page_title: Phototropism
hierarchical_section_title: Phototropism
caption_attribution_description: English: Exemple of phototropism with a small orchid (Phalaenopsis)&#160;: leaves and flowers grow to the light and aerial roots grow away. Español: Ejemplo de fototropismo con una pequeña orquídea (Phalaenopsis): Hojas y flores crecen hacia la luz y el aire, las raíces crecen alejándose. Français&#160;: Exemple de phototropisme sur une petite orchidée (Phalaenopsis)&#160;: les feuilles et les fleurs se tendent vers la lumière et les racines aériennes la fuient.
context_page_description: Phototropism is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the furthest side from the light. Phototropism is one of the many plant tropisms or movements which respond to external stimuli. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism. Most plant shoots exhibit positive phototropism, and rearrange their chloroplasts in the leaves to maximize photosynthetic energy and promote growth. Some vine shoot tips exhibit negative phototropism, which allows them to grow towards dark, solid objects and climb them. The combination of phototropism and gravitropism allow plants to grow in the correct direction.
context_section_description: Phototropism is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the furthest side from the light. Phototropism is one of the many plant tropisms or movements which respond to external stimuli.  Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism (skototropism). Most plant shoots exhibit positive phototropism, and rearrange their chloroplasts in the leaves to maximize photosynthetic energy and promote growth. Some vine shoot tips exhibit negative phototropism, which allows them to grow towards dark, solid objects and climb them. The combination of phototropism and gravitropism allow plants to grow in the correct direction.
caption: Example on a Phalaenopsis
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