AP BIOLOGY

Detailed explanation-1: -The casparain strip prevents water from entering the pericycle except through the cytoplasm of endodermal cells. Because of the casparian strip, water and minerals cannot cross the endodermis and enter the vascular cylinder via the apoplast.

Detailed explanation-2: -The Casparian strips in the endo-and exodermis of vascular plant roots appear to play an important role in preventing the non-selective apoplastic bypass of salts into the stele along the apoplast under salt stress.

Detailed explanation-3: -Casparian strips do not directly block apoplastic water transport while suberin does. Yet, both act on aquaporin activity. Characterization of esb1-1 revealed that CIF/SGN3 dependent signaling, which inhibits aquaporin activity, is its primary cause of Lpr downregulation (Wang et al., 2019).

Detailed explanation-4: -Casparian strips have pretty much the same function as tight junctions in animal epithelia. They were shown to provide an extracellular (paracellular) diffusion barrier within the plant roots, forcing nutrients to pass into the cells and thus to be subjected to the action of plasma membrane transport proteins.