Adaptation

Dendrobium officinale is a monocot, therefore it does not have secondary tissues and once the orchid has reached maturity the stem will not increase in girth. Dendrobium officinale also develops a pseudobulb and leaves which are also known as the cane. The leaves are covered in leathery cuticle and are dark green in color. The leaves are attached at nodes along the stem. The flowers have a grayish appearance about 3.5-4 cm.










Roots

The root system of D. officinale is very unique due to the fact it is a epiphyte. The roots are made up of secondary roots which means they have branched off from the stem. Velamen, a layer of cells that surrounds the root, is usually white and spongy which helps the root to absorb water and nutrients from its substrate. Although the root is surrounded in velamen, the roots can contain chloroplasts which can photosynthesize.




The roots also have a symbiotic relationship with fungi. Mychorrizae of the fungi incorporates itself within the roots of D. officinale and aids in acquiring nutrients and water from the substrate. In return for the water and the nutrients D. officinale provides extra sugars to the fungi in which both the orchid and the fungi benefit in a mutalistic relationship.








Leaves
The leaves of D. officinale lie very flat in order to maximize absorption of sunlight. Due to the habitat, which is in tropical and subtropical parts of China, D. officinale must have large surface area in order to increase sunlight absorption. The substrate in which Dendrobium officinale lives is a very shady region and the leaves must collect the sun's rays to aid in photosynthesis.

To learn how Dendrobium officinale produces sugars for itself and provide some sugars to the fungi check out my Nutrition page.

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