ACCELERATED LABORATORY TEST OF THREE AMAZONIAN WOOD SPECIES CALLED TAUARI, EXPOSED TO WHITE- AND BROWN-ROT FUNGI AND COLOR RESPONSE ACCORDING TO CIE <b><i>L* A* B*</i></b> SYSTEM

Okino, Esmeralda Yoshico Arakaki; Pastore, Tereza Cristina Monteiro; Camargos, José Arlete Alves; Coradin, Vera Terezinha Rauber; Teixeira, Divino Eterno; Santana, Marcos Antonio Eduardo; Fagg, Christopher William

doi:10.5902/1980509819609

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Artigos • Ciênc. Florest. 25 (3) • Sept 2015 • https://doi.org/10.5902/1980509819609 copy

ACCELERATED LABORATORY TEST OF THREE AMAZONIAN WOOD SPECIES CALLED TAUARI, EXPOSED TO WHITE- AND BROWN-ROT FUNGI AND COLOR RESPONSE ACCORDING TO CIE L* A* B* SYSTEM

ENSAIO ACELERADO DE LABORATÓRIO DE TRÊS ESPÉCIES DE MADEIRAS DA AMAZÔNIA CHAMADAS DE TAUARI, EXPOSTAS AOS FUNGOS DE PODRIDÃO-BRANCA E PARDA E RESPOSTA COLORIMÉTRICA DE ACORDO COM O SISTEMA CIE L* A* B*

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

The purposes of this study were to: evaluate de natural durability of three species of tauari (Couratari guianensis Aublet, Couratari oblongifolia Ducke & R.Knuth and Couratari stellata A.C.Smith), report the colorimetric parameters according to CIE L*a*b* 1976 system and also show the appearance of control and attacked wood blocks. Two brown-rot [Gloeophyllum trabeum (Persoon ex Fries) Murril. and Lentinus lepideus Fr.] and two white-rot [Trametes versicolor (Linnaeus ex Fries) Pilat and Ganoderma applanatum (Pers. ex Wallr.)] fungi were used.Tauari wood was classed as "moderately resistant" to "resistant" when exposed toGloeophyllum trabeum, Trametes versicolor andGanoderma applanatum fungi. All extractives' contents of attacked samples decreased when compared with the control (sound wood), exceptCouratari stellata exposed to Ganoderma applanatum.Conversely, all ash contents increased when compared with the control, except Couratari stellata exposed to Gloeophyllum trabeum. All attacked wood blocks and wood meal samples were darker, except wood meal from Couratari stellata exposed toTrametes versicolor, and redder than the control. The∆E* mean value in attacked wood blocks and wood meal samples attained 29.5 and 14.3, respectively.

Keywords:
natural durability; extractives; ashes; Couratari sp.; colorimetry

Universidade Federal de Santa Maria Av. Roraima, 1.000, 97105-900 Santa Maria RS Brasil, Tel. : (55 55)3220-8444 r.37, Fax: (55 55)3220-8444 r.22 - Santa Maria - RS - Brazil
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[TFN1] Where in: ^aMean values of 12 samples per fungus.^b HR = highly resistant, MR = moderately resistant and R = resistant. ^cValues in parentheses are standard deviations.

Species	Brown-rot percentage weight loss^a
Species	Gloeophyllum trabeum	Resistance class ^b	Lentinus lepideus	Resistance class
Couratari oblongifolia	34.58 (9.85) ^c	MR	6.31 (0.24)	HR
Couratari guianensis	25.01(5.17)	MR	1.93 (1.28)	HR
Couratari stellata	21.04 (4.53)	R	0.93 (0.59)	HR
	White-rot percentage weight loss^a			HR
	Trametes versicolor	Resistance class	Ganoderma applanatum	Resistance class
Couratari oblongifolia	32.34 (9.71)	MR	19.36 (4.02)	R
Couratari guianensis	28.44 (6.83)	MR	26.94 (4.09)	MR
Couratari stellata	18.46 (4.19)	R	16.74 (2.60)	R

