Search

The first use of the word 'chlorophyll' (chlorophile or chlorophyle in the French original) appeared in two papers by Pierre-Joseph Pelletier and Joseph Bienaimé Caventou, pharmacists in Paris who isolated and studied the green pigment from plants. Here, we provide English translations of their 1818 note and the slightly longer 1817 paper. Historical context is provided including a timeline of key discoveries in chlorophyll chemistry pertaining to photosynthesis., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

A merged system incorporating paperfluidics and papertronics has recently emerged as a simple, single-use, low-cost paradigm for disposable point-of-care (POC) diagnostic applications. Stand-alone and self-sustained paper-based systems are essential to providing effective and lifesaving treatments in resource-constrained environments. Therefore, a realistic and accessible power source is required for actual paper-based POC systems as their diagnostic performance and portability rely significantly on power availability. Among many paper-based batteries and energy storage devices, paper-based microbial fuel cells have attracted much attention because bacteria can harvest electricity from any type of organic matter that is readily available in those challenging regions. However, the promise of this technology has not been translated into practical power applications because of its short power duration, which is not enough to fully operate those systems for a relatively long period. In this work, we for the first time demonstrate a simple and long-lasting paper-based biological solar cell that uses photosynthetic bacteria as biocatalysts. The bacterial photosynthesis and respiration continuously and self-sustainably generate power by converting light energy into electricity. With a highly porous and conductive anode and an innovative solid-state cathode, the biological solar cell built upon the paper substrates generated the maximum current and power density of 65 µA/cm 2 and 10.7 µW/cm 2 , respectively, which are considerably greater than those of conventional micro-sized biological solar cells. Furthermore, photosynthetic bacteria in a 3-D volumetric chamber made of a stack of papers provided stable and long-lasting electricity for more than 5 h, while electrical current from the heterotrophic culture on 2-D paper dramatically decreased within several minutes.

To eliminate the negative effect of soil contamination with heavy metals on plant growth and crop yield, different methods and techniques are the subject of discussion and study. In this study, we aimed to evaluate the effect of secondary pulp and paper-mill sludge application to soil on the response of the main physiological processes such as the growth, photosynthesis, and respiration of lettuce (Lactuca sativa L.) plants to soil contamination with Pb. For the pot experiment, Pb was added to sandy loam soil at concentrations of 0, 50, and 250 mg Pb(NO3)2 per kg of the soil, and secondary sludge was added to a 0, 20, or 40% sludge solution during each plant watering. The Pb-mediated change in plant biomass allocation, decrease in the photosynthetic rate, increase in leaf respiration rate, and the degree of light inhibition of respiration were closely associated with increases in both root and shoot Pb content. For the Pb-free soil condition, secondary sludge application contributed to the allocation of plant biomass towards a greater accumulation in the shoots than in the roots. Although stomatal opening was not affected by either Pb or sludge, sludge application increased photosynthetic CO2 assimilation regardless of soil Pb content, which was associated with an increase in the electron-transport rate and carboxylase activity of Rubisco. Soil contamination with Pb significantly increased the ratio of respiration to photosynthesis, reflecting a shift in the carbon balance toward carbon losses in the leaves, but sludge application modified the coupling between the processes with a decrease in the proportion of respiratory carbon losses. The sludge-mediated recovery of the physiological processes of L. sativa reflected an increase in plant tolerance to soil contamination with heavy metals, the formation of which is associated with plant and soil adjustments initiated by secondary sludge application.

