ORCID Profile
0000-0002-5908-1939
Current Organisation
University of Nottingham
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Publisher: Frontiers Media SA
Date: 28-04-2020
Publisher: Wiley
Date: 23-05-2016
DOI: 10.1111/NPH.14000
Abstract: Both photosynthesis ( A ) and stomatal conductance ( g s ) respond to changing irradiance, yet stomatal responses are an order of magnitude slower than photosynthesis, resulting in noncoordination between A and g s in dynamic light environments. Infrared gas exchange analysis was used to examine the temporal responses and coordination of A and g s to a step increase and decrease in light in a range of different species, and the impact on intrinsic water use efficiency was evaluated. The temporal responses revealed a large range of strategies to save water or maximize photosynthesis in the different species used in this study but also displayed an uncoupling of A and g s in most of the species. The shape of the guard cells influenced the rapidity of response and the overall g s values achieved, with different impacts on A and W i . The rapidity of g s in dumbbell‐shaped guard cells could be attributed to size, whilst in elliptical‐shaped guard cells features other than anatomy were more important for kinetics. Our findings suggest significant variation in the rapidity of stomatal responses amongst species, providing a novel target for improving photosynthesis and water use.
Publisher: Springer International Publishing
Date: 2015
Publisher: Oxford University Press (OUP)
Date: 08-05-2015
DOI: 10.1093/JXB/ERV204
Publisher: Oxford University Press (OUP)
Date: 31-03-2017
DOI: 10.1104/PP.17.00125
Publisher: Oxford University Press (OUP)
Date: 16-09-2013
DOI: 10.1093/JXB/ERT288
Publisher: Oxford University Press (OUP)
Date: 28-07-2017
DOI: 10.1104/PP.17.00622
Publisher: Cold Spring Harbor Laboratory
Date: 14-05-2017
DOI: 10.1101/133702
Abstract: In this study we have generated transgenic Arabidopsis plants over-expressing the Rieske FeS protein (PetC), a component of the cytochrome b 6 f (cyt b 6 f ) complex. Increasing the levels of this protein, resulted in the concomitant increase in the levels of cyt f (PetA) and cyt b 6 (PetB), core proteins of the cyt b 6 f complex. Interestingly, an increase in the levels of proteins in both the PSI and PSII complexes was also seen in the Rieske FeS ox plants. Although the mechanisms leading to these changes remain to be identified, the transgenic plants presented here provide novel tools to explore this. Importantly, the overexpression of the Rieske FeS protein resulted in a substantial and significant impact on the quantum efficiency of PSI and PSII, electron transport, biomass and seed yield in Arabidopsis plants. These results demonstrate the potential for manipulating electron transport processes to increase crop productivity. Over-expression of the Rieske FeS protein results in significant increases in the quantum efficiencies or PSI and PSII, increases in A max and has the potential to increase crop productivity
Publisher: Wiley
Date: 10-09-2020
DOI: 10.1111/NPH.16832
Abstract: The wild relatives of modern wheat represent an underutilized source of genetic and phenotypic ersity and are of interest in breeding owing to their wide adaptation to erse environments. Leaf photosynthetic traits underpin the rate of production of biomass and yield and have not been systematically explored in the wheat relatives. This paper identifies and quantifies the phenotypic variation in photosynthetic, stomatal, and morphological traits in up to 88 wheat wild relative accessions across five genera. Both steady‐state measurements and dynamic responses to step changes in light intensity are assessed. A 2.3‐fold variation for flag leaf light and CO 2 ‐saturated rates of photosynthesis A max was observed. Many accessions showing higher and more variable A max , maximum rates of carboxylation, electron transport, and Rubisco activity when compared with modern genotypes. Variation in dynamic traits was also significant with distinct genus‐specific trends in rates of induction of nonphotochemical quenching and rate of stomatal opening. We conclude that utilization of wild relatives for improvement of photosynthesis is supported by the existence of a high degree of natural variation in key traits and should consider not only genus‐level properties but variation between in idual accessions.
