Background: Vanilla planifolia is an important tropical orchid for production of natural vanilla flavor. Traditionally, V. planifolia is propagated by stem cuttings, which produces identical genotype that are sensitive to virulent pathogens. However, sexual propagation with seed germination of V. planifolia is intricate and unstable because of the extremely hard seed coat. A better understanding of seed development, especially the formation of impermeable seed coat would provide insights into seed propagation and conservation of genetic resources of Vanilla.
Results: We found that soaking mature seeds in 4 % sodium hypochlorite solution from 75 to 90 min significantly increased germination and that immature seeds collected at 45 days after pollination (DAP) had the highest germination percentage. We then investigated the anatomical features during seed development that associated with the effect of seed pretreatment on raising seed germination percentage. The 45-DAP immature seeds have developed globular embryos and the thickened non-lignified cell wall at the outermost layer of the outer seed coat. After 60 DAP, the cell wall of the outermost layer of the outer seed coat became lignified and finally compressed into a thick envelope. These features matches the significant decreases of immature seed germination percentage after 60 DAP.
Conclusion: We report a reliable protocol for seed pretreatment of mature seeds and for immature seeds culture based on a defined time schedule of V. plantifolia seed development. The thickened and lignified seed coat formed an impermeable envelope surrounding the embryo, and might play an important role in seed dormancy of V. plantifolia.
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Posted 31 Mar, 2021
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Posted 31 Mar, 2021
On 31 Mar, 2021
On 31 Mar, 2021
On 31 Mar, 2021
Posted 02 Mar, 2021
On 02 Mar, 2021
Received 02 Mar, 2021
On 01 Mar, 2021
On 01 Mar, 2021
Invitations sent on 01 Mar, 2021
On 01 Mar, 2021
On 01 Mar, 2021
On 01 Mar, 2021
Posted 05 Jan, 2021
On 30 Jan, 2021
Received 29 Jan, 2021
Received 11 Jan, 2021
Received 10 Jan, 2021
On 04 Jan, 2021
On 03 Jan, 2021
Invitations sent on 02 Jan, 2021
On 02 Jan, 2021
On 23 Dec, 2020
On 23 Dec, 2020
On 23 Dec, 2020
On 22 Dec, 2020
Background: Vanilla planifolia is an important tropical orchid for production of natural vanilla flavor. Traditionally, V. planifolia is propagated by stem cuttings, which produces identical genotype that are sensitive to virulent pathogens. However, sexual propagation with seed germination of V. planifolia is intricate and unstable because of the extremely hard seed coat. A better understanding of seed development, especially the formation of impermeable seed coat would provide insights into seed propagation and conservation of genetic resources of Vanilla.
Results: We found that soaking mature seeds in 4 % sodium hypochlorite solution from 75 to 90 min significantly increased germination and that immature seeds collected at 45 days after pollination (DAP) had the highest germination percentage. We then investigated the anatomical features during seed development that associated with the effect of seed pretreatment on raising seed germination percentage. The 45-DAP immature seeds have developed globular embryos and the thickened non-lignified cell wall at the outermost layer of the outer seed coat. After 60 DAP, the cell wall of the outermost layer of the outer seed coat became lignified and finally compressed into a thick envelope. These features matches the significant decreases of immature seed germination percentage after 60 DAP.
Conclusion: We report a reliable protocol for seed pretreatment of mature seeds and for immature seeds culture based on a defined time schedule of V. plantifolia seed development. The thickened and lignified seed coat formed an impermeable envelope surrounding the embryo, and might play an important role in seed dormancy of V. plantifolia.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
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