Posts Tagged: water

New strategies to save the world’s most indispensable grain

Genetic insights help rice survive drought and flood

Plants — they're just like us, with unique techniques for handling stress. To save one of the most important crops on Earth from extreme climate swings, scientists are mapping out plants' own stress-busting strategies.

A UC Riverside-led team has learned what happens to the roots of rice plants when they're confronted with two types of stressful scenarios: too much water, or too little. These observations form the basis of new protective strategies.

“This one crop is the major source of calories for upwards of 45 percent of humanity, but its harvests are in danger,” said Julia Bailey-Serres, UCR geneticist and study lead. “In the U.S., floods rival droughts in terms of damage to farmers' crops each year.”

While it is possible for rice to flourish in flooded soils, the plants yield less food or even die if the water is too deep for too long. This work simulated prolonged floods of five days or longer, in which plants were completely submerged. It also simulated drought conditions.

In particular, the researchers examined the roots' response to both types of conditions, because roots are the unseen first responders to flood and drought-related stress.

Their work is described in a new paper published in the journal Developmental Cell.

One key finding is about a cork-like substance, suberin, that's produced by rice roots in response to stress. It helps protect from floods as well as from drought.

“Suberin is a lipid molecule that helps any water drawn up by the roots make it to the shoots, and helps oxygen from shoots to reach roots,” Bailey-Serres said. “If we reinforce the plant's ability to create suberin, rice has better chances for survival in all kinds of weather.”

The researchers were able to identify a network of genes that control suberin production and can use this information for gene editing or selective breeding.

“Understanding suberin is particularly exciting because it is not susceptible to breakdown by soil microbes, so carbon that the plant puts into suberin molecules in the roots is trapped in the ground,” said Alex Borowsky, UCR computational biologist and study co-author.

“This means that increasing suberin could help combat climate change by removing and storing carbon from the atmosphere.”

The researchers also identified the genes controlling some of rice's other stress behaviors.

“One of our interesting findings is that when rice plants are submerged in water, the root cell growth cycle goes on pause, then switches back on shortly after the shoots have access to air,” Bailey-Serres said.

In the future, the research team plans to test how modifying these stress responses can make the plant more resilient to both wet and dry conditions.

“Now that we understand these responses, we have a roadmap to make targeted changes to the rice genome that will result in a more stress-tolerant plant,” Bailey-Serres said.

Though heavy rains and droughts are both increasing as threats, Bailey-Serres has hope that new genetic technology can increase its resilience before it's too late.

“With genome editing, the fact that we can make a tiny but targeted change and protect a plant from disease is amazing. Though our crops are threatened, new technologies give us reasons to hope,” Bailey-Serres said.

Avocado growers to get irrigation tools, strategies from UC ANR’s Montazar

CDFA grant supports research to optimize water use for iconic California crop

California growers, who account for more than 90% of avocado production in the U.S., will soon be getting some help in weathering the extreme fluctuations of climate change.

Ali Montazar, a University of California Cooperative Extension irrigation and water management advisor, recently received a grant to develop tools and strategies that optimize growers' irrigation practices across Southern California – the state's avocado belt. California avocados are valued at more than $411 million, according to the National Agricultural Statistics Service.

“This region faces uncertain water supplies, mandatory reductions of water use, and the rising cost of water – while efficient use of irrigation water is one of the highest conservation priorities,” Montazar said. “Water is the most critically important input to avocado production.”

Montazar will be conducting field experiments in six commercial fields of Hass avocados, located in San Diego, Riverside and Orange counties, in collaboration with the California Avocado Commission and supported by a California Department of Food and Agriculture Specialty Crop Block Grant.

At the California Avocado Commission's suggestion, Orange County was added to the study to better capture the range of climates and cropping systems across the region, Montazar said.

He hopes to develop “crop coefficients” that avocado growers can use to determine the optimal irrigation for their crop based on a host of factors: soil type and salinity, canopy features, row orientation, slopes, soil and water management practices, and more.

“Growers are unclear on how much water the crop actually needs under those conditions,” Montazar said.

He will incorporate data from the actual water use in the experimental orchards – including information from the newest soil moisture and canopy temperature sensors – to help ensure growers do not under- or overwater their crops. Overirrigating contributes to a devastating disease, avocado root rot, caused by the plant pathogen Phytophthora cinnamomi.

