. 2013 Dec 17;4:509. doi: 10.3389/fpls.2013.00509

Table 1.

Mean concentrations and ranges of the seven phenolic compounds identified in the rhizosphere soil of wild oat.

The maximum values relating to the developmental stages of the plant growth are also given.

Compound	Concentration (μg/kg soil dry matter)			Growth stage of peak concentration
	Mean^†	Range	Peak
4-Hydroxybenzoic acid	0.0855^b ^c ^†	0.1134	0.1555^b	Heading
Vanillic acid	0.0153^d	0.0149	0.0251^d	Heading
Syringic acid	0.1082^a	0.2198	0.2382^a	Stem elongation
Vanillin	0.1008^a ^b	0.1053	0.1685^b	Heading
p-Cumaric acid	0.0190^d	0.0278	0.0354^d	Heading
Syringaldehyde	0.0742^c	0.0457	0.0971^c	Tillering
Ferulic acid	0.0258^d	0.0158	0.0313^d	Stem elongation
LSD_(0.05)	0.0186		0.0359

^†

Means represent net concentrations (n = 33).

^‡Values within a column not followed by the same letter are significantly different at P ≤ 0.05.

The letters

^{“a”, “b”, “c”, and “d”}

indicate that the values are statistically different.