Caltech Science Question of the Month: When Do Plants Flower?
Question: How does a plant “know” when it is time to bloom? Answer: Many factors work together to “tell” a plant when it is time to flower, including the amount of food and water available, light, temperature, and a plant’s age. But just how a plant senses many of these things remains a puzzle. To begin with, food and water regulate flowering time in many plants. For example, starved plants often flower earlier than well-fed ones. Somehow the lack of nutrients forces early blooming, as the plant tries to reproduce before it dies an early death. Daylight affects all plants. Most people know that green chlorophyll absorbs light to make energy for the plant, but the light sensors that influence flowering are independent of photosynthesis. In fact, it is these other sensors that tell a seedling that it is above soil after it has sprouted, so that it can turn green and begin to photosynthesize. There are several classes of plant photoreceptors—proteins that sense light. Proteins called phyt
Question: How does a plant “know” when it is time to bloom? Answer: Many factors work together to “tell” a plant when it is time to flower, including the amount of food and water available, light, temperature, and a plant’s age. But just how a plant senses many of these things remains a puzzle. To begin with, food and water regulate flowering time in many plants. For example, starved plants often flower earlier than well-fed ones. Somehow the lack of nutrients forces early blooming, as the plant tries to reproduce before it dies an early death. Daylight affects all plants. Most people know that green chlorophyll absorbs light to make energy for the plant, but the light sensors that influence flowering are independent of photosynthesis. In fact, it is these other sensors that tell a seedling that it is above soil after it has sprouted, so that it can turn green and begin to photosynthesize. There are several classes of plant photoreceptors—proteins that sense light. Proteins called phyt
