the layer that makes the casparian strip waterproof is made of
Casparian strip The chemistry of the Casparian strip has been described as composed of suberin. According to some studies,[3] the Casparian strip begins as a localized deposition of phenolic and unsaturated fatty substances in the middle lamella between the radial walls, as partly oxidized films. The primary wall becomes encrusted with and later thickened by deposits of similar substances on the inside of that wall. The encrustation of the cell wall by the material constituting the Casparian strip presumably plugs the pores that would have otherwise allowed the movement of water and nutrients via capillary action along that path.[4] The cytoplasm of the endodermal cell is firmly attached to the Casparian strip so that it does not readily separate from the strip when the cells are subjected to contraction of the protoplasts. At the root, the casparian strip is embedded within the cell wall of endodermal cells in the non-growing region of the root behind the root tip.[5] Here, the casparian strip serves as a boundary layer separating the apoplast of the cortex from the apoplast of the vascular tissue thereby blocking diffusion of material between the two.[6] This separation forces water and solutes to pass through the plasma membrane via a symplastic route in order to cross the endodermis layer.[5]
Artex Until the mid-1980s,[2] the Artex coating was made with white asbestos to strengthen it. Therefore old Artex manufactured by Artex Ltd. will contain asbestos while Artex coatings applied after 2000 may or may not contain asbestos. It is also worth noting that the texture is only harmful when in a powder form, i.e., being sanded, and poses no risk while it is undisturbed (without drilling holes or more substantial practices) on ceilings or walls and covered with emulsion paint.