1 September, 2014
A large sector of the forestry industry in SA relies on seed for the
reproduction of trees, and although SA does not harbour the diverse
natural resources from which these material originates, many of you are
involved in or aware of e.g. the work that CAMCORE does in terms of seed preservation. Below a news story and attached a scientific paper about long term seed storage of Arabidopsis thaliana, a
herbacious model plant for scientists. I think the take home message
is that we should not only store seed of plants (trees) that are of
value to us now for the future, as these might be unsuitable in a
changed environment (also think pests and pathogens) decades from
now. We should protect bio-(and thus genetic) diversity and thus conserve
populations within species, which will ensure that the genetic
plasticity of a species to adapt in a future environment is preserved.
Seeds of Hopelessness
banks adequately prepare for the future if wild plant populations are
already lagging behind in adapting to rapid climate change?
By Kerry Grens | August 1, 2014
DOOMED?: Banking a narrow selection of seeds and other plant material may be insufficient in a rapidly changing climate.
In 2006, plant geneticist Johanna
Schmitt, then of Brown University, and her colleagues set out on a
massive gardening experiment that would span four countries and come to
include thousands of Arabidopsis thaliana plants, millions of
fruit specimens, and a lot of chocolate chip cookies. In gardens in
Finland, Germany, England, and Spain, Schmitt's team sowed Arabidopsis
seeds collected from all over Europe and Asia-from as far afield as
Uzbekistan, Tajikistan, and eastern Russia to sites in Western Europe
and Scandinavia. The researchers were testing which seeds would fare
best when grown in each of the four countries. (The cookies were later
used to incentivize Brown undergraduates to manually count the small,
cigar-shape fruits that grew in the gardens-every 10,000 fruits they
counted earned them a treat.)
The team was unknowingly collecting data that could complicate plant
conservation approaches-in particular, banking seeds to later
reintroduce plants whose populations have declined. It turned out that
the Arabidopsis plants from southern collection sites were more fit in all the planting sites than those sites' own native Arabidopsis
varieties, especially at the northernmost sites in Finland. "We were,
frankly, pretty surprised to see this," says Schmitt, now at the
University of California, Davis. She'd expected to see variation in the
performance of the different plants, given that adaptation to the local
environment is a well-established phenomenon. But Schmitt's study showed
what others had speculated: that climate change was already happening
too quickly for evolution to keep up (PNAS, 111:7906-13, 2014).
"There've been a lot of papers suggesting [lagging adaptation] has
been a problem, but ours has been the first to explicitly demonstrate
it," says Schmitt. In her own data, she adds, "this is the first time I
saw [the effects of climate change] tangibly, so starkly."
The results may mean that conservation efforts that employ seed
banking for preservation or reintroduction face an extra challenge in
anticipating and accommodating adaptation lag. For instance, if seeds
had been collected decades earlier from a particular population that has
since fallen behind in its adaptation to the climate, a reintroduction
project might be doomed. "What our results suggest is there's some value
in preserving genetic variety from across the species range," says
"In theory, it would be possible; in practice, it's probably
unachievable because of the huge effort," says Wolfgang Stuppy, a seed
morphologist at the Millennium Seed Bank Partnership at the Royal
Botanic Gardens in the U.K. The partnership is the largest conservation
program of its kind in the world, aiming to bank 75,000 plant species-25
percent of the world's flora-by 2020. Collecting such a massive number
of species is a mammoth project in itself, and multiplying it to include
a variety of regional genotypes is not feasible, he says.
If you're collecting things, perhaps you should be focusing on collecting genotypes from what you think the climate will be.
Indiana University Bloomington
Stuppy admits that adaptation lag could complicate reintroduction
efforts, which incorporate predictive models of climate and plant
fitness to determine if a species might succeed at a particular locale.
Adaptation lag is especially worrisome for plants with long generation
times, such as trees. (Arabidopsis is an annual.) One way for
seed banks to buffer against adaptation lag in the face of climate
change might be to refrain from collecting specimens from colder
northern latitudes, says Leonie Moyle, who studies the genetic basis of
plant adaptation at Indiana University Bloomington. But even that is too
simplistic, she adds, given that climate change is not unidirectional.
"The take-home message is if you're collecting things, perhaps you
should be focusing on collecting genotypes from what you think the
climate will be. That's very difficult."
Juliette de Meaux, who researches the molecular basis of adaptation in Arabidopsis
at the University of Münster in Germany, says the evidence for lagging
adaptation "supports the idea that, actually, seed banks will not
provide a solution because the things we store are not the things that
are adapted" to future climate scenarios. Instead, she says, policies to
preserve species should be based on protecting biodiversity. "[We] have
to maintain populations in situ... making sure that evolutionary
processes can still happen." But just like banking a vast diversity of
plant genotypes, it might be easier said than done.
Download the PDF paper : wilzcek et al 2014