We describe a latex wet coalescence extrusive coating method that produces up to 10-fold specific photosynthetic rate enhancements by nitrate-limited non-growing cyanobacteria deposited onto paper, hydrated and placed in the gas-phase of small tube photobioreactors. These plant leaf-like biocomposites were used to study the tolerance of cyanobacteria strains to illumination and temperature using a solar simulator. We report sustained CO2 absorption and O2 production for 500 h by hydrated gas-phase paper coatings of non-growing Synechococcus PCC7002, Synechocystis PCC6803, Synechocystis PCC6308, and Anabaena PCC7120. Nitrate-starved cyanobacteria immobilized on the paper surface by the latex binder did not grow out of the coatings into the bulk liquid. The average CO2 consumption rate in Synechococcus coatings is 5.67 mmol m(-2)  h(-1) which is remarkably close to the rate reported in the literature for Arabidopsis thaliana leaves under similar experimental conditions (18 mmol m(-2)  h(-1) ). We observed average ratios of oxygen production to carbon dioxide consumption (photosynthetic quotient, PQ) between 1.3 and 1.4, which may indicate a strong dependence on nitrate assimilation during growth and was used to develop a non-growth media formulation for intrinsic kinetics studies. Photosynthetic intensification factors (PIF) (O2 production by nitrate-limited cyanobacteria in latex coatings/O2 produced by nitrate-limited cell suspensions) in cyanobacteria biocomposites prepared from wet cell pellets concentrated 100- to 300-fold show 7-10 times higher specific reactivity compared to cells in suspension under identical nitrate-limited non-growth conditions. This is the first report of changes of cyanobacteria tolerance to temperature and light intensities after deposition as a thin coating on a porous matrix, which has important implications for gas-phase photobioreactor design using porous composite materials. Cryo-fracture SEM and confocal microscopy images of cell coating distribution on the paper biocomposite suggest that the spatial arrangement of the cells in the coating can affect photoreactivity. This technique could be used to fabricate very stable, multi-organism composite coatings on flexible microfluidic devices in the gas-phase capable of harvesting light in a broader range of wavelengths, to optimize thermotolerant, desiccation tolerant, or halotolerant cyanobacteria that produce O2 with secretion of liquid-fuel precursors synthesized from CO2 ., (© 2014 Wiley Periodicals, Inc.)

Abstract Background Lysine succinylation is a naturally occurring post-translational modification (PTM) that is ubiquitous in organisms. Lysine succinylation plays important roles in regulating protein structure and function as well as cellular metabolism. Global lysine succinylation at the proteomic level has been identified in a variety of species; however, limited information on lysine succinylation in plant species, especially paper mulberry, is available. Paper mulberry is not only an important plant in traditional Chinese medicine, but it is also a tree species with significant economic value. Paper mulberry is found in the temperate and tropical zones of China. The present study analyzed the effects of lysine succinylation on the growth, development, and physiology of paper mulberry. Results A total of 2097 lysine succinylation sites were identified in 935 proteins associated with the citric acid cycle (TCA cycle), glyoxylic acid and dicarboxylic acid metabolism, ribosomes and oxidative phosphorylation; these pathways play a role in carbon fixation in photosynthetic organisms and may be regulated by lysine succinylation. The modified proteins were distributed in multiple subcellular compartments and were involved in a wide variety of biological processes, such as photosynthesis and the Calvin-Benson cycle. Conclusion Lysine-succinylated proteins may play key regulatory roles in metabolism, primarily in photosynthesis and oxidative phosphorylation, as well as in many other cellular processes. In addition to the large number of succinylated proteins associated with photosynthesis and oxidative phosphorylation, some proteins associated with the TCA cycle are succinylated. Our study can serve as a reference for further proteomics studies of the downstream effects of succinylation on the physiology and biochemistry of paper mulberry.

