Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Efficient photosynthesis in dynamic light environments: A chloroplast's perspective
Kaiser, Elias ; Galvis, Viviana Correa ; Armbruster, Ute - \ 2019
Biochemical Journal 476 (2019)19. - ISSN 0264-6021 - p. 2725 - 2741.

In nature, light availability for photosynthesis can undergo massive changes on a very short timescale. Photosynthesis in such dynamic light environments requires that plants can respond swiftly. Expanding our knowledge of the rapid responses that underlie dynamic photosynthesis is an important endeavor: It provides insights into nature's design of a highly dynamic energy conversion system and hereby can open up new strategies for improving photosynthesis in the field. The present review focuses on three processes that have previously been identified as promising engineering targets for enhancing crop yield by accelerating dynamic photosynthesis, all three of them involving or being linked to processes in the chloroplast, i.e. relaxation of non-photochemical quenching, Calvin-Benson-Bassham cycle enzyme activation/deactivation and dynamics of stomatal conductance. We dissect these three processes on the functional and molecular level to reveal gaps in our understanding and critically discuss current strategies to improve photosynthesis in the field.

Far-red radiation increases dry mass partitioning to fruits but reduces Botrytis cinerea resistance in tomato
Ji, Yongran ; Ouzounis, Theoharis ; Courbier, Sarah ; Kaiser, Elias ; Nguyen, Phuong T. ; Schouten, Henk J. ; Visser, Richard G.F. ; Pierik, Ronald ; Marcelis, Leo F.M. ; Heuvelink, Ep - \ 2019
Environmental and Experimental Botany 168 (2019). - ISSN 0098-8472
Botrytis cinerea - Dry mass partitioning - Far red - Growth component analysis - LED lighting - Solanum lycopersicum

The addition of far-red (FR, 700–800 nm) radiation to standard growth light triggers a set of photomorphogenic responses collectively termed shade avoidance syndrome. Recent research showed that additional FR increased fruit yield in greenhouse tomato production. However, the mechanism behind this increase is not clear; nor is it known whether there is a trade-off between growth and defense against plant diseases in tomato under additional FR. The aims of this study were 1) to quantify the effect of additional FR on tomato fruit growth, 2) to explain this effect based on underlying growth components and 3) to examine the FR effect on resistance against the necrotrophic fungus Botrytis cinerea. Tomato (Solanum lycopersicum ‘Moneymaker’) plants were grown for four months with 30 or 50 μmol m−2 s−1 of FR added to 150 μmol m−2 s−1 red + blue or white background LED lighting. Growth and development parameters were recorded, and a growth component analysis was conducted. Bioassays for resistance against B. cinerea were conducted on leaf samples collected from each light treatment. Additional FR increased total fruit dry mass per plant by 26–45%. FR affected multiple growth components, among which the fraction of dry mass partitioned to fruits was the most prominent with a 15–35% increase. Truss appearance rate was increased 11–14% by FR while instantaneous net photosynthesis rate was not affected. FR also resulted in more severe disease symptoms upon infection with B. cinerea. In conclusion, additional FR increases tomato fruit production mainly by increasing dry mass partitioning to fruits, rather than improving photosynthesis or increasing total plant biomass. However, FR also reduces resistance of tomato leaves against B. cinerea.

Nitrogen and phosphorus constrain the CO2 fertilization of global plant biomass
Terrer, César ; Jackson, Robert B. ; Prentice, I.C. ; Keenan, Trevor F. ; Kaiser, Christina ; Vicca, Sara ; Fisher, Joshua B. ; Reich, Peter B. ; Stocker, Benjamin D. ; Hungate, Bruce A. ; Peñuelas, Josep ; McCallum, Ian ; Soudzilovskaia, Nadejda A. ; Cernusak, Lucas A. ; Talhelm, Alan F. ; Sundert, Kevin Van; Piao, Shilong ; Newton, Paul C.D. ; Hovenden, Mark J. ; Blumenthal, Dana M. ; Liu, Yi Y. ; Müller, Christoph ; Winter, Klaus ; Field, Christopher B. ; Viechtbauer, Wolfgang ; Lissa, Caspar J. Van; Hoosbeek, Marcel R. ; Watanabe, Makoto ; Koike, Takayoshi ; Leshyk, Victor O. ; Polley, H.W. ; Franklin, Oskar - \ 2019
Nature Climate Change 9 (2019). - ISSN 1758-678X - p. 684 - 689.

Elevated CO2 (eCO2) experiments provide critical information to quantify the effects of rising CO2 on vegetation1–6. Many eCO2 experiments suggest that nutrient limitations modulate the local magnitude of the eCO2 effect on plant biomass1,3,5, but the global extent of these limitations has not been empirically quantified, complicating projections of the capacity of plants to take up CO2 7,8. Here, we present a data-driven global quantification of the eCO2 effect on biomass based on 138 eCO2 experiments. The strength of CO2 fertilization is primarily driven by nitrogen (N) in ~65% of global vegetation and by phosphorus (P) in ~25% of global vegetation, with N- or P-limitation modulated by mycorrhizal association. Our approach suggests that CO2 levels expected by 2100 can potentially enhance plant biomass by 12 ± 3% above current values, equivalent to 59 ± 13 PgC. The global-scale response to eCO2 we derive from experiments is similar to past changes in greenness9 and biomass10 with rising CO2, suggesting that CO2 will continue to stimulate plant biomass in the future despite the constraining effect of soil nutrients. Our research reconciles conflicting evidence on CO2 fertilization across scales and provides an empirical estimate of the biomass sensitivity to eCO2 that may help to constrain climate projections.

