Q.When the plants shed their leaves how do they respire?

A lenticel is a raised opening or pore that develops on the epidermis or, later, on the bark of a stem or root as it undergoes secondary growth. It forms in a region where the phellogen (cork cambium) becomes locally more active than in the surrounding tissue, producing a mass of loosely arranged, thin-walled parenchyma cells there instead of compact, suberised cork; this loosely packed patch is called the complementary tissue or filling tissue, and it is precisely what keeps the lenticel from sealing over the way the rest of the corky bark does. Anatomically, a lenticel's raised opening penetrates the otherwise near-continuous phellem layer, connecting the loosely packed complementary tissue beneath it to the outside air, and structures such as a first cork cell, cuticle remnants and the underlying phellogen can all be identified around a lenticel's margin in cross section. …