Tropism
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In biology, a tropism is a phenomenon indicating the growth or turning movement of an organism, usually a plant, in response to an environmental stimulus. In tropisms, this response is dependent on th
Daisies (Bellis perennis) facing the Sun after opening in the morning showing heliotropism
Phycomyces, a fungus, exhibiting phototropism
Example of gravitropism in the remains of a cellar of a Roman villa in the Archeologic Park in Baia, Italy
Gravitropism
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Gravitropism is a coordinated process of differential growth by a plant in response to gravity pulling on it. It also occurs in fungi. Gravity can be either artificial gravity or natural gravity. It i
Tropism
…tropism in emerging shoots of monocotyledons, including the tendencies for the stalk to grow towards light (phototropism) and the roots to grow downward (gravitropism). In both cases, the directional growth is considered to be due to asymmetrical distribution of auxin, a plant growth hormone. The term "tropism" (from…
Example of gravitropism in a tree from central Minnesota. This tree has fallen over and due to gravitropism exhibits this arched growth.
Gravitropism maintains vertical orientation of these trees. These trees, typical of those in steep subalpine environments, are covered by deep snow in winter. As small saplings they are overwhelmed by the snow and bent nearly flat to the ground. During spring growth, and more so as larger trees, gravitropism allows them to orient vertically over years of subsequent growth.
Banana fruit exhibiting negative geotropism.