Data from: The interplay of landscape composition and configuration: new pathways to manage functional biodiversity and agro-ecosystem services across Europe
Martin, Emily A. ; Dainese, Matteo ; Clough, Yann ; Báldi, András ; Bommarco, R. ; Gagic, Vesna ; Garratt, Michael P.D. ; Holzschuh, Andrea ; Kleijn, D. ; Kovács-Hostyánszki, Anikó ; Marini, Lorenzo ; Potts, Simon G. ; Smith, Henrik G. ; Hassan, Diab Al; Albrecht, Matthias ; Andersson, Georg K.S. ; Asís, Josep D. ; Aviron, Stéphanie ; Balzan, M.V. ; Baños-Picón, Laura ; Bartomeus, Ignasi ; Batáry, Péter ; Burel, Francoise ; Caballero-lópez, Berta ; Concepción, Elena D. ; Coudrain, Valérie ; Dänhardt, Juliana ; Diaz, Mario ; Diekötter, Tim ; Dormann, Carsten F. ; Duflot, Rémi ; Entling, Martin H. ; Farwig, Nina ; Fischer, Christina ; Frank, Thomas ; Garibaldi, Lucas A. ; Hermann, John ; Herzog, Felix ; Inclán, Diego J. ; Jacot, Katja ; Jauker, Frank ; Jeanneret, Philippe ; Kaiser, Marina ; Krauss, Jochen ; Féon, Violette Le; Marshall, Jon ; Moonen, Anna Camilla ; Moreno, Gerardo ; Riedinger, Verena ; Rundlöf, Maj ; Rusch, Adrien ; Scheper, J.A. ; Schneider, Gudrun ; Schüepp, Christof ; Stutz, Sonja ; Sutter, Louis ; Tamburini, Giovanni ; Thies, Carsten ; Tormos, José ; Tscharntke, Teja ; Tschumi, Matthias ; Uzman, Deniz ; Wagner, Christian ; Zubair Anjum, Muhammad ; Steffan-Dewenter, Ingolf - \ 2019
biodiversity - agroecosystem - landscape composition - landscape configuration - functional traits - arthropods - natural pest control - pollination - yields
Managing agricultural landscapes to support biodiversity and ecosystem services is a key aim of a sustainable agriculture. However, how the spatial arrangement of crop fields and other habitats in landscapes impacts arthropods and their functions is poorly known. Synthesising data from 49 studies (1515 landscapes) across Europe, we examined effects of landscape composition (% habitats) and configuration (edge density) on arthropods in fields and their margins, pest control, pollination and yields. Configuration effects interacted with the proportions of crop and non‐crop habitats, and species’ dietary, dispersal and overwintering traits led to contrasting responses to landscape variables. Overall, however, in landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7‐ and 1.4‐fold respectively. Arable‐dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield‐enhancing ecosystem services.
The interplay of landscape composition and configuration: new pathways to manage functional biodiversity and agroecosystem services across Europe
Martin, Emily A. ; Dainese, Matteo ; Clough, Yann ; Báldi, András ; Bommarco, Riccardo ; Gagic, Vesna ; Garratt, Michael P.D. ; Holzschuh, Andrea ; Kleijn, David ; Kovács-Hostyánszki, Anikó ; Marini, Lorenzo ; Potts, Simon G. ; Smith, Henrik G. ; Hassan, Diab Al; Albrecht, Matthias ; Andersson, Georg K.S. ; Asís, Josep D. ; Aviron, Stéphanie ; Balzan, Mario V. ; Baños-Picón, Laura ; Bartomeus, Ignasi ; Batáry, Péter ; Burel, Francoise ; Caballero-López, Berta ; Concepción, Elena D. ; Coudrain, Valérie ; Dänhardt, Juliana ; Diaz, Mario ; Diekötter, Tim ; Dormann, Carsten F. ; Duflot, Rémi ; Entling, Martin H. ; Farwig, Nina ; Fischer, Christina ; Frank, Thomas ; Garibaldi, Lucas A. ; Hermann, John ; Herzog, Felix ; Inclán, Diego ; Jacot, Katja ; Jauker, Frank ; Jeanneret, Philippe ; Kaiser, Marina ; Krauss, Jochen ; Féon, Violette Le; Marshall, Jon ; Moonen, Anna Camilla ; Moreno, Gerardo ; Riedinger, Verena ; Rundlöf, Maj ; Rusch, Adrien ; Scheper, Jeroen ; Schneider, Gudrun ; Schüepp, Christof ; Stutz, Sonja ; Sutter, Louis ; Tamburini, Giovanni ; Thies, Carsten ; Tormos, José ; Tscharntke, Teja ; Tschumi, Matthias ; Uzman, Deniz ; Wagner, Christian ; Zubair-Anjum, Muhammad ; Steffan-Dewenter, Ingolf - \ 2019
Ecology Letters 22 (2019)7. - ISSN 1461-023X - p. 1083 - 1094.
Agroecology - arthropod community - biological control - edge density - pest control - pollination - response trait - semi-natural habitat - trait syndrome - yield

