Late in January researchers at Cornell University announced the discovery of a gene they have called Scarecrow. The gene controls the photosynthesis structures found in plant leaves. Known as Kranz anatomy, this novel leaf anatomical structure provides plants which have it considerable advantage over those that don't.
To understand the implications you need to know a little more about plant anatomy and physiology. Plants use photosynthesis to harvest the energy from sunlight and CO2 and convert these two into sugar. Plants over time have evolved two different methods of photosynthesis. One is called C3, the predominant method. The other, C4, is an adaptation that gives those plants with it a more efficient production mechanism with the added benefit of being able to better deal with more intense sunlight, high levels of heat, low nitrogen soils and prolonged drought. The C3 photosynthesis mechanism evolved early in Earth's history when there was much more atmospheric CO2 and less free oxygen. The C4 adaptation came later after C3 plants added considerable amounts of free oxygen to the atmosphere.
C4 plants feature an extra layer of bundle sheath cells encircling the core cells involved in converting sunlight and CO2 into sucrose. And C4 plants, unlike C3 produce no byproduct associated with handling oxygen that needs to be further degraded, making the latter 50% less efficient in making sucrose. And although researchers have understood the difference in the two mechanisms what they didn't know was the underlying genetics responsible for C4. The discovery of Scarecrow means that scientists through genetic modification can begin to introduce C4 into C3 plants.
Why is this important? Because wheat and rice, two principle food staples are both C3. With 7 billion human mouths to feed today, and projections of population growth to 9.5 billion by mid-century, and with the increasing impact of global warming on weather patterns, the promise of 50% higher crop yields is significant. C4 versions of C3 plants will grow in a hotter, drier world and will need less nitrogen-based fertilizers.
For those who oppose genetic modifications to food crops, this discovery may further spook them. But I am increasingly convinced by the hard science that GMO represents a key strategy for our species as we progress through the 21st century. Without it we will find the limits imposed by changing climate and finite agricultural land a potential death sentence for billions.
In this cross section of a corn leaf you can see the wreath of cells in lighter red surrounding the plant's vascular core. That wreath consists of bundle sheath (BS) cells. The darker red are mesophyll cells (M). It is the interaction and cooperation between the BS and M that represents the evolutionary advantage that is the C4 mechanism.
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May 27, 2015 - In the last week or so we've seen the convergence of energy companies and climate change action in a number of announcements from the fossil fuel industry. I share these with you because they illustrate the beginning of a change in attitude from positions of keeping the status quo to acknowledgement of the validity of the science of climate change.
May 24, 2015 - What started as a social media phenomenon on many university campuses has blossomed into a global movement by institutions, corporations, foundations, pension funds and even governments. It involves wiping hands clean of stocks and bonds issued by fossil fuel companies.
May 22, 2015 - California has a lot of negatives going on right now. It is in the middle of the worst drought the state has experienced since records were kept, watching its in-state and out-of-state water reserves dry up. It is over populated and yet still a draw for tens of thousands of illegal immigrant crossing from Mexico each year. And it is perennially in debt.
May 22, 2015 - Researchers at Hebrew University of Jerusalem have developed a product that oxidizes soil polluted by oil and other contaminants.
May 21, 2015 - This week in Paris world business leaders have gathered to talk about climate change and investment. Two months ago 266 large investors responsible for managing $20 trillion U.S.
May 20, 2015 - An Antarctic ice shelf located on the continent's peninsula that juts northward towards South America is expected to collapse into the Southern Ocean possibly within the next few decades.