Breeding New Plants to Survive Drought
Genetic engineering and advanced plant breeding techniques appear to be the next frontier in helping food crops and ornamental plants survive drought.
The National Science Foundation is funding research to learn how plants cope with weather extremes. One outcome thus far is the revelation that the cells in one species of clover, which is a close relative of alfalfa, have a kind of “memory” for drought that allows them to recover faster and better from water shortage. Alfalfa is one of the world’s most important forage crops for livestock.
“Plants can actually remember when they’ve been exposed to drought,” says Roger Deal, a geneticist at Emory University. “If you restrict the amount of water an alfalfa plant receives, it’s going to begin to wilt. Then, if you water it and bring it back to life, it’s basically more resistant to drought. We’re trying to learn the basis of this remembrance.”
Elsewhere, scientists at Rutgers University are studying how to genetically modify turfgrass to withstand water with more salt content. This would make it possible to irrigate grass with treated wastewater, for example, or groundwater that is too salty to use for other purposes.
Another group of scientists is studying the agave plant, a native of dry climates and perhaps best known as a key ingredient in tequila. The agave plant can thrive almost without water because it uses a different form of photosynthesis, called crassulacean acid metabolism, or CAM.
Unlike most plants that take up carbon dioxide through stomata in their leaves during the day, CAM plants absorb most of their CO2 at night. This timing shift means CAM plants require between a fifth and a third of the water that other plants need. Scientists are working to isolate this genetic mechanism and transfer it to other plants.
A group of 51 scientists from around the world recently published an article laying out additional research needed to understand the CAM photosynthesis process.
Dead Trees in Bakersfield: A Warning for Other Cities
Water shortages are likely causing the death of thousands of trees in Bakersfield, a city that can’t afford to lose even one. It’s a warning for many other communities as the drought continues.
The city has already removed 900 trees that have recently died because of water stress. Another 1,000 are about to be removed for the same reason.
Bakersfield is a hot city, one of the hottest in California. It’s also among those with the worst air quality in the U.S. Yet the city has long had a love-hate relationship with trees. Whereas other Central Valley cities such as Fresno and Sacramento have planted and nurtured tens of thousands of trees, Bakersfield has always been far behind and has often neglected the trees it does have.
Fresno, for example, has created a program to water important street trees with recycled water from trucks, because sprinklers that would normally irrigate street landscaping have been turned off to save water.
Fire and water officials have been urging Californians to cut back on their landscape watering – but to keep on watering trees. That’s because trees represent a long-term landscaping investment with many benefits. Trees help keep urban areas cool, which improves quality of life and reduces smog. They also actively reduce air pollution by absorbing and filtering some pollutants. And, of course, trees provide important habitats, which are also suffering in this four-year drought.
L.A. Wasn’t the First to Plumb Owens Valley Water
In 1913 the city of Los Angeles finished building the L.A. Aqueduct, a huge system of canals, pipelines and pumps that divert water from Owens Valley to the sprawling SoCal metropolis. But it turns out this was not the first massive plumbing project in the Owens Valley.
A teaching project at U.C. Berkeley has unearthed evidence that Paiute Indians built canals thousands of years ago to manage water in the Owens Valley for agriculture and human sustenance.
Bishop Paiute elder Harry Williams has spent several decades exploring, in his spare hours, the remnants of a sophisticated network of ditches created by the original inhabitants of the valley. Long before the arrival of white settlers, his Paiute ancestors designed these channels to flow at a specific gradient, directing water into the valley from creeks running off the eastern face of the Sierra.
“The ditches were like plumbing” that raised the water table, made the high desert bloom and served Paiute communities’ daily needs, says Williams. Ironically, for many years the modern Paiute themselves had little knowledge of these ancient ditches. “We never were taught,” Williams says
That has changed. The Owens Valley Paiute are now quite familiar with the area’s ancient irrigation system, thanks in large part to contributions by U.C. Berkeley students and staff, collaborating with Williams, since the launch of a spring course, called “Water in the West,” four years ago.
Top image: Medicago truncatula, a type of clover that is a close relative of alfalfa, has a kind of cellular memory that helps it survive water shortage, researchers have found. (Ninjatacoshell via Wikimedia Commons)