The Jordan block structure of images of long root elements in modular representations of algebraic groups of types $B_n$ and $F_4$

For $p>2$ the Jordan block structure of images of long root elements in modular irreducible representations of algebraic groups of type $B_n$, $n>2$, and images of such elements in irreducible $p$-restricted representations of algebraic group of type $F_4$ with highest weight $m_1\omega_1+\dots+m_4\omega_4$ and $m_3<p-1$, in characteristic $p$ is described.