Induction and proliferation of axillary shoots from in vitro culture of Paeonia lactiflora Pall. mature zygotic embryos

Figures & data

Table 1 Assessment of three parameters using explants derived from zygotic embryos of P. lactiflora ‘Fen Yu Nu’ (n = 30).

Treatments	Contamination (%)	Germination (%)	Seedling conversion to plantlets (%)
Seeds with testa retained	37.67 ± 2.36^b	0.00 ± 0.00^c	0.00 ± 0.00^b
Seeds with testa peeled off	62.91 ± 1.96^a	6.67 ± 2.68^b	0.00 ± 0.00^b
ESEs	6.67 ± 1.88^c	89.43 ± 2.18^a	61.33 ± 1.35^a

Different letters within a column indicate significant differences according to Duncan’s multiple range test (P ≤ 0.05). Explants were inoculated on to BM supplemented with 1.0 mg L⁻¹ BA and 1.0 mg L⁻¹ GA₃.

Table 2 Effect of age on culture of young embryos of ‘Fen Yu Nu’ (n = 30).

Sampling time	Germination (%)	Seedling conversion to plantlets (%)
50 d after flowering	51.67^c	41.67^c
70 d after flowering	72.00^b	59.33^b
90 d after flowering	90.54^a	71.29^a

Different letters within a column indicate significant differences according to Duncan’s multiple range test (P ≤ 0.05). Explants were inoculated on to BM supplemented with 1.0 mg L⁻¹ BA and 1.0 mg L⁻¹ GA₃.

Table 3 Effect of age on culture of young embryos of ‘Zhong Sheng Fen’ (n = 30).

Sampling time	Germination (%)	Seedling conversion to plantlets (%)
50 d after flowering	61.67^b	49.73^c
70 d after flowering	86.67^a	63.33^b
90 d after flowering	95.33^a	81.29^a

Different letters within a column indicate significant differences according to Duncan’s multiple range test (P ≤ 0.05). Explants were inoculated on to BM supplemented with 1.0 mg L⁻¹ BA and 1.0 mg L⁻¹ GA₃.

Table 4 Effect of age on culture of young embryos of ‘Zhu Sha Pan’ (n = 30).

Sampling time	Germination (%)	Seedling conversion to plantlets (%)
50 d after flowering	76.79^c	54.72^c
70 d after flowering	87.88^b	58.79^b
90 d after flowering	95.00^a	66.67^a

Different letters within a column indicate significant differences according to Duncan’s multiple range test (P ≤ 0.05). Explants were inoculated on to BM supplemented with 1.0 mg L⁻¹ BA and 1.0 mg L⁻¹ GA₃.

Table 5 The influence of different PGRs on seedling production of P. lactiflora ‘Fen Yu Nu’ EZEs (L₉ (3³)) (n = 30).

Treatments	BA (mg L^−1)	NAA (mg L^−1)	GA3 (mg L^−1)	Germination (%)	Seedling conversion to plantlets (%)
1	1 (0.2)	1 (0)	1 (0)	40.00 ± 1.06^d	0.00 ± 0.00^d
2	1 (0.2)	2 (0.05)	2 (0.5)	70.00 ± 3.87^a	30.68 ± 2.38^b
3	1 (0.2)	3 (0.1)	3 (1.0)	46.67 ± 0.00^c	0.00 ± 0.00^d
4	2 (0.5)	1 (0)	2 (0.5)	60.00 ± 10.00^b	40.00 ± 10.00^a
5	2 (0.5)	2 (0.05)	3 (1.0)	26.67 ± 1.89^e	10.00 ± 0.00^c
6	2 (0.5)	3 (0.1)	1 (0)	13.33 ± 0.00^g	0.00 ± 0.00^d
7	3 (1.0)	1 (0)	3 (1.0)	23.56 ± 1.76^e,f	5.56 ± 5.09^c,d
8	3 (1.0)	2 (0.05)	1 (0)	17.72 ± 1.00^f,g	3.33 ± 5.77^c,d
9	3 (1.0)	3 (0.1)	2 (0.5)	30.00 ± 0.00^e	0.00 ± 0.00^d

Different letters within a column indicate significant differences according to Duncan’s multiple range test (P ≤ 0.05). EZEs were inoculated on to BM supplemented with different concentrations of PGRs. Values in parenthesis = level of concentration of the different factors. The PGR combination in treatments 1, 6 and 9 were unsuitable for tender/true leaves, so seedlings were unable to convert into plantlets even though they developed roots. Seedling conversion to plantlets is different from germination. This is because in the process of embryo growth, many cotyledons are unable to expand normally and cannot form healthy seedlings, so there is some difference between both processes, hence the use of two terms.

Table 6 Analysis of average rate of seedling conversion to plantlets.

Treatments	BA (mg L^−1)	NAA (mg L^−1)	GA3 (mg L^−1)
R (seedling)	13.71	15.19	22.45
x̄1 (seedling)	10.23	15.19	1.11
x̄2 (seedling)	16.67	14.67	23.56
x̄3 (seedling)	2.96	0	5.19

Range = the detection of that concentration of PGR that was most suitable for the experiment. X₁, X₂ and X₃ are the average values of each concentration of PGR for three tests whose maximum minus minimum represents the range, R. For example, for BA: X1: 10.23 = (0.00 + 30.68 + 0.00)/3; X2: 16.67 = (40.00 + 10.00 + 0.00)/3; X3: 2.96 = (5.56 + 3.33 + 0.00)/3; R: 13.71 = 16.67−2.96.

Table 7 Impact of three PGR treatments on axillary shoot proliferation and growth of P. lactiflora ‘Fen Yu Nu’ seedlings (n = 30).

Treatment (mg L^−1)	Leaf expansion (number of times that leaves expanded)	Number of axillary shoots
1.0 BA + 1.0 GA3	3.76 ± 0.28^a	10.98 ± 0.85^a
1.0 BA + 1.5 Kin	2.69 ± 0.09^b	7.43 ± 1.15^b
1.0 BA + 1.0 GA3 + 1.5 Kin	2.72 ± 0.16^b	7.38 ± 1.29^b

Different letters within a column indicate significant differences according to Duncan’s multiple range test (P ≤ 0.05). EZEs were inoculated on to BM supplemented with different concentrations of PGRs.

Table 8 Treatments used to increase lateral root induction and strengthen seedlings (n = 10).

		Seedlings with defined root length (L) (%)
Treatments (mg L^−1)	Rooting (%)	L < 2 cm	2 cm ≤ L ≤ 5 cm	L > 5 cm
1/2 MS (control)	100.00 ± 0.00^a	25.26 ± 1.72^a	32.82 ± 2.52^c	41.92 ± 0.73^a
2.0 BA + 0.2% AC	98.89 ± 1.92^a	21.68 ± 2.05^b	47.53 ± 1.48^a	30.79 ± 1.51^c
2.0 BA + 2.0 IBA + 0.2% AC	96.67 ± 0.00^b	21.41 ± 2.38^b	41.36 ± 2.77^b	37.23 ± 0.84^b

Different letters within a column indicate significant differences according to Duncan’s multiple range test (P ≤ 0.05). BM supplemented with different concentrations of PGRs.