Managing agricultural landscapes to support biodiversity and ecosystem services is a key aim of a sustainable agriculture. However, how the spatial arrangement of crop fields and other habitats in landscapes impacts arthropods and their functions is poorly known. Synthesising data from 49 studies (1515 landscapes) across Europe, we examined effects of landscape composition (% habitats) and configuration (edge density) on arthropods in fields and their margins, pest control, pollination and yields. Configuration effects interacted with the proportions of crop and non-crop habitats, and species’ dietary, dispersal and overwintering traits led to contrasting responses to landscape variables. Overall, however, in landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7- and 1.4-fold respectively. Arable-dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield-enhancing ecosystem services.

Doing the City from the Margins : Critical Perspectives on Urban Marginality
Aceska, Ana ; Heer, Barbara ; Kaiser-Grolimund, Andrea - \ 2019
Anthropological Forum : a journal of social anthropology and comparative sociology 29 (2019)1. - ISSN 0066-4677 - p. 1 - 11.
This special issue focuses on urban marginality in diverse contexts across the world (Africa, Latin America, Arab States and Europe) and proposes anthropological perspectives on contemporary urbanity that take into account the complexity of the social positions of those city dwellers that are on the margins. Three aspects of urban margins come to the fore. First, urbanites respond to increasing marginalisation through the production of alternative meanings and narratives about the city. While grand, powerful narratives may present cities as ‘divided’, ‘dual’ or ‘conflicted’, urban dwellers may carve out symbolic space through discourses of the non-spectacular and non-political, emerging out of lived space. Second, the cuts and frictions constituting urban margins do not only limit urban dwellers capacities, but can also provide spaces of agentic possibilities. As it is well known, the absence of state control can be turned by versatile urbanites into opportunities of the ‘informal’ economy. Third, urban dwellers engage in manifold practices that connect and entangle their marginalised position with spaces of power and resources. Through their practices urban margins become a relation to, not a disconnection from the ‘centre’. In this special issue we understand ‘urban margins’ not as essence or entities, but as forms of relations between urban dwellers shaped by processes of political, economic, spatial and social marginalisation. Seen in this way, urban margins constitute a perspective on the urban: a lens to entice comparisons of urban agency in the world of cities [Robinson, J. 2011. “Cities in a World of Cities: The Comparative Gesture.” International Journal of Urban and Regional Research 35 (1): 1–23. doi:10.1111/j.1468-2427.2010.00982.x]].
Partial replacement of red and blue by green light increases biomass and yield in tomato
Kaiser, E. ; Weerheim, C. ; Schipper, R. ; Dieleman, J.A. - \ 2019
Scientia Horticulturae 249 (2019). - ISSN 0304-4238 - p. 271 - 279.
Light spectrum; Green light; Light use efficiency; Solanum lycopersicum
Effects of green light on plant growth are relatively understudied, and published results are contradictory. Although per unit leaf area, green light drives photosynthesis less efficiently than does red light, on a whole-plant level green light may increase growth due to changes in vertical light distribution, leaf light acclimation and canopy architecture. As most studies were conducted on small plants with compact stems, positive effects may have remained unnoticed. In a greenhouse experiment, a tomato (Solanum lycopersicum) crop was exposed to 7, 20 or 39% of green light in a background of narrow bandwidth red and blue light, as well as sunlight, for 76 days. The intensity supplied by lamps (171 μmol m−2 s−1) and the red:blue ratio were similar between treatments. Adding green light (+32%) to the spectrum significantly and linearly increased plant biomass and yield (+6.5%). With increasing green light percentage, there were tendencies for linear increases in leaf biomass (P = 0.06), specific leaf area (P = 0.09), stem biomass (P = 0.07), stem length (P = 0.05) and number of internodes (P = 0.05). In the top and middle leaf layers of the canopy, net photosynthesis rate, stomatal conductance and leaf thickness were unaffected by the treatment while in leaves in the middle leaf layer, chlorophyll a:b ratio and carotenoid concentrations increased with the percentage of green light. This study shows that partial replacement of red by green light increases growth of plants in dense canopies and suggests that the combined effects of a light spectrum on plant growth are more than the sum of wavelength effects on photosynthetic efficiency.
Adding Blue to Red Supplemental Light Increases Biomass and Yield of Greenhouse-Grown Tomatoes, but Only to an Optimum
Kaiser, M.E. ; Ouzounis, Theoharis ; Giday, Habtamu ; Schipper, R. ; Heuvelink, E. ; Marcelis, L.F.M. - \ 2019
Frontiers in Plant Science 9 (2019). - ISSN 1664-462X - 11 p.
LED, biomass, blue light, red light, photosynthesis, tomato, greenhouse, yield
Greenhouse crop production in northern countries often relies heavily on supplemental lighting for year-round yield and product quality. Among the different spectra used in supplemental lighting, red is often considered the most efficient, but plants do not develop normally when grown solely under monochromatic red light (“red light syndrome”). Addition of blue light has been shown to aid normal development, and typical lighting spectra in greenhouse production include a mixture of red and blue light. However, it is unclear whether sunlight, as part of the light available to plants in the greenhouse, may be sufficient as a source of blue light. In a greenhouse high-wire tomato (Solanum lycopersicum), we varied the percentage of blue supplemental light (in a red background) as 0, 6, 12, and 24%, while keeping total photosynthetically active radiation constant. Light was supplied as a mixture of overhead (99 μmol m-2 s-1) and intracanopy (48 μmol m-2 s-1) LEDs, together with sunlight. Averaged over the whole experiment (111 days), sunlight comprised 58% of total light incident onto the crop. Total biomass, yield and number of fruits increased with the addition of blue light to an optimum, suggesting that both low (0%) and high (24%) blue light intensities were suboptimal for growth. Stem and internode lengths, as well as leaf area, decreased with increases in blue light percentage. While photosynthetic capacity increased linearly with increases in blue light percentage, photosynthesis in the low blue light treatment (0%) was not low enough to suggest the occurrence of the red light syndrome. Decreased biomass at low (0%) blue light was likely caused by decreased photosynthetic light use efficiency. Conversely, decreased biomass at high (24%) blue light was likely caused by reductions in canopy light interception. We conclude that while it is not strictly necessary to add blue light to greenhouse supplemental red light to obtain a functional crop, adding some (6–12%) blue light is advantageous for growth and yield while adding 24% blue light is suboptimal for growth.
Assessing bottom trawling impacts based on the longevity of benthic invertebrates
Hiddink, Jan Geert ; Jennings, Simon ; Sciberras, Marija ; Bolam, Stefan G. ; Cambiè, Giulia ; McConnaughey, Robert A. ; Mazor, Tessa ; Hilborn, Ray ; Collie, Jeremy S. ; Pitcher, C.R. ; Parma, Ana M. ; Suuronen, Petri ; Kaiser, Michel J. ; Rijnsdorp, Adriaan D. - \ 2019
Journal of Applied Ecology 56 (2019)5. - ISSN 0021-8901 - p. 1075 - 1084.
benthic invertebrates - bottom trawl - fisheries management - impact assessment - life-history meta-analysis - seabed disturbance - systematic review

