Morphology of Plants
Morphology is the study of the external feature and types. Morphology of plants refers to the study of stem, roots, flower, seed, androecium (stamen) and gynoecium (pistil) of the plant. Let’s first study the stem and sources in this part, and the rest will be in other regions.
Ascending part of the plant. It is positively phototropic and negative geotropic. It is characterized by the presence of the nodes and internodes. Buds are present, which are compact structures. The main function of the stem is to spread out the branches, but can-do other services also like.
Modification of stem:
1. Rhizome – they grow horizontally under the soil surface. Example: turmeric, ginger, ferns.
2. Tuber: the tip is swollen up and function to store food. Example: potato.
3. Corn: they grow vertically under the surface. Diameter is more than its length. Example: gladiolus, crocus, colchicum, amorphophallus.
4. Bulb: the stem is reduced to form the disc, and leaves are scaly and fleshy. Example: onion, lily.
Sub-aerial stem: half underground and a half in the air.
1. Runner – grasses
2. Sucker – chrysanthemum, pineapple, banana.
3. offset – Pistoia and euchronia.
Aerial stem: in this type of stem all the part of the stem is in the air none were in the ground.
1. Phylloclade – stem is modified to the flattened structure to perform the function of photosynthesis. Leaves are reduced to the spine to minimize water loss. Example: opuntia and euphoria.
2. Cladode – they are the one internode tall structure. Example: asparagus.
3. Thorn – stem is modified into a spiral formation and helps in climbing. Example: cucumber, pumpkin, watermelon, grapevines.
Roots are the descending part develop from the radicle of the seed. They are a non-green part. They are positively geotropic and negative phototropic. They do not bear nodes and internodes. The primary function of the roots is to get water and minerals from the soil but perform many other services also.
Parts of roots:
1. Region of maturation – this is the first part of the heart where the heart is attached to the plants directly. It is the oldest root part of the plant. It helps in the maturation of the plant. It also contains numerous root hair, which helps in the absorption of various types of nutrients from the soil as they increase the surface area of the roots.
2. Region of elongation – this part of the heart is meant for the increase in the length of the sources as its name suggests the zone of elongation means elongation of the period.
3. Area of meristematic activity – this is the part where all the cellular event of the plant takes place. This part of the root is filled with the meristematic tissue.
There is also the presence of the root cap, which helps in protecting the root tip as it penetrates the soil.
Types of roots:
1. Taproots – they are mostly in dicot plants. There is also the presence of primary, secondary, and tertiary roots. Example – mustard.
2. Fibrous roots – they are present mostly in monocot plants. They are developed from the lower nodes. Example – wheat.
3. Adventitious roots – these are the roots that are grown from any other part than the radicle. Example: grasses, banyan tree.
The function of roots:
- Absorption of water and minerals.
- Provide support
- Stimulate the plant growth hormones (PGR)
Storage – some are swollen and store food. Example: radish, beetroot, carrot.
Respiratory root/ pneumatophores: some origins come out of the surface for their respiration. These types of sources are mostly found in marshy areas. Example: Rhizophora, Avicenna.
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