Aerial Stem Modifications
The aerial stem is a stem that grows vertically or erect above the earth. The two types of aerial stems are reduced stems and erect stems. Aerial stem modifications serve a variety of unique purposes, including climbing, food storage, plant protection, and vegetative propagation. The aerial stem can be modified in 6 different ways.
Stem Tendrils
Tendrils, which are green structures that resemble leafless threads and are utilized for climbing, are modified versions of the plant’s stem or branches. A scale leaf can be observed at the branching point of these tendrils, which can also be unbranched. Tendrils can be categorized into the following four categories.
- Axillary tendrils: Example: Passiflora
- Extra axillary tendrils: Example: Cucurbita
- Floral bud tendrils: Example: Antigonon
- Apical bud tendrils:Example: Grapevine
Thorns
These are sharp, solid, or woody objects that occasionally have leaves and flowers. Additionally, they may branch. Thorns, which are altered axillary buds, are seen on plants including Duranta and Citrus. Thorns are utilized for climbing or defense. They control breathing as well.
Phylloclade
These flattened or cylindrical branches are fleshy in nature. The leaves change into spines or scales, and they control transpiration as well. Phylloclades store water and participate in photosynthesis. Euphorbia, coccoloba, etc.
Cladophylls
These flattened or cylindrical branches, also known as cladodes, aid in photosynthesis. Contrary to asparagus (another cladode), which has one long internode, Ruscus has two long internodes.
Bulbil
These are modified vegetative or floral buds that have food reserves for the plant’s body. They are designed to be multiplied vegetatively. Bulbils split off to form new plants. Example: In lilies, the floral buds develop into bulbils, unlike in Dioscorea, where bulbils are compressed axillary buds.
Thalamus
The corolla, calyx, and androecium, together with other floral organs, are carried by the thalamus, which is a compressed stem axis.
Stem – Characteristics and Functions
The scientific field of morphology is concerned with the examination of the composition, traits, and forms of living things. Despite the great structural variation that amazes us in flowering plants (Angiosperms), they all have a few things in common. Examples include roots, stalks, leaves, flowers, fruits, and seeds. As a result, all angiosperm plant morphologies may share these five characteristics. However, if you look closely at a plant, you’ll note that they always have root and shoot systems, and within them, the plant may or may not have flowers and fruit. Plant morphology helps us understand its complex components. Angiosperms, or flowering plants, are plants that produce flowers. The plant has 5 main parts, i.e., roots, stems, leaves, flowers, fruits, and seeds. These parts perform different functions in their own way. Let’s have a glance over the part “the stem”.