How must salt is just enough?

This video explains soil and plant water potential and resulting hydraulic flow, completely and clearly and in plain language in a mere sentence or two. It represents, in the very simple drawing, the notion of a semi-permeable membrane that would allow water to pass into the plant, but not salt, and simultaneously that when salt levels were high in the soil solution this would act to slow the flow of water into the roots. Yes, a more detailed explanation would be that the water potential gradient is the driving force (and water always moves from high to low water potential); when soil water is fresh (not salty), water potential is more negative in the root than in the soil solution, and more negative yet at the leaf than root, and more negative in the air than the leaf- creating a gradient that “pulls” the water upwards through the soil-plant-air continuum. When solutes, like salt, are in high concentration in the soil water, that lowers the water potential in the soil water to levels that can be as low or lower than the water potential in the roots, slowing or stopping the influx of water.


Author: FRAC Labs

FRAC is NABL accredited, BIS Certified, DPCC and FSSAI Empanelled; our testing scope includes testing of all Foods, Beverages and Environment (air, noise, waste water, hazardous waste).

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