In recent findings, scientists discovered how plants protect themselves from
a possible danger that may be brought by external factors such as stressful
environmental conditions.

In an ideal situation, photosynthesis starts when light is absorbed by the
plant to produce energy molecules. Then these energy molecules make it
possible for the plant to process carbon dioxide found in the air to fix it
into sugars to serve as the plant's energy reserve. During stressful
situations for the plant, the second stage of photosynthesis is affected. In
the absence of light, for example, the second stage photosynthesis slows
down or even completely shuts off. Once the plant detects light again, there
is a build-up of oxygen byproducts. If not neutralized, these highly
reactive oxygen molecules can cause cellular damage to the plant.

It is the second stage of the photosynthesis process that the scientists
focused their study on using the Chlamydomonas algae. They investigated the
functions of two plant proteins that protect plant cells by turning the
reactive oxygen molecules to water: flavodiiron proteins (FLV) and plasmid
terminal oxidases (PTOX). FLV was found to serve as a switch to speed up the
sugar-manufacturing stage once the light is detected by the plant. PTOX, on
the other hand, was likened to the release valve of a pressure cooker that
signals the plant to release the built-up oxygen byproducts caused by the
slow down or shut off of the photosynthesis' second stage.

Upon determination of the roles of these two proteins, scientists have a
better understanding of how plants neutralize self-inflicted cellular damage
as a result of extreme environmental conditions. Such findings can pave a
better direction for other scientists to engineer crops and algae that can
maximize the photosynthetic process to address climate change and higher
yield demands.

[www.pnas.org]