It’s common knowledge that trees and plants are massive carbon sinks. They temporarily store carbon in their wood, roots and leaves, then decompose and transfer a portion of it to the soil where it stays for centuries. Unfortunately, a large percentage of that carbon is released directly back to the atmosphere when the tree dies. Therefore the process is quite inefficient. To address this issue, scientists are coming up with ways to genetically modify trees and plants into carbon sinking machines.
A study, by researchers at Lawrence Berkeley National Laboratory and Oak Ridge National Laboratory, outlines a variety of strategies for augmenting the processes that trees and plants use to sequester carbon dioxide from the air and convert it into long-lived forms of carbon, first in vegetation and ultimately in soil.
There are a number of ways to improve the sequestration process.
- The most obvious one is improving photosynthesis. Growth is most dependent on two factors: light interception and conversion to biomass. To improve light interception, they would make leaves less prone to sun damage because over time exposure causes light capturing proteins to degrade. The energy generated from the light eventually gets converted to biomass, but only at reasonable temperatures and carbon dioxide levels. To ensure that energy doesn’t go to waste when it gets cold out, a specific enzyme, rubisco activase, must be altered. Another important aspect of conversion to biomass is how much of the energy is directed towards storage and structural components since these two sections improve sink strength. Certain hormones are responsible for coordinating the distribution of carbon material. By identifying genes responsible for the release of these hormones, the sink strength can be modified. They can then engineer the plant or tree to release more hormones that instruct construction of storage and structural biomass.
- Roots are the main site of carbon to soil transfer, so getting more biomass in the root system will improve efficiency. It turns out root mass is an inherited trait, so modification is definitely possible once the contributing genes have been identified.
- Trees and plants get stressed out too, and like us their productivity is negatively affect. Improving tolerance to drought, heat and salinity will allow rate of growth to stay relatively constant. This can be achieved by altering the genes that govern when to send out stress hormones
- Biomass that is easy to digest for aerobic organisms will transfer a lot of its carbon to the atmosphere. So engineering trees and plants to synthesize large quantities of lignin, tannins, and other aromatic compounds that make digestion difficult will allow more time for the soil to interact with the biomass.
- Most of the worlds crops are annual plants like corn. The problem with this is annuals is they exhaust carbon based nutrients in the soil and give little back. Alternatively, most perennials have extensive root systems. This makes them ideal because they give back a lot of what they take. Cereals are annual crops that could one day be perennial. They have perennial relatives, but their yields are lower and farmers will always opt for higher yielding crops. If the genes that determine perennial growth were introduced to the annual strain, a significant portion of farmland would be able to maintain carbon based nutrients as opposed to losing them to the atmosphere.
Even if we genetically engineered every tree and plant in the world to have these traits, it wouldn’t halt global warming, but it would certainly help slow it down. Soil sequestration via biomass has many areas that are open to improvement. Recognizing and acting on the areas is just one of the many things that can be done today. We have the ability to improve what nature has established. Lets do it!
Works Cited
Christer Jansson, Stan D. Wullschleger, Udaya C. Kalluri, and Gerald A. Tuskan. Phytosequestration: Carbon Biosequestration by Plants and the Prospects of Genetic Engineering. BioScience, October 2010
"023964704_972509009." http://pictures.wayn.com/. Web. 14 Oct 2010.
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