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| Nobbies are draught tolerant |
By ScienceDaily, March 15, 2012
Plants subjected to
a previous period of drought learn to deal with the stress thanks to their
memories of the experience, new research has found. The findings could lead to
development of crops better able to withstand drought.
The research also
confirms for the first time the scientific basis for what home gardeners and
nursery professionals have often learned through hard experience: Transplants
do better when water is withheld for a few days to drought harden them before
the move.
"This
phenomenon of drought hardening is in the common literature but not really in
the academic literature," said Michael Fromm, a University of
Nebraska-Lincoln plant scientist who was part of the research team. "The
mechanisms involved in this process seem to be what we found."
Working with Arabidopsis,
a member of the mustard family considered an excellent model for plant
research, the team of Fromm, plant molecular biologist Zoya Avramova and
post-doctoral fellow Yong Ding compared the reaction of plants that had been
previously stressed by withholding water to those not previously stressed.
The pre-stressed
plants bounced back more quickly the next time they were dehydrated.
Specifically, the nontrained plants wilted faster than trained plants and their
leaves lost water at a faster rate than trained plants.
"The plants
'remember' dehydration stress. It will condition them to survive future drought
stress and transplanting," Fromm said.
The team found that
the trained plants responded to subsequent dehydration by increasing
transcription of a certain subset of genes. During recovery periods when water
is available, transcription of these genes returns to normal levels, but
following subsequent drought periods the plants remember their transcriptional
response to stress and induce these genes to higher levels in this subsequent
drought stress.
"All of this
is driven by events at the molecular level," Avramova said. "We
demonstrate that this transcriptional memory is associated with chromatin
changes that seem to be involved in maintaining this memory."
Arabidopsis forgets
this previous stress after five days of watering, though other plants may
differ in that memory time.
This is the first
instance of transcriptional memory found in any life form above yeasts. This
discovery may lead to breeding or engineering of crops that would better
withstand drought, although practical applications of these findings in
agriculture are years away, Fromm said.
"We're a long
way off. We're just starting to get a basic understanding," Fromm said.
"It's possible plants overreact to a first drought stress. They panic,
they slow down more than they need to."
Perhaps scientists
can modify those instincts in plants to help maintain or improve productivity
during times of drought, he added.
But home gardeners
can make immediate use of these findings.
"If I was
transplanting something, I would deprive it of water for a couple of days, then
water overnight, then transplant," Fromm said.
The
work is the subject of an article this week in the online journal Nature
Communications and is funded by the National Science Foundation.
Story Source:
The above story is reprinted from materials provided byUniversity of Nebraska-Lincoln, via Newswise.Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Yong Ding, Michael Fromm, Zoya Avramova. Multiple exposures to drought 'train' transcriptional responses in Arabidopsis. Nature Communications, 2012; 3: 740 DOI: 10.1038/ncomms1732
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