We present our results concerning a systematical analysis of helioseis
mic implications on solar structure and neutrino production. We find Y
-ph = 0.238 - 0.259, R-b/R. = 0.708 - 0.714 and rho(b) = (0.185 - 0.19
9) gr/cm(3). In the interval 0.2 < R/R. < 0.65, the quantity U = P/rho
is determined with and accuracy of +/-5 parts per thousand or better.
At the solar center still one has remarkable accuracy, Delta U/U <4%.
We compare the predictions of recent, solar models (standard and non-
standard) with the helioseismic results. By constructing helioseismica
lly constrained solar models, the central solar temperature is found t
o be T = 1.58 x 10(7) K with a conservatively estimated accuracy of 1.
4%, so that the major unceratainty on neutrino fluxes is due to nuclea
r cross section and not to salar inputs.