Active control of photosynthetic activities is important in plant physiological study. Although models of plant photosynthesis have been built at different scales, they have not been fully examined for their application in plant growth control. However, we do not have an infrastructure to support such experiments since current plant growth chambers usually use fixed control protocols. In our current paper, an open IoT-based framework is proposed. This framework allows a plant scientist or agricultural engineer, through an application programming interface (API), in a desirable programming language, (1) to gather environmental data and plant physiological responses; (2) to program and execute control algorithms based on their models, and then (3) to implement real-time commands to control environmental factors. A plant growth chamber was developed to demonstrate the concept of the proposed open framework.
Large amounts of antibiotics and microplastics are used in daily life and agricultural production, which affects not only plant growth but also potentially the food safety of vegetables and other plant products. Fast detection of the presence of antibiotics and microplastics in leafy vegetables is of great interest to the public. In this work, a method was developed to detect sulfadiazine and polystyrene, commonly used antibiotics and microplastics, in vegetables by measuring and modeling photosystem II chlorophyll a fluorescence (ChlF) emission from leaves. Chrysanthemum coronarium L., a common beverage and medicinal plant, was used to verify the developed method. Scanning electron microscopy, transmission electron microscopy, and liquid chromatograph-mass spectrometer analysis were used to show the presence of the two pollutants in the samples. The developed kinetic model could describe measured ChlF variations with an average relative error of 0.6%. The model parameters estimated for the chlorophyll a fluorescence induction kinetics curve (OJIP) induction can differentiate the two types of stresses while the commonly used ChlF OJIP induction characteristics cannot. This work provides a concept to detect antibiotic pollutants and microplastic pollutants in vegetables based on ChlF.
NYB is chlorophyll-less barley mutant, which is controlled by a recessive nuclear gene. The mutation mechanism is revealed. The activities of enzymes transforming 5-aminolevulinic acid into protochlorophyllide were the same in both NYB and the wild type (WT), but the activity of the protochlorophyllide oxidoreductase (POR) in WT was much higher than that of NYB. Most of the photosystem 2 apoproteins were present in both WT and NYB, suggesting that the capability of protein synthesis was probably fully preserved in the mutant. Thus chlorophyll (Chl) biosynthesis in NYB was hampered at conversion form protochlorophyllide (Pchlide) into chlorophyllide. The open reading frame of porB gene in NYB was inserted with a 95 bp fragment, which included a stop codon. The NYB mutant is a very useful material for studies of Chl biosynthesis, chloroplast signalling, and structure of light-harvesting POR-Pchlide complex (LHPP). and Z.-L. Liu ... [et al.].