What Is The Thalamus In A Flower?
The thalamus is found close to the flower's stem. It consists of a modified stem with separate nodes and internodes. The thalamus provides the flower with nutrition.
The thalamus is the short axis that bears four pairs of floral leaves. It is the inflated end of the peduncle or pedicel, which has four nodes and internodes that are very compressed.
The floral leaves stay spirally or in whorls on the nodes. In certain flowers in which the thalamus is quite long, and the internodes are conspicuous, the axis character of the thalamus becomes particularly apparent.
Anthophore is the internode between the calyx and corolla, androphore is the internode between the corolla and androecium, and gynophore is the internode between the androecium and gynoecium.
Androphore in passionflower is unique from gynophore in Pterospermum. Both androphore and gynophore evolve into the gynandrophore in Gynandropsis.
The thalamus may be somewhat elongated, as in Michelia (B. Champaka), convex in flowers such as China-rose and Datura, cup-shaped in roses, or have a spongy, flat top in lotus.
Flowers may be hypogynous, perigynous, or epigynous according to the structure of the thalamus and the way of insertion of the first three floral sets regarding the gynoecium.
In a hypogynous flower, the thalamus is convex and dome-shaped, and the stigma occupies the leading position of the thalamus, with additional whorls staying inserted sequentially below the pistil. Here, the ovary is termed superior. Examples—China-rose, Datura.
The thalamus of a perigynous flower is concave or cup-shaped, generating rims or flanges on which stamens, petals, and sepals are arranged in additional whorls. It is said that the ovary is inferior.
Examples—pea, roses. The epigynous flower is characterized by hollow, cup-shaped thalamus that entirely unites with the base of the pistil (ovary).
The pistil is located in the stamens, flowers, and sepals. In epigynous flowers, the ovary is inferior. Sunflower, Cucurbita (B. Gourd), and tuberose are examples.
The function of the thalamus in flower
Flowers are the reproductive structures of flowering plants. It is sometimes referred to as a flower. The biological function of a flower is to facilitate reproduction, often by facilitating the union of sperm and eggs.
In angiosperms, the receptacle or torus (an earlier name, thalamus, as in Thalamiflorae) is the section of the stem (pedicel) from which the flower organs develop.
The edible portion of some accessory fruits, like the pome and strawberry, develops from the fruit's receptacle. Rubus species have fruit in the shape of drupelets clustered atop a conical receptacle. In raspberries, the receptacle splits from the fruit upon picking, but in blackberries, it remains connected.
Thalamus grows close to the flower's stem. This archaic name refers to the thickened portion of the flower's stalk known as the receptacle. From here, the flower's structures evolve. In other words, it is an altered stem with distinct internodes and nodes. It is important to feed flowers with nutrients.
Following fertilization, the corolla, androecium, stigma, and style of the gynoecium wither. Some species still include the calyx. In contrast, the pedicel strengthens to support the fruit. The ovary transforms into the fruit on the thalamus, also referred to as the flower's receptacle.
The calyx is composed of four whorls located on the thalamus. The outer whorl consists of sepals. The corolla consists of petals and is the second whorl of a flower.
