Simulation · Biology · Class 11

Why does a grass leaf roll up?

From the lesson Isobilateral leaf in Anatomy of Flowering Plants. Change the values and watch what happens.

The idea behind it

NCERT §6.2.6, Figure 6.5

A monocot leaf is isobilateral. It is built much like the dorsiventral leaf, with two key differences.
Stomata occur on both the upper and the lower epidermis.
The mesophyll is not divided into palisade and spongy parenchyma.
In grasses, some adaxial epidermal cells along the veins become large, empty, colourless bulliform cells.
When bulliform cells are full of water (turgid), the leaf lies open and its surface is exposed.
When water is short and they go flaccid, the leaf rolls inwards, which reduces water loss.
Because venation is parallel, the vascular bundles in a vertical section are of nearly the same size, except in the main veins.

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