Effect of explant type (leaf, stem) and 2,4-D concentration on callus induction: influence of elicitor type (biotic, abiotic), elicitor concentration and elicitation time on biomass growth rate and costunolide biosynthesis in gazania (Gazania rigens) cell suspension cultures

Bioresources and Bioprocessing

Table 3 Effect of elicitation time combined with 200 mg/L YE or 150 mg/L MeJA on cell growth parameters and costunolide accumulation

Treatments	Fresh weight (mg)	Dry weight (mg)	Costunolide (ppm)
YE elicitation time (days)
0	730.7 ± 5.2^d(E)	47.0 ± 3.1^b(D)	3.47 ± 0.01^e(J)
5	796.0 ± 2.5^c(D)	68.3 ± 1.3^a(BC)	4.98 ± 0.01^d(I)
10	823.3 ± 3.5^b(C)	70.0 ± 2.5^a(ABC)	5.94 ± 0.01^b(F)
15	784.7 ± 9.8^c(D)	72.7 ± 1.3^a(ABC)	7.37 ± 0.01^a(D)
20	932.0 ± 0.6^a(B)	74.0 ± 2.3^a(AB)	5.60 ± 0.00^c(G)
p values (one-way ANOVA) [YE, Elicitation time]	0.000***	0.000***	0.000***
MeJA elicitation time (days)
0	302.0 ± 0.6^d(G)	36.0 ± 0.0^c(E)	5.50 ± 0.06^e(H)
5	543.0 ± 1.5^c(F)	66.0 ± 2.1^b(C)	13.94 ± 0.01^b(B)
10	732.0 ± 1.2^b(E)	72.7 ± 2.9^ab(ABC)	18.47 ± 0.02^a(A)
15	954.0 ± 2.3^a(A)	76.3 ± 3.2^a(A)	10.29 ± 0.01^c(C)
20	951.0 ± 2.6^a(A)	73.0 ± 1.2^ab(ABC)	7.11 ± 0.01^b(E)
p values (one-way ANOVA) [MeJA, Elicitation time]	0.000***	0.000***	0.000***
Two-way ANOVA/general linear model
Elicitor type (A)	0.000***	0.266 ns	0.000***
Elicitation time (B)	0.000***	0.000***	0.000***
(A)*(B)	0.000***	0.026*	0.000***

Means (n = 30) ± standard error (S.E.) with the same letter in a column are not statistically significant different from each other according to the Duncan’s multiple range test at p ≤ 0.05. ns p > 0.05; *p ≤ 0.05; ***p ≤ 0.001. Superscript small letters—differences between five elicitation times for each elicitor type (either YE or MeJA) separately (one-way ANOVA). Superscript capital letters in parenthesis—differences between samples from the combined effect of two elicitor types and five elicitation times (two-way ANOVA)