Question

The flowers of Oxalis open during the day and close at night. Such type of movement is
A. Photonasty
B. Nyctinasty
C. Phototropic
D. Seismonastic

Answer 1

Hint: It is native to many countries in southern South America. This woodsorrel is usually grown as a houseplant but may be grown outside, preferably in light shade.

Complete answer:
To answer this question we need to discuss Oxalis in detail.
Leaves of the many plants move in response to light. This is often particularly noticeable within the "sleep movements" which will be observed between day and night in many plants. Sleep movements include closing and/or bending of flowers and folding of leaves.

Oxalis triangularis, commonly called false shamrock, may be a species of edible perennial plant within the wood-sorrel family. It's deep maroon leaves that are trifoliate. Also, the leaves close like an umbrella at midnight or when disturbed or if kept under harsh sunlight. The white or pale pink five-petalled flowers also close at nighttime.

Therefore, the leaves of O. triangularis move in response to light levels, opening in high ambient light (in the day) and shutting at low light levels (at night). During this movement, the leaflets fold at the extent of the central vein. This movement isn't because of growth and is instead powered by changes in turgor pressure in cells at the bottom of the leaf. It's an example of photonasty.

Therefore, the correct option is a, photonasty.

Note: Cultivation: O. triangularis requires bright indirect sunlight supplemented with a cool indoor temperature of 15 °C (59 °F). It can tolerate higher indoor temperatures but will come in dormancy prematurely and/or begin to require a "tired" appearance if temperatures exceed 27 °C (81 °F) for prolonged periods of your time. It thrives in a mean potting soil with good drainage.
Mature plants reduce to the soil every 3–5 years in early summer or during the dormancy period. Young plants reduce to the soil each year in early summer or during the dormancy period until they reach maturity. Fearing frost, they're usually grown indoors. they're planted in soil rich in humus and well-drained. They must be watered only if the topsoil looks dry. In winter, they ought to not be watered.

Usage: The leaves are eaten raw or cooked and have an acidic taste thanks to their acid content. Leaves and flowers are used as decoration for salads. When consuming larger amounts of leaves, ethanedioic acid can cause discomfort. The rhizomes are eaten raw or cooked and have a sweet taste.