Why do brides throw rice?

Why do brides throw Dhan(paddy ) or haldi Akshat ( Rice) behind when leaving their father’s house after marriage?
And why does her mother collect that Dhan or Haldi Akshat with her anchal?

Because When Maa Mahalakshmi leaves the house, she takes all the wealths, prosperities, happiness and peace of that house with her.

But the daughter is such BhagyaLakshmi for her parents that when she leaves her parental home after marriage, she leaves all her Virtue, wealths, prosperities, happiness for her parents and enters the new house to make her own fortune.

For this reason, daughters throw Dhan and Haldi Akshat behind at the time of farewell after Marriage and leave their virtue in their father’s house along with wealth,prosperity Happiness and peace

And the mother collects that punyo of Bhagya Lakshmi that resides in her daughter and keeps the punyo in the Mahalakshmi pot in their home Mandir along with Dhan,Haldi Akshat.