Percentage^a		Attacked by fungi
Percentage^a	Control	Gloeophyllum trabeum	Lentinus lepideus	Trametes versicolor	Ganoderma applanatum
Couratari oblongifolia
Moisture content	8.18 (0.02) ^b	7.00 (0.16)	6.61 (0.09)	7.16 (0.10)	6.64 (0.06)
Extractives	3.17 (0.06)	2.26 (0.04)	1.65 (0.21)	2.43 (0.05)	2.17 (0.04)
Ash	0.52 (0.02)	0.63 (0.04)	0.55 (0.00)	0.60 (0.03)	0.54 (0.01)
Couratari guianensis
Moisture content	8.49 (0.04)	6.13 (0.01)	6.69 (0.40)	7.04 (0.04)	7.47 (0.31)
Extractives	3.24 (0.12)	2.40 (0.10)	1.72 (0.03)	2.09 (0.22)	2.72 (0.08)
Ash	0.52 (0.01)	0.58 (0.09)	0.57 (0.01)	0.59 (0.02)	0.57 (0.08)
Couratari stellata
Moisture content	7.59 (0.04)	6.58 (0.25)	6.45 (0.17)	7.18 (0.01)	5.80 (0.10)
Extractives	1.70 (0.11)	1.57 (0.10)	1.25 (0.13)	1.27 (0.18)	1.89 (0.13)
Ash	0.34 (0.05)	0.25 (0.08)	0.48 (0.02)	0.50 (0.01)	0.56 (0.02)

	CIE ^_Lab*	^_L*	^_a*	^_b*	^_L*	^_a*	^_b*	∆L*	∆a*	∆b*	∆E*
		Control			Attacked			Color variations
Fungus		Upper surface wood blocks^a						Color variations
	Gloeophyllum trabeum	65.5 ^A	6.3 ^A	21.0 ^A	36.3 ^A	10.1 ^B	21.5 ^A	-29.3 ^A	3.8 ^A	0.5 ^A	29.5 ^C
	Lentinus lepideus	68.2 ^A	5.5 ^A	21.0 ^A	57.6 ^B	7.9 ^A	24.3 ^B	-10.6 ^B	2.4 ^A	3.3 ^A	11.4 ^A
	Trametes versicolor	67.4 ^A	5.4 ^A	20.3 ^A	59.2 ^B	13.8 ^C	37.5 ^C	-8.1 ^B	8.3 ^B	17.2 ^B	20.7 ^B
	Ganoderma applanatum	66.3 ^A	5.8 ^A	20.1 ^A	55.3 ^B	15.0 ^C	36.8 ^C	-11.0 ^B	9.2 ^B	16.8 ^B	22.1 ^B
		Lower surface wood blocks					36.8 ^C	-11.0 ^B	9.2 ^B	16.8 ^B	22.1 ^B
	Gloeophyllum trabeum	66.4 ^A	5.8 ^A	21.7 ^A	37.5 ^A	9.8 ^B	21.0 ^A	-28.9 ^A	4.0 ^B	-0.7 ^A	29.2 ^C
	Lentinus lepideus	68.4 ^A	5.4 ^A	21.2 ^A	59.4 ^B	7.0 ^A	23.2 ^A	-9.0 ^B	1.6 ^A	2.0 ^B	9.4 ^A
	Trametes versicolor	67.2 ^A	5.4 ^A	20.0 ^A	63.3 ^B	12.0 ^C	35.1 ^B	-3.9 ^C	6.5 ^C	15.1 ^C	17.0 ^B
	Ganoderma applanatum	68.1 ^A	5.2 ^A	19.7 ^A	61.2 ^B	13.6 ^D	37.5 ^B	-6.9 ^BC	8.3 ^D	17.8 ^D	20.8 ^B
		Upper surface wood blocks^b					37.5 ^B	-6.9 ^BC	8.3 ^D	17.8 ^D	20.8 ^B
Wood species		^_L*	^_a*	^_b*	^_L*	^_a*	^_b*	∆L*	Da*	Db*	∆E*
	Couratari oblongifolia	70.4 ^C	5.9 ^A	23.0 ^A	55.9 ^A	12.0 ^A	32.0 ^A	-14.4 ^A	6.0 ^A	9.0 ^A	18.0 ^A
	Couratari guianensis	67.0 ^B	5.8 ^A	19.6 ^A	53.2 ^A	11.7 ^A	30.3 ^A	-13.8 ^A	5.9 ^A	10.7 ^A	18.4 ^A
	Couratari stellata	61.7 ^A	5.3 ^A	17.6 ^A	50.0 ^A	12.1 ^A	29.9 ^A	-11.7 ^A	6.9 ^A	12.3 ^A	18.3 ^A
		Lower surface wood blocks					29.9 ^A	-11.7 ^A	6.9 ^A	12.3 ^A	18.3 ^A
	Couratari oblongifolia	70.7 ^C	5.7 ^B	23.1 ^A	58.8 ^C	10.7 ^A	31.2 ^A	-11.9 ^A	5.0 ^A	8.1 ^A	15.2 ^A
	Couratari guianensis	67.3 ^B	5.6 ^A	19.7 ^AB	56.5 ^B	10.1 ^A	28.3 ^A	-10.8 ^A	4.5 ^A	8.6 ^A	14.5 ^A
Couratari stellata	63.2 ^A	4.9 ^A	17.4 ^A	54.4 ^A	11.3 ^A	30.1 ^A	-8.8 ^A	6.4 ^A	12.7 ^A	16.7 ^A

