How to identify the Root of Orchid

The root of the genus Cymbidium is stout and fat. Generally, there is no distinction between the main root and the branch root.

The internal structure of Langen is a typical Monocotyledon type. Its cortical cells are more developed, and there are symbiotic fungi called root fungi. Those that grow in the ground are called ground roots, and those that grow in the air are called aerial roots. No matter ground root or aerial root, its internal structure is basically the same, which can be divided into outer layer, middle layer and inner layer.

The outermost layer is the root integument tissue, which originates from the epidermis. The cells of the root tissue are long cylindrical and polygonal, arranged outward from the center and arranged radially. When the root cover cell matures, the protoplast disintegrates and the cell develops thickened stripes. The function of root cover tissue is to protect the cortex, absorb water, reduce and protect the loss of water in the cortex.

The middle layer of Langen is cortical tissue, and the cells are relatively well developed. there are about 20 layers of polygonal cells, which are about 3 times thicker than the root tissue, accounting for most of the root. The outermost layer next to the root cover tissue is the outer cortex, which is composed of monolayer cells, arranged radially, neatly and larger than ordinary root cover cells; the inner layer is the cortex, some of which contain acicular crystals, some contain chloroplasts, and some contain symbiotic root fungi.

The inner layer of Langen is the central column, the outermost layer of the central column is connected with the cortex, and the Kjeldahl zone on the endothelial cells is well developed. Close to the endodermis is a vascular bundle sheath. Both the endothelial layer and the vascular bundle sheath have two different structures of cells. There are parenchyma cells in the phloem periphery and parenchyma cells in the xylem periphery. The thick-walled cells mainly strengthen the strength of the roots, and the parenchyma cells are the transport tissues that transport water and nutrients. Langen has many vascular bundles, and its xylem and phloem are separated and arranged radially. There is fibrous tissue around the xylem and phloem, which forms a column, and the center is the pith of the membrane cells.

Most epiphytic orchids have many aerial roots in addition to underground roots. The function of aerial root, in addition to absorbing, fixing and protecting, has the part of chlorophyll, but also can carry out photosynthesis and make food.