#phytochromes

"The phytoplankton that populate oceans are known to play a key role in marine ecosystems and climate regulation. Like terrestrial plants, they store atmospheric CO₂, and produce half of our planet's oxygen via photosynthesis. However, the mechanisms that control their distribution remain poorly understood.

By studying the light perception process of diatoms, a group of phytoplankton, scientists from the CNRS and Sorbonne University discovered that these microalgae use light variation sensors which are codified in their genomes: phytochromes.

These photoreceptors enable them to detect changes in the light spectrum in the water column, thereby providing information regarding their vertical position within it. This function is especially important in turbulent aquatic environments subject to substantial water mixing—such as high latitude, temperate, and polar regions—in order to adjust their biological activity, in particular photosynthesis."

When plants are grown under artificial lighting, such as LED grow lights, the leaves might turn red in colour, due to a phenomenon known as anthocyanin accumulation. Anthocyanins are water-soluble flavonoid plant pigments that produce the major red, blue and purple colours in flowers, fruits and vegetables to attract pollinators and seed dispersers. An interesting fact about anthocyanins is that…

Plant development is responsive to temperature, and the phenology and distribution of crops and wild plants have already altered in response to climate change.

[...] We used transcriptome analysis to determine whether disrupted thermomorphogenesis in phyABCDE is specific for temperature signaling or is a consequence of misregulated growth pathways.

 Plant ‘thermometer’ triggers springtime budding by measuring night-time heat

An international team of scientists led by the University of Cambridge has discovered the 'thermometer' molecule that enables plants to develop according to seasonal temperature changes.

Researchers have revealed that molecules called phytochromes -- used by plants to detect light during the day -- actually change their function in darkness to become cellular temperature gauges that measure the heat of the night.

The new findings, published today in the journal Science, show that phytochromes control genetic switches in response to temperature as well as light to dictate plant development.

At night, these molecules change states, and the pace at which they change is "directly proportional to temperature" say scientists, who compare phytochromes to mercury in a thermometer. The warmer it is, the faster the molecular change -- stimulating plant growth.