Potential of Piper Germplasm Against Pathogenic Bacteria: Tropical Bay Islands in India
Megh R. Goyal, Durgesh Nandini Chauhan in Assessment of Medicinal Plants for Human Health, 2020
Chlorophyll is a vital component for photosynthesis, which is comprised of Chl-a (primary pigment) and Chl-b (accessory pigment). Significant differences were noticed among the samples studied for total chlorophyll content (Table 5.4). In general, total chlorophyll content varied from 0.60 to 6.72 mg/g. Wide variations were noticed among genotypes of P. sarmentosum as the values varied between 0.90 and 6.72 mg/g in this species. In case of Chl-a and Chl-b, P. sarmentosum-4 was found to contain the highest amount of pigments of 3.31 mg/g and 3.42 mg/g, respectively. P. colubrinum-2 was found to contain lowest amount of Chl-a (0.24 mg/g) and Chl-b (0.37 mg/g) among all the genotypes studied. In general, concentration of Chl-b was comparatively higher than that of Chl-a, except in case of P. sarmentosum-1.
New Strategies for the Design and Control of Raceway Reactors to Optimize Microalgae Production
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
The most important factor governing the photosynthesis process is light availability, with the general culture conditions such as nutrient availability, temperature, pH and dissolved oxygen modulating this response (Costache et al., 2013). Nutrients can be provided easily whereas temperature is determined by the climatic conditions at the reactor site, so it is hard to manipulate. Therefore, to optimize the performance of any microalgae, suitable pH and dissolved oxygen levels must be ensured. To do this, control systems must be installed; and this design is only possible when the overall system behavior is understood. Accordingly, adequate control techniques are necessary to keep the culture conditions close to their optimal values, even when the photosynthesis rate is modified by changes in solar radiation (Pawlowski et al., 2014b). The pH level is directly related to CO2 injection, which is necessary to meet the culture’s carbon supply requirements. Oxygen is produced by the photosynthesis process, and it can inhibit the culture’s biological activity when it exceeds 250% air saturation.
Photomodulation of Protonema Development
R. N. Chopra, Satish C. Bhatla in Bryophyte Development: Physiology and Biochemistry, 2019
The specific developmental patterns throughout the ontogeny of plants depend on regulation by environmental factors. The most important external factor is light. Two fundamentally different aspects of light action on green plants have to be distinguished. On the one hand, light supplies energy necessary for photosynthesis; on the other hand, it acts as an external signal in the regulation of plant development. The specific influence of photosynthesis on morphogenetic processes is not yet quite clear. Of course, photosynthetic activity is essential to maintain growth in green plants and is therefore a prerequisite of development. Its involvement in photomorphogenesis could be excluded in several cases; nevertheless, there are certain experimental conditions wherein it seems impossible to separate trophic and regulatory effects of light exactly.
Facile biosynthesis, characterisation and biotechnological application of ZnO nanoparticles mediated by leaves of Cnidoscolus aconitifolius
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2023
Reuben Samson Dangana, Reama Chinedu George, Umulkhayr Oyenike Shittu, Femi Kayode Agboola
Photosynthesis, which is the basis for all plant metabolic functions, is considered to be one of the most vulnerable physiological processes to environmental pressures. Various literature reports have indicated that metal oxide nanoparticles affect the energy transfer efficiency of isolated reaction centres, leading to changes in plant photosynthetic efficiency, photochemical fluorescence, and quantum yield [29–32]. Studies using ZnO NPs on tomato plants with varying exposure durations have shown an increase in chlorophyll content [33]. Global agricultural systems are facing increasing strain due to rising food demand, climate change, and environmental concerns. One potential solution to improve the efficiency of agrochemicals (fertilisers and pesticides) is through the use of nanostructures, which can reduce runoff, increase foliar absorption and bioavailability, and have lower environmental consequences. However, there is a gap in knowledge regarding the synthesis and use of these nanoparticles as fertilisers that needs further exploration. This article reports on the green synthesis of ZnO NPs using Cnidoscolus aconitifolius and its potential as a bionanofertilizer as we have reported the green synthesis of ZnO NPs from this plant and its antioxidant activities [34]. The level of toxicity exerted by the NPs on sorghum plants was evaluated by measuring the activity of antioxidant enzymes (catalase and superoxide dismutase). The plant’s ethnopharmacological potential, as reported in previous studies, prompted its use in this research [62,63].
Ultrasound irradiation effect on photosynthesis and transpiration of aquatic lirium plants
Published in International Journal of Radiation Biology, 2021
José Antonio Calderón, Jeniffer Yeismar Calderón, Alejandro Rojas, Joel Hernández-Wong, Uriel Nogal, Ernesto Marin, Antonio Gustavo Juárez-Gracia, Gabriel Peña-Rodríguez, José Bruno Rojas-Trigos
The PA signal consists of two parts, namely, the photothermal and the photobaric contributions. The modulated heat generated by the incident light's absorption diffuses from the leaf surface to the air inside the PA chamber gives rise to the signal’s photothermal part. In contrast, the other one is due to the modulated emission of oxygen from the leaf stomas due to photosynthesis, a process in which chlorophylls absorption of light is a fundamental step. Thus, the PAS results show a decrease in the intensity of the chlorophyll optic response overtime after irradiation, consistent with the decrease of the PA signal’s photobaric contribution, reported elsewhere (Calderón et al. 2014). However, the preservation of the shape of the chlorophyll bands in the PAS spectra of irradiated samples, despite the decrease in its amplitude, makes doubt about the argument of Calderón et al. on alleged damage to the centers where generate photosynthesis.
Biomimetic phototherapy in cancer treatment: from synthesis to application
Published in Drug Delivery, 2021
Yifan Zhao, Cuixia Shi, Jie Cao
Apart from animal cell membranes, it should be noted that plant cell membranes, such as powerful chloroplast thylakoids, H2O2 will gradually accumulate in chloroplasts under the influence of low temperature or high salt environment. In order to reduce the damage caused by high oxidative stress, plant leaves have evolved to form a powerful antioxidant system in the body. For example, the hydrogen peroxide decomposing enzyme on the thylakoid membrane can break down H2O2 into O2. Furthermore, the photosynthesis of green plants can release O2, and chlorophyll itself is a kind of fluorescent PS (Sewelam et al., 2014; Wang et al., 2017). Based on this inspiration, Ouyang et al. (2018) designed biomimetic plant thylakoids for PDT guided by fluorescence imaging of tumors. They firstly extracted the functional thylakoid cell membrane from spinach and then squeezed by the extruder successfully prepared the nanothylakoids (NTs), the membrane with a particle size of 50 nm. H2O2 decomposing enzyme can catalyze the decomposition of tumor endogenous H2O2 and effectively alleviate the problem of hypoxia. Under the irradiation of the near-infrared laser, the energy level transition of fluorescent dye chlorophyll occurs, which transfers the energy to O2 and then produces 1O2, which realizes the PDT guided by fluorescence imaging of tumor.