Reproduction

Dendrobium officinale can reproduce two different ways, sexually and asexually.

Sexual Reproduction

Dendrobium officinale is an orchid that can grow up to 9-35 cm in height and 2-5 mm in diameter. Dendrobium officinale blooms between May and June every year. (He, Song, Luo, et al. 2009) Dendrobium officinale mainly reproduces asexually by means of colonal propagation (aka by sympodial or keikis). Although D. officinale does not have flashy colors on its petals, it does have a colorful labellum to attract pollinators (insects such as bees, or birds). Once the pollinators have been attracted, they land on the labellum and collect pollinia from the stamen. The pollinia is then taken by the pollinator to another orchid where it is deposited on the stigma, which is covered in a sticky substance. The pollinia then travels down the pistil to the ovary. Once inside the ovary the pollinia joins with the ovule resulting in fertilization and a seed begins to form.










Pictured right, critical reproductive structures*

1.Tepals
2.Gynostemium
3. Anther
4. Stamen
6. Labellum
7. Ovary
9. Style





In order for the seeds to germinate they must be near a fungi in which they can create a symbiotic relationship. Therefore, the seeds normally fall near the mother orchid in order to benefit from the original fungi too. The seedling begins to germinate and becomes a protocorm. Both the fungi and D. officinale benefit from their new relationship because the fungi assists in absorbing nutrients for the orchid and the orchid provides extra sugars to the fungi. In this relationship, the fungi is incorporated within the roots of D. officinale.



Asexual



Dendrobium orchids are unique in the fact that they can also reproduce asexually. When asexual reproduction occurs, a growth develops along the rhizome called a sympodial. This sympodial becomes the new growth and then in turn are replaced by a other sympodial. At the base of the sympodial a pseudobulb is formed which helps to store food and water.



Photo of sympodial growth on Dendrobium orchid

Dendrobium also can reproduce by a keikis, which is an offshoot off of the mother plant. If the light level is too low Dendrobium can reproduce by keikis instead of flowering to produce a new plant. The keikis forms from sprouting along the length of the stem. An accumulation of growth hormones is at the base of the keikis, which produces the new growth.

                                               Photo of keikis growth on Dendrobium stem.

Keikis picture courtesy of Kennis Wong,  Sympodial picture courtesy of David K. Sharpio, Orchid picture courtesy of Jennifer Possley.

To find out more about the ways that D. officinale interact fungi or other organisms check out my interactions page.

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*Structures are of flower Dactylorhiza sambucina, not Dendrobium officinale.