For a bounded domain D and a real number p > 0, we denote by A p (D) the space of L p integrable holomorphic functions on D, equipped with the L p -pseudonorm. We prove that two bounded hyperconvex domains D 1 ⊂ C n and D 2 ⊂ C m are biholomorphic (in particular n = m) if there is a linear isometry between A p (D 1 ) and A p (D 2 ) for some 0 < p < 2. The same result holds for p > 2, p = 2, 4, · · · , provided that the p-Bergman kernels on D 1 and D 2 are exhaustive. With this as a motivation, we show that, for all p > 0, the p-Bergman kernel on a strongly pseudoconvex domain with C 2 boundary or a simply connected homogeneous regular domain is exhaustive. These results shows that spaces of pluricanonical sections of complex manifolds equipped with canonical pseudonorms are important invariants of complex manifolds. The second part of the present work devotes to studying variations of these invariants. We show that the direct image sheaf of the twisted relative mpluricanonical bundle associated to a holomorphic family of Stein manifolds or compact Kähler manifolds is positively curved, with respect to the canonical singular Finsler metric.2010 Mathematics Subject Classification. 53C55, 32Q57, 32Q15, 53C65.