Osmotic Pressure and pH Measurements on Cell Sap of Pinus ponderosa

Differences in Survival of Excised Ponderosa Pine Leaves of Various Ages

“…Gail and Cone (2) found that both pH and osmotic pressure increased with age in ponderosa pine leaves. More recently photosynthesis has been shown to decline noticeably with age in a number of conifers and especially in ponderosa pine (1).…”