Morning routines vary from person to person — and from plant to plant. In a new image, NASA reveals just how plants wake up in the morning, and why some plants choose to sleep in.
NASA's ECOsystem Spaceborne Thermal Radiometer on Space Station (ECOSTRESS) captured an aerial view of a group of plants west of Lake Superior, which lies near the Canadian-United States borders, that reveals them waking up at different times.
The image highlights the different times that the plants wake up by using different colors. Those in the red and pink areas started waking up at around 7 a.m., while the plants highlighted in green woke up closer to 8 a.m., and those in the blue areas slept in till a little closer to 9 a.m, according to a statement by NASA.
As shown in the image, the plants closer to the water got an earlier start to their day while those further away had their leafy hands on the snooze button.
But what, exactly, does it mean for plants to "wake up?"
Humans are programmed to turn in at the end of every day in order to restore our bodies and minds, plants sort of do the same thing.
Although plants don’t have a central nervous system regulating their sleep like humans do, they similarly operate on a 24-hour circadian rhythm. The circadian rhythm acts like an internal clock — a daily cycle of physical changes that the plants undergo.
Much like our own, a plant’s circadian cycle is ruled by the Sun. During the day, a plant focuses its attention on getting as much sunlight as possible for photosynthesis — the process by which plants use sunlight to convert carbon dioxide and water into food. After the Sun sets, a plant starts going into a food-storage phase, using the stores to grow through a process of metabolization.
As day is breaking, a plant will begin a process called evapotranspiration — essentially plant sweat.
During this process, plants transfer water from the land and send it floating through the atmosphere by evaporating it through the pores on their leaves. This leaves a temperature signature — one that ECOSTRESS' instruments can spot from space.
That process was the main clue behind figuring out the plants’ sleep cycle in the above image.
ECOSTRESS had been observing this plot of land over the summer, and compiled data from each morning. The bulk of data showed which plants woke up first by detecting when their evapotranspiration process began. Plants further out from the lake gradually became more active as the morning progressed.
The ECOSTRESS mission was launched to the International Space Station in June, 2018 with the aim of measuring the temperature of plants on Earth in order to understand how vegetation and agriculture responds to changes in water availability.
This new data not only gives scientists new insight into the daily routines of plants, but it may also help farmers determine how much water their plot of land needs, and which plants use water more efficiently than others and those that require more water before their crops begin displaying signs of dehydration, according to the statement.