Sun September 09, 2012 By:

why do shoots exhibit negative geotropism?

Expert Reply
Mon September 10, 2012

Due to the negative geotropism of stems?,? ??????t?????he stems will grow towards the light and up and away from gravity. ?This places the leaves in better light ?c?a?u?s?i?n?g? ?????increase in photosynthesis.?? ???More food means better growth and reproduction.?

Plant shoots show negative geotropism because gravity causes auxins to build up on the bottom which causes the cells on the bottom to elongate. If a shoot is laid horizontally, the auxins redistribute to the lower side resulting in a higher concentration in those cells. In the shoot, the higher concentration causes increased cell growth, so the shoot bends upwards or against gravity, a negative geotropism.

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