Sepals

The flower’s outermost component, the sepals, is a small, leaf-shaped, green-colored component. They are the vegetative part of a flower that protects the growing buds and holds the petals in place while the flower is in bloom. The sepals are the leaves that have been changed. Depending on the flower species, the sepals vary in size and shape. They are found in various numbers and are either fused or separated. On a single flower, the calyx is a collection of sepals. 

Structure of sepals:

Sepals are green-coloured vegetative parts of plants that are exclusively found in flowering plants. The calyx is the flower’s outermost layer, which encloses the flower bud and is collectively known as the calyx. A flower’s leaf-like component is called a stamen. The majority of the sepals are made up of parenchyma, secretory cells called laticifers, tannin cells, and other specialised plant cell organelles. The colour of the sepals varies greatly according to the plant species. Chloroplasts, as well as separate palisade and spongy mesophylls, are found in the cells of green sepals. 

The function of sepals:

1. Assist the flowers with their needs.
2. Ensures that the blossom does not dry out.
3. Within the flower, it protects the reproductive organs.
4. Sepals serve as petals in some plants that lack petals.
5. Protect the buds and blossoms from the effects of the environment.
6. Both flowers and fruits are protected by sepals, which produce compounds that fight off predators.
7. Some unusual plant species have sepals that act as thorns and defend the blossom.
8. They form a protective cover for a flower’s bud stage by wrapping themselves around it until it is ready to bloom.
9. In some circumstances, the sepal expands and protects the fruits from honey bees, birds, and other insects. 

Example of sapels:

Acaena species, several Solanaceae (such as the Tomatillo, Physalis philadelphica), and the water caltrop, Trapa natans, are examples. In some species, the calyx not only survives flowering but also grows until it forms a bladder-like enclosure around the fruit, rather than withering. This is an excellent repellent for some birds and insects, as seen in Hibiscus trionum and the Cape gooseberry, for example. The calyx develops into an extra fruit in other species. 

Tepal:

When the parts of the perianth are difficult to discern, such as when the petals and sepals are the same colour or when the petals are absent and the sepals are colourful, the term tepal is used. Lilioid monocots is another term for them because they include Liliales. Genera such as Aloe and Tulipa are examples of plants where the term tepal is applicable. Rosa and Phaseolus, on the other hand, have clearly defined sepals and petals. 

Merosity:

The merosity of a flower is determined by the number of sepals present. The merosity of a plant’s flowers indicates its categorization. A eudicot flower’s merosity is usually four or five. A monocot or palaeodicot flower’s merosity is three or a multiple of three. 

Perianth:

Sepals and petals make compose the perianth or flower envelope. The flower’s petals are usually colourful and conspicuous, whereas the sepals are usually greenish and resemble shrunken leaves. Tepals are the indistinguishable sepals and petals seen in flowers such as lilies and tulips. The stamens, also known as the androecium or male portions of the flower, are made up of a supporting filament and an anther, which produces pollen. 

Conclusion:

The production of sepals is the first step in a plant’s preparation to produce a flower. The top of the stem produces sepals. The sepals come together to form a tightly closed region known as a bud. A flower develops inside the bud. This contains the flower petals as well as the reproductive elements of the flower, such as the stamens and pistils. The sepals offer a protective enclosure for the flower during this stage of development, preventing it from drying out.