Volatile oil concentration and growth of thyme (<i>Thymus vulgaris</i> L.) plants responded to red to blue light ratios

Hassan Essam Ali; Yuxin Tong; Hassan Essam Ali; Yuxin Tong

doi:10.48130/TIH-2023-0002

Days after treatment	Light quality	Plant height (cm)	Branch numbers	shoots fresh weight (g)	shoots dry weight (g)	Leaf area (cm²)	Root length (cm)	Roots fresh weight (g)	Roots dry weight (g)
12 days	R4B1	15.63 A	15.33 A	2.56 A	0.57 A	27.47 A	17.37 A	0.76 A	0.06 A
	R2B1	14.63AB	14.00 AB	1.86 B	0.51 B	25.30 A	15.60 A	0.59 B	0.06 A
	R1B1	13.73 B	12.00 BC	1.55 BC	0.41 C	20.20 B	14.80 A	0.57 B	0.05 A
	R1B2	13.97 B	14.33 AB	1.57 BC	0.33 D	18.04 BC	15.53 A	0.60 B	0.05 A
	FL.	13.37 B	11.00 C	1.32 C	0.27 D	15.68 C	11.30 B	0.34 C	0.03 B
24 days	R4B1	26.00 A	28.00 A	20.28 A	4.69 A	156.80 A	18.33 A	3.20 A	0.26 A
	R2B1	25.00 AB	26.33 AB	19.46 AB	4.22 A	150.30 A	16.00 B	2.66 AB	0.20 AB
	R1B1	23.00 AB	23.00 BC	17.42 AB	2.96 B	134.40 B	15.00 B	2.27 AB	0.16 BC
	R1B2	23.83 B	24.0 ABC	18.02 AB	3.00 B	131.60 B	14.67 B	1.98 B	0.15 BC
	FL.	20.00 C	21.00 C	17.13 B	2.79 B	127.90 B	14.00 B	2.04 B	0.11 C
36 days	R4B1	29.67 A	40.67 A	32.24 A	5.60 A	199.80 A	21.33 A	3.73 A	0.27 A
	R2B1	27.33 AB	38.00 AB	29.81 A	5.15 A	191.30 A	20.00 AB	2.89 AB	0.24 AB
	R1B1	26.00 B	35.33 BC	29.21 A	4.88 AB	159.80 B	18.67 B	2.56 B	0.22 AB
	R1B2	26.67 B	32.00 CD	23.31 B	3.81 B	154.20 B	19.00 AB	2.44 B	0.20 B
	FL.	25.00 B	28.67 D	22.13 B	3.88 B	137.90 C	18.00 B	2.19 B	0.14 C
FL = fluorescent lamp; R = Red; B = Blue. Means followed by different letters within a column are significantly different at P < 0.05 by Duncan's test.

Table 1.

Thyme plant morphology and growth as affected by different light qualities.

Days after treatment	12 days					24 days					36 days
Light quality	R4B1	R2B1	R1B1	R1B2	FL	R4B1	R2B1	R1B1	R1B2	FL	R4B1	R2B1	R1B1	R1B2	FL
Chl(a) ( mg/l)	16.75 AB	18.64 A	16.38 AB	16.49 AB	14.43 B	15.71 A	18.91 A	17.77 A	16.92 A	15.26 A	19.90 B	23.10 A	19.36 B	18.30 BC	16.45 C
Chl(b) ( mg/l)	6.29 AB	6.82 A	4.83 B	4.96 B	4.98 B	5.11 A	6.30A	5.56 A	4.80 A	4.73 A	6.63 B	7.73 A	5.96 BC	5.90 BC	5.37 C
FL = fluorescent lamp; R = Red; B = Blue. Means followed by different letters within a column are significantly different at P < 0.05 by Duncan's test.

Table 2.

Chlorophyll a and b concentration of thyme leaves as affected by different light qualities.

Light quality	Volatile oil (%)	Volatile oil yield (mL plant⁻¹)
R4B1	2.82A	0.16 A
R2B1	2.77 A	0.14 A
R1B1	2.70 A	0.13 A
R1B2	2.25 B	0.09 B
FL	2.21 B	0.09 B
FL = fluorescent lamp; R = Red; B = Blue. Means followed by different letters within a column are significantly different at P < 0.05 by Duncan's test.

Table 3.

Volatile oil of thyme plants as affected by different light qualities.

