A number of additives have been tested for their effects on o-diphenol: O2 oxidoreductase activity of cane leaves. The most inhibitory compounds were thioglycollate, β-mercaptoethanol, polyethylene glycol and bovine serum albumin. Sulphydryl (SH) compounds did not affect rates of photosynthetic CO2 assimilation when used at concentrations below 10(-2) M. However, in the presence of Mn(++) ions they contributed to an O2 consumption which masked photosynthetic O2 evolution. Addition of SH compounds or of polymers to the grinding media increased rates of enzymic CO2 assimilation in crude enzyme preparations from cane leaves, but did not affect rates of CO2 assimilation in similar spinach preparations. Strong reducing agents, copper chelators, low O2 tension and high pH were effective in reducing phenoloxidase activity, but presented problems in the isolation and assay of chloroplasts. The results are discussed in relation to (a) design of suitable media for preparation of active cane chloroplasts and (b) comparative studies of enzyme levels in plants of various genera.
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Plants (Basel)
December 2024
Laboratório da Interação Planta-Patógeno, Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa 36570-900, Minas Gerais, Brazil.
Maize leaf blight (MLB), caused by the fungus , is an important disease affecting maize production. In order to minimize the use of fungicides in agriculture, nutrient-based resistance inducers may become a promising alternative to manage MLB. The goal of this study was to investigate the potential of Semia (zinc (20%) complexed with a plant-derived pool of polyphenols (10%)) to hamper the infection of maize leaves by by analyzing their photosynthetic performance and carbohydrate and antioxidative metabolism, as well as the expression of defense-related genes.
View Article and Find Full Text PDFPlants (Basel)
December 2024
Laboratory of Plant Biochemistry, Department of Biochemistry, State University of Maringá, Maringá 87020-900, Brazil.
Chemical weed control is a significant agricultural concern, and reliance on a limited range of herbicide action modes has increased resistant weed species, many of which use C4 metabolism. As a result, the identification of novel herbicidal agents with low toxicity targeting C4 plants becomes imperative. An assessment was conducted on the impact of 3-cyanobenzoic acid on the growth and photosynthetic processes of maize (), a representative C4 plant, cultivated hydroponically over 14 days.
View Article and Find Full Text PDFPlant Cell Environ
January 2025
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
Nitrate reduction requires reducing equivalents produced by the photosynthetic electron transport chain. Therefore, it has been suggested that nitrate assimilation provides a sink for electrons under high light conditions. We tested this hypothesis by monitoring photosynthetic efficiency and the chloroplastic glutathione redox potential (chl-E) of plant lines with mutated glutamine synthetase 2 (GS2) and ferredoxin-dependent glutamate synthase 1 (GOGAT1).
View Article and Find Full Text PDFJ Integr Plant Biol
January 2025
Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
Carbon assimilation is a crucial part of the photosynthetic process, wherein inorganic carbon, typically in the form of CO, is converted into organic compounds by living organisms, including plants, algae, and a subset of bacteria. Although several carbon fixation pathways have been elucidated, the Calvin-Benson-Bassham (CBB) cycle remains fundamental to carbon metabolism, playing a pivotal role in the biosynthesis of starch and sucrose in plants, algae, and cyanobacteria. However, Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), the key carboxylase enzyme of the CBB cycle, exhibits low kinetic efficiency, low substrate specificity, and high temperature sensitivity, all of which have the potential to limit flux through this pathway.
View Article and Find Full Text PDFFront Plant Sci
December 2024
Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.
Drought conditions severely curtail the ability of plants to accumulate biomass due to the closure of stomata and the decrease of photosynthetic assimilation rate. Additionally, there is a shift in the plant's metabolic processes toward the production of metabolites that offer protection and aid in osmoadaptation, as opposed to those required for development and growth. To limit water loss via non-stomatal transpiration, plants adjust the load and composition of cuticle waxes, which act as an additional barrier.
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