Vapour-pressure deficit the plant may dry out and die. For this reason the ideal range for VPD in a greenhouse is from 0.45 kPa to 1.25 kPa, ideally sitting at around 0.85 kPa. As a general rule, most plants grow well at VPDs of between 0.8 and 0.95 kPa. In ecology, it is the difference between the actual water vapour pressure and the saturation water vapour pressure at a particular temperature. Unlike relative humidity, vapour-pressure deficit has a simple nearly straight-line relationship to the rate of evapotranspiration and other measures of evaporation. To compute the VPD, we need the ambient (greenhouse) air
Amount realized than money) received." Generally, it is the value of what the taxpayer receives in the exchange. To have an "amount realized" there must be a kind of exchange, known as a "realization event." The first step in calculating the amount realized is determining when an exchange that qualifies as a "realization event" has occurred. Section 1001 requires that it be an exchange through which the taxpayer receives money or other property. In "Helvering v. Bruun", the United States Supreme Court has held that a "[g]ain may occur as a result of exchange of property, payment of the taxpayer's indebtedness, relief