There are some photoreceptors that are necessary for plant
growth and development, including seed germination. For example,
phytochrome B proteins, which are stable and found in green
tissues (Quail, 1997) are able to regulate the hormonal signaling
pathways of auxin and cytokinin (Tian et al., 2002; Fankhauser,
2002; Choi et al., 2005). Phytochromes in the seeds are necessary
for controlling seed germination, especially when the seeds are subjected
to light. Light activates phytochromes, as well as hormonal
activities in plants