• Plants evolved ability to actively contr

    From ScienceDaily@1:317/3 to All on Thu Aug 26 21:30:32 2021
    Plants evolved ability to actively control water-loss earlier than
    previously thought

    Date:
    August 26, 2021
    Source:
    University of Birmingham
    Summary:
    New research has shed light on when plants first evolved the
    ability to respond to changing humidity in the air around them,
    and was probably a feature of a common ancestor of both flowering
    plants and ferns.



    FULL STORY ==========================================================================
    New research has shed light on when plants first evolved the ability to
    respond to changing humidity in the air around them, and was probably
    a feature of a common ancestor of both flowering plants and ferns.


    ==========================================================================
    Key to the regulation mechanism are tiny holes, or pores, on the surface
    of leaves, called stomata. These enable the plant to regulate the uptake
    of CO2 gas as fuel for photosynthesis, and the loss of water vapour -- a constant balancing act that requires the pores to open and close according
    to changing conditions. This ability is important to agriculture because
    it helps crops to use less water to grow.

    Plants first evolved stomata soon after they moved from water to land,
    some 450 million years ago, but scientists are still uncertain about
    the evolutionary pathway they took and the point at which plants became
    able to choose whether to open or close the pores in response to their environment.

    In the most recently evolved plants -- flowering plants -- stomata
    closure in response to drought is actively triggered by a number of
    internal signals, including a hormone called abscisic acid (ABA), but scientists have been struggling to understand if this mechanism is also
    present in older groups of plants. In a new study, published in Current Biology, researchers at the University of Birmingham have found evidence
    that the fern species Ceratopteris richardii actively closes its stomata
    using similar signals.

    This semi-aquatic tropical fern has recently become the first model for exploring genetic control of development in the fern family, and is now
    helping scientists to unpick the long evolutionary history between the
    earliest land- living plants (mosses, liverworts and hornworts) and the
    modern flowering plants that dominate today's ecosystems.

    The team used RNA sequencing technology to identify the genetic mechanisms behind different stomatal responses and was able to demonstrate the fern's ability to close stomata in response to low humidity or in response
    to ABA involves copies of genes already known to control stomata in
    flowering plants.

    The results suggest that both ferns and flowering plants evolved using
    similar stomatal closure methods. This indicates that these mechanisms
    were present - - at least in some form -- in the stomata of the last
    common ancestor of both groups.

    Dr Andrew Plackett, of the University of Birmingham's School of
    Biosciences and Birmingham Institute of Forest Research, led the
    research in collaboration with groups at the University of Bristol and the University of Oxford. He said: "We know that plants have possessed stomata
    for most of their evolutionary history, but the point in evolution where
    plants became able to actively open and close them has been controversial.

    "We've been able to show the same active closure mechanisms found
    in flowering plants are also present in ferns, a much older group of
    plants. Being able to better understand how these mechanisms have changed during plant evolution gives us useful tools to learn more about how they
    work. This will be important for helping our crops to adapt to future environmental changes." Alistair Hetherington from the University of
    Bristol said: "This new work confirms that the earliest plants were
    able to actively control the water they lost through the microscopic
    valve like structures on the surfaces of leaves known as stomata. This
    is important because it shows that the intracellular machinery
    allowing stomata to open and close was present in the earliest land
    plants. The research also shows that, whether stomata respond actively
    or passively is dictated by the environment in which the plants lived." ========================================================================== Story Source: Materials provided by University_of_Birmingham. Note:
    Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Andrew R.G. Plackett, David M. Emms, Steven Kelly, Alistair M.

    Hetherington, Jane A. Langdale. Conditional Stomatal Closure
    in a Fern Shares Molecular Features with Flowering Plant Active
    Stomatal Responses.

    Current Biology, 2021 DOI: 10.1101/2021.03.06.434194 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2021/08/210826111639.htm

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