In the typically submerged Alg~ and in submerged plants of every group this is the absorptive and the main.
epiphytic plants and desert plants) have absorptive hairs or scales on the leaf epidermis through which rain and dew can be absorbed.
The part in contact with the endosperm is plate-like, and is known as the scutellum; the surface in contact with the endosperm forms an absorptive epithelium.
When none of the radiations which fall on a body penetrates through its substance, then the ratio of the amount of radiation of a given wave-length which is absorbed to the total amount received is called the "absorptive power" of the body for that wave-length.
Thus if the body absorbed half the incident radiation its absorptive power would be 2, and if it absorbed all the incident radiation its absorptive power would be r.