Scientists Aim To Improve Photosynthesis

vasanth writes "Two new initiatives at the University of Cambridge aim to address the growing demand on the Earth's resources for food and fuel by improving the process of photosynthesis. Four transatlantic research teams – two of which include academics from Cambridge's Department of Plant Sciences – will explore ways to overcome limitations in photosynthesis which could then lead to ways of significantly increasing the yield of important crops for food production or sustainable bioenergy. Despite the fact that photosynthesis is the basis of energy capture from the sun in plants, algae and other organisms, it has some fundamental limitations. There are trade-offs in nature which mean that photosynthesis is not as efficient as it could be – for many important crops such as wheat, barley, potatoes and sugar beet, the theoretical maximum is only 5%, depending on how it is measured. There is scope to improve it for processes useful to us, for example increasing the amount of food crop or energy biomass a plant can produce from the same amount of sunlight."

how about using the plants we have efficiently?

[nido]

Feeding grain to animals in concentrated animal feeding operations [cafothebook.org] is stupid. Farms should be run by farmers [cafothebook.org], NOT "absentee landlords" (like my dad & his two siblings, who inherited some ~200 acres from their parents. Grandma grew up on her farm, while Grandpa's parents owned their farm but never worked it). From the second link:

And yet it is not impossible to imagine a far different food and farming system than the one we have today, beginning with a long-term commitment to pasture-based farming. Many have been advocating for some time for an ambitious transformation in U.S. agriculture: away from soil-eroding feed grains toward deep-rooted perennial pastures; converting large-areas of the High Plains back to grass and grazing operations; diversifying the corn and soybean dominated Midwest. In fact, thousands of family farmers are managing appropriately-scaled, grass-fed meat, dairy and egg farms without raising animals in vile and sordid conditions. A smart pasture operation (SPO)—to pick up on a new phrase—is one of the easiest entry points for beginning farmers in current U.S. agriculture. Start-up costs are relatively modest and markets for healthfully raised animal products are underserved and growing rapidly. These pasture-based rotational grazing systems can be extremely resource efficient, and often have the advantage of not needing the energy- and capital-intensive inputs such as heating, ventilation, and cooling systems, housing construction, imported industrial feeds, and mechanized manure management systems. They rely on sound animal husbandry techniques and integrate farm animals into a healthy landscape, using manure as a source of soil fertility. But this will require whole new generations of farmers willing to join the ranks of this noble profession, and legions of consumers and an financial and production infrastructure to support them.

Many of humanity's health problems stem from the inappropriate use of grain crops. Grain-finished cattle have a fraction of the beta carotene and vitamin A as grass-finished beef.

Feeding cattle directly on land currently used to grow soybeans & corn would be a lot more productive. But I don't think all the "farmers" (who really just hire tenants to plant crops) would approve.

Re:New Pigments!

[Anonymous Coward]

Disclaimer: My group is collaborating with one of the guys from the FA.

It is not so simple as you think. But I see the same type of misunderstanding in many people in the field (especially the kind that is good at getting grants and bad at doing science, there are many of them...).

Leaves are pretty well designed (I mean that not in the intelligent way), and being green is one of them. The pigments that absorb the majority of the light (chlorophylls) have absorption peaks in the blue and red, and the absorption for green is indeed quite low. However, if you look at the total absorption spectrum of a whole leaf you will see the dip in the green is only 10-20% for most leaves. It is even less if you consider the whole canopy. Nevertheless our eyes pick up this small difference so that leaves look green.

The problem with having black leaves (i.e. absorbing all light, some seeweeds do that) is that you get too much energy in the upper most layer of your leaf (a leaf is several hundred micrometers thick), giving you plenty of energy, but other things (enzyme capacity, CO2 levels, etc) become limiting. Thus, this absorbed energy is wasted, or even starts to damage things (lots of electrons flying around is not always a good thing).

Thus, the green "window" allows part of the light to travel into deeper layers of the leaf, which is also often more porous, resulting in more scattering (longer pathlength, thus increasing chance of absorption) of the light. In this way, the green light drives much of the photosynthesis in the lower part of a leaf. Spreading out the light energy over several 100 micrometers makes the leaves much more efficient, but this would not work if the pigments absorbed green light equally well.

That is not to say that nothing in the pigments can be optimized. Crops are often large stands of genetically identical organisms. We want to optimize the growth of the whole group. This is different from what might have been selected for by evolution (in a mixed canopy, a good survival strategy is to overshadow your competitors, i.e. become tall and allocate more pigments to the top). Big increases in grain yields were realized by breeding for shorter plants (little stem, mostly leaves). This would not work in nature because if one genotype starts to cheat (become bigger), the others will be starved of light. A similar gain might be possible by optimizing pigment allocation to allow a better distribution of the light (most plants still put too much in the top).

Re:how about using the plants we have efficiently?

[dkleinsc]

Sorry, but there is no way that pasture systems can be as efficient as the modern intensive farming system.

Sure it can, once you factor in all the costs, rather than the costs that the farmer pays directly. The kinds of costs I'm thinking of here:
- Environmental damage caused by fertilizer runoff
- The wars to secure the oil to create the chemical fertilizers that the farmers depend on
- The depletion of the arable land, so that in a couple more generations the land that's currently used for growing feed corn will be able to grow nothing at all, ending up with another Dust Bowl
- The CO2 emissions from the more intensive farming methods, which are higher for modern agriculture than the entire US transportation system

I could go on. The point is that modern farming appears cheaper because it's effectively convinced everyone else to pay much of the bill in the form of taxes or inflation or deferred costs.