“After determining the relative abundance of each of the proteins
involved in photosynthesis, the researchers created a series of linked
differential equations, each mimicking a single photosynthetic step.
The team tested and adjusted the model until it successfully predicted
the outcome of experiments conducted on real leaves, including their
dynamic response to environmental variation.
“The researchers then programmed the model to randomly alter
levels of individual enzymes in the photosynthetic process.
“Before a crop plant, like wheat, produces grain, most of the
nitrogen it takes in goes into the photosynthetic proteins of its leaves.
Knowing that it was undesirable to add more nitrogen to the plants,
Long said, the researchers asked a simple question: "Can we do
a better job than the plant in the way this fixed amount of nitrogen
is invested in the different photosynthetic proteins?"
“Using "evolutionary algorithms," which mimic evolution
by selecting for desirable traits, the model hunted for enzymes that
- if increased - would enhance plant productivity. If higher concentrations
of an enzyme relative to others improved photosynthetic efficiency,
the model used the results of that experiment as a parent for the next
generation of tests.
“This process identified several proteins that could, if present
in higher concentrations relative to others, greatly enhance the productivity
of the plant. The new findings are consistent with results from other
researchers, who found that increases in one of these proteins in transgenic
plants increased productivity.
“ "By rearranging the investment of nitrogen, we could
almost double efficiency," Long said.
“An obvious question that stems from the research is why plant
productivity can be increased so much, Long said. Why haven’t
plants already evolved to be as efficient as possible?
“ "The answer may lie in the fact that evolution selects
for survival and fecundity, while we were selecting for increased productivity,"
he said. The changes suggested in the model might undermine the survival
of a plant living in the wild, he said, "but our analyses suggest
they will be viable in the farmer’s field." ”
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