To eliminate the negative effect of soil contamination with heavy metals on plant growth and crop yield, different methods and techniques are the subject of discussion and study. In this study, we aimed to evaluate the effect of secondary pulp and paper-mill sludge application to soil on the response of the main physiological processes such as the growth, photosynthesis, and respiration of lettuce (Lactuca sativa L.) plants to soil contamination with Pb. For the pot experiment, Pb was added to sandy loam soil at concentrations of 0, 50, and 250 mg Pb(NO3)2 per kg of the soil, and secondary sludge was added to a 0, 20, or 40% sludge solution during each plant watering. The Pb-mediated change in plant biomass allocation, decrease in the photosynthetic rate, increase in leaf respiration rate, and the degree of light inhibition of respiration were closely associated with increases in both root and shoot Pb content. For the Pb-free soil condition, secondary sludge application contributed to the allocation of plant biomass towards a greater accumulation in the shoots than in the roots. Although stomatal opening was not affected by either Pb or sludge, sludge application increased photosynthetic CO2 assimilation regardless of soil Pb content, which was associated with an increase in the electron-transport rate and carboxylase activity of Rubisco. Soil contamination with Pb significantly increased the ratio of respiration to photosynthesis, reflecting a shift in the carbon balance toward carbon losses in the leaves, but sludge application modified the coupling between the processes with a decrease in the proportion of respiratory carbon losses. The sludge-mediated recovery of the physiological processes of L. sativa reflected an increase in plant tolerance to soil contamination with heavy metals, the formation of which is associated with plant and soil adjustments initiated by secondary sludge application. [ABSTRACT FROM AUTHOR]

Premise: While some studies have found leaf variegation to reduce photosynthetic capacity, others showed that it can increase photosynthesis. Thus, what maintains variegation remains an open question. Two primary hypotheses-the anti-herbivory and abiotic heterogeneity hypotheses-have been posited, yet little empirical research explicitly investigates the maintenance of naturally occurring variegation., Methods: We used field surveys, image analysis, and climatic associations to explore the anti-herbivory and abiotic heterogeneity hypotheses in 21 populations of Hexastylis heterophylla and H. shuttleworthii, both polymorphic for leaf variegation. We measured the frequency of variegated individuals, variegation intensity, and herbivory for each morph, assessed abiotic correlates with variegation, and measured photosynthetic efficiency., Results: We found a strong elevational cline in leaf variegation strongly linked with abiotic heterogeneity; variegation was more common in lower-elevation populations characterized by higher temperatures, UV-B exposure, seasonal light change, and drier, more basic soils. Variegated and nonvariegated individuals experienced similar levels of herbivory. Morphs had similar photosynthetic quantum yields. However, nonvariegated leaves experienced more nonphotochemical quenching, an indication of photoinhibition, and had higher surface temperatures under high light., Conclusions: Our results suggest that variegation may serve as an adaptation to high temperatures and light conditions and can reduce photoinhibition in certain environmental contexts. Thus, abiotic factors can maintain variegation in wild populations and shape geographic clines in variegation., (© 2024 The Author(s). American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)

