Water is essential for the existence of all living forms on the earth, and the kinds and amounts of vegetation occurring on various parts of the earth’s surface depend more on the quantity of water available than on any other single environmental factor. Therefore, the need for the non-subjective, diagnostic assessment tools for water status measurements of plants and soils is indispensable to avoid water shortage problems and achieve sustainable development goals (SDGs) of agricultural sector. The best measure of the energy status of water in plants and soils is the water potential (Ψ w ), which has the advantage of being physically defined and the force that causes water movement. There are many different instruments that have essential roles for measuring water status of plant, for example, Pressure Chamber, Isopiestic Psychrometer, Pressure Probe, and Osmometers. Each had the ability to indicate not only the water status of various parts of plants and soils but also the forces used to move water from place to place. Nowadays, speaking plant approach (SPA) identifies the optimal crop cultivation conditions based on the physiological status of the plants. The physiological status information from a living plant can be achieved by using a chlorophyll fluorescence imaging robot, which is a powerful tool for early detection of drought stress in plants under practical production greenhouse conditions. Moreover, recently thermal imaging and remote sensing technology are both feasible for precise irrigation guidance and precision water management.
Kramer, P.J. and Boyer, J.S. (1995) Water Relations of Plants and Soils. Academic Press, San Diego.
Kramer, P.J. (1983) 2—Water Relations of Plants. In: Kramer, P.J., Ed., Water Relations of Plants, Academic Press, Inc., San Diego, 23-56. https://doi.org/10.1016/B978-0-12-425040-6.50005-9
Awad-Allah, E.F.A., Gholipour, Y. and Nonami, H. (2012) Growth Promotion with Osmotic Adjustment at Low Water Potentials after H2O2 Pretreatment in Soybean Seeds. Environmental Control in Biology, 50, 263-276.
Awad-Allah, E.F.A., Gholipour, Y., Nonami, H. and Erra-Balsells, R. (2011) Enhancing Soybean Germination in Arid Areas with H2O2 Pretreatment. CIGR International Symposium on “Sustainable Bioproduction—Water, Energy, and Food”, Tokyo, 19-23 September 2011, 1-5.
Hung, S., Yu C. and Lin, C.H. (2005) Hydrogen Peroxide Functions as a Stress Signal in Plants. Botanical bulletin of Academia Sinica, 46, 1-10.
Kaur, N. and Gupta, A.K. (2005) Signal Transduction Pathways under Abiotic Stresses in Plants. Current Science, 88, 1771-1780.
Ishibashi, Y., Yamaguchi, H., Yuasa, T., Iwaya-Inoue, M., Arima, S. and Zheng, S. (2011) Hydrogen Peroxide Spraying Alleviates Drought Stress in Soybean Plants. Journal of Plant Physiology, 168, 1562-1567. https://doi.org/10.1016/j.jplph.2011.02.003
Valliyodan, B. and Nguyen, H.T. (2006) Understanding Regulatory Networks and Engineering for Enhanced Drought Tolerance in Plants. Current Opinion in Plant Biology, 9, 189-195. https://doi.org/10.1016/j.pbi.2006.01.019
Singh, A., Singh, S. and Prasad, S. M. (2017) Silicon and Nanotechnology Role in Agriculture and Future Perspectives. In: Tripathi, D.K., Singh, V.P., Ahmed. P., Chauhan, D.K. and Prasad, S.M., Eds., Silicon in Plants: Advances and Future Prospects, CRC Press, Taylor & Francis Group, Boca Raton, 101-116.
Walley, J.W., Coughlan, S., Hudson, M.E., Covington, M.F., Kaspi, R., Banu, G., Harmer, S.L. and Dehesh, K. (2007) Mechanical Stress Induces Biotic and Abiotic Stress Responses via a Novel CIS-Element. PLoS Genetics, 3, e172. https://doi.org/10.1371/journal.pgen.0030172
Hemantaranjan, A. (2016) Plant Stress Tolerance Physiological & Molecular Strategies. Scientific Publishers, India.
Boyer, J.S. (1995) Measuring the Water Status of Plants and Soils. Academic Press, San Diego.
Nonami, H. and Boyer, J.S. (1987) Origin of Growth-Induced Water Potential: Solute Concentration Is Low in Apoplast of Enlarging Tissues. Plant Physiology, 83, 596-601. https://doi.org/10.1104/pp.83.3.596
Wada, H. (2004) Roles of Water Potential Gradients and Turgor in Cell Elongation, Flowering and Bulb Formation. Ph.D. Thesis, Faculty of Agriculture, Ehime University, Matsuyama.
Awad-Allah, E.F.A. (2012) Mechanisms for Drought Tolerance during Germination of Soybean Seeds Pretreated with H2O2. Ph.D. Thesis, Faculty of Agriculture, Ehime University, Matsuyama.
