  Stellar parameters of 25 planet-hosting stars and abundances of Li, C, O, Na,
Mg, Al, S, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Zn, Y, Zr, Ba, Ce, Pr, Nd, Sm and
Eu, were studied based on homogeneous high resolution spectra and uniform
techniques. The iron abundance [Fe/H] and key elements (Li, C, O, Mg, Si)
indicative of the planet formation, as well as the dependencies of [El/Fe] on
$T_{cond}$, were analyzed. The iron abundances determined in our sample stars
with detected massive planets range within -0.3<[Fe/H]<0.4. The behaviour of
[C/Fe], [O/Fe], [Mg/Fe] and [Si/Fe] relative to [Fe/H] is consistent with the
Galactic Chemical Evolution trends. The mean values of C/O and [C/O] are <C/O>=
0.48 +/-0.07 and <[C/O]>=-0.07 +/-0.07, which are slightly lower than solar
ones. The Mg/Si ratios range from 0.83 to 0.95 for four stars in our sample and
from 1.0 to 1.86 for the remaining 21 stars. Various slopes of [El/Fe] vs.
Tcond were found. The dependencies of the planetary mass on metallicity, the
lithium abundance, the C/O and Mg/Si ratios, and also on the [El/Fe]-Tcond
slopes were considered.
