How leaves reflect light reveals evolutionary history of seed plants


Date:
October 14, 2020
Source:
University of Maine
Summary:
The way leaves reflect light, known as plant reflectance spectra,
can illuminate the evolutionary history of seed plants, according
to researchers. The researchers found that by measuring the light
spectrum reflected by leaves, they can identify the plant and its
chemistry, evolution and place in the tree of life.



FULL STORY ==========================================================================
The way leaves reflect light can illuminate the evolutionary history of
seed plants, according to an international team of scientists led by a University of Maine researcher.


========================================================================== Plant reflectance spectra, or the light profile leaves reflect across
different wavelengths, capture the change and diversification of seed
plants as a result of evolution, according to Dudu Meireles. The UMaine assistant professor of plant evolution and systematics and colleagues
from the United States, Canada, Switzerland and England explored how
spectra have evolved and diversified over the last 350 million years of
plant evolution.

Researchers found that by measuring the light spectrum reflected
by a leaf, they can identify the plant, learn about its chemistry
and evolution, and pinpoint its place in the tree of life, Meireles
says. Spectra also can be used to "provide breakthrough assessments
of leaf evolution and plant phylogenetic diversity at global scales,"
the group wrote in its report for the study.

Meireles says he hopes to eventually perform these measurements remotely
using unmanned aerial vehicles, airplanes, or satellites.

"We know little about how plant traits and chemistry evolved because
collecting the data is difficult and slow, but spectra enables us to
gather those data at unprecedented rates." Meireles says.

New Phytologist, an international plant science research journal,
published the group's findings in its October 2020 issue and promoted
the study on the cover.

The cover also features art by Adriana Cavalcanti of Orono, an Intermedia
MFA student. According to the journal, the leaf art created from hole
punches of autumn foliage evokes "how light reflectance spectra capture
leaf chemical diversity and reveal the evolutionary history of plants." Cavalcanti says she created the artwork, titled "Biomimicry," last fall
by hole punching a variety of leaves and gluing the different circles
to reclaimed wood to form a multicolored leaf. The ways technology
intertwines with science and nature inspired the piece, she says,
adding how nature observations have influenced several technological advancements.



========================================================================== While working on his plant reflectance spectra research, Meireles
encouraged Cavalcanti, who is also a botanist, to submit "Biomimicry" to
New Phytologist, she says. The journal, which accepts original artwork
that reflects the primary topic of each issue, selected her piece to
represent Merieles' findings.

"When I heard that my work was selected for the cover, it was a big
surprise.

First, because I don't usually see art pieces on the cover of scientific journals. Secondly, because It wasn't created with that in mind,"
Cavalcanti says. "For me, it is just an example of how open minded
we need to be about our own art creations; the importance of leaving
space for people to get their own perception about art." The research
team conducted the study using a dataset of more than 16,000 leaf-
level reflectance spectra, ranging from visible to infra-red light,
from 544 seed plant species in the tropical and temperate latitudes of
the Americas and Europe. They measured leaf spectra using two full-range
field spectroradiometers, leaf clips and artificial light sources.

While spectra highlights the phylogenetic history of seed plants, the
location of the signal presenting that information in spectra can vary
among plant lineages, according to researchers. They found, for example,
that the signal yielding the evolutionary record for the monocot lineage
of plants is located in near-infrared light reflected from their leaves,
but the signal for the gymnosperm lineage resides in short-wave infrared
light reflected from leaves.

To monitor plant diversity, Meireles says scientists have to measure
the full spectrum of light reflected from leaves rather than a handful
of bands.

The team created a model that can help simulate how different evolutionary dynamics, such as convergent adaptation to shade, affect spectra. Their framework also revealed that evolution constrains the variation of spectra
in seed plants to different extents, particularly for the visible region associated with pigments such as chlorophyll and carotenoids.

Meireles and his colleagues hope that increasing availability of high- resolution spectral data not only for leaves, but also at the canopy-
and landscape-levels will help improve how scientists monitor plant biodiversity.

"Ecosystem function, and by extension human wellbeing, depend on
biodiversity.

We must monitor diversity to understand, manage and preserve it, and reflectance spectra is one of the best tools we have to do that job efficiently." Meireles says.


========================================================================== Story Source: Materials provided by University_of_Maine. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jose' Eduardo Meireles, Jeannine Cavender‐Bares, Philip A.

Townsend, Susan Ustin, John A. Gamon, Anna K. Schweiger, Michael E.

Schaepman, Gregory P. Asner, Roberta E. Martin, Aditya Singh,
Franziska Schrodt, Adam Chlus, Brian C. O'Meara. Leaf reflectance
spectra capture the evolutionary history of seed plants. New
Phytologist, 2020; 228 (2): 485 DOI: 10.1111/nph.16771 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201014171316.htm

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