

Similarly, a study was undertaken by Agata Pawlika et al. (2013) on chemical composition of wood species of Africa. They estimated holocel- lulose, pentosans, and substances soluble in organic solvents, such as 1% NaOH, in cold and hot water, and also determined mineral substances.

Their results are shown below. Constituents: Koto Sip Mahogany, cellulose: 43.03, 41.59, 43.14; holocellulose 71.76, 64.28, 59.91; lignin 22.43, 30.36, 30.20. Very recently Schamweber et al. (2016) studied variations of wood’s chemistry among trees using X-ray fluorescence. They observed the variation of chemical composition between one coniferous and one broadleaf (Castanea sativa) grown in different conditions. Pine showed greater values.

The common signal was stronger for pine than for chestnut.

Maiti et al. (2015) studied variability of wood-density of ten woody species and its possible relation with wood’s chemical composition at Linares, Northeast Mexico. They observed large variations in the wood’s density and wood’s chemical composition. In general, though there was no clear relationship between wood density and other chemical composition of wood, it is observed that the species having wood of moderate and high- wood density contained >30% sulfur, >40% cellulose, and more or less 20% (Maiti et al., 2016) lignin.

The present study was undertaken on the chemical composition of 37 woody shrubs and trees in Northeast Mexico.

MATERIALS AND METHODS

In the present study, 37 woody trees and shrubs are taken for the chemical composition of wood (species are shown in the graphs in results).

The woody species included in the study are mentioned below.

Family

Growth type

Scientific name

Rutaceae

Shrub

Heliettaparvifolia (A. Gray) Benth.

Zygophyllaceae

Shrub

Guaiacum angustifolium (Engelm.) A. Gray.

Scrophulariaceae

Shrub

Leucophyllum futescens (Berland) I. M. Johnst.

Euphrobiaceae

Shrub

Bernardia myricifolia (Scheele) S. Watson.

Fabaceae

Shrub

Eysenhardtiapolystachya (Ortega) Sarg.

Fabaceae

Shrub

Leucaena leucocephala (Lam.) de Wit

Fabaceae

Tree

Ebenopsis ebano (Berland.) Barneby & J. W. Grimes

Rutaceae

Tree

Sargentia greggn S. Watson

Ebenaceae

Shrub

Dwspyros palmeri Eastw.

Leguminoseae

Shrub

Acacia rigidula Benth.

Rutaceae

Shrub

Amyris texana (Buckley) R Wilson.

Boraginaceae

Shrub

Cordia boissieri A.DC.

Ulmaceae

Shrub

Celtis pallida Torr.

Rutaceae

Shrub

Zanthoxylum fagara (L.) Sarg.

Asteraceae

Shrub

Gymnospenna glutinosum (Spreng.) Less.

Leguminoseae

Shrub

Acacia farnesiana (L) Willd

Leguminoseae

Shrub

Acacia farnesiana

Verbenaceae

Shrub

Lantana macropoda Torr.

Oleaceae

Shrub

Forestiera angustifolia Torr.

Euphrobiaceae

Shrub

Croton snareolens Torr.

Berberidaceae

Shrub

Berberis trifoliata Torr.

Boraginaceae

Shrub

Ehretia anacua I. M. Johnst.

Rhamnaceae

Shrub

Condalia hookeri M. C. Johnst.

Ebenaceae’

Shrub

Diospyros texana Scheele

Sapotacee

Tree

Sideroxylon celastrina (Kunth) T. D. Penn.

TABLE (Continued)

Family

Growth type

Scientific name

Leguminoseae

Tree

Caesalpinia mexicana A. Gray

Rhaiunaceae

Slirub

Karwinskia humboldtiana (Willd. ex Roem. & Schult.) Zucc.

Mimosaceae

Tree

Acacia schaffneri (S.Watson) F. J. Herm.

Fabaceae

Tree

Prosopis laevigata (Humb. & Bonpl. ex Willd.) M. CJfohnst.

Fabaceae

Tree

Acacia berlandieri Benth.

Leguminosae

Tree

Cercidium macrum I. M. Johnst.

Fagaceae

Tree

Ouercus polymorpha Schltdl. & Cham.

Caesalpiniaceae

Tree

Parkinsonia aculeata L

Salicaceae

Tree

Salix lasiolepis Benth.

Fabaceae

Tree

Acacia wrightii Benth.

Oleaceae

Tree

Fraxinus greggii A. Gray

Ulmaceae

Tree

Celtis laevigata Willd.

Fabaceae

Tree

Hatvadiapallens (Benth.) Britton & Rose.

Triplicate samples of wood are collected from each of 37 species and then were subjected to chemical analysis for neutral detergent fiber (NDF), and detergent fiber lignin (ADL) contents following Anken procedure. Hemicel- lulose (NDF-ADF) and cellulose (ADF-lignin) were obtained by difference by cambium but its contents decrease in old trees (Technique of Ankon).

Estimation of each component was done in five replications. The procedures are mentioned below:

Estimation of each component was done in five replications.

The procedures mentioned below:

A—scientific name В—common name C— diy matter D—dry weight E—P. sample F—FDN

G—(F2-[D2* 1.00507611])

H—% NDF = (G2/[E2*C2])*100 I—% NDF coit = (H2-S2)

J—ADF К—(J2/D2)

L—% ADF = ([J2-{D2* 1.001191319} ]/[E2*C2] * 100)

M—% ADF corr = (L2-S2),

N—lignina,

O—lignin corr = ([N2-{D2* 1.00045152}]/[E2>

P—% lignin = (02-S2).........Q = peso del crisol, R = cenizas,

S—% ashes = ([{R2-Q2}-0]/[E2*C2])*100 T—hemicel = (H2-L2)

U—cellulose = (L2-P2)

V—% cellulose = ([E2-{N2-D2}/E2]*100)*(L2/100)

W—% lignina = ([N2-D2]-[R2-Q2]/E2)*100*(L2/100)

X—% acid insoluble detergent fiber = (R2-Q2)/E2*100*(L2/100)

8.2.1 DATA ANALYSIS

Comparison of average values is a way of comparing relationships between species. Statistical analysis of the variables are undertaken, such as analysis of variance (ANOVA), among and between groups.

A statistically significant result, when a probability (p value) is less than a threshold (significance level), justifies the rejection of the null hypothesis (Box. 1953). ANOVA tests the null hypothesis about equality of the means of all the groups that are compared; however, this statistic only demonstrates the presence or absence of difference between species and groups, it answers the question, whether we should accept or reject the null hypothesis. We also analyzed Tukey’s HSD test to evaluate the differences between species.

If the null hypothesis is rejected (differences are statistically significant), then we should search the answer to a question which of the species and groups is actually different from others. Parametric variants of ANOVA calculate for this purpose so-called post hoc (after the event) tests, which are aimed to point the group being different from others. Multiple comparison procedures and statistical tests were carried out (Morrison et al., 2013)

 
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