Osmotic Pressure of Leaves of Pinus scopulorum, and Certain Environmental Factors

Abstract

1. A correlation was noted between the osmotic pressure and the rate of evaporation in leaves of Pinus scopulorum, the higher pressures generally occurring with the higher rates of evaporation, and vice versa. A difference of approximately three atmospheres was noted between the pressure occurring with the lowest and highest rates of evaporation. 2. A correlation was noted between the monthly mean temperature and the monthly averages of osmotic pressure. In general, lower pressures (13 atmospheres) occurred with the lower temperatures (35⚬) and higher pressures (16.7 atmospheres) with the higher temperatures (73⚬). The highest pressures for the year (an average of 16.7 atmospheres) were found in July, and the lowest (an average of 13 atmospheres) were found in January. 3. No definite correlation was noted between the osmotic pressure of the leaves and soil moisture. 4. No correlation was shown between the amount of precipitation and the osmotic pressure over a period of one year. 5. No correlation was sho...