Thursday, March 19

Experts learning that plants are quite limited in ability to adjust to drought conditions

Plants Are Less Prepared for Drought Than Experts Thought
By Brian Stallard
Nature World News
November 15, 2014

As extreme weather patterns continue to change with the global climate and shifting trade winds, drought conditions are expected to become more frequent or even worsen for some parts of the world. That's bad news for a stunning number of plant species, which appear to be even more vulnerable to drought conditions than experts expected.
That's at least according to a study recently published in the journal Ecology Letters, which details how plants "plasticity" their ability to adapt to changing environments, is disturbingly low when it comes to reacting to sudden drought.
According to the study, plants are traditionally "masters of plasticity." Senior author Lawren Sack explained in a recent release that they can change their size, branching patterns, leaf colors, and even their internal biochemistry to adjust to changes in climate.
That may sound like good news, but while "plants have evolved this amazing ability to sync with their environment... they are facing their limits," Megan Bartlett, the study's lead author added.
This was determined after the researchers and their colleagues compiled a set of data from numerous species from various ecosystems around the world. They found that plants can effectively adapt to increased rainfall by increasing their tolerance to salinity concentrations. However, when the opposite happens, the very nature of their cell structure means there is little they can do.
That's because the strength of their cell walls - what keeps a plant's stem rigid - is dependent on high saturation of water. If a plant continues to grow without enough moisture to fill these new cells, the plant wilts.
"During a drought, plants have to choose between closing their stomata and risking starvation, and continuing to photosynthesize and risking cell damage from wilting," said Sack.
The researchers measured the "turgor loss point" - the level of dehydration that causes leaves to wilt in their data set and found that adjustments of this point loss are small at best.
"This means they have only limited wiggle room as droughts become more serious," Sack added. "On the plus side, this discovery means we can estimate species' drought tolerance relatively simply. We can make a reasonable drought tolerance measurement for most species regardless of time of year or whether we are sampling during wet or dry conditions."

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