T.P – Turgor Pressure:
It is the hydro-static pressure developed when a cell is placed in hypertonic solution or pure water resulting in endosmosis.
DPD – Diffusion Pressure Deficit:
The quantitative decrease or deficit in diffusion pressure caused due to the addition of solutes is called DPD. In a turgid cell, DPD equals zero. The hydathodes are present at the tips of the veins It consists of pore in the epidermis and it is guarded by guard cells. Just below the pore there is an air chamber. Just below the air chamber there is a group of loosely arranged thin walled, colourless cells (parenchyma like cells) are called epithem (Epithem are loosely arranged thin walled parenchyma cells present just below the air chamber of hydathode). Tracheids of xylem open just below the epithem. They are the ends of the xylem tissue of the veins.
