Near infrared spectroscopy (NIRS) is regarded as a potential medical diagnostic technique for investigation of hemodynamic changes. However, uncertainties pertaining to the origin of NIRS signals have hampered its clinical interpretation. The uncertainities in NIRS measurements especially in case of living tissues are due to lack of rigorous combined theoretical-experimental studies resulting in clear understanding of the origin of NIRS signals. For their reliable interpretation it is important to understand the relationship between spatial changes in optical properties and corresponding changes in the NIRS signal. We investigated spatial sensitivity of near infrared optical measurements using an experimental approach. It uses a liquid optical phantom as tissue equivalent, which is explored under robot-control by a small, approximately point like perturbation of desired optical properties, and a NIRS instrument for trans-illumination/reflection measurements. The experimentally obtained sensitivity has been analyzed and compared with numerical simulations. In preliminary experiments we investigated the influence of various optical properties of the medium and of source/detector distances on the spatial sensitivity distribution. The acquired sensitivity maps can be used to define characteristic parameters. As an example, we used a 25% threshold to define a penetration depth measure which provides values in good accordance with published ones. To the best of our knowledge this is the first experimental study of NIRS spatial sensitivity. The presented method will allow in depth experimental investigation of the influence of various conditions pertaining to medium such as optical properties of tissue (scattering and absorption) and of the source/detector configuration. 1977-1981 (1996). Zakynthinos, and I. Vogiatzis, "Near-infrared spectroscopy and indocyanine green derived blood flow index for non-invasive measurement of muscle perfusion during exercise," J. Appl. Physiol. 108(4), 962-967 (2010). 19. M. Xia, V. Kodibagkar, H. Liu, and R. P. Mason, "Tumour oxygen dynamics measured simultaneously by nearinfrared spectroscopy and 19f magnetic resonance imaging in rats," Phys. Med. Biol. 51, 45-60 (2006). 20. S. Nioka and B. Chance, "Nir spectroscopic detection of breast cancer," Technol. Cancer Res. Treat. 4, 497-512 (2005). 21. M. Firbank, M. Oda, and D. T. Delpy, "An improved design for a stable and reproducible phantom material for use in near-infrared spectroscopy and imaging," Phys. Med. Biol. 40, 955-961 (1995). 22. M. Firbank, E. Okada, and D. T. Delpy, "Investigation of the effect of discrete absorbers upon the measurement of blood volume with near-infrared spectroscopy," Phys.

a sand culture experiment was designed to study the effect of sodium chloride salinity on phosphorus metabolism in the roots and leaves of one month old Prosopis juliflora (Sw.) Dc seedlings. it was found that the P level in the roots as well as leaves was decreased with increasing level of salinity in rooting medium. However, the activities of enzymes acid phosphatase and atPase were increased in both the parts of seedlings grown in saline conditions. the activities of alkaline phosphatase and inorganic pyrophosphatase were found to be decreased in the root and leaves of seedlings grown under saline conditions.

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The effect of NaCl salinity on the growth and mineral nutrition of one month old Prosopis juliflora seedlings was studied with the help of sand culture experiment. The seedlings were treated with 100, 200 and 300 mM NaCl concentrations, respectively. It was found that there was stimulation in plant growth at low concentrations of salt, while at higher concentrations it was hampered causing a marked decrease in the fresh (60%) and dry weight (80%). The level of sodium, chloride and calcium was found to increase in the roots as well as leaves with increasing levels of salinity in the rooting medium. The level of potassium and phosphorus however, was found to decrease in the leaves and roots of seedlings grown under NaCl stress.

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