Question

Can a stem of a plant be compared with a street with two way traffic? Give reason.

Answer 1

Hint:-Yes, a stem can be compared with a street with two way traffic as in plants we can see movements of water and minerals in one direction while food moves in the opposite direction. Plants have a special mechanism of transportation of different nutrients along with water, minerals and ions.

Complete answer:
Plants have a special mechanism of transportation of water and minerals to upwards direction whereas transportation of food in downwards direction. Plants have vascular tissues which help in transportation of these elements that is Xylem and Phloem. Xylem helps in transporting the water and minerals from roots to the leaves and other parts of the plant. Phloem helps in transporting the food synthesized by the leaves in the presence of sunlight by the process of photosynthesis to the roots and the stem needed for strengthening of the plant.
Xylem is present at the centre of vascular bundles where the transportation of water and minerals is unidirectional, in these bundles quantity of xylem is more than that of phloem. It also contains parenchyma that provides support to the in the form of long fibres in the soft parts of the plants.
Phloem is present towards the periphery of the vascular bundles and is less in the quantity than the xylem as mentioned above. They are long flexible cells that make up the soft fibres in plants like hemp and flex.

Note:- The transportation of water and minerals which is carried out by xylem tissue is unidirectional whereas the transportation of prepared food like sugars which is carried out by phloem tissue is bidirectional that means it can travel in both the direction upwards and downwards.