David Mauzerall was born on July 22, 1929 to a working-class family in the small, inland textile town of Sanford, Maine. Those humble origins instilled a lifelong frugality and an innovative spirit. After earning his PhD degree in 1954 in physical organic chemistry with Frank Westheimer at the University of Chicago, he joined The Rockefeller Institute for Medical Research (now University) as a postdoctoral fellow that summer, rose to the rank of professor, and remained there for the rest of his career. His work over more than 60 years encompassed porphyrin biosynthesis, photoinduced electron-transfer reactions in diverse architectures (solutions, bilayer lipid membranes, reaction centers, chromatophores, and intact leaves), the light-saturation curve of photosynthesis, statistical treatments of photoreactions, and "all-things porphyrins." His research culminated in studies he poetically referred to as "listening to leaves" through the use of pulsed photoacoustic spectroscopy to probe the course and thermodynamics of photosynthesis in its native state. His research group was always small; indeed, of 185 total publications, 39 were singly authored. In brief, David Mauzerall has blended a deep knowledge of distinct disciplines of physical organic chemistry, photochemistry, spectroscopy and biophysics with ingenious experimental methods, incisive mathematical analysis, pristine personal integrity, and unyielding love of science to deepen our understanding of photosynthesis in its broadest context. He thought creatively - and always independently. His work helped systematize the fields of photosynthesis and the origin of life and made them more quantitative. The present article highlights a number of salient scientific discoveries and includes comments from members of his family, friends, and collaborators (Gary Brudvig, Greg Edens, Paul Falkowski, Alzatta Fogg, G. Govindjee, Nancy Greenbaum, Marilyn Gunner, Harvey Hou, Denise and Michele Mauzerall, Thomas Moore, and William Parson) as part of a celebration of his 95th birthday., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Abstract Studies on the influence of paper mill wastewater, which affects photosynthesis, on reed chlorophyll and biomass can provide a theoretical basis for the ecological restoration of wetland plants. The influence of different concentrations of wastewater (chemical oxygen demands (COD) of 300, 175 and 50 mg•L−1) and different irrigation times (germination, blade-expansion, rapid-growth, heading and maturity stages) on the contents of chlorophyll a , chlorophyll b , total chlorophyll and chlorophyll a /b in reeds were tested in experimental pools that simulated the wetland ecosystem of the Liaoning Shuangtai estuary. The contents of chlorophyll a , chlorophyll b , total chlorophyll and chlorophyll a /b all increased significantly with increasing concentrations of wastewater, and their contents all differed significantly from each other. The contents of chlorophyll a , chlorophyll b and total chlorophyll were maximal when irrigated at the beginning of all growth stages with COD of 300 mg•L−1(C 1 O) at 2.253, 0.458 and 2.711 mg•g−1 fresh weight (FW), respectively, with irrigation at the rapid-growth stage and were minimal in the control plants at 0.142, 0.068 and 0.210 mg•g−1 FW, respectively, with irrigation at maturity. Chlorophyll a /b was maximal at C 1 O at 5.753 with irrigation at germination stage and was minimal in the control plants at 2.113 with irrigation at maturity. Reed biomass was maximal at C 1 O at 3.26 kg, which was 2.76 times higher than the control. Reed biomass was positively correlated with the content of chlorophyll and with COD in the wastewater. Paper mill wastewater generally increased the content of chlorophyll and the net photosynthesis rate and enhanced the growth of reeds. Highlights • Different concentrations of wastewater and different irrigation times on the contents of chlorophyll in reeds were tested. • The contents of chlorophyll increased with increasing concentrations of wastewater, they contents differed from each other. • Reed biomass was positively correlated with chlorophyll content and the level of COD of the wastewater. • Paper mill wastewater increased the content of chlorophyll and the net photosynthesis rate of the reeds. • Paper mill wastewater enhanced the growth of the reeds. [ABSTRACT FROM AUTHOR]

Plant growth and development relies on the conversion of light energy into chemical energy, which takes place in the leaves. Chlorophyll mutant variations are important for studying certain physiological processes, including chlorophyll metabolism, chloroplast biogenesis, and photosynthesis. To uncover the mechanisms of the golden-yellow phenotype of the hybrid paper mulberry plant, this study used physiological, cytological, and iTRAQ-based proteomic analyses to compare the green and golden-yellow leaves of hybrid paper mulberry. Physiological results showed that the mutants of hybrid paper mulberry showed golden-yellow leaves, reduced chlorophyll, and carotenoid content, and increased flavonoid content compared with wild-type plants. Cytological observations revealed defective chloroplasts in the mesophyll cells of the mutants. Results demonstrated that 4766 proteins were identified from the hybrid paper mulberry leaves, of which 168 proteins displayed differential accumulations between the green and mutant leaves. The differentially accumulated proteins were primarily involved in chlorophyll synthesis, carotenoid metabolism, and photosynthesis. In addition, differentially accumulated proteins are associated with ribosome pathways and could enable plants to adapt to environmental conditions by regulating the proteome to reduce the impact of chlorophyll reduction on growth and survival. Altogether, this study provides a better understanding of the formation mechanism of the golden-yellow leaf phenotype by combining proteomic approaches.

