Fluorescence Lifetime-Based Photosynthesis Analyzer

Ciencia has recently developed instrumentation and methods, which for the first time offer the capability to measure PS II chlorophyll fluorescence lifetimes in situ and in real time, enabling sophisticated field analysis of photosynthetic systems. This system directly measures photochemical efficiency in Photosystem II and provides advanced technology for photosynthesis research, and for plant health assessment in oceanographic, agricultural, aquaculture, environmental and forestry applications.

Photosynthesis is one of the most important processes that transform, transport and disperse energy-related materials in the atmosphere and in the terrestrial and marine ecosystems. Directly or indirectly, photosynthesis fills all our food requirements, and many of our needs for fiber and building materials. The energy stored in petroleum, natural gas and coal was generated through photosynthesis, as is the energy in firewood and ethanol, which are major fuels in many parts of the world. Burning of firewood, ethanol, coal, oil and other fossil fuels consumes oxygen and releases carbon dioxide into the atmosphere, while photosynthesis converts carbon dioxide from the air to carbohydrates and other kinds of "fixed" carbon and releases oxygen into the atmosphere. Thus photosynthesis has a profound effect on global climate.

PS II chlorophyll fluorescence lifetime analysis is a powerful tool for the study of photosynthetic systems. It provides direct information on the quantum yield of photochemistry and detailed information about the distribution of excitation energy in photosynthetic organisms between radiative (fluorescence), dissipative (heat), and photosynthetic pathways. This distribution is governed by the quantum yield of fluorescence, quantum yield of photochemistry, and by the current level of photosynthetic activity. Determination of fluorescence lifetimes independently from photosynthetic activity can be applied toward more accurate estimates of chlorophyll biomass, primary production, and a general assessment of plant physiological status. Another fundamental advantage of lifetime measurements is that models of in vivo chlorophyll fluorescence and photosynthesis are most robustly related to lifetimes. Parameters such as FV/FM based on chlorophyll induction kinetics are empirical. In contrast, lifetimes provide mechanistic information, and therefore offer a unique and powerful tool to experimentally test models of photosynthesis. Detailed information available from multicomponent analysis should also prove useful in elucidating biophysical mechanisms for plant responses to various stresses such as nutrient limitation, photoinhibition, herbicides and environmental pollutants.

Ciencia has recently delivered to NASA a shipboard instrument for phytoplankton studies to provide ground truth for primary production determinations from satellite remote sensing of ocean color.