internode

An internode is the portion of a plant stem between two adjacent nodes. Nodes are the points on a stem from which leaves, buds, or branches emerge, while internodes are the intervening stem segments. Internodes contain vascular tissues, including xylem and phloem, and they contribute to the stem’s length and overall architecture.

The length and structure of internodes influence leaf spacing, light interception, and stem stability. In many plants, internode elongation is governed by developmental programs and environmental cues. Hormonal regulation plays a key role; gibberellins promote elongation, while light availability, nutrients, and mechanical stress can modify internode length. Etiolation, growth under low light, often results in longer, thinner internodes as the plant seeks to reach brighter conditions.

Internode length varies widely among species and growth forms. Grasses and some vines can have long internodes that yield tall shoots, whereas shrubs and compact varieties may exhibit short internodes for a denser habit. Management practices, such as pruning and training in horticulture, as well as genetic selection in breeding programs, can alter internode length to optimize canopy structure, lodging resistance, and resource use.

In agricultural contexts, internode length contributes to plant height and stem robustness, influencing harvestability, yield, and mechanical support. In cereals like maize, rice, and wheat, internodes partition the stem into discrete segments that grow in length as the plant matures, while in sugarcane and many woody climbers, elongated internodes form the recognizable cane or culm.

Overall, internodes are a fundamental component of plant morphology, mediating growth between the points of attachment along the stem.