Simulation · Biology · Class 11

Which bundle is which?

From the lesson Vascular bundles in Anatomy of Flowering Plants. Change the values and watch what happens.

The idea behind it

NCERT §6.1.3, Figure 6.2

Xylem and phloem are complex tissues; together they make up a vascular bundle.
Open bundle: cambium lies between phloem and xylem, so the bundle can later add secondary xylem and phloem. Found in dicot stems.
Closed bundle: no cambium, so no secondary tissues form. Found in monocots.
Radial arrangement: xylem and phloem lie in separate patches on different radii, alternating round the centre. This is the root pattern.
Conjoint arrangement: xylem and phloem lie together on the same radius. This is common in stems and leaves.
In a conjoint bundle the phloem is usually only on the outer side of the xylem.
Combine the two words for a full description: dicot stem bundles are conjoint and open; monocot stem bundles are conjoint and closed; root bundles are radial.

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