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Plants
with dormant seeds give rise to more species
Plants
with dormant seeds give rise to more species
Date:
April 18,
2014
Source:
National Evolutionary Synthesis
Center (NESCent)
Summary:
Seeds that sprout as soon as they're planted may be
good news for a garden. But in the wild, a plant whose seeds sprouted at the
first warm spell or rainy day would risk disaster. More than just an insurance
policy against late frosts or unexpected dry spells, it turns out that seed
dormancy has long-term advantages too: plants whose seeds put off sprouting
until conditions are more certain give rise to more species.
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Seeds that sprout as soon as they're planted may be good
news for a garden. But wild plants need to be more careful. In the wild, a
plant whose seeds sprouted at the first warm spell or rainy day would risk
disaster. More than just an insurance policy against late frosts or unexpected
dry spells, it turns out that seed dormancy has long-term advantages too:
Plants whose seeds put off sprouting until conditions are more certain give
rise to more species, finds in a team of researchers working at the National
Evolutionary Synthesis Center in North Carolina.
When they
first emerge from the soil, plant seedlings are very vulnerable, said co-author
Rafael Rubio de Casas of the Universidad of Granada in Spain. "They're
like babies. They don't have protective thorns or woody tissue any of the other
defenses that are more typical of adult plants yet."
The tiny
embryos of many plants can lie huddled inside their seed coats in a state of
suspended animation for years before finally springing to life. The oldest
known was a date palm that sprouted from a 2000-year-old seed recovered from
the ruins of a fortress in Israel.
Taking
advantage of data compiled over more than forty years by University of Kentucky
seed scientists Jerry and Carol Baskin, who were also co-authors on the study,
researchers analyzed seed dormancy data for more than 14,000 species of trees,
shrubs, vines and herbs from across the globe.
When the
researchers mapped the data onto the seed plant family tree, they found that
plants with the ability to regulate the timing of germination in response to
environmental cues were more likely to spin off new species.
"Having
the capacity to fine-tune their development to the environment seems to be
crucial for diversification," de Casas said.
Seed
dormancy may help plants colonize new environments by preventing new arrivals
from sprouting under conditions or at times of year when the probability of
seedling survival is low.
The strategy
is as ancient as seeds themselves. "Our results suggest that even the
earliest seeds had this ability," de Casas said.
Plants whose
seeds have since lost the ability may be more prone to extinction under future
climate change, especially if the timing of sprouting is no longer in tune with
their environment, he added.
The study
appears in the journal New Phytologist.
Story
Source:
The above
story is based on materials provided by National Evolutionary Synthesis Center (NESCent). Note:
Materials may be edited for content and length.
Journal
Reference:
- Charles G. Willis, Carol C. Baskin, Jerry M. Baskin, Josh R. Auld, D. Lawrence Venable, Jeannine Cavender-Bares, Kathleen Donohue, Rafael Rubio de Casas. The evolution of seed dormancy: environmental cues, evolutionary hubs, and diversification of the seed plants. New Phytologist, 2014; DOI: 10.1111/nph.12782
Cite This
Page:
National Evolutionary Synthesis
Center (NESCent). "Plants with dormant seeds give rise to more
species." ScienceDaily. ScienceDaily, 18 April 2014.
<www.sciencedaily.com/releases/2014/04/140418141238.htm>.