Bottom trawling is the most widespread human activity directly affecting seabed habitats. Assessment and effective management of the effects of bottom trawling at the scale of fisheries requires an understanding of differences in sensitivity of biota to trawling. Responses to disturbance are expected to depend on the intrinsic rate of increase in populations (r), which is expected to be linearly related to the reciprocal of longevity. We examine the relationship between the longevity of benthic invertebrates and their response to bottom trawling; both in terms of the immediate mortality following a trawl pass and their subsequent rates of recovery. We collate all available data from experimental and comparative trawling studies, and test how longevity influences these aspects of sensitivity. The shortest lived organisms (<1 year) increased in abundance shortly after experimental trawling but showed no response to trawling in long-term comparative studies. Conversely, the abundance of biota with a life span >1 year decreased by ~9% immediately following a trawl pass. The effect of bottom trawling in comparative studies increased with longevity, with a 2–3× larger effect on biota living >10 years than on biota living 1–3 years. We attribute this difference to the slower recovery rates of the long-lived biota. The observed relationship between the intrinsic rate of population increase (r, our metric of recovery rate) and the reciprocal of longevity matches theoretical expectation and predicts that the sensitivity of habitats to bottom trawling is higher in habitats with higher proportions of long-lived organisms. Synthesis and applications. Where the longevity of a species or the longevity distribution of a community is known or can be inferred, our estimates of depletion and intrinsic rate of increase can be combined with high-resolution maps of trawling intensity to assess trawling impacts at the scale of the fishery or other defined unit of assessment. Our estimates of r may also be used to estimate recovery times following other forms of seabed disturbance.

Red/blue light ratio strongly affects steady-state photosynthesis, but hardly affects photosynthetic induction in tomato (Solanum lycopersicum)
Zhang, Yuqi ; Kaiser, Elias ; Zhang, Yating ; Yang, Qichang ; Li, Tao - \ 2019
Physiologia Plantarum 167 (2019)2. - ISSN 0031-9317 - p. 144 - 158.

Plants are often subjected to rapidly alternating light intensity and quality. While both short- and long-term changes in red and blue light affect leaf photosynthesis, their impact on dynamic photosynthesis is not well documented. It was tested how dynamic and steady-state photosynthetic traits were affected by red/blue ratios, either during growth or during measurements, in tomato leaves. Four red/blue ratios were used: monochromatic red (R100), monochromatic blue (B100), a red/blue light ratio of 9:1 (R90B10) and a red/blue light ratio of 7:3 (R70B30). R100 grown leaves showed decreased photosynthetic capacity (maximum rates of light-saturated photosynthesis, carboxylation, electron transport and triose phosphate use), leaf thickness and nitrogen concentrations. Acclimation to various red/blue ratios had limited effects on photosynthetic induction in dark-adapted leaves. B100-grown leaves had a approximately 15% larger initial NPQ transient than the other treatments, which may be beneficial for photoprotection under fluctuating light. B100-grown leaves also showed faster stomatal closure when exposed to low light intensity, which likely resulted from smaller stomata and higher stomatal density. When measured under different red/blue ratios, stomatal opening rate and photosynthetic induction rate were hardly accelerated by increased fractions of blue light in both growth chamber-grown leaves and greenhouse-grown leaves. However, steady-state photosynthesis rate 30 min after photosynthetic induction was strongly reduced in leaves exposed to B100 during the measurement. We conclude that varying red/blue light ratios during growth and measurement strongly affects steady-state photosynthesis, but has limited effects on photosynthetic induction rate.

