Living things are metabolizing and exchanging substances with their surroundings every moment. As long as the plant is alive, its components are replaced within a few dozen days.

This has been recognized only in the last 20 years or so. The composition of plants is constantly changing, and chlorophyll is certainly changing.

The soybean sprouts and mung bean sprouts that we usually eat are yellow, and the leaves of plants that grow in the dark are also yellow. Why is this? It turns out that most plants without sunlight, it can not produce chlorophyll. If you put soybean sprouts or mung bean sprouts in the sun for two days, their leaves will also turn green. Being covered and yellow plant leaves by sunlight, the generation of chlorophyll, yellow leaves will become green again.

If you cover the whole plant with aluminum foil, its leaves will turn yellow because they can't breathe and the temperature is too high. And soon the plant will die.