Differences in Orchids' Roots & Shoots



Normally, roots are plant parts that grow underground and shoots are erect, aboveground structures. Orchid plant parts broaden the definitions of both of these words. Some orchid roots never permeate the ground, and some shoots division out horizontally rather than taking upright forms. Based on variety, it is at times hard to discern the difference between orchid roots and shoots.

Orchid Family

Since the largest plant family, it is no wonder that orchids exhibit such diversity. The University of Vermont Extension cites 1,000 genera, 25,000 species and 100,000 hybrids in the family. Orchids are grouped into three key types: terrestrial, which grow in soil; epiphytic, which grow on trees ; and lithophytic, which grow on rocks. Roots and shoots of those kinds are adapted for their exceptional growing conditions, and are often so distinctive that they don’t resemble those of family members.

Roots

In nature, epiphytic orchids grow attached to trees. Their aerial roots don’t grow in soil, but they adhere to tree bark or even dangle freely from limbs. Epiphytes are not parasites, which rob trees of nutrients. These orchids utilize trees only as a structural support upon which they grow. They derive their moisture from natural rainfall, and their fertilizer from decaying leaves and dead insects. Terrestrial orchid roots penetrate soil, where they anchor plants into the forest ground. Many terrestrial orchid roots grow from rhizomes, which are modified stems that lie horizontally just under or above the ground.

Shoots

Orchid shoots produce leaves or flower stems, which can also be called spikes. Normally, once a spike has finished blooming, it dies. Phalaenopsis differs from other commercially available orchids since it may decide on a second round of flower buds on a spike after its initial pair of blooms dies. Some orchids, like Phalaenopsis and Vanda, are monopodial plants which have erect shoots. Sympodial orchids, like Cattleya and Dendrobium, produce various structures. Horizontal stems support erect, fleshy stems which are called pseudobulbs, which function as water and food storage organs.

Function

Although orchid structures take various forms depending on genus and species types, their roots and shoots serve similar functions. Whether orchid roots are covered with soil or openly exposed in a soilless surroundings, they absorb and conduct nutrients and water through a plant, and they anchor and support its leading growth. Shoots produce leaves which run photosynthesis to manufacture food; stems which transport nutrients and water through a plant; and spikes that bear flowers, which attract pollinators that finally help produce future plants.

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