Two of the quotes on this panel deal with the topic of praying to Heavenly Mother. The quote from President Hinckley says we do not pray to her because we are taught in scripture to pray to the Father in the name of the Son. The quote from Orson Pratt in its entirety is this:
"But if we have a heavenly Mother as well as a heavenly Father, is it not right that we should worship the Mother of our spirits as well as the Father? No; for the Father of our spirits is at the head of His household, and his wives and children are required to yield the most perfect obedience to their great Head. It is lawful for the children to worship the King of Heaven, but not the 'Queen of heaven.'... we are nowhere taught that Jesus prayed to His heavenly Mother..."
He also believes that God has more than one wife, which would make praying to a specific being pretty difficult. This quote can be found in The Seer page 159.
The Gordon B. Hinckley quote is found here: https://www.lds.org/general-conference/1991/10/daughters-of-god?lang=eng
The third quote, by Carol Lynn Pearson, is from an article titled Healing the Motherless House.