Question

what will happen to the sunflower and ipomea if sun is not there

Answer 1

Due to the lack of sunlight, (as they need it) they may die

Answer 2

The sunflowers will continue to bend in darkness demonstrates that it is a mistake to think too literally of plants as “seeking” the sunlight. Sunflowers don’t bend themselves with any purpose in mind. More accurately, we can say they have evolved over millions of years into the solar tracking rhythm because it helps catch light effectively, and the ones that catch the light best, are the ones most likely to survive. In all living things, natural selection favors.