The
conventional methods of orchid propagation are generally executed by seeds,
division of rhizomes and axillary buds from the mother plant, cuttings or
seperation of offshoots. The major disadvantage of those methods is that
they’re time consuming and inefficient [1] [2] [3]. Because of the complexiy
and the dependence on many factors (e.g. fungal stimulants [6]) for a
succesfull propagation, in nature only 2 to 5% of the seeds germinate [4] [5].
Due to those disadvantages the available Paphiopedilum on the market originate
almost excusively from in vitro
propagation and cultivation methods. One of those methods is the in vitro plant regeneration from callus
culture.
The first
method is the plant regeneration from callus culture. Green seed-capsules were collected and
sterilized with ethanol. The caspules were then cut open and then placed on an
agar plate. These cultures were then illuminated for 3 months and the
seed-derived protocroms were used for callus induction. Also stems, root tips
and green leaves werde used for callus formation. It became apparent that calli
that was cultured on media containing both 2,4-D and TDZ proliferated the best
[7].
Another
method that had shown to be succesfull is a plantregeneration through direct
shoot bud formation from leaf cultures [8]. Leaf explants (1.5cm & 0.5cm
long) which were excised from intact leaves were placed on a culture medium. In
this experiment the 2,4-D and TDZ concentrations did not affect the percentage
of shoot bud formation
One of the
main problems with in vitro sowing of
Paphiopedilum orchids is that little
is known about the specific requirements for seed germination. These lesser
known requirements lead to low surviving rates of the seedlings [7], aswell as
to low percentages of seeds that germinated beforehand [1]. An aproach to solve
that these issues, is that there must be done more scientific research in terms
of specificly searching for the perfect conditions.
References
[1] Zeng, S., Huang, W., Wu, K., Zhang, J., Teixeira da
Silva, J. A., & Duan, J. (2015). In vitro propagation of Paphiopedilum orchids. Critical reviews in
biotechnology, (0), 1-14.
[2] Asghar,
S., Ahmad, T., Hafiz, I. A., & Yaseen, M. (2013). In vitro propagation of
orchid (Dendrobium nobile) var. Emma white. African Journal of Biotechnology,
10(16), 3097-3103.
[3] Schoser,
G. (1993). Orchid Growing Basics. Sterling Publishing Company, Inc.
[4] Pant,
B., & Thapa, D. (2012). In vitro mass propagation of an epiphytic orchid,
Dendrobium primulinum Lindl. through shoot tip culture. African Journal of
Biotechnology, 11(42), 9970-9974.
[5] McCormick,
M. K., Whigham, D. F., Sloan, D., O'Malley, K., & Hodkinson, B. (2006).
Orchid-fungus fidelity: a marriage meant to last?. Ecology, 87(4), 903-911.
[6] Dearnaley,
J. D. (2007). Further advances in orchid mycorrhizal research. Mycorrhiza,
17(6), 475-486.
[7] Lin, Y.
H., Chang, C., & Chang, W. C. (2000). Plant regeneration from callus
culture of a Paphiopedilum hybrid. Plant cell, tissue and organ culture, 62(1),
21-25.
[8] Chen,
T. Y., Chen, J. T., & Chang, W. C. (2004). Plant regeneration through
direct shoot bud formation from leaf cultures of Paphiopedilum orchids. Plant
Cell, Tissue and Organ Culture, 76(1), 11-15.
