The Philodendron I got my Mom last week is doing great, but is also VERY interesting. Last night we noticed that from the very tips of some of the leaves there was little water droplets forming. Only they felt just a touch stickier than water. Any idea of what it was? NEVER seen this before in a Philly.
Philodendron species are members of the larger family Araceae. There are approximately 1000 species in the genus Philodendron. It is not uncommon to see water dripping from the leaf tips, although many growers assume the liquid is a result of dew it would be unlikely to observe dew forming inside a home on a house plant. Even the droplets of water seen on grass in morning are frequently caused by guttation, rather than dew and guttation occurs in many plant species. Aroids and other plant species possess glands known as hydathodes that are capable of producing a clear liquid through a process of guttation. The word guttation is derived from the Latin word gutta "gut-TA" meaning droplet. Excess moisture in the leaf blade normally transpires through pores of the leaf blade and is evaporated by heat and wind. During periods of low temperatures and still air motion the water just accumulates at the leaf's tip. Although sometimes called "sap" on plant discussion websites guttation is just the watery liquid that comes out of the plant and is common especially at night. During the heat of the year the warmth of the sun pulls the water inside the stem (base of the plant) through the petiole (support of the leaf blade) to the lamina of the leaf so the blade is filled with water. Natural evaporation causes the water to be raised upwards. When evaporation is not "pulling" the water out of the plant as a result of the lower natural temperatures during fall and winter the water inside the blade has no place to go and must find a method of escape since the petiole and stem are already filled. The water just seeks the easiest route out of the plant and chooses a gland. The weight of the water builds pressure pushing downward on the petiole toward the stem and finally builds to a point where the plant is simply forced to release the liquid through the leaf. Guttation commonly happens at night when the transpiration rates are naturally low. It is possible for guttation to occur when the hydrostatic pressure is insufficient to prevent the flow of water into the xylem. The xylem is a plant tissue of various cells that is capable of transporting water and other substances including salts to the leaves. Guttation frequently occurs in tropical plants when high humidity inhibits the natural transpiration or the loss of water vapor inside the plant to the outside air. Guttation often occurs through the hydathodes that are found on the leaf tips of many Araceae (aroids). A hydathode is a modified stoma which is normally involved in photosynthesis that must secrete water as a result of the pressure of the excess water. The hydathodes of Araceae are commonly localized in the leaf tip but may be found elsewhere on the leaves. I hope that is not overly technical and will give you an idea why this happens.