Another component of the grant supports outreach in disseminating these resources and best practices to the broader agricultural community.

“Developing and adopting these tools and information may have a significant impact on water quality and quantity issues and bolster the economic sustainability of avocado production not only in the well-established production region of Southern California, but also in Kern and Tulare counties where new avocado plantings are growing,” Montazar said.

Preliminary findings and recommendations are expected at the end of 2022.

Coastal grape growers can use less water during drought

Study finds using less doesn't compromise quality

California grape growers in coastal areas can use less water during times of drought and cut irrigation levels without affecting crop yields or quality, according to a new study out of the University of California, Davis.

The findings, published today (Sept. 1) in the journal Frontiers in Plant Science, show that vineyards can use 50% of the irrigation water normally used by grape crops without compromising flavor, color and sugar content.

It sheds new light on how vineyards can mitigate drought effects at a time when California is experiencing a severe water shortage and facing more extreme weather brought on by climate change, according to lead author Kaan Kurtural, professor of viticulture and enology and an extension specialist at UC Davis.

“It is a significant finding,” Kurtural said. “We don't necessarily have to increase the amount of water supplied to grape vines.”

Growers will also be able to use this information to plan for the next growing season. “Everybody's worried about what's going to happen next year,” he said.

Kurtural and others from his lab studied irrigation and cabernet sauvignon grape quality at a research vineyard in Napa Valley over two growing seasons, a rainy one in 2019 and a hyper-arid one in 2020.

They focused on crop evapotranspiration, which was the amount of water lost to the atmosphere from the vineyard system based on canopy size. The weekly tests used irrigation to replace 25%, 50% and 100% of what had been lost by the crop to evapotranspiration.

Researchers found that replacing 50% of the water was the most beneficial in maintaining the grape's flavor profile and yield. The level of symbiotic arbuscular mycorrhizal fungi, which help grapevines overcome stresses such as water deficits, was also not compromised. And the water used to dilute nitrogen application was also reduced, making the process more environmentally friendly. 

The water footprint for growing grapes also decreased. For both the 25% and 50% replacement levels, water use efficiency increased between 18.6% and 29.2% in the 2019 growing season and by 29.2% and 42.9% in the following dry year. 

While focused on cabernet sauvignon, most red grapes will respond similarly, he said.  

“In the end, drought is not coming for wine,” Kurtural said. “There doesn't need to be a tremendous amount of water for grapes. If you over irrigate in times like these, you're just going to ruin quality for little gain.”

Members of Kurtural's lab — Nazareth Torres, Runze Yu, Johann Martinez-Lüscher and Evmorefia Kostaki — are also credited as authors. 

University of California Agriculture and Natural Resources provided partial funding.

For more information, contact:

• Kaan Kurtural, Viticulture and Enology, skkurtural@ucdavis.edu
• Amy Quinton, UC Davis News and Media Relations, amquinton@ucdavis.edu
• Emily C. Dooley, College of Agricultural and Environmental Sciences, ecdooley@ucdavis.edu

Interactive map flags locations of tap water contamination

Drinking water safety, especially for children, has become an issue of heightened concern since the water crisis in Flint, Michigan, in 2014. 

The  National Drinking Water Alliance map has recently been updated to add over 235 new points linking to news reports of tap water contamination, with nearly half of the incidents emerging since 2019.

“We created the map to help community members, advocates and decision-makers visualize the tap water contamination landscape, particularly for incidents of lead that exceed state action levels,” said Christina Hecht, UC Nutrition Policy Institute senior policy advisor and National Drinking Water Alliance coordinator.

Residents can zoom in on their state to check for contamination incidents that were reported in the news. Red pins indicate lead contamination in schools and parks. Clicking on a pin on the map produces a pop-up box containing the name of the town, date and link to the news story.

“Although most tap water is safe for drinking, the number of dots on the map show that there are times and places where tap water is not safe,” Hecht said. “The only way to know if tap water has elevated lead is by testing through an accredited lab.”

The interactive map was created by the Nutrition Policy Institute and Informatics and Geographic Information System at the University of California Agriculture and Natural Resources. The map only includes tap water contamination with lead and contaminants regulated by the U.S. Environmental Protection Agency. For example, reports of perfluoroalkyl substances, or PFAS, contaminating drinking water are not included because PFAS are not regulated by the EPA. 

