  Motivated by the recent angle-resolved photoemission spectroscopy (ARPES)
measurements on one-dimensional Mott insulators, SrCuO${}_{2}$ and
Na${}_{0.96}$V${}_{2}$O${}_{5}$, we examine the single-particle spectral weight
of the one-dimensional (1D) Hubbard model at half-filling. We are particularly
interested in the temperature dependence of the spinon and holon excitations.
For this reason, we have performed the dynamical density matrix renormalization
group and determinantal quantum Monte Carlo (QMC) calculations for the
single-particle spectral weight of the 1D Hubbard model. In the QMC data, the
spinon and holon branches become observable at temperatures where the
short-range antiferromagnetic correlations develop. At these temperatures, the
spinon branch grows rapidly. In the light of the numerical results, we discuss
the spinon and holon branches observed by the ARPES experiments on
SrCuO${}_{2}$. These numerical results are also in agreement with the
temperature dependence of the ARPES results on Na${}_{0.96}$V${}_{2}$O${}_{5}$.