Data from: Assessing bottom-trawling impacts based on the longevity of benthic invertebrates
Hiddink, Jan Geert ; Jennings, Simon ; Sciberras, Marija ; Bolam, Stefan G. ; Cambiè, Giulia ; Mcconnaughey, Robert A. ; Mazor, Tessa ; Hilborn, Ray ; Collie, Jeremy S. ; Pitcher, C.R. ; Parma, Ana M. ; Suuronen, Petri ; Kaiser, Michel J. ; Rijnsdorp, A.D. - \ 2018
fisheries management - bottom trawl - benthic invertebrates - impact assessment - meta-analysis - systematic review - life history - seabed disturbance
Bottom trawling is the most widespread human activity directly affecting seabed habitats. Assessment and effective management of the effects of bottom trawling at the scale of fisheries requires an understanding of differences in sensitivity of biota to trawling. Responses to disturbance are expected to depend on the intrinsic rate of increase of populations (r), which is expected to be linearly related to the reciprocal of longevity. 2. We examine the relationship between the longevity of benthic invertebrates and their response to bottom trawling; both in terms of the immediate mortality following a trawl pass and their subsequent rates of recovery. We collate all available data from experimental and comparative trawling studies, and test how longevity influences these aspects of sensitivity. 3. The shortest-lived organisms (<1yr) increased in abundance shortly after experimental trawling, but showed no response to trawling in longer-term comparative studies. Conversely, the abundance of biota with a life-span >1yr decreased by ~9% immediately following a trawl pass. The effect of bottom trawling in comparative studies increased with longevity, with a 2-3× larger effect on biota living >10yr than on biota living 1-3yr. We attribute this difference to the slower recovery rates of the longer-lived biota. 4. The observed relationship between the intrinsic rate of population increase (r, our metric of recovery rate) and the reciprocal of longevity matches theoretical expectation and predicts that the sensitivity of habitats to bottom trawling is higher in habitats with higher proportions of long-lived organisms. 5. Synthesis and Applications. Where the longevity of a species or the longevity distribution of a community is known or can be inferred, our estimates of depletion and intrinsic rate of increase can be combined with high-resolution maps of trawling intensity to assess trawling impacts at the scale of the fishery or other defined unit of assessment. Our estimates of r may also be used to estimate recovery times following other forms of seabed disturbance.
Dr. Elias Kaiser, PHD student at the Wageningen University in the Netherlands, is measuring the chlorophyll inside a strawberry greenhouse
Kaiser, Elias - \ 2018

Dr. Elias Kaiser, PHD student at the Wageningen University in the Netherlands, is measuring the chlorophyll inside a strawberry greenhouse. This high end agro farming technology can grow much more with less and without use of any pesticides. In fact 95% less of water is used to grow crops and this system can grow up to 10 times the amount of a traditional strawberry land field. This futuristic way of farming might be the solution to grow massive amount of fruits and vegetables with a smaller impact on the planet? Follow me @lucalocatelliphoto to see more about the future of farming

Sustainable crop production in greenhouses based on understanding crop physiology
Marcelis, L.F.M. ; Kaiser, E. ; Westreenen, A. van; Heuvelink, E. - \ 2018
Acta Horticulturae 1227 (2018). - ISSN 0567-7572 - p. 1 - 12.
Controlled environment agriculture - Dynamic photosynthesis - Leaf area - Light-emitting diodes - Macroclimate - Microclimate

More precise control of growth conditions has led to a strong increase in crop yield in greenhouses. To further improve crop production, product quality and sustainability, we need profound knowledge of the responses of plants to environmental conditions as well as crop management by growers (e.g., pruning and plant density). In young plants, rapid leaf formation initially boosts production through its role in intercepting light. However, we propose that many full-grown crops invest too much assimilate in new leaves. Responses of plants to the environment are seldom linear, and show many interactions. Furthermore, short- and long-term responses can be very different because of acclimation and feedback mechanisms. Therefore, research should not only study plant responses under constant conditions, but also analyse multiple interacting factors under fluctuating conditions. Controlling the climate should focus more on the microclimate near plant organs than on the average greenhouse climate. For instance, the temperature of the apical meristem may deviate by 4°C from that of the air. Leaf initiation rate depends on the temperature of the apical meristem, independent of the temperature of the other plant organs, and this has a significant impact on the plant phenotype. LED lamps open opportunities for energy saving while improving growth, yield and product quality, as they allow the instantaneous control of spectrum, intensity and direction of light, and the decoupling of lighting from heating. Effects of LED light on yield can be attributed to effects on leaf photosynthesis, plant morphology, which affects the absorption of light, and dry-matter partitioning. LED light can also trigger secondary metabolite production, resulting in increased disease resistance, or increased antioxidants such as vitamin C or anthocyanins. A next step in the control of the production process is indoor production without solar light in vertical farms. This step is boosted by developments in LED technology.