Although a few states now maintain some type of online database of results from school or childcare tests for lead in tap water, to date, there is no national database of lead exceedances in school or childcare drinking water. 

The National Drinking Water Alliance map includes information on state policies and programs to test for lead in school drinking water. Almost one-third of U.S. states have enacted legislation providing policy to test for lead in drinking water in schools and, in some cases, in child-care centers. California tests for lead in drinking water at all public K-12 schools and posts the results online. Policies for mandatory testing have recently passed in Oregon and Vermont. New legislation has been proposed in Wisconsin, Iowa, Nebraska and Connecticut. Voluntary programs are now present in every state, funded by nationwide federal grants supporting testing in child-care facilities and schools.

More information on each state's actions can be found on the interactive map at www.drinkingwateralliance.org/new-map, which was updated by Nutrition Policy Institute intern Laurel Denyer, a recent UC Davis graduate.

For more information about drinking water safety, and to propose additions to the map, please contact the NDWA at DWAalliance@ucanr.edu.

 

New policies can inspire families to provide healthy beverages to children

At fast food and sit-down restaurants across California, kids' meals come with water or milk automatically. At least, that should be the case since state law requires restaurants to offer the healthy beverages by default to reduce the amount of sugary beverages served to children.

California Senate Bill 1192, authored by Sen. Bill Monning (D-San Luis Obispo), went into effect Jan. 6, 2019, but research by the UC Nutrition Policy Institute (NPI) has found that implementation has not been universal and more can be done. The results, along with results from a similar study in Wilmington, Del., were published Aug. 20 on HealthyEatingResearch.org.

Before the law, 10% of menu boards observed by the researchers in California listed only the healthy beverages. Data collected after the law went into effect showed 66% of menu boards list the healthy default beverages. The researchers also collected data on the proportion of cashiers who verbally offered only healthy beverages with kids' meals when orders were placed. This happened only 5% of the time before the law was enacted, and dropped to 1% after.

“Parents look at menu boards and kids look at menu boards, but it is likely that what the cashier says also influences which drink they choose,” said Lorrene Ritchie, NPI director and UC Cooperative Extension nutrition specialist. Ritchie was the lead researcher on the California portion of the study. “In our data collection, we would order a kids' meal and wait for them to offer a drink. But mostly they said, ‘What drink do you want?' instead of ‘Do you want water or milk with that?'”

The law doesn't specify whether the cashier must offer the default beverages, but the spirit of the law suggests they should, as it would likely have a greater impact on the selections that children and parents make, Ritchie said.

According to Gail Woodward-Lopez, an NPI researcher and co-investigator on the study, most restaurant managers expressed support for the legislation, but didn't know much about it.

“NPI in partnership with the California Department of Public Health is working with some local health departments to provide training and materials to help restaurants comply with the letter and spirit of the law,” Woodward-Lopez said. “Our next step is to measure whether this health department support is effective.”

The dire need to direct children away from sugary sodas is clear. Empty calories from soda and other sugar-sweetened beverages is the No. 1 cause of obesity in children, Ritchie said. Obese children are at least twice as likely as non-obese children to become obese adults. Obese children and adults are at greater risk for Type 2 diabetes, heart disease, stroke, high blood pressure, high cholesterol, certain cancers, asthma, low self-esteem, depression and other diseases. The Centers for Disease Control and Prevention names obesity as one of the conditions that increase risk of severe illness from COVID-19.

Many open questions remain, such as how drinks are portrayed on drive-thru signs and offered by drive-thru order takers. The COVID-19 pandemic has also altered the way Americans purchase food, with increased online ordering, delivery and drive-thru usage. In-store kiosk ordering is also growing in popularity.

“The role of default beverage policies in this context is important and not well understood,” Woodward-Lopez said.

Woodward-Lopez and Ritchie are working with colleagues around California and across the country to design follow-up studies of newer food technologies and beverage policies being passed elsewhere, to determine how government policies can protect children's health by steering them toward healthy beverage consumption.

The newly published research was funded by the Robert Wood Johnson Foundation and by the California Department of Public Health with funding from the United States Department of Agriculture.

 

Read more