Copper oxide nanoparticles (CuONPs) have been produced on a large scale because they can be applied across various fields, especially in nano-enabled healthcare and agricultural products. However, the increasing use of CuONPs leads to their release and accumulation into the environment. The CuONPs uptaken by seeds and their implications on germination behavior have been reported, but little is known or understood about their impact on photosynthesis in seed tissues. To fill knowledge gaps, this study evaluated the effects of CuONP concentrations (0-300 mg L -1 ) on the photosynthetic activity of Inga laurina seeds. The microscopy data showed that CuONPs had an average size distribution of 57.5 ± 0.7 nm. Copper ion release and production of reactive oxygen species (ROS) by CuONPs were also evaluated by dialysis and spectroscopy experiments, respectively. CuONPs were not able to intrinsically generate ROS and released a low content of Cu 2 ⁺ ions (4.5%, w/w). Time evolution of chlorophyll fluorescence imaging and laser-induced fluorescence spectroscopy were used to monitor the seeds subjected to nanoparticles during 168 h. The data demonstrate that CuONPs affected the steady-state maximum chlorophyll fluorescence ( F m ' ), the photochemical efficiency of photosystem II ( F v / F m ), and non-photochemical quenching ( NPQ ) of Inga laurina seeds over time. Besides, the NPQ significantly increased at the seed development stage, near the root protrusion stage, probably due to energy dissipation at this germination step. Additionally, the results indicated that CuONPs can change the oscillatory rhythms of energy dissipation of the seeds, disturbing the circadian clock. In conclusion, the results indicate that CuONPs can affect the photosynthetic behavior of I. laurina seeds. These findings open opportunities for using chlorophyll fluorescence as a non-destructive tool to evaluate nanoparticle impact on photosynthetic activity in seed tissues., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Peanut production is threatened by climate change. Damage to seedlings from low temperatures in early spring can limit yield. Plant adaptations to chilling stress remain unclear in peanut seedlings. It is essential to understand how peanut acquires chilling tolerance. We evaluated effects of chilling stress on growth and recovery of peanut seedlings. We compared and analysed biological characteristics, antioxidants, photosynthesis, biochemical and physiological responses, and nutrient absorption at varying levels of chilling. Compared with chilling-sensitive FH18, the reduced impact of chilling stress on chilling-tolerant NH5 was associated with reduced ROS accumulation, higher ascorbate peroxidase activity and soluble sugar content, lower soluble protein content, and smaller reductions in nutrient content during stress. After removal of chilling stress, FH18 had significant accumulation of O 2 •- and H 2 , which decreased photosynthesis, nutrient absorption, and transport. ROS-scavenging reduced damage from chilling stress, allowed remobilization of nutrients, improved chilling tolerance, and restored plant functioning after chilling stress removal. These findings provide a reference for targeted research on peanut seedling tolerance to chilling and lay the foundation for bioinformatics-based research on peanut chilling tolerance mechanisms.2 , which decreased photosynthesis, nutrient absorption, and transport. ROS-scavenging reduced damage from chilling stress, allowed remobilization of nutrients, improved chilling tolerance, and restored plant functioning after chilling stress removal. These findings provide a reference for targeted research on peanut seedling tolerance to chilling and lay the foundation for bioinformatics-based research on peanut chilling tolerance mechanisms., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

The repeated emergence of NADP-malic enzyme (ME), NAD-ME and phosphoenolpyruvate carboxykinase (PEPCK) subtypes of C 4 photosynthesis are iconic examples of convergent evolution, which suggests that these biochemistries do not randomly assemble, but are instead specific adaptations resulting from unknown evolutionary drivers. Theoretical studies that are based on the classic biochemical understanding have repeatedly proposed light-use efficiency as a possible benefit of the PEPCK subtype. However, quantum yield measurements do not support this idea. We explore this inconsistency here via an analytical model that features explicit descriptions across a seamless gradient between C 4 biochemistries to analyse light harvesting and dark photosynthetic metabolism. Our simulations show that the NADP-ME subtype, operated by the most productive crops, is the most efficient. The NAD-ME subtype has lower efficiency, but has greater light harvesting plasticity (the capacity to assimilate CO 2 in the broadest combination of light intensity and spectral qualities). In both NADP-ME and NAD-ME backgrounds, increasing PEPCK activity corresponds to greater light harvesting plasticity but likely imposed a reduction in photosynthetic efficiency. We draw the first mechanistic links between light harvesting and C 4 subtypes, providing the theoretical basis for future investigation., (© 2024 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Treatment of upflow anaerobic sludge blanket (UASB) effluent from a paper mill in aerated activated sludge reactors involves high aeration costs. Moreover, this calcium-rich effluent leads to problematic scale formation. Therefore, a novel strategy for the aerobic treatment of paper mill UASB effluent in microalgal bacterial floc sequencing batch reactors (MaB-floc SBRs) is proposed, in which oxygen is provided via photosynthesis, and calcium is removed via bio-mineralization. Based on the results of batch experiments in the course of this study, a MaB-floc SBR was operated at an initial neutral pH. This SBR removed 58 ± 21% organic carbon, 27 ± 8% inorganic carbon, 77 ± 5% nitrogen, 73 ± 2% phosphorus, and 27 ± 11% calcium. MaB-flocs contained 10 ± 3% calcium, including biologically-influenced calcite crystals. The removal of calcium and inorganic carbon by MaB-flocs significantly decreased when inhibiting extracellular carbonic anhydrase (CA), an enzyme that catalyses the hydration and dehydration of CO 2 . This study demonstrates the potential of MaB-floc SBRs for the alternative treatment of calcium-rich paper mill effluent, and highlights the importance of extracellular CA in this treatment process. [ABSTRACT FROM AUTHOR]

