If you grew a plant in a Petri dish and then turned it on its side, the roots would change (probably over a day or two) to grow down towards gravity. Overall, it would look like the roots had become bent -- the part of the roots near the stem of the plant would point down towards the bottom of the petri dish, but because you then turned it on its side, the part of the roots near the root tips would be bent pointing down towards the new direction of gravity, running along the bottom of the dish.

Please click on here to read more for this question

Yes, the roots may very well grow up against gravity as long as they are still acquiring nutrients. The plant, however, should turn and grow upwards rather than straight out to the side.