Real-time imaging of photosynthetic oxygen evolution from spinach using LSI-based biosensor

Abstract

The light-driven splitting of water to oxygen (O 2 ) is catalyzed by a protein-bound tetra-manganese penta-oxygen calcium (Mn 4 O 5 Ca) cluster in Photosystem II. In the current study, we used a large-scale integration (LSI)-based amperometric sensor array system, designated Bio-LSI, to perform two-dimensional imaging of light-induced O 2 evolution from spinach leaves. The employed Bio-LSI chip consists of 400 sensor electrodes with a pitch of 250 μm for fast electrochemical imaging. Spinach leaves were illuminated to varying intensities of white light (400–700 nm) which induced oxygen evolution and subsequent electrochemical images were collected using the Bio-LSI chip. Bio-LSI images clearly showed the dose-dependent effects of the light-induced oxygen release from spinach leaves which was then significantly suppressed in the presence of urea-type herbicide 3-(3,4-dichlorophenyl)−1,1-dimethylurea (DCMU). Our results clearly suggest that light-induced oxygen evolution can be monitored using the chip and suggesting that the Bio-LSI is a promising tool for real-time imaging. To the best of our knowledge, this report is the first to describe electrochemical imaging of light-induced O 2 evolution using LSI-based amperometric sensors in plants.

Reactive Oxygen Species as a Response to Wounding: In Vivo Imaging in Arabidopsis thaliana

“…In biological systems, the metabolism is affected by non-physiological conditions which lead to stress reactions (Foyer et al, 1994;Cramer et al, 2011). The stress conditions in plants are categorized as biotic or abiotic; the former include herbivory, viral, bacterial, and fungal infections and damage by pests while the later include extreme environmental factors such as temperature, UV radiation, light, water availability, pH, salinity, toxic chemicals, burning, and mechanical injury among others (Garces et al, 2001;Johansson Jankanpaa et al, 2013;Kasai et al, 2019). The stressors can act independently or in various combinations (Savatin et al, 2014).…”

Printable Transparent Microelectrodes toward Mechanically and Visually Imperceptible Electronics

“…The electrophysiological signal of plants could be correlated with the water status, wounded parts, and photosynthetic activity, which would help producers with the healthcare of plants. [ 40–43 ] We used Egeria densa as the target plant because its leaves easily come in contact with a surrounding medium owing to their thin structure (1.9 μm thickness). [ 44 ] As the sensors, the cross‐aligned AgNW electrodes are patterned with a width of 60 μm.…”

“…Steady‐state data can provide important information for understanding the state of the plant because changes in the EP according to the plant state appear after a long time (>10 min) after the environment changes. [ 40,41,43,44 ] A previous study [ 41 ] also detected the EP difference and assessed the health of a plant in terms of its water stress conditions and nycthemeral rhythm. However, a complete understanding of the reason behind changes in the EPs of plants has not been realized because it requires the consideration of several factors such as the kinetics of ion transport and photosynthetic activity.…”

“…However, a complete understanding of the reason behind changes in the EPs of plants has not been realized because it requires the consideration of several factors such as the kinetics of ion transport and photosynthetic activity. [ 40,43,44 ] We believe that the developed flexible and transparent microelectrodes will further this understanding because the microelectrodes can enable multimodal assessments owing to their visible transparency (Figure 5b). Furthermore, owing to their ultrathinness, the microelectrodes can be attached without damaging the plants, which can allow plants to be assessed in their natural state.…”

Limnology and Oceanography Bulletin Volume 30 Number 4 November 2021 121–145

“…With improved equipment, today's research has turned away from roughly adjusting prismatically dispersed light to Fraunhofer lines and toward the use of higher resolution radiation per respective wavelength (e.g., by high-intensity monochromators; Björn 2008). The measurement of the photosynthetic response does not rely on bacterial aerotaxis anymore, but can be directly measured (e.g., by real-time imaging of photosynthetic O 2 development; Kasai et al 2019). Yet, the concepts of action spectra, the exemplary "green gap" of chlorophyll absorption, and dependency of photosynthesis on the specific light absorption are still valid.…”