Background: Most studies on the paper mulberry are mainly focused on the medicated and pharmacology, fiber quality, leaves feed development, little is known about its mechanism of adaptability to abiotic stress. Physiological measurement, transcriptomics and proteomic analysis were employed to understand its response to cold stress in this study. Methods: The second to fourth fully expanded leaves from up to down were harvested at different stress time points forthe transmission electron microscope (TEM) observation. Physiological characteristics measurement included the relative electrolyte leakage (REL), SOD activity assay, soluble sugar content, and Chlorophyll fluorescence parameter measurement. For screening of differentially expressed genes, the expression level of every transcript in each sample was calculated by quantifying the number of Illumina reads. To identify the differentially expressed protein, leaves of plants under 0, 6, 12, 24, 48 and 72 h cold stress wereharvested for proteomic analysis. Finally, real time PCR was used to verify the DEG results of the RNA-seq and the proteomics data. Results: Results showed that at the beginning of cold stress, respiratory metabolism was decreased and the transportation and hydrolysis of photosynthetic products was inhibited, leading to an accumulation of starch in the chloroplasts. Total of 5800 unigenes and 38 proteins were affected, including the repressed expression of photosynthesis and the enhanced expression in signal transduction, stress defense pathway as well as secondary metabolism. Although the transcriptional level of a large number of genes has been restored after 12 h, sustained cold stress brought more serious injury to the leaf cells, including the sharp rise of the relative electrolyte leakage, the declined Fv/Fm value, swelled chloroplast and the disintegrated membrane system. Conclusion: The starch accumulation and the photoinhibition might be the main adaptive mechanism of the paper mulberry responded to cold stress. Most of important, enhancing the transport and hydrolysis of photosynthetic products could be the potential targets for improving the cold tolerance of the paper mulberry. [ABSTRACT FROM AUTHOR]

Iron is an essential, yet scarce, nutrient in marine environments. Phytoplankton, and especially cyanobacteria, have developed a wide range of mechanisms to acquire iron and maintain their iron-rich photosynthetic machinery. Iron limitation studies often utilize either oceanographic methods to understand large scale processes, or laboratory-based, molecular experiments to identify underlying molecular mechanisms on a cellular level. Here, we aim to highlight the benefits of both approaches to encourage interdisciplinary understanding of the effects of iron limitation on cyanobacteria with a focus on avoiding pitfalls in the initial phases of collaboration. In particular, we discuss the use of trace metal clean methods in combination with sterile techniques, and the challenges faced when a new collaboration is set up to combine interdisciplinary techniques. Methods necessary for producing reliable data, such as High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS), Flow Injection Analysis Chemiluminescence (FIA-CL), and 77K fluorescence emission spectroscopy are discussed and evaluated and a technical manual, including the preparation of the artificial seawater medium Aquil, cleaning procedures, and a sampling scheme for an iron limitation experiment is included. This paper provides a reference point for researchers to implement different techniques into interdisciplinary iron studies that span cyanobacteria physiology, molecular biology, and biogeochemistry.

