Question

What is aestivation? Describe its various types found in petals.

Answer 1

Hint: The most important part of a flower is sepals and petals. Sepals are modified leaves under which the flower grows. Petals are often sterile floral sections that attract particular pollinators to the flower.

Complete Answer:
Aestivation or estivation is the positional organisation of the sections of the flower inside the bud of the flower before it is opened. That is also the manner in which sepals or petals are arranged in a flower bud with respect to the other members of the same whorl.

Types of aestivation are:
1. Valvate Aestivation:-This is a form of aestivation in which sepals or petals are arranged in a whorl and only meet each other's margin. For example, as seen in Hibiscus sepals.
2. Twisted Aestivation: In this type of aestivation, one margin of each sepal or petal overlaps with the next one and the other margin overlaps with the previous one. Here the overlapping is normal in one direction, either clockwise or anticlockwise For example, as seen in Hibiscus petals.
3. Imbricate Aestivation: In this type, one internal sepal or petal overlap at both margins, and one external sepal or petal with both margins overlap. One margin overlaps the remaining sepals or petals and the other margin overlaps.
4. Vexillary Aestivation: It is known as Vexillary Aestivation when five petals are separated into large standard petals or vexillum that overlap two lateral petals, which in turn overlap the smallest anterior petals.
5. Quincuncial Aestivation: Where the petals are arranged in such a way that two petals are entirely outside the whorl and two are fully within, while one is half outside and half is within.

Note: A petal is a part of a flower that is coloured. Cellulose and other organic matter are produced from petals. Petals are modified leaves that cover the reproductive sections of the flowers.