Dear Student
Plants do not have a heart or blood or a circulatory system to transport the food, minerals and nutrients. So,there is a need for proper transport system for the movement of these particles. They are autotrophs. They prepare their own food. The food that is prepared should be available to all the parts of the plant body. This would be possible only if there is a proper transport system.
In plants, transportation is not only required for gaseous exchange but also for circulation is water, essential nutrients, excretory products within the plants for various purposes, transportation in plants is necessary.
Regards