In the first decades of the twentieth century, the process of photosynthesis was still a mystery: Plant scientists were able to measure what entered and left a plant, but little was known about the intermediate biochemical and biophysical processes that took place. This state of affairs started to change between the two world wars, when a number of young scientists in Europe and the United States, all of whom identified with the methods and goals of physicochemical biology, selected photosynthesis as a topic of research. The protagonists had much in common: They had studied physics and chemistry (although not necessarily plant physiology) to a high level; they used physicochemical methods to study the basic processes of life; they believed these processes were the same, or very similar, in all life forms; and they were affiliated with institutions that fostered this kind of study. This set of cognitive, methodological, and material resources enabled these protagonists to transfer their knowledge of the concepts and techniques from microbiology and human biochemistry, for example, to the study of plant metabolism. These transfers of knowledge had a great influence on the way in which the biochemistry and biophysics of photosynthesis would be studied over the following decades. Through the use of four historical cases, this paper analyzes these knowledge transfers, as well as the investigative pathways that made them possible., (© 2019. Springer Nature B.V.)

I provide here both my personal and scientific autobiography. After giving a background and summary of most of my research, I present information on my parents, my childhood, schooling, university education, and postdoctoral research, all in Australia. This is followed by a presentation of my life and research in Cambridge, UK and then at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), in Australia, since 1955, where most of my research was done, especially on photosynthesis which included the following areas: Purification of a protochlorophyllide-protein complex; separation of the photochemical systems of photosynthesis; development of photochemical activity in photosynthesis; protein synthesis in plants; comparative photosynthesis of sun and shade plants; role of chlorophyll b in photosynthesis; photochemical properties of C4 plants; molecular interaction of thylakoid membranes; electron transport and ATP formation; and solar energy conversion in photosynthesis. In addition to research on the basics and applications of photosynthesis, I also mention at the end my service as a member of the executive of CSIRO., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Improving photosynthetic efficiency has recently emerged as a promising way to increase crop production in a sustainable manner. While chloroplast size may affect photosynthetic efficiency in several ways, we aimed to explore whether chloroplast size manipulation can be a viable approach to improving photosynthetic performance. Several tobacco (Nicotiana tabacum) lines with contrasting chloroplast sizes were generated via manipulation of chloroplast division genes to assess photosynthetic performance under steady-state and fluctuating light. A selection of lines was included in a field trial to explore productivity. Lines with enlarged chloroplasts underperformed in most of the measured traits. Lines with smaller and more numerous chloroplasts showed a similar efficiency compared with wild-type (WT) tobacco. Chloroplast size only weakly affected light absorptance and light profiles within the leaf. Increasing chloroplast size decreased mesophyll conductance (g m ) but decreased chloroplast size did not increase g m . Increasing chloroplast size reduced chloroplast movements and enhanced non-photochemical quenching. The chloroplast smaller than WT appeared to be no better than WT for photosynthetic efficiency and productivity under field conditions. The results indicate that chloroplast size manipulations are therefore unlikely to lead to higher photosynthetic efficiency or growth., (© 2023 The Authors New Phytologist © 2023 New Phytologist Foundation.)