The role of local adaptation in sustainable production of village chickens
Bettridge, Judy M. ; Psifidi, Androniki ; Terfa, Zelalem G. ; Desta, Takele T. ; Lozano-Jaramillo, Maria ; Dessie, Tadelle ; Kaiser, Pete ; Wigley, Paul ; Hanotte, Olivier ; Christley, Robert M. - \ 2018
Nature Sustainability 1 (2018)10. - ISSN 2398-9629 - p. 574 - 582.

Village chickens are ubiquitous in smallholder farming systems, contributing to household, local and national economies under diverse environmental, economic and cultural settings. However, they are raised in challenging environments where productivity is low while mortality is high. There is much interest in utilizing indigenous genetic resources to produce a chicken that is resilient to its environment, while at the same time providing the basis of an economically sustainable enterprise. Globally, however, a wide variety of interventions have so far proved unable to deliver sustainable improvements. Here we show that regional differences in trait preferences and parasite burden are associated with distinct chicken gene pools, probably in response to interactions between natural and human-driven (economic and social) selection pressures. Drivers of regional differences include marketing opportunities, cultural preferences, agro-ecologies and parasite populations, and are evident in system adaptations, such as management practices, population dynamics and bird genotypes. Our results provide sound multidisciplinary evidence to support previous observations that sustainable poultry development interventions for smallholder farmers, including breeding programmes, should be locally tailored and designed for flexible implementation.

Monitoring emissions from the 2015 Indonesian fires using CO satellite data
Nechita-Banda, Narcisa ; Krol, Maarten ; Werf, Guido R. van der; Kaiser, Johannes W. ; Pandey, Sudhanshu ; Huijnen, Vincent ; Clerbaux, Cathy ; Coheur, Pierre ; Deeter, Merritt N. ; Röckmann, Thomas - \ 2018
Philosophical Transactions of the Royal Society B. Biological sciences 373 (2018)1760. - ISSN 0962-8436 - 9 p.
atmosphere - biomass burning - emissions - peat - satellite data

Southeast Asia, in particular Indonesia, has periodically struggled with intense fire events. These events convert substantial amounts of carbon stored as peat to atmospheric carbon dioxide (CO2) and significantly affect atmospheric composition on a regional to global scale. During the recent 2015 El Niño event, peat fires led to strong enhancements of carbon monoxide (CO), an air pollutant and well-known tracer for biomass burning. These enhancements were clearly observed from space by the Infrared Atmospheric Sounding Interferometer (IASI) and the Measurements of Pollution in the Troposphere (MOPITT) instruments. We use these satellite observations to estimate CO fire emissions within an inverse modelling framework. We find that the derived CO emissions for each sub-region of Indonesia and Papua are substantially different from emission inventories, highlighting uncertainties in bottom-up estimates. CO fire emissions based on either MOPITT or IASI have a similar spatial pattern and evolution in time, and a 10% uncertainty based on a set of sensitivity tests we performed. Thus, CO satellite data have a high potential to complement existing operational fire emission estimates based on satellite observations of fire counts, fire radiative power and burned area, in better constraining fire occurrence and the associated conversion of peat carbon to atmospheric CO2 A total carbon release to the atmosphere of 0.35-0.60 Pg C can be estimated based on our results.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition
