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 Roots of the plant grow towards the earth which shows positive geotropism
and stem grows upward away from the pull of gravity which shows negative
geotropism.

 Concluded from the experiment.

Response of plants to chemicals: Chemotropism

 This diagram shows the response of a plant part ‘pollen’to chemical
secreted by stigma or chemotropism.

 Sugary substance acts as a stimulus for the growth of pollen tube towards the
ovule.
 This happens because ripe stigma in the carpel of a flower secrets a chemical
substance into the style towards the ovary.
 This sugary substance acts as a stimulus for the pollen grain which responds
by growing a pollen tube in the downward direction into the style of a carpel
and reaches the ovule of the flower for fertilisation.

Response of plants to water: Hydrotropism