Kramer, P.J. (1988) Measurement of Plant Water Status: Historical Perspectives and Current Concerns. Irrigation Science, 9, 275-287. https://doi.org/10.1007/BF00296703
Boyer, J.S. and Knipling, E.B. (1965) Isopiestic Technique for Measuring Leaf Water Potentials with a Thermocouple Psychrometer. Proceedings of the National Academy of Sciences of the United States of America, 54, 1044-1051.
Ehlig, C.F. (1962) Measurement of Energy Status of Water in Plants with a Thermocouple Psychrometer. Plant Physiology, 37, 288-290. https://doi.org/10.1104/pp.37.3.288
Nonami, H., Boyer, J.S. and Steudle, E. (1987) Pressure Probe and Isopiestic Psychrometer Measure Similar Turgor. Plant Physiology, 83, 592-595. https://doi.org/10.1104/pp.83.3.592
Hossain, M.M. (2010) Growth Mechanisms of Tomato Fruit Associated with Water Relations in Leaves and Fruits. Ph. D. Thesis, Faculty of Agriculture, Ehime University, Matsuyama.
Ikeda, T., Nonami, H., Fukuyama, T. and Hashimoto, Y. (1999) Hydraulic Contribution in Cell Elongation of Tissue-Cultured Plants: Growth Retardation Induced by Osmotic and Temperature Stresses and Addition of 2,4-dichlorophenoxyacetic Acid and Benzylaminopurine. Plant, Cell & Environment, 22, 899-912. https://doi.org/10.1046/j.1365-3040.1999.00463.x
Pérez-Harguindeguy, N., Díaz, S., Garnier, E., Lavorel, S., Poorter, H., Jaureguiberry, P., Bret-Harte, M.S., Cornwell, W.K., et al. (2013) New Handbook for Standardised Measurement of Plant Functional Traits Worldwide. Australian Journal of Botany, 61, 167-234. https://doi.org/10.1071/BT12225
Fisher, D.B. (1985) In Situ Measurement of Plant Water Potentials by Equilibration with Microdroplets of Polyethylene Glycol 8000. Plant Physiology, 79, 270-273. https://doi.org/10.1104/pp.79.1.270 https://www.jstor.org/stable/4269501
Taiz, L., Zeiger, E., Moller, I.M. and Murphy, A. (2015) Plant Physiology and Development. 6th Edition, Sinauer Associates, Sunderland.
Chang, R. (2005) Physical Chemistry for the Biosciences. University Science Books Cop., Sausalito.
Takayama, K. (2013) Second Generation Speaking Plant Approach: Practical Application. Journal of Science and High Technology in Agriculture, 25, 165-174.
Takayama, K. and Nishina, H. (2015) Intelligent Growth Management Based on the Biological Information of Crop. Journal of the Japanese Society for Quality Control, 45, 149.
Takayama, K., Nishina, H., Iyoki, S., Arima, S., Hatou, K., Ueka, Y. and Miyoshi, Y. (2011) Early Detection of Drought Stress in Tomato Plants with Chlorophyll Fluorescence Imaging—Practical Application of the Speaking Plant Approach in a Greenhouse. Proceedings of the 18th World Congress, the International Federation of Automatic Control, Milano, 28 August-2 September 2011, 1785-1790.
Nishina, H. (2015) Development of Speaking Plant Approach Technique for Intelligent Greenhouse. Agriculture and Agricultural Science Procedia, 3, 9-13. https://doi.org/10.1016/j.aaspro.2015.01.004
Jones, H.G. and Leinonen, I. (2003) Thermal Imaging for the Study of Plant Water Relations. Journal of Agricultural Meteorology, 59, 205-217.
Benavente, E., García-Toledano, L., Carrillo, J.M. and Quemada, M. (2013) Thermographic Imaging: Assessment of Drought and Heat Tolerance in Spanish Germplasm of Brachypodium distachyon. Procedia Environmental Sciences, 19, 262-266. https://doi.org/10.1016/j.proenv.2013.06.030
Neupane, J. and Guo, W.X. (2019) Agronomic Basis and Strategies for Precision Water Management: A Review. Agronomy, 9, 87. https://doi.org/10.3390/agronomy9020087
Damm, A., Paul-Limoges, E., Haghighi, E., Simmer, C., Morsdorf, F., Schneider, F.D., van der Tol, C., Migliavacca, M. and Rascher, U. (2018) Remote Sensing of Plant-Water Relations: An Overview and Future Perspectives. Journal of Plant Physiology, 227, 3-19. https://doi.org/10.1016/j.jplph.2018.04.012
Balafoutis, A., Beck, B., Fountas, S., Vangeyte, J., van der Wal, T., Soto, I., Gómez-Barbero, M., Barnes, A. and Eory, V. (2017) Precision Agriculture Technologies Positively Contributing to GHG Emissions Mitigation, Farm Productivity and Economics. Sustainability, 9, 1339. https://doi.org/10.3390/su9081339