The meetings come a day after the Palaniswami government won the vote of confidence by a margin of 122-11 in the Assembly.
Palaniswami was accompanied by his cabinet colleagues including P Thangamani, S P Velumani, C Ve Shanmugam and D Jayakumar during his meeting with Rao which an official release described as a "courtesy call".
Palaniswami had a brief discussion with Rao, it said.
DMK, whose MLAs were en masse evicted from the Assembly before the voting on the confidence motion, appealed to Rao to "nullify" the vote of confidence won by Sasikala loyalist Palaniswami, alleging it was adopted by contravening the Assembly rules.
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DMK Rajya Sabha members R S Bharathi, T K S Elangovan, and Tiruchi N Siva met Rao and submitted the representation.
Later, O Panneerselvam also met Rao and requested him not to recognise the confidence motion adopted in the Assembly.
Panneerselvam, along with some of his supporters including MLA S Semmalai, met the Governor for about 20 minutes.
K Pandiarajan, a former minister and Panneerselvam loyalist, told reporters that they told Rao "the trust vote does not fit into the Constitutional scheme of things".
Panneerselvam also apprised the Governor that he and Opposition parties had demanded secret ballot for voting on the trust motion so that legislators could "express their choice in a free manner".
Rao was also informed about the unsavoury incidents in the House yesterday.
After having separate meetings with Palaniswami, DMK MPs, and Pannerselvam and his followers, Rao left for Mumbai.