Planographic printing plate precursor, substrate for the same and surface hydrophilic material

A planographic printing plate precursor comprising a substrate having disposed thereon a hydrophilic layer which includes hydrophilic graft chains and a crosslinked structure formed through hydrolytic polycondensation of an alkoxide of an element selected from Si, Ti, Zr and Al, wherein the hydrophilic layer includes a polymer compound represented by the following general formula (I):

• wherein each of R1, R2, R3 and R4 independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms;
• m is an integer of 0 to 2;
• n is an integer of 1 to 8;
• L represents a single bond or an organic linking group Y represents —NHCOR5, —CONH2, —CON(R5)2, —COR5, —OH, —CO2M or —SO3M;
• R5 represents an alkyl group having 1 to 8 carbon atoms;
• and M represents one of a hydrogen atom, an alkali metal, an alkaline earth metal and an onium, said planographic printing plate precursor further comprising an image forming layer on said hydrophilic layer.