  We consider the pion pole contribution and transversity effects determined by
the $H_T$ and $\bar E_T$ Generalized Parton Distributions (GPDs) which are
essential in hard pseudoscalar and vector meson leptoproduction. We investigate
spin effects in the $\omega$ and $\rho^0$ reactions. It is shown that the pion
pole contribution is very important in the $\omega$ production. Such effects in
the $\rho^0$ channel are much smaller. Our results on spin asymmetries and spin
density matrix elements in these reactions were found to be in good agreement
with HERMES data.
