Apr
19
A Booster for Food and Fuel Production
April 19, 2013 | 1 Comment
Hydrogen sulfide, the gas with a telltale rotten-egg smell often called and found in sewer gas could greatly enhance plant growth in low doses. Hydrogen sulfide remains in higher concentrations a deadly substance implicated in several mass extinctions. At high concentrations – levels of only 30 to 100 parts per million in water – hydrogen sulfide can be lethal to humans.
Hydrogen Sulfide Treatment Comparison. A bean plant treated with hydrogen sulfide (top) is substantially bigger at two weeks after gestation than the control plant (bottom) that was untreated. Image Credit: Frank Dooley, University of Washington. Click image for the largest view.
But in low doses, hydrogen sulfide could greatly enhance plant growth, about a doubling, leading to a sharp increase in global food supplies and plentiful stocks for biofuel production.
The research has published online in PLOS ONE, a Public Library of Science journal.
Frederick Dooley, a University of Washington (UW) doctoral student in biology who led the research, said, “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.”
Dooley’s story starts with examining 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. Serendipity.
“Everything else that’s ever been done on plants was looking at hydrogen sulfide in high concentrations,” he said.
Hydrogen sulfide is interesting, dangerous stuff. At one part per million it emits a telltale rotten-egg smell. Then at higher concentrations beginning at of levels of 30 to 100 parts per million in water hydrogen sulfide is lethal to animals and humans. Its famed for ending the Permian period 251 million years ago wiping out more than three-quarters of all species on Earth.
But 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.
A time-lapse video shows how a seed of dwarf wheat treated with a low dose of hydrogen sulfide begins growing at an accelerated rate compared with an untreated seed.
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.
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.
Professor Ward explains the current understanding that hydrogen sulfide was probably produced when sulfates in the oceans were decomposed by sulfur bacteria and are believed to have played a significant role in several extinction events, in particular the “Great Dying” at the end of the Permian period. Professor 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 believes most significant near-term promise 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. There also wouldn’t be the consumer recoil so likely if used on foods.
The critical insight is the view of the cellular propagation from hydrogen sulfide treatment. Typically when plants grow to larger than normal size, they usually 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.
“If you look at a slide of the cells under a microscope, anyone can understand it. It is that big of a difference,” Dooley said.
1 part per billion isn’t very much and the basic sulfur is cheap. It looks like the plants don’t ‘need’ it so much as respond to a wee whiff of it.
Amazing. Dangerous.
Comments
1 Comment so far
Feedburner
Reddit
Stumbleupon
Here in NC we have plenty of pig waste we would gladly share. As a matter of fact, my neighbor has 5 hog barns and when the wind is right – he shares hydrogen sulfide with me.