Functional role of aquaporins models plant to beech trees: David Israel’s PhD defence

The public PhD defence of David Israel is on Friday 27th Jan 2023 13:15-15:15 EET with opponent Oliver Brendel from INRAE at Nancy, France.

David Israel: The ecophysiology of plasma membrane aquaporins in Arabidopsis thaliana and Fagus sylvatica
Biokeskus 2, auditorio 1041, Viikinkaari 5

This research makes the connection from expression of aquaporins in plant membranes to identify their functional role in plant water use, growth and photosynthesis, under imposed stress and seasonal changes in the environment of both model plants and European beech trees.

David’s research is published in four papers:

Israel D, Lee SH, Robson* TM, Zwiazek* JJ (2022) Plasma membrane aquaporin PIP2;3 facilitates hydrogen peroxide transport into root cells, meaning Arabidopsis knockout mutants lacking this function grow more when under oxidative stress. BMC Plant Biology 22, 566.

Israel D, Durand M, Salmon Y, Zwiazek JE, Robson TM, (2023) Genome-wide identification of Fagus sylvatica aquaporins and their comparative spring and late-summer expression profiles.  Trees: Structure and Function 1-16,

Israel D, Khan S, Warren CR, Zwiazek J,* Robson TM* (2021) The contribution of PIP2-type aquaporins to photosynthesis in response to increased vapour pressure deficit. Journal of Experimental Botany 72(13) 5066–5078. erab187,

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.

David Israel making gas exchange measurements.
David Israel making gas exchange measurements.

Sunflecks in the crops & forests

Fast fluctuations in light condition plant photosynthesis within canopies of crops and in forests. In a series of recent publications, we consider both the dynamics of these changes in illumination and what they mean for plant photosynthesis.

In crop canopies movements in the wind create extremely fast fluctuations defined as windflecks, while in forests the greater canopy depth means that differences in spectral composition between sunflecks and shade can be important for the ecophysiology of photosynthesis and its induction.

Our three recent publications below take the first steps towards describing the processes involved at the canopy level. They (1) defines sunflecks, (2) explain how they are modified by (5) a crop canopy and (4) a forest canopy. We also consider how (3) leaf morphology, (6) pigmentation and senescence change when we manipulate light quality under the canopy.

(1) 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

(2) 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, 4411), 3524– 3537

(3) 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

(4) Durand M, Stangl ZR, Salmon Y, Burgess AJ, Murchie EH, and RobsonTM. (2022) Sunflecks in the upper canopy: dynamics of light-use efficiency in sun and shade leaves of Fagus sylvatica. New Phytologist. 235:1365–1378. Major Revision 04/03/2022, Accepted 08/05/2022.

(5) Durand M, Robson TM (2023) Canopy architecture determines how wind affects sunflecks. Revised for New Phytologist, 08/01/2023.

(6) Brelsford CC, Trasser M, Paris T, Hartikainen SM, Robson TM. (2022) Understorey light quality influences leaf pigments and leaf phenology in different plant functional types. Physiologia Plantarum, 174( 3), e13723.

Monitoring understorey traits
Craig Brelsford of the University of Helsinki, CanSEE group scores spring phenology in the CostE52 European beech provenance trial in La Rioja Spain

Plant species adaptation to high irradiances in the French Alps

Among plant species there are large differences in photoprotection against high irradiance and UV radiation. To explore how these differences are driven by taxonomic relatedness, geographical origin, and local environment we compared a huge database of plant species growing in alpine and boreal botanical gardens.

Hartikainen SM, Robson TM (2022) The roles of species’ relatedness and climate of origin in determining optical leaf traits over large set of taxa from high elevation and latitude. Frontiers in Plant Science 13 .

Santa Neimane and Twinkle Solanki recording diurnal patterns in leaf optical properties of alpine plants under UV filters

The Station Alpin du Lautaret in the French Alps, is 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.


Pedro J Aphalo measures solar radiation; to better understand how reflection from the snow pack affects exposure of plants in the environment.


We collaborated 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.

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.

Solanki T, García Plazaola JI, Robson TM*, Fernandez-Marin B* (2022) Comparative Assessment of Changes in Leaf Transmittance in Alpine Plant Species Following Freezing. Photochemical & Photobiological Sciences.

Fernández-Marín B, Sáenz A, Solanki T, Robson TM, García-Plazaola JI, (2021) Alpine forbs rely on different photoprotective strategies during spring snow melt. Physiologia Plantarum. 172, 1506-1517.

Photodegradation contributes to forest leaf litter decomposition

Qing-Wei Wang and Marta Pieriste inspecting leaf-litter decomposition filters in the understorey site of a Japanese beech forest

The spectral composition of light in a forest gap and understorey through the year affects 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  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

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 research supports findings of our meta-analysis, that 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.

Wang Q-W, Robson TM, Pieristè M, Kenta T, Kurokawa H. (2022) Photodegradation dynamics below a forest canopy. Science of the Total Environment 820 153185.

Wang Q-W*, Pieristè M*, Kotilainen TK, Forey E, Chauvat M, Kurokawa H, Robson TM, Jones AG. (2022) The crucial role of blue light as a driver of litter photodegradation in terrestrial ecosystems.  Plant & Soil,

Defining the success of the Montreal Protocol as a global climate treaty

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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.

This success story is explained in our recent piece: Barnes et al., (2021).  Global Change Biology275681– 5683

The recent Nature paper Young et al., 2021 considering the “World Avoided” by the Montreal Protocol was further explored by Simon Clark below.

Tribute to Martyn M. Caldwell

You can read here a tribute to the life and research career of Martyn M. Caldwell who died earlier this year, in a piece written by Paul Barnes, Steve Flint and myself for the UV4Plants special issue of Physiologia Plantarum.  In addition to his personal qualities, Martyn made a  great contribution to plant ecophysiology and in particular understanding the ecological effects of UV radiation.

Martyn M Caldwell

Barnes, PWRobson, TMFlint, SDMartyn M. Caldwell, 1941–2021, in memoriamPhysiologia Plantarum2021173663– 665

Fitness of beech seedlings growing in Finland

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.

Beech seedlings under drought (front) & well watered (back) treatments.

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.