BIO-GEO CHEMICAL CYCLE OR NUTRIENT CYCLE Bio - Living organism Geo - Rock, Soil, Air, Water Chemical - Material or Nutrients Cycle - Path All the types of material required by ecosystem in addition of energy, are available continuously to system through recycling. Thus there is a constant exchange of materials between the living organism and their abiotic environment through the recyling of materials. This phenomenon is called Bio-geo chemical cycle. Note: Environment factors,e.g soil , moisture, ph, temperature etc, regulate the release of nutrients into the atmosphere. Biochemical cycle The following types of cycle are found in an ecosystem. (i) Gaseous Cycle - C, H, N. O cycles. Reservoir is in the atmosphere (air) or in Hydrosphere(water). Sedimentary cycle - P. S, Ca cycles reservoirs are in earth's crust (lithosphere). Note : ...
Facebook STRUCTURE OF MICROSPORE OR POLLEN GRAIN : pollen grain is the first cell of a male gametophyte. Pollen grain is termed as immature male gametophyte. Usually, they are in round shape. Pollen grain surrounded by two distinct layers. The outer layer (wall) is thick, rigid and ornamented, called exine . This layer is formed by cutin and sporopollenin , Sporopollenin is highly resistent material. It is nonbiodegradable. Due to the presence of sporopollenin, fossils of pollen grain are always found in good condition. The presence of fossils of STRUCTUREOF POLLENGRAINS pollengrains can forecast the presence of natural resources like petroleum, coals etc. in the earth. The internal layer is thin, soft and elastic in nature. It is called intine . It is made up of pectin and Cellulose or pecto-cellulose . Usually, at few places on outer surface exine is absent or present in the form of thin layer. These thin places are called germ pore. The intine comes out through t...