Launaea sarmentosa (Willd.) Sch. Bip ex Kunze (Asteracaeae) is a littoral sand dune herb found in the Indian Ocean region, used as a folk medicine and as a savory vegetable in Thailand. It is in the transition stage from a kitchen & cottage industry to a commercial proposition. Rapid light curves to measure the photosynthetic electron transport rate (ETR) were conducted on the plants over the course of daylight from 6:00 to 18:00 using a PAM fluorometer on plants grown under 50% (nominal) green horticultural and 20% black (nominal) shade cloth and in the open. Plants grown in the open were sun plants. E opt (µmol photon m -2  s -1 ) decreased slightly under shade cloth (open air: 890 > green shade cloth, 778 > green shade cloth, 713). Launaea shows limited shade adaptation. ETR decreased under shade cloth on both a surface area and Chl a basis (µmol e - g Chl a -1  s -1 ) [open air: 388 > (green shade cloth, 209 = black shade cloth, 263)]. Maximum non-photochemical quenching (NPQ max ) was significantly decreased under black shade cloth [(open air: 1.02 = green shade cloth, 0.969) > black shade cloth, 0.694]. ETR showed midday inhibition (9:00-15:00) when irradiance exceeded the E opt of Launaea. Daily total photosynthetic electron transport was (mmol e - m -2 d -1 ): open air, 1890 ± 157; green shade cloth, 1620 ± 203, black shade cloth, 1217 ± 143. Green shade cloth has no effect on total daily photosynthetic electron transport of Launaea but offers some protection from desiccation and excessive evapotranspiration. Waterlogging decreases ETR by about 40%. Launaea can be grown watered with brackish (½ seawater) water unlike many other vegetables. Launeae is a physiologically undemanding cottage industry/market garden crop suitable for sandy coastline fishing communities., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature.)

Heavy metals released by anthropogenic activities are extremely toxic to animals and plants due to their bioaccumulative and persistent environmental presence. In the current study, silver nanoparticles (AgNPs) were synthesized utilizing eco-friendly processes, and their potential in colorimetric Hg2+ ion sensing in environmental samples was examined. An aqueous extract of Hemidesmus indicus root (Sarsaparilla Root, ISR) rapidly converts silver ions into AgNPs within 5 min of exposure to sunlight. Transmission electron microscopy confirms that ISR-AgNPs are spherical, ranging from 15 to 35 nm. Fourier-transform infrared spectroscopy revealed phytomolecules stabilized the NPs with hydroxyl and carbonyl substituents. The ISR-AgNPs detect Hg2+ ions by a colour change that can be seen with the naked eye within 1 min. The probe is interference-free and detects the presence of Hg2+ ions in sewage water. A method for fabricating ISR-AgNPs onto paper was disclosed, and this portable ISR-AgNPs embedded paper device was found to be good at sensing mercury present in the water. The findings show that environmentally friendly synthesized AgNPs can contribute to developing onsite colorimetric sensors. [Display omitted] • Rapid silver nanoparticles synthesis using sunlight and Hemidesmus indicus root extract. • Phytochemicals stabilize the AgNPs. • Paper fabricated with AgNPs sense mercury with good selectivity. • AgNPs disrupt bacterial membranes and kill them. [ABSTRACT FROM AUTHOR]

We conducted a progressive-drought greenhouse experiment, using potted paper birch (Betula papyrifera) seedlings in their third year of growth, to investigate whether a commercially available organic biostimulant improved plant health and stress tolerance, and to compare four noninvasive, instrument-based methods for monitoring plant stress. In the well-watered (no drought) plants, the biostimulant application significantly increased foliar nitrogen concentrations (P = 0.01) and led to marginally higher rates of photosynthesis (P = 0.10) and slightly higher F/Fm fluorescence ratios (P = 0.14). Reflectance indices further indicated that the biostimulant application resulted in increased chlorophyll content (Chl NDI, P = 0.07) and either (depending on interpretation) a significantly higher Chl:carotenoid ratio or a lower proportion of xanthophyll cycle pigments in the de-epoxidated state (PRI, P = 0.02). The PRI results suggest less oxidative stress in the treated plants, which may be related to the fact that the biostimulant used (Roots 3) contained ascorbate, an antioxidant. In the plants exposed to progressive drought, the biostimulant application had similar effects but did not appear to dramatically improve the drought stress tolerance of seedlings, in that impaired physiology occurred at about the same level of soil moisture in both treated and untreated seedlings. Photosynthesis responded to the drought treatment at about 12% to 15% soil moisture content (SMC), whereas PRI did not respond until about 9% to 10% SMC, and F/Fm did not respond until about 4% to 5% SMC. Chl NDI did not show a significant response to SMC. [ABSTRACT FROM AUTHOR]