Modifications of plant parts
Compare the given plants and discuss with your teacher.
Carefully remove a fresh carrot plant from the soil. Observe it. Look at the part we usually consume as ‘carrort vegetable’. However it is not a unripe fruit, but the tap root of the carrot plant. We can see that the tap root of the carrot is swollen. In the case of the carrot plant, the tap root has a different characteristics than the usual plants. Normally, each plant organ, originally evolved to meet certain needs of the plant. For example, roots evolved primarily to anchor the plant and also absorb water and mineral nutrients from soil. Leaves were adapted to optimize photosynthesis.
Stems evolved to reach out to sunlight and also served to conduct water from roots to leaves. However in certain plant species, specific parts have evolved further in unusual and surprising ways to meet certain other specific needs, In some plants root, stem, and leaves change their shape and structure to perform special functions like storage of food, mechanical support, protection and other vital functions. This is known as modification.
What appear as the ‘leaf’ of a cacti are actually their stem and what appear as ‘spine’ on them are actually leaf. Its leaves are modified into spines, an adaptation to reduce transpiration. Photosynthesis is performed by the stem part of the plant.
In this lesson let us study about the modification of root, stem and leaves.