2.5. Culm

  2.5. Culm

 

  A culm is a jointed stem of rice made up of a series of nodes and internodes. The node is solid portion of the culm. The node or nodal region bears a leaf and a bud. From the axils of nodes on the culm may arise a leaf, a tiller, or crown roots. The bud is between the node and the base of a leaf sheath. The bud may give rise to a tiller. Internodes are the elongated parts between two nodes. The internodes of a culm vary in length from the lower internodes to the upper ones. Generally, the basal internodes are short and thickened into a soid section. There are normally 4 to 6 elongated internodes at harvest. The uppermost internode is the longest. The longer the lower internodes, the greater the tendency for the plant to lodge. Closer planting, cloudy weather, higher nitrogen level in the soil, and higer temperatures will cause longer internodes.