  Using a phenomenological model, we discuss the consequences of spinon-holon
binding in the U(1) slave-boson approach to $t-J$ model. Within a small $x$
($x=$ hole concentration) expansion, we show that spinon-holon binding produces
a pseudo-gap normal state with a segmented Fermi surface and the
superconducting state is formed by opening an "additional" d-wave gap on the
segmented Fermi surface. The d-wave gap merge with the pseudo-gap smoothly as
temperature $T\to0$. The quasi-particles in the superconducting state are
coupled to external electromagnetic field with a coupling constant of order
$x^{\gamma}$ where $0\leq\gamma\leq1/2$, depending on the strength of the
effective spinon-holon binding potential.