Publisher: Springer Science and Business Media LLC
Date: 18-09-2019
DOI: 10.1186/S13007-019-0485-X
Abstract: As yields of major crops such as wheat ( T. aestivum ) have begun to plateau in recent years, there is growing pressure to efficiently phenotype large populations for traits associated with genetic advancement in yield. Photosynthesis encompasses a range of steady state and dynamic traits that are key targets for raising Radiation Use Efficiency (RUE), biomass production and grain yield in crops. Traditional methodologies to assess the full range of responses of photosynthesis, such a leaf gas exchange, are slow and limited to one leaf (or part of a leaf) per instrument. Due to constraints imposed by time, equipment and plant size, photosynthetic data is often collected at one or two phenological stages and in response to limited environmental conditions. Here we describe a high throughput procedure utilising chlorophyll fluorescence imaging to phenotype dynamic photosynthesis and photoprotection in excised leaves under controlled gaseous conditions. When measured throughout the day, no significant differences ( P 0.081) were observed between the responses of excised and intact leaves. Using excised leaves, the response of three cultivars of T. aestivum to a user—defined dynamic lighting regime was examined. Cultivar specific differences were observed for maximum PSII efficiency ( F v ′/ F m ′— P 0.01) and PSII operating efficiency ( F q ′/ F m ′— P = 0.04) under both low and high light. In addition, the rate of induction and relaxation of non-photochemical quenching (NPQ) was also cultivar specific. A specialised imaging chamber was designed and built in-house to maintain gaseous conditions around excised leaf sections. The purpose of this is to manipulate electron sinks such as photorespiration. The stability of carbon dioxide (CO 2 ) and oxygen (O 2 ) was monitored inside the chambers and found to be within ± 4.5% and ± 1% of the mean respectively. To test the chamber, T. aestivum ‘Pavon76’ leaf sections were measured under at 20 and 200 mmol mol −1 O 2 and ambient [CO 2 ] during a light response curve. The F v ′/ F m ′was significantly higher ( P 0.05) under low [O 2 ] for the majority of light intensities while values of NPQ and the proportion of open PSII reaction centers (qP) were significantly lower under 130 μmol m −2 s −1 photosynthetic photon flux density (PPFD). Here we demonstrate the development of a high-throughput ( 500 s les day −1 ) method for phenotyping photosynthetic and photo-protective parameters in a dynamic light environment. The technique exploits chlorophyll fluorescence imaging in a specifically designed chamber, enabling controlled gaseous environment around leaf sections. In addition, we have demonstrated that leaf sections do not different from intact plant material even 3 h after s ling, thus enabling transportation of material of interest from the field to this laboratory based platform. The methodologies described here allow rapid, custom screening of field material for variation in photosynthetic processes.
Publisher: The Royal Society
Date: 19-04-2014
Abstract: The rapid induction of the bundle sheath cell (BSC)-specific expression of ASCORBATE PEROXIDASE2 ( APX2 ) in high light (HL)-exposed leaves of Arabidopsis thaliana is, in part, regulated by the hormone abscisic acid (ABA) produced by vascular parenchyma cells. In this study, we provide more details of the ABA signalling that regulates APX2 expression and consider its importance in the photosynthetic responses of BSCs and whole leaves. This was done using a combination of analyses of gene expression and chlorophyll a fluorescence of both leaves and in idual BSCs and mesophyll cells. The regulation of APX2 expression occurs by the combination of the protein kinase SnRK2.6 (OST1):protein phosphatase 2C ABI2 and a Gα (GPA1)-regulated signalling pathway. The use of an ost1-1/gpa1-4 mutant established that these signalling pathways are distinct but interact to regulate APX2 . In HL-exposed leaves, BSC chloroplasts were more susceptible to photoinhibition than those of mesophyll cells. The activity of the ABA-signalling network determined the degree of susceptibility of BSCs to photoinhibition by influencing non-photochemical quenching. By contrast, in HL-exposed whole leaves, ABA signalling did not have any major influence on their transcriptomes nor on their susceptibility to photoinhibition, except where guard cell responses were observed.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Lorna Mcausland.