Nav: Home

Cell structure linked to longevity of slow-growing Ponderosa Pines

June 18, 2019

MISSOULA - Slow-growing ponderosa pines may have a better chance of surviving longer than fast-growing ones, especially as climate change increases the frequency and intensity of drought, according to new research from the University of Montana.

Researchers found that ponderosa longevity might hinge on the shape of microscopic valve-like structures between the cells that transport water through the tree.

The study, led by UM alumna Beth Roskilly and Professor Anna Sala, was published in the Proceedings of the National Academy of Sciences this week. The researchers sampled growth rates of ponderosa pine trees of varying ages at two remote sites in Idaho. They also studied structural traits of the trees' xylem - vascular tissue that transports water and minerals through the wood and provides structural support.

Their findings reveal that some young trees grow quickly while others grow slowly. But old ponderosa pine trees - those older than 350 years - are slow growers compared to younger trees, and these individual trees have always been slow growing, even when they were young.

In contrast to predictions, slow-growing trees, whether old or young, did not produce denser, tougher wood, which might have made the trees more resistant to disease or decay. Instead, a key difference between fast and slow growers resides in a microscopic valve-like structure between the cells that transport water in the wood, called the pit membrane. The unique shape of this valve in slow-growing trees provides greater safety against drought, but it slows down water transport, limiting growth rate.

"Ponderosa pines, like people, cannot have it all," said Roskilly, the paper's lead author. "Drought resistance contributes to longevity but also to slow growth. In other words, there is a fundamental tradeoff based on xylem structure. Our study suggests that trees with fast growth become large quickly, which can be beneficial for young trees competing for resources, but they are more vulnerable to drought and can die at earlier ages. On the other hand, trees that grow slowly are more drought resistant, which enhances longevity."

Roskilly earned her UM master's degree in organismal biology, ecology and evolution in 2018, and the study is a result of her degree work in UM's College of Humanities and Sciences.

"Ancient trees are special for many reasons," said Sala, a professor in UM's Division of Biological Sciences and an adjunct professor in the W.A. Franke College of Forestry and Conservation. "They are beautiful, they make the highest quality musical instruments, they help maintain diversity, and they store atmospheric carbon in wood for a long time. But the results of this research also suggest they are special because forest managers cannot make just any ponderosa pine tree live for centuries no matter how hard they try. For ponderosa pines to become centennials, their wood must possess this unique structure."
-end-
Other co-authors in the study include UM alumnus Eric Keeling, a professor at the State University of New York; UM alumna Sharon Hood, a research ecologist with the U.S. Forest Service; and Arnaud Giuggiola, a former visiting master's student from the University of Bordeaux. This project built on dissertation work by Keeling and began as an undergraduate research project started by Roskilly.

The article, "Conflicting functional effects of xylem pit structure relate to the growth-longevity trade-off in a conifer species" can be accessed online at http://bit.ly/2wZWTyZ.

The University of Montana

Related Drought Articles:

Vinegar: A cheap and simple way to help plants fight drought
Researchers at the RIKEN Center for Sustainable Resource Science (CSRS) have discovered a new, yet simple, way to increase drought tolerance in a wide range of plants.
Lending plants a hand to survive drought
A research team led by the Australian National University has found a new way to help plants better survive drought by enhancing their natural ability to preserve water.
New rice fights off drought
Scientists at the RIKEN Center for Sustainable Resource Science (CSRS) have developed strains of rice that are resistant to drought in real-world situations.
Drought linked with human health risks in US analysis
A Yale-led analysis of health claims in 22 US states found that severe drought conditions increased the risk of mortality -- and, in some cases, cardiovascular disease -- among adults 65 or over.
A basis for the application of drought indices in China
The definition of a drought index is the foundation of drought research.
Under the Dead Sea, warnings of dire drought
Nearly 1,000 feet below the bed of the Dead Sea, scientists have found evidence that during past warm periods, the Mideast has suffered drought on scales never recorded by humans -- a possible warning for current times.
Forests worldwide threatened by drought
Forests around the world are at risk of death due to widespread drought, University of Stirling researchers have found.
How much drought can a forest take?
Why do some trees die in a drought and others don't?
Pressures from grazers hastens ecosystem collapse from drought
Ecosystem collapse from extreme drought can be significantly hastened by pressures placed on drought-weakened vegetation by grazers and fungal pathogens, a new Duke-led study finds.
Molecular conductors help plants respond to drought
Salk scientists find key players in complex plant response to stress, offering clues to coping with drier conditions.

Related Drought Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...