title: Instrumentation for plant health and growth.
abstract: Comprehensive spectroscopic monitoring of plant health and growth in bioregenerative life support system environments is possible using a variety of spectrometric technologies. Absorption spectrometry and atomic emission spectrometry in combination allow for direct, on-line, reagentless monitoring of plant nutrients from nitrate and potassium to micronutrients such as copper and zinc. Fluorometric spectrometry is ideal for the on-line detection, identification and quantification of bacteria and fungi. Liquid Atomic Emission Spectrometry (LAES) is a new form of spectrometry that allows for direct measurement of atomic emission spectra in liquids. An electric arc is generated by a pair of electrodes in the liquid to provide the energy necessary to break molecular bonds and reduce the substance to atomic form. With a fiber probe attached to the electrodes, spectral light can be transmitted to a photodiode array spectrometer for light dispersion and analysis. Ultraviolet (UV) absorption spectrometry is a long-established technology, but applications typically have required specific reagents to produce an analyte-specific absorption. Nitrate and iron nutrients have native UV absorption spectra that have been used to accurately determine nutrient concentrations at the +/- 5% level. Fluorescence detection and characterization of microbes is based upon the native fluorescent signatures of most microbiological species. Spectral and time-resolved fluorometers operating with remote fiber-optic probes will be used for on-line microbial monitoring in plant nutrient streams.
authors.affiliation: Biotronics Technologies Inc., Waukesha, WI 53186, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Schlager
mesh_terms: D002118:Calcium / Q000032:analysis; D003470:Culture Media / Q000032:analysis; D018504:Ecological Systems, Closed; D004566:Electrodes; D004783:Environmental Microbiology; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005470:Fluorometry; D018527:Hydroponics / Q000295:instrumentation*; D008021:Life Support Systems / Q000295:instrumentation*; D008274:Magnesium / Q000032:analysis; D008903:Minerals / Q000032:analysis; D063245:Plant Development; D018521:Plant Physiological Phenomena; D011188:Potassium / Q000032:analysis; D012815:Signal Processing, Computer-Assisted; D012964:Sodium / Q000032:analysis; D013050:Spectrometry, Fluorescence; D013054:Spectrophotometry, Atomic; D013056:Spectrophotometry, Ultraviolet
chemical_list: D003470:Culture Media; D008903:Minerals; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium