How does Circumnutation work?

Plant organs display helical growth movements known as circumnutation (8-11). These movements help plant organs find suitable environmental cues. The amplitude, period, and shape of the circumnutation depend on the plant species, the plant organs involved, and the developmental stage of growth.

Why do Arabidopsis flowering stems Circumnutation?

Abstract: Circumnutation is a periodic growth movement, which is an important physiological mechanism of plants to adapt to their growth environments. Gravity and photoperiod are two key environmental factors in regulating the circumnutation of plants, but the coordination mechanism between them is still unknown.

Is Circumnutation affected by gravity?

In experiments with the use of the clinostat and centrifuge as well as the microgravity in the circumterrestial orbit, it was repeatedly demonstrated that changes in gravity affected the intensity, period and amplitude of circumnutations.

Which gene is required for primary root formation in Arabidopsis thaliana?

Our data suggest a model in which IAA is required for at least two steps in lateral root development: (1) to initiate cell division in the pericycle, and (2) to promote cell division and maintain cell viability in the developing lateral root.

Is Circumnutation observed in all plants?

Circumnutation occurs in almost all plant organs throughout all stages of development (Johnsson, 1997; Larson, 2000). In the late 19th century, plant scientists noted that plant organs, including roots, shoots, stems, hypocotyls, branches, leaves and flower stalks, did not grow exactly in a linear direction.

What happens to plants in microgravity?

On Earth, aerial parts of the plant (shoots) grow upward while roots grow downward. However, the experiments showed that in a microgravity environment, the growth direction is unregulated, and some roots even extend in the same direction as the aerial stems (Figure 1).

What causes Circumnutation in plants?

Circumnutation refers specifically to the circular movements often exhibited by the tips of growing plant stems, caused by repeating cycles of differences in growth around the sides of the elongating stem.

Which hormone is responsible for shoot development?

Shoot and root development are coordinated by hormones, such as auxin and cytokinins (CKs). Auxin is primarily synthesized in shoots and actively transported to roots where it promotes root development (for recent reviews, see Peret et al., 2009; Coudert et al., 2010).

Which scientist said Circumnutation was due to Gravitropism?

On the other side, Gradmann (1926) introduced the idea that circumnutations could be the result of delayed gravitropic responses: the deviation from the vertical line triggers a correcting movement that, due to a reaction time between perception and actuation, makes the plant overshoot giving rise to self-sustained …

What happens when a plant is grown in space?

In the context of human spaceflight, they can be consumed as food and/or provide a refreshing atmosphere. Plants can metabolize carbon dioxide in the air to produce valuable oxygen, and can help control cabin humidity. Growing plants in space may provide a psychological benefit to human spaceflight crews.

What is circumnutation in plants?

Circumnutation is a helical organ movement widespread among plants. It is variable due to a different magnitude of trajectory (amplitude) outlined by the organ tip, duration of one cycle (period), circular, elliptical, pendulum-like or irregular shape and clock- and counterclockwise direction of rotation.

Does circumnutation amplitude depend on the length of the organ?

The amplitude of circumnutations differs in various plant species and, in a particular species, it does not depend on changes in the length of the circumnutating organ, which was observed in Arabidopsis thaliana.9Changes in circumnutation amplitude have repeatedly been shown to be evoked by various stimuli.

What causes circumnutations in the Earth?

Nowadays circumnutations are more readily presumed to be induced by both the inner oscillator and gravity. , , Following experiments in the circumterrestial orbit, which excluded the indispensability of gravity in generation of circumnutations, a growth-affected symplastic-communication control model was elaborated.