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Hydrogen sulfide greatly enhances plant growth: Key ingredient in mass extinctions could boost food, biofuel production

TGF-FruitImageApr. 17, 2013 — Hydrogen sulfide, the pungent stuff often referred to as sewer gas, is a deadly substance implicated in several mass extinctions, including one at the end of the Permian period 251 million years ago that wiped out more than three-quarters of all species on Earth.

But in low doses, hydrogen sulfide could greatly enhance plant growth, leading to a sharp increase in global food supplies and plentiful stock for biofuel production, new University of Washington research shows.

“We found some very interesting things, including that at the very lowest levels plant health improves. But that’s not what we were looking for,” said Frederick Dooley, a UW doctoral student in biology who led the research.

Dooley started off to examine the toxic effects of hydrogen sulfide on plants but mistakenly used only one-tenth the amount of the toxin he had intended. The results were so unbelievable that he repeated the experiment. Still unconvinced, he repeated it again — and again, and again. In fact, the results have been replicated so often that they are now “a near certainty,” he said.

“Everything else that’s ever been done on plants was looking at hydrogen sulfide in high concentrations,” he said.

The research is published online April 17 in PLOS ONE, a Public Library of Science journal.

At high concentrations — levels of 30 to 100 parts per million in water — hydrogen sulfide can be lethal to humans. At one part per million it emits a telltale rotten-egg smell. Dooley used a concentration of 1 part per billion or less to water seeds of peas, beans and wheat on a weekly basis. Treating the seeds less often reduced the effect, and watering more often typically killed them.

With wheat, all the seeds germinated in one to two days instead of four or five, and with peas and beans the typical 40 percent rate of germination rose to 60 to 70 percent.

“They germinate faster and they produce roots and leaves faster. Basically what we’ve done is accelerate the entire plant process,” he said.

Crop yields nearly doubled, said Peter Ward, Dooley’s doctoral adviser, a UW professor of biology and of Earth and space sciences and an authority on Earth’s mass extinctions.

Hydrogen sulfide, probably produced when sulfates in the oceans were decomposed by sulfur bacteria, is believed to have played a significant role in several extinction events, in particular the “Great Dying” at the end of the Permian period. Ward suggests that the rapid plant growth could be the result of genetic signaling passed down in the wake of mass extinctions.

At high concentrations, hydrogen sulfide killed small plants very easily while larger plants had a better chance at survival, he said, so it is likely that plants carry a defense mechanism that spurs their growth when they sense hydrogen sulfide.

“Mass extinctions kill a lot of stuff, but here’s a legacy that promotes life,” Ward said.

Dooley recently has applied hydrogen sulfide treatment to corn, carrots and soybeans with results that appear to be similar to earlier tests. But it is likely to be some time before he, and the general public, are comfortable with the level of testing to make sure there are no unforeseen consequences of treating food crops with hydrogen sulfide.

The most significant near-term promise, he believes, is in growing algae and other stock for biofuels. Plant lipids are the key to biofuel production, and preliminary tests show that the composition of lipids in hydrogen sulfide-treated plants is the same as in untreated plants, he said.

When plants grow to larger-than-normal size, they typically do not produce more cells but rather elongate their existing cells, Dooley said. However, in the treatment with hydrogen sulfide, he found that the cells actually got smaller and there were vastly more of them. That means the plants contain significantly more biomass for fuel production, he said.

“If you look at a slide of the cells under a microscope, anyone can understand it. It is that big of a difference,” he said.

Ward and Suven Nair, a UW biology undergraduate, are coauthors of the PLOS ONE paper. The work was funded by the UW Astrobiology Program.

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The above story is reprinted from materials provided by University of Washington. The original article was written by Vince Stricherz.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

  1. Frederick D. Dooley, Suven P. Nair, Peter D. Ward. Increased Growth and Germination Success in Plants following Hydrogen Sulfide Administration. PLoS ONE, 2013; 8 (4): e62048 DOI: 10.1371/journal.pone.0062048

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

ScienceDaily: Agriculture and Food News

CAC’s social media outreach enhances retail programs

Social media continues to evolve at a rapid pace, and the California Avocado Commission is taking full advantage of these new opportunities to reach consumers with targeted messages. CAC has expanded its social media efforts to fully support retailers with a variety of customer-specific programs and communications.

Jan-DeLyser-newJan DeLyserA key component of CAC’s social media program is providing timely content to retailers for their shopper outreach. Supermarket registered dietitians have been able to use this content, adapting and personalizing to fit their own communication styles. CAC also supports retailers by geo-targeting Facebook posts to provide information about California avocado availability in specific regions as well as to publicize local retailer events such as demos and cooking schools that encourage California avocado sales.

According to a 2012 study titled “U.S. Grocery Shoppers,” 28 percent of respondents said they use Facebook to gather and share information on food products, nutrition and recipes.

“The sweet spot of social media geo-targeting is the three-way intersection of CAC targeted social media outreach, consumer fans looking to buy California avocados and retailers who merchandise them and want to bring those shoppers into their stores,” Jan DeLyser, CAC vice president of marketing, said in a press release. “We approach this engagement the same way with foodservice operators who feature California avocados on their menus.”

The commission integrates social media with CAC marketing programs, both online and offline, to ensure consistency of message wherever the consumer may be and from whichever device they use. For example, the same key communication points of CAC’s traditional advertising campaign are part of the commission’s social media messaging.

Social media plays an integral part in promoting and engaging users around CAC’s themed promotions and co-marketing efforts such as CAC’s Wake up to Breakfast with California Avocados breakfast promotion, Cinco de Mayo, and the promotion with Naturipe Berries. CAC also recently launched a Fourth of July campaign, with a recipe contest, co-marketing recipe exchanges, tweets and posts.

“By integrating social media into our marketing communications we are able to add a much deeper level of engagement with our consumers,” said DeLyser. “We have had success with our integrated approach and find it to be much more effective than managing social media as an independent silo.”

California avocados now have more than 200,000 very enthusiastic Facebook fans engaging with our product and brand. More than 5,600 Twitter followers help promote CAC recipes and usage tips. CAC also uses Twitter to promote events and activities, both in advance of the events and with live coverage.

Newer social media for CAC include Pinterest, with more than 10,000 followers of the California avocados page. The top category of “pins” on Pinterest is Food & Drink, and 75 percent of respondents to a 2013 survey conducted by reported that the site inspired them to try new dishes. Importantly this social media outlet skews heavily to women and drives considerable traffic to the Commission website.

Instagram has been added to the CAC social media line-up and appeals to an expanded demographic. DeLyser calls it “a grand slam” that reaches a younger demographic, including more men, African Americans and Hispanics than Pinterest. CAC already has more than 7,800 followers on Instagram, which now has 100 million monthly active users.

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