What is phytochrome and which PS is involved in bacterial photosynthesis

Phytochrome=colour absorbing substance.
In plants these phyto chromes are present, they help in absobing light and regulates the development process.
Example:chlorophyll,xanthophyll,flavonoids,carotenoids etc.,
PS=Photosystem
In bacteria only PS-I is present they help in producing energy equivalents like ATP and NADPH