Compound	KI^*	R4B1	R2B1	R1B1	R1B2	FL
[I]: Monoterpenes Hydrocarbons [MH]
α-Thujene	913	2.18	1.98	2.18	2.18	1.91
α-Pinene, (−)-	938	0.96	0.99	0.96	0.96	0.94
Camphene	953	0.22	0.30	0.22	0.22	0.23
Sabinene	965	0.06	0.05	0.06	0.06	0.05
(−)-β-Pinene	980	0.27	0.28	0.27	0.27	0.30
β-Myrcene	986	2.25	2.27	2.25	2.25	2.42
α--Phellandrene	996	0.43	0.43	0.43	0.43	0.48
DELTA3-Carene	1004	0.12	0.12	0.12	0.12	0.14
p-Cymene	1025	7.48	7.70	7.48	7.48	7.54
D-Limonene	1030	0.65	0.67	0.65	0.65	1.10
Eucalyptol	1046	0.17	0.19	0.17	0.17	0.32
α-Terpinene	1057	4.25	4.03	4.25	4.25	4.23
γ-Terpinene	1057	19.11	18.72	19.11	19.11	17.89
α-Terpinolene	1087	0.15	0.14	0.15	0.15	0.16
Total MH		38.30	37.87	38.30	38.30	37.71
[II] Oxygenated Monoterpenes Hydrocarbons [OM]
cis-Sabinene hydrate	1063	1.13	1.15	1.13	1.13	1.29
Linalool	1098	1.91	1.87	1.91	1.91	1.98
Terpinen-4-ol	1176	0.69	1.06	0.69	0.69	0.63
alpha-Terpineol	1189	0.13	0.13	0.13	0.13	0.15
Thymol methyl ether	1217	0.07	0.29	0.07	0.07	0.65
Carvacrol methyl ether	1247	0.16	0.34	0.16	0.16	0.78
Thymol	1293	49.83	49.06	49.83	49.83	48.22
Phenol, 2-methyl-5-(1-methylethyl)-	1307	3.71	3.26	3.71	3.71	3.76
Total OM		57.63	57.16	57.63	57.63	57.46
[III] Sesquterpenes Hydrocarbons [SH]
Caryophyllene	1415	2.03	2.29	2.03	2.03	2.33
α-Humulene	1455	0.06	0.08	0.06	0.06	0.08
γ-Muurolene	1478	−	0.30	0.27	−	0.30
α-Muurolene	1486	0.27	−	0.14	0.27	0.06
γ-Cadinene	1515	0.15	0.23	0.15	0.15	0.24
delta-Cadinene	1526	0.25	0.32	0.25	0.25	0.34
γ-eudesmol	1608	−	0.13	−	−	0.10
Total SH		2.76	3.35	2.90	2.76	3.45
IV: Oxygenated Sesquterpenes [OS]
tau-Cadinol	1640	0.15	0.28	0.15	0.15	0.31
Total OS		0.15	0.28	0.15	0.15	0.31
[V]: Various compounds [VC]
1-Octen-3-ol	977	0.85	0.80	0.85	0.85	0.59
Total VC		0.85	0.80	0.85	0.85	0.59
Total Identified Compounds		99.69	99.46	99.83	99.69	99.52
FL = fluorescent lamp; R = Red; B = Blue.

Table 4.

Volatile oil constituents of thyme plants as affected by different light qualities.

Parameters	Height (cm) 1	Fresh weight (g) 2	Dry weight (g) 3	Branches number/plant 4	Leaf area (cm²) 5	Root length (cm) 6	Root fresh weight (g) 7	Root dry weight (g) 8	Chl (a) (mg L⁻¹) 9	Chl (b) (mg L⁻¹) 10	V. oil (%) 11	V. oil yield (L Plant⁻¹) 12
1	1	0.882^*	0.774	0.771^**	0.959^**	0.935^**	0.919^**	0.823^**	0.604^*	0.674^**	0.680^**	0.773^**
2		1	0.958^**	0.933^**	0.898^**	0.900^**	0.961^**	0.930^**	0.807^**	0.790^**	0.925^**	0.958^**
3			1	0.907^**	0.788^**	0.815^**	0.891^**	0.884^**	0.755^**	0.724^**	0.978^**	0.961^**
4				1	0.832^**	0.883^**	0.852^**	0.811^**	0.735^**	0.712^**	0.899^**	0.983^**
5					1	0.950^**	0.891^**	0.821^**	0.683^**	0.733^**	0.697^**	0.820^**
6						1	0.872^**	0.817^**	0.601^*	0.640^*	0.739^**	0.871^**
7							1	0.858^**	0.744^**	0.736^**	0.841^**	0.871^**
8								1	0.796^**	0.807^**	0.868^**	0.863^**
9									1	0.956^**	0.790^**	0.773^**
10										1	0.748^**	0.750^**
11											1	0.956^**
12												1
Correlation is significant at the 0.05 level (2-tailed). *Correlation is significant at the 0.01 level (2-tailed).

Table 5.

Correlation coefficient between the parameters.