One type of it is stem cells. Queiscent cells are adult cells which do not divide, but under certain stimulation when it is needed, it can undergo cell division. One example are hepatocytes (liver cells).Permanent cells are cells that do not divide at all and have no such capabilities.ne type of it is stem cells. Queiscent cells are adult cells which do not divide, but under certain stimulation when it is needed, it can undergo cell division. One example are hepatocytes (liver cells).
Hairs trap a still layer of air to slow the rate of water vapor loss. Epidermal tissue has stomatal guard cells that regulate transpiration. Vascular tissue has a role in internal transport of water from root to leaf. The xylem is lignified to control water dispersal from the column. Limiting water exit to the plasmodesmata (desmodesmata) channels through cell walls.
The leaves of crop plants often function at -1 MPa, and some desert plants can tolerate leaf water potentials as low as -10 MPa. The water in plants can exist at such low water potentials due to the cohesive forces of water molecules. The chemical structure of water molecules is such that they cohere very strongly. By the cohesion-tension theory, when sunlight strikes a leaf, the resultant evaporation first causes a drop in leaf water potential.