Karp, Daniel S. ; Chaplin-Kramer, Rebecca ; Meehan, Timothy D. ; Martin, Emily A. ; Declerck, Fabrice ; Grab, Heather ; Gratton, Claudio ; Hunt, Lauren ; Larsen, Ashley E. ; Martínez-Salinas, Alejandra ; O’Rourke, Megan E. ; Rusch, Adrien ; Poveda, Katja ; Jonsson, Mattias ; Rosenheim, Jay A. ; Schellhorn, Nancy A. ; Tscharntke, Teja ; Wratten, Stephen D. ; Zhang, Wei ; Iverson, Aaron L. ; Adler, Lynn S. ; Albrecht, Matthias ; Alignier, Audrey ; Angelella, Gina M. ; Zubair Anjum, Muhammad ; Avelino, Jacques ; Batáry, Péter ; Baveco, Johannes M. ; Bianchi, Felix J.J.A. ; Birkhofer, Klaus ; Bohnenblust, Eric W. ; Bommarco, Riccardo ; Brewer, Michael J. ; Caballero-López, Berta ; Carrière, Yves ; Carvalheiro, Luísa G. ; Cayuela, Luis ; Centrella, Mary ; Ćetković, Aleksandar ; Henri, Dominic Charles ; Chabert, Ariane ; Costamagna, Alejandro C. ; La Mora, Aldo De; Kraker, Joop De; Desneux, Nicolas ; Diehl, Eva ; Diekötter, Tim ; Dormann, Carsten F. ; Eckberg, James O. ; Entling, Martin H. ; Fiedler, Daniela ; Franck, Pierre ; Veen, F.J.F. van; Frank, Thomas ; Gagic, Vesna ; Garratt, Michael P.D. ; Getachew, Awraris ; Gonthier, David J. ; Goodell, Peter B. ; Graziosi, Ignazio ; Groves, Russell L. ; Gurr, Geoff M. ; Hajian-Forooshani, Zachary ; Heimpel, George E. ; Herrmann, John D. ; Huseth, Anders S. ; Inclán, Diego J. ; Ingrao, Adam J. ; Iv, Phirun ; Jacot, Katja ; Johnson, Gregg A. ; Jones, Laura ; Kaiser, Marina ; Kaser, Joe M. ; Keasar, Tamar ; Kim, Tania N. ; Kishinevsky, Miriam ; Landis, Douglas A. ; Lavandero, Blas ; Lavigne, Claire ; Ralec, Anne Le; Lemessa, Debissa ; Letourneau, Deborah K. ; Liere, Heidi ; Lu, Yanhui ; Lubin, Yael ; Luttermoser, Tim ; Maas, Bea ; Mace, Kevi ; Madeira, Filipe ; Mader, Viktoria ; Cortesero, Anne Marie ; Marini, Lorenzo ; Martinez, Eliana ; Martinson, Holly M. ; Menozzi, Philippe ; Mitchell, Matthew G.E. ; Miyashita, Tadashi ; Molina, Gonzalo A.R. ; Molina-Montenegro, Marco A. ; O’Neal, Matthew E. ; Opatovsky, Itai ; Ortiz-Martinez, Sebaastian ; Nash, Michael ; Östman, Örjan ; Ouin, Annie ; Pak, Damie ; Paredes, Daniel ; Parsa, Soroush ; Parry, Hazel ; Perez-Alvarez, Ricardo ; Perović, David J. ; Peterson, Julie A. ; Petit, Sandrine ; Philpott, Stacy M. ; Plantegenest, Manuel ; Plećaš, Milan ; Pluess, Therese ; Pons, Xavier ; Potts, Simon G. ; Pywell, Richard F. ; Ragsdale, David W. ; Rand, Tatyana A. ; Raymond, Lucie ; Ricci, Benoît ; Sargent, Chris ; Sarthou, Jean-Pierre ; Saulais, Julia ; Schäckermann, Jessica ; Schmidt, Nick P. ; Schneider, Gudrun ; Schüepp, Christof ; Sivakoff, Frances S. ; Smith, Henrik G. ; Stack Whitney, Kaitlin ; Stutz, Sonja ; Szendrei, Zsofia ; Takada, Mayura B. ; Taki, Hisatomo ; Tamburini, Giovanni ; Thomson, Linda J. ; Tricault, Yann ; Tsafack, Noelline ; Tschumi, Matthias ; Valantin-Morison, Muriel ; Trinh, Mai Van; Werf, Wopke Van Der; Vierling, Kerri T. ; Werling, Ben P. ; Wickens, Jennifer B. ; Wickens, Victoria J. ; Woodcock, Ben A. ; Wyckhuys, Kris ; Xiao, Haijun ; Yasuda, Mika ; Yoshioka, Akira - \ 2018
Proceedings of the National Academy of Sciences of the United States of America 115 (2018)33. - ISSN 0027-8424 - p. E7863 - E7870.
IPM
The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.
A comparison of VMS and AIS data : The effect of data coverage and vessel position recording frequency on estimates of fishing footprints
Shepperson, Jennifer L. ; Hintzen, Niels T. ; Szostek, Claire L. ; Bell, Ewen ; Murray, Lee G. ; Kaiser, Michel J. - \ 2018
ICES Journal of Marine Science 75 (2018)3. - ISSN 1054-3139 - p. 988 - 998.
automatic identification system - extent - fisheries - footprint - scallop dredging - vessel monitoring system

