Figure 1.
Total number (A), total fresh weight (B) and photographs (C) of PLBs of Dendrobium Sonia 'Earsakul' and 'Jindasweet' cultured in liquid medium (control) or medium supplemented with 150 mM NaCl for 0, 2, 4 and 6 weeks. PLB numbers were categorised by size of diameter: S (<0.5 cm), M (0.5–1.0 cm) and L (>1.0 cm). All data are presented as the means of independent samples (n = 5). The error bars indicated ± standard error. A single asterisk (*) indicates significant difference at p < 0.05, and double asterisks (**) indicate p < 0.01, and triple asterisks (***) indicate p < 0.001 according to a t-test for each cultivar. PLBs, protocorm-like bodies.
Table 1.
Primers for gene expression analysis by qRT-PCR.
| Gene | Forward primer (5′-3′) | Reverse primer (5′-3′) | Accession No. | Reference |
|---|---|---|---|---|
| CDKA1 | TTCTCCGTGGCATTGCTTACTG | TCCAAGGAGGATTTCTGGTGCT | HQ904083.1 | Zhang et al. (2012) |
| TUBB3 | CCGTTGTGGAACCATACAATGC | GTAGCCGAGATGAGGTGATTGA | KX524085.1 | An et al. (2016) |
| EXP | AAAGGAGGGATTCGGTTCAC | ACGAGTTGCTTTGCCAATTC | KM408748.1 | - |
| CK1 | TCTCCCCTCACTCATTCACC | GCCCCAGCATCTACAAACAT | AJ294542 | - |
| rbcL | TGTCTACGGGGTGGACTTGA | AGCCAGGCTAGTATTTGCGG | AB519791.1 | - |
| LEA2 | ATGAGGAGAAGGGTGGCTTC | ACACAAGCTTCCTCCCATCA | KY626329.1 | - |
| EF1-a | TCAGGCTGACTGTGCTGTCCT | GTGGTGGCGTCCATCTTGTT | Zhang et al. (2012) |
Figure 2.
EL of PLBs of Dendrobium Sonia 'Earsakul' and 'Jindasweet' cultured in liquid medium (control) or medium supplemented with 150 mM NaCl for 2, 4 and 6 weeks. All data are presented as the means of independent samples (n = 5). The error bars indicate ± standard error. A single asterisk (*) indicates a significant difference at p < 0.05, double asterisks (**) indicate p < 0.01 and triple asterisks (***) indicate p < 0.001 according to a t-test for each cultivar. PLBs, protocorm-like bodies. EL, electrolyte leakage.
Figure 3.
Representative PLBs and their histology by a longitudinal section of PLBs of Dendrobium Sonia 'Earsakul' (A–D) and 'Jindasweet' (E–H), cultured in liquid medium (control, A, C, E, G) or medium supplemented with 150 mM NaCl (B, D, F, H) for 6 weeks. White and black scale bars represent 1 cm and 500 μm, respectively. PLBs, protocormlike bodies; SAM, shoot apical meristem.
Figure 4.
Pigment contents including chlorophyll a (A), b (B), total chlorophyll (C) and carotenoid (D) in PLBs of Dendrobium Sonia 'Earsakul' and 'Jindasweet' cultured in liquid medium (control) or medium supplemented with 150 mM NaCl for 2, 4 and 6 weeks. The contents are fresh weight. All data are presented as the means of independent samples (n = 5). The error bars indicate ± standard error. A single asterisk (*) indicates a significant difference at p < 0.05, double asterisks (**) indicate p < 0.01 and triple asterisks (***) indicate p < 0.001 according to a t-test for each cultivar. PLBs, protocorm-like bodies.
Figure 5.
Relative expressions of CDKA1, TUBB3, EXP, CKX1, rbcL and LEA2 in PLBs of Dendrobium Sonia 'Earsakul' and 'Jindasweet' cultured in liquid medium (control) or medium supplemented with 150 mM NaCl for 24 h. EF1-a was used as a reference gene. All data are presented as the means of independent samples (n = 3). The error bars indicate ± standard error. A single asterisk (*) indicates a significant difference at p < 0.05, double asterisks (**) indicate p < 0.01 and triple asterisks (***) indicate p < 0.001 according to a t-test for each cultivar. PLBs, protocorm-like bodies.