We use these values to assist in monitoring water to ensure your plants have adequate water, while also helping you save as much as possible by not over-watering. Meaning of Permanent wilting point. Permanent wilting point (PWP) is defined as the largest water content of a soil at which indicator plants, growing in that soil, wilt and fail to recover when placed in a humid chamber. It’s the soil potential at which sunflowers wilt and are unable to recover overnight. Permanent wilting point (PWP) or wilting point (WP) is defined as the minimum amount of water in the soil that the plant requires not to wilt.If the soil water content decreases to this or any lower point a plant wilts and can no longer recover its turgidity when placed in a saturated atmosphere for 12 hours. The uncertainties in permanent wilting point could introduce large simulation errors under severe stress conditions. Definition of Permanent wilting point in the Definitions.net dictionary. Information and translations of Permanent wilting point in the most comprehensive dictionary definitions resource on the web. (2001 a) by applying two soil water thresholds, the hygroscopic point ([s.sub.e_h]) and the permanent wilting point ([s.sub.e_w]) to the evapotranspiration term, which could more accurately describe soil water dynamics under conditions of water stress, and especially during drought. Soil at the Permanent Wilting Point is not completely dry, as it still has a little bit of water; but the amount is so little it is not accessible by plants. Soil parameters related to soil water holding capacity could play an important role in simulating winter wheat growth under severe soil water stress, which could heavily influence the simulated soil water contents, and then biomass and final yield. As mentioned and the most well-known cause of wilting in plants, is a lack of water. Why do plants wilt? Then it comes to the point that the plant can no longer extract water from the soil (Permanent Wilting Point). Abstract. Permanent wilting point was experimentally determined in sunflowers and defined as -15 bars (-1500 kPa, Briggs and Shantz, 1912, p. 9). What does Permanent wilting point mean? Permanent wilting point is the minimum soil moisture required by a plant not to wilt, specifically at the root level. Permanent wilting Point : Permanent wilting point is the moisture content at which the moisture is no longer available in sufficient quantity so that the plants can sustain. It’s theoretically the empty tank, where there is a complete loss of turgor pressure, and the plant has wilted. Even though the soil contains some moisture but it was so held by the soil that roots of plants cannot uptake it and results in wilting of plant.