Understanding the distribution of fishing activity is fundamental to quantifying its impact on the seabed. Vessel monitoring system (VMS) data provides a means to understand the footprint (extent and intensity) of fishing activity. Automatic Identification System (AIS) data could offer a higher resolution alternative to VMS data, but differences in coverage and interpretation need to be better understood. VMS and AIS data were compared for individual scallop fishing vessels. There were substantial gaps in the AIS data coverage; AIS data only captured 26% of the time spent fishing compared to VMS data. The amount of missing data varied substantially between vessels (45-99% of each individuals' AIS data were missing). A cubic Hermite spline interpolation of VMS data provided the greatest similarity between VMS and AIS data. But the scale at which the data were analysed (size of the grid cells) had the greatest influence on estimates of fishing footprints. The present gaps in coverage of AIS may make it inappropriate for absolute estimates of fishing activity. VMS already provides a means of collecting more complete fishing position data, shielded from public view. Hence, there is an incentive to increase the VMS poll frequency to calculate more accurate fishing footprints.

Response of benthic fauna to experimental bottom fishing : A global meta-analysis
Sciberras, Marija ; Hiddink, Jan Geert ; Jennings, Simon ; Szostek, Claire L. ; Hughes, Kathryn M. ; Kneafsey, Brian ; Clarke, Leo J. ; Ellis, Nick ; Rijnsdorp, Adriaan D. ; Mcconnaughey, Robert A. ; Hilborn, Ray ; Collie, Jeremy S. ; Pitcher, C.R. ; Amoroso, Ricardo O. ; Parma, Ana M. ; Suuronen, Petri ; Kaiser, Michel J. - \ 2018
Fish and Fisheries 19 (2018)4. - ISSN 1467-2960 - p. 698 - 715.
Dredging - Effects of trawling - Fishing impacts - Invertebrate communities - Systematic review - Taxonomic analysis
Bottom-contact fishing gears are globally the most widespread anthropogenic sources of direct disturbance to the seabed and associated biota. Managing these fishing disturbances requires quantification of gear impacts on biota and the rate of recovery following disturbance. We undertook a systematic review and meta-analysis of 122 experiments on the effects-of-bottom fishing to quantify the removal of benthos in the path of the fishing gear and to estimate rates of recovery following disturbance. A gear pass reduced benthic invertebrate abundance by 26% and species richness by 19%. The effect was strongly gear-specific, with gears that penetrate deeper into the sediment having a significantly larger impact than those that penetrate less. Sediment composition (% mud and presence of biogenic habitat) and the history of fishing disturbance prior to an experimental fishing event were also important predictors of depletion, with communities in areas that were not previously fished, predominantly muddy or biogenic habitats being more strongly affected by fishing. Sessile and low mobility biota with longer life-spans such as sponges, soft corals and bivalves took much longer to recover after fishing (>3 year) than mobile biota with shorter life-spans such as polychaetes and malacostracans (<1 year). This meta-analysis provides insights into the dynamics of recovery. Our estimates of depletion along with estimates of recovery rates and large-scale, high-resolution maps of fishing frequency and habitat will support more rigorous assessment of the environmental impacts of bottom-contact gears, thus supporting better informed choices in trade-offs between environmental impacts and fish production.
Short-term salt stress strongly affects dynamic photosynthesis, but not steady-state photosynthesis, in tomato (Solanum lycopersicum)
Zhang, Yuqi ; Kaiser, Elias ; Zhang, Yating ; Yang, Qichang ; Li, Tao - \ 2018
Environmental and Experimental Botany 149 (2018). - ISSN 0098-8472 - p. 109 - 119.
Dynamic photosynthesis - Fluctuating light - Salt stress - Solanum lycopersicum - Stomatal conductance - Tomato
Salt stress occurs worldwide due to widespread soil salinization. Also, plants are often subjected to rapidly alternating periods of sun and shade (sunflecks). Despite this combined occurrence of salt stress and sunflecks, dynamic photosynthetic responses to sunflecks under salt stress remain unknown. This study addresses this discrepancy by exploring photosynthetic gas exchange and chlorophyll fluorescence, both after dark-light transitions and during artificial light fluctuations (lightflecks and shadeflecks), in salt stressed leaves. Three weeks old growth-chamber grown tomato (Solanum lycopersicum Mill ‘Beijing Cherry Tomato’) plants were exposed to 0, 70 or 140 mM of sodium chloride (NaCl), for 7–9 days. Photosynthetic induction after dark-light transitions was strongly inhibited in salt-stressed leaves, due to increased transient stomatal limitation and slower apparent Rubisco activation. During photosynthetic induction, non-photochemical quenching (NPQ) and intrinsic water use efficiency (WUEi) were positively correlated with [NaCl]. Under periods of low light (shadeflecks), the longer the shadefleck lasted, the more strongly photosynthesis after re-illumination was downregulated by salt stress, and this downregulation in photosynthesis was positively correlated with the severity of salt stress. Under regularly applied lightflecks, salt stress decreased photosynthesis by 12–42%, which was mainly caused by decreased stomatal conductance. Salt-stressed leaves also displayed significantly lower stomatal pore area and stomatal index. Crucially, salt stress did not affect steady-state photosynthetic capacity as indicated by similar light and CO2 response curves of photosynthesis. We conclude that a short-term salt stress strongly affects dynamic leaf photosynthesis in tomato while its effect on steady state photosynthesis is negligible.
Acclimation of photosynthesis to lightflecks in tomato leaves: interaction with progressive shading in a growing canopy
Kaiser, M.E. ; Matsubara, Shizue ; Harbinson, J. ; Heuvelink, E. ; Marcelis, L.F.M. - \ 2018
Physiologia Plantarum 162 (2018)4. - ISSN 0031-9317 - p. 506 - 517.
Plants in natural environments are often exposed to fluctuations in light intensity, and leaf-level acclimation to light may be affected by those fluctuations. Concurrently, leaves acclimated to a given light climate can become progressively shaded as new leaves emerge and grow above them. Acclimation to shade alters characteristics such as photosynthetic capacity. To investigate the interaction of fluctuating light and progressive shading, we exposed three-week old tomato (Solanum lycopersicum) plants to either lightflecks or constant light intensities. Lightflecks of 20 s length and 1000 μmol m-2  s-1 peak intensity were applied every 5 min for 16 h per day, for 3 weeks. Lightfleck and constant light treatments received identical daily light sums (15.2 mol m-2  day-1 ). Photosynthesis was monitored in leaves 2 and 4 (counting from the bottom) during canopy development throughout the experiment. Several dynamic and steady-state characteristics of photosynthesis became enhanced by fluctuating light when leaves were partially shaded by the upper canopy, but much less so when they were fully exposed to lightflecks. This was the case for CO2 -saturated photosynthesis rates in leaves 2 and 4 growing under lightflecks 14 days into the treatment period. Also, leaf 2 of plants in the lightfleck treatment showed significantly faster rates of photosynthetic induction when exposed to a stepwise change in light intensity on day 15. As the plants grew larger and these leaves became increasingly shaded, acclimation of leaf-level photosynthesis to lightflecks disappeared. These results highlight continuous acclimation of leaf photosynthesis to changing light conditions inside developing canopies.
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