Question

1. Describe the different molecular interactions that a water molecule can have inside a plant body. What is it attracted to? When is it in a liquid phase? When is it in a gas phase?

2. Name some molecules/conditions that trigger stomata to open. Name some that trigger stomata to close.

Answer 1

Inside a plant body, water source three types of interactions -

1. Hydrogen bonding - it is the bond present between hydrogen atom and oxygen atom of water molecule. It is present within the water molecule which is called as intramolecular hydrogen bonding and also between water molecules which is called intermolecular hydrogen bonding.

2. Adhesion - water molecules are able to attach two different types of molecules present in the plant body like xylem vessels and tracheids. Because of this, they move upstream from roots to the aerial parts of the plant. This is because water molecules are able to form adhesive interactions with other molecules.

3. Cohesion - water molecule attach with themselves to form a single continuous stream of water inside the plant body. This is because of cohesive forces which can be formed between water molecules.

Stomata opening - high humidity, high water of water in soil

Stomata closing - low humidity, low amount of water in soil, high temperature, bright sunlight

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