We recently spent the afternoon in Viikki Arboretum, Helsinki, enjoying a spring day just as the trees were coming into leaf. Janne Halme and Bart Vandeput recorded our conversation about forests and their use of light for the Painting Energies Podcast which you can listen to below.
Our improved capacity to measure rapid changes in the under-canopy light environment allows us to look closer at how plants use sunflecks to maximise carbon gain.
Our three recent publications below take the first steps towards describing the processes involved at the canopy level. The first defines sunflecks, the second explains how they are modified by a crop canopy, and the third considers how leaf morphology changes with light quality under the canopy.
Durand M, Matule B, Burgess A, Robson TM (2021) A method to identify and measure sunfleck properties from irradiance time series of fluctuating light in agricultural crop canopies. Ag. For Met. 308-309 108554 https://doi.org/10.1016/j.agrformet.2021.108554
Burgess AJ†, Durand M†, Gibbs JA, Retkute R, Robson TM*, Murchie EH*. (2021) The effect of canopy architecture on the patterning of ‘windflecks’ within a wheat canopy. Plant Cell and Environment,44( 11), 3524– 3537. https://doi.org/10.1111/pce.14168
Wang Q-W, Liu C, Robson TM, Hikosaka K, Kurokawa H (2021) Leaf density and chemical composition explain variation in leaf mass area with spectral composition among 11 widespread forbs in a common garden. Physiologia Plantarum. 173: 698–708 https://doi.org/10.1111/ppl.13512
With COP26 so prominently in the headlines it is prescient to consider the effects of the Montreal Protocol limiting ozone depleting chemicals as both a success in halting the increase in UV radiation & as a global effort to reduce greenhouse gas emissions.
We spent the last two weeks of May 2019 at the Station Alpin du Lautaret in the French Alps, which has been designated a Research Platform for long-term ecological studies under the framework of Horizon 2020 Transnational Access – who funded our research visit through the French National Centre for Scientific Research, CNRS.
Our team of researchers, collaborating with José Ignacio García Plazaola and Beatriz Fernandez-Marin from the University of the Basque-Country, to study how plants response to the steep increases in UV radiation that they receive on emergence from under snow cover in spring.
You can read about our finding in Physiology Plantarum following this link: Full Text Access
By characterising the patterns of response to UV radiation in terms of the photoprotection and UV-screening of plants across a diversity of species, we hope to better understand how and why these response evolved and what environmental cues underpin their induction.
We tested how European beech seedlings from across Europe respond to manipulations of light and watering conditions during the growing season in Finland. Our recent paper in Trees: Structure & Function reports on differences among populations receiving combinations of drought, and sun or shade conditions, including gas exchange, water relations, and UV-abs compounds in the leaf epidermis.
Wang F, Israel D, Ramírez-Valiente J-A, Sánchez-Gómez D, Aranda I, Aphalo PJ, Robson TM. (2021) Seedlings from marginal and core populations of European beech (Fagus sylvatica L.) respond differently to imposed drought and shade. Trees Structure and Function, 35, 53-67. https://doi.org/10.1007/s00468-020-02011-9
The UNEP EEAP 2020 Update has just been published in Photochemical and Photobiological Sciences. This year the assessment includes a section & supplement on the implications of these environmental effects for the COVID-19 pandemic.
Changes in UV radiation and climate have the potential to alter habitat suitability for plant species in terrestrial ecosystems.
Species native to Antarctic are adapted to live under the extreme conditions, but continued changes in UV radiation and climate in this environment could exceed the limits of tolerances and survival of many native species of animal and plants.
Stratospheric ozone depletion affects the Antarctic climate with direct consequences for the environment of terrestrial Antarctic ecosystems.
Plant responses to UV radiation are contingent on other changing environmental conditions, and these effects collectively influence crop quality and production
Acclimation of plants to changes in UV radiation may depend on the adaptation of species to grow in more open or shaded environments and could lead to shifts in functional diversity as vegetative cover changes with climate change and land use.
The sensitivity of pollen to UV radiation and its preservation in the fossil record make it attractive for use in reconstructing UV radiation from the geological past.
Technological advances are allowing for the use of UV radiation to improve agricultural sustainability.
To find out more the open-access publication: Neale, et al. (2021) Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate: UNEP Environmental Effects Assessment Panel, Update 2020. Photochemical & Photobiological Sciences, https://doi.org/10.1007/s43630-020-00001-x
Two PhD students in the CanSEE group will start their studies joining our Academy Project studying how climate change, altering cloudiness and atmospheric features, affects the light use of forest and crop canopies.
The contribution of photodegradation to litter decomposition in a temperate forest gap and understorey
In a study recently published in New Phytologist with our collaborator Qing-Wei Wang, we found that the spectral composition of light in a forest gap and understorey through the year affected the rate of photodegradation of senescent leaf litter material across a variety of native plant species. This finding that photodegradation plays an important role in forest litter decomposition has potentially far-reaching consequences, and could partially explain the hole in the carbon budget in this ecosystem.
Wang QW, Pieristè M, Kenta T, Liu C, Robson TM†, Kurokawa H† (2020) Photodegradation enhances litter decomposition modulated with canopy openness in a temperate forest. New Phytologist. NPH17022 https://doi.org/10.1111/nph.17022
Enhanced decomposition can occur through direct photochemical mineralisation, but in temperate forests effects of increased temperature and the availability of substrates for microbial decompositions can be even more important. These actions of photofacilitation are highly wavelength dependent and the subtilties of these responses can only be identified through very large scale experimental manipulations of sunlight, as was done in this ambitious experiment.