Sample	Colorimetric parameters^a of wood meal
	Effect of extractives withdrawal
	Unextracted			Extractive-free				Color variations
Control	^_L*		^_a*		^_b*	^_L*		^_a*		^_b*		∆L*	∆a*	∆b*	∆E*
Couratari oblongifolia	53.6		8.1		25.9	55.5		9.2		27.3		2.0	1.1	1.4	2.7
Couratari guianensis	51.0		9.2		24.5	51.3		9.7		25.8		0.3	0.5	1.2	1.6
Couratari stellata	51.1		8.4		24.4	50.4		8.3		24.7		-0.7	-0.1	0.3	0.8
	Effect of fungus in color parameters
	Couratari oblongifolia			Couratari guianensis				Couratari stellata
Attacked by	^_L*		^_a*		^_b*	^_L*		^_a*		^_b*		^_L*		^_a*	^_b*
Gloeophyllum trabeum	44.4		7.7		22.3	41.6		8.4		21.7		37.4		7.9	20.6
Lentinus lepideus	48.5		7.7		23.6	48.2		8.0		22.9		50.2		6.9	23.3
Trametes versicolor	49.4		10.1		28.5	48.5		9.7		26.7		53.2		8.7	28.1
Ganoderma applanatum	49.1		10.1		28.1	45.1		10.0		26.0		49.9		8.6	27.0
	Couratari oblongifolia			Couratari guianensis				Couratari stellata
Attacked by	∆L*	∆a*	∆b*	∆E*	∆L*	∆a*	∆b*	∆E*	∆L*	∆a*	∆b*	∆E*
Gloeophyllum trabeum	-9.2	-0.4	-3.6	9.9	-9.3	-0.8	-2.9	9.8	-13.8	-0.5	-3.8	14.3
Lentinus lepideus	-5.1	-0.4	-2.3	5.6	-2.7	-1.2	-1.7	3.4	-0.9	-1.5	-1.1	2.1
Trametes versicolor	-4.2	2.0	2.6	5.3	-2.5	0.5	2.1	3.3	2.1	0.3	3.7	4.3
Ganoderma applanatum	-4.4	2.0	2.2	5.3	-5.9	0.8	1.5	6.1	-1.2	0.2	2.5	2.8

Wood species	Number of wood samples
Wood species	Gloeophyllum trabeum	Lentinus lepideus	Trametes versicolor	Ganoderma applanatum	Control (blank)
Couratari oblongifolia	12	12	12	12	12
Couratari guianensis	12	12	12	12	12
Couratari stellata	12	12	12	12	12
Reference blocks	9	9	9	9	-