Chennai: An international team of scientists has deciphered that a short-cut in the photosynthetic machinery allows the needles of Christmas trees to stay green.
In winter, light energy is absorbed by the green chlorophyll molecules but cannot be utilised by the downstream reactions in the photosynthetic machinery as freezing temperatures stop most biochemical reactions.
This is especially a problem in the early spring when temperatures can still be very low, but sunlight is already strong, and the excess light energy can damage the proteins of the photosynthetic machinery.
The researchers led by Umea University in Sweden showed that the photosynthetic apparatus is wired in a special way which allows pine needles to stay green all year long.
“We have followed several pine trees growing in Umea in northern Sweden over three seasons,” says Pushan Bag, PhD student at Umea University.
“It was essential that we could work on needles ‘straight from outdoors’ to prevent that they adjusted to the higher temperatures in the lab environment before we analysed them for example with electron microscopy which we used to visualise the structure of the thylakoid membrane”.
The study was published in the journal Nature Communications.
The research team combined biochemistry and ultrafast fluorescence analysis, a very sophisticated method that can resolve chlorophyll fluorescence light at a picosecond time scale.