Global Journal of Science Frontier Research, D: Agriculture and Veterinary, Volume 23 Issue 1

The plant response under environmental abiotic stressed conditions could be discussed from the side of dynamics in plant roots and shoots used to minimize stress, reduce consumed energy, and maintain water and nutrient uptake. (Arsova et al., 2020 and Munns et al., 2020b). Firstly, plant enhances the uptake of nutrient element responsible for combating abiotic stress, silicon. Secondly, the beneficial functional element, silicon, interact positively with macro and micronutrient and stimulate the biophysical functions inside plant’s tissues (Epstein, 2009). Thirdly, Plant responds to applied stress by accumulating osmolytes (Tuna et al., 2008), Silicon also appears to be a part of the osmoregulation within cells subjected to drought stress which enables the plant to uptake and transpirate more water for combating the stressed conditions. (Figs. 6 and 7) (Amin et al., 2014). Fourthly, the wheat’s hydraulic signal reduces water loss via transpiration by decreasing leaf area index and increasing leaves rolling (Nar et al., 2009). Fifthly, the adaptive root growth (Clausnitzer and Hopmans 1994), the compensated root water uptake (Simunek and Hopeman, 2009) and root hydraulic redistribution to cope with the heterogeneity in soil moisture regime ( Thomas et al., 2020 ). The soil system under drought cycles shrinks its energy to the half of its value at the wetting cycles to save plant’s life and prevent the plasmolysis (Homaee et al., 2002, Wang et al., 2020, and Hegazy, 2022a). The shrinkage of soil energy exceeds with the existence of salinity beside drought (Hegazy, 2020). Drought concentrates the soil solution, increases its conductivity which is already high due salinity, decreases the thickness of electric double layer, increases the diffused ions swarm (Sposito, 2008) which satisfies the remaining charges of the soil particles electrostatically, and therefore reduces the surface potential of highly energetic clayey particles. Accordingly, drought reduces the free energy of the background soil solution. In fact, it reduces the free energy responsible for the capillarity phenomenon (Fig. 4). Therefore, the in-vitro geo-regulated abiotic stress signal causes two in-vivo strains, the strain of osmoregulation achieved by osmaticum on one hand and the strain of cell turgidity on the other hand supporting plant growth (Nassar and Horton, 1997). At equilibrium, the latter strains are balancing each other to make the biological system holds minimum free energy and maximum entropy. Silicon increases the water potential of the root’s sap (Gong and Chen, 2012 and Amin et al., 2014) and leaf area index (Hegazy, 2022b) which enables plants to uptake and transpirate more water for combating the stressed conditions. Therefore silica enhances the latter in vivo strains (Figs. 6 and 7). The turgor strain causes cell wall expansion, rigidity, and optical growth which enable Plant roots to penetrate the soil system categorizing the energy states of soil water seeking the easiest available water to compensate with minimum plant consumed energy. In tillering crops such as wheat, a drying non-friable soil was found to limit root growth at the top 30 cm using the hydraulic signal for increasing cell wall elastic modulus and maintaining turgidity strain while promoting root extension and growth into depth. As dry soil was re-watering, it would become moist and friable, and the plant would be converting the fast root growth to the topsoil instead of the deep. As a result of the latter turgidity strain, plant roots elongated started to absorb water from less stressful parts of root zones (Albasha, 2015). Si depositions in the roots can increase cell wall elasticity during root cell elongation (Laing et al., 2007). Therefore, silicon makes the © 2023 Global Journals 1 Year 2023 36 Global Journal of Science Frontier Research Volume XXIII Issue ersion I VI ( ) III. R esults and D iscussions a) The response to silica under saline and drought conditions D The Modified Richard’s Equation for Assessing the Impact of Drought and Salinity in Arid and Semi-Arid Zones. Part Two: A Soil Hydraulic Capacitance