investigating tropisms Flashcards
what is geotropism
directional growth to gravity
what is phototropism
a directional growth response to light
where in plant does growth occur
growth occurs in plant where immature cells are still capable of dividing- meristems
what are the lateral mersitems responsible for
responsible for shoots and roots getting wider
where are intercalary meristems located
located between the nodes. Where the leaves and buds branch off the stem.
responsible for the shoot getting longer
how do we experiment phototropic and geotropic responses
phototropic responses can be investigated by a control plant and an experimental plant. the control plant is illuminated from all the sides, while the experimental plant is only illuminated on one side.
the shoots are marker every 2mm to show growth. Shoot should bend towards the light
how are geotropic responses investigated
a control plant is on a klinostat, so it is spun constantly, so gravity is applied equally to all sides of the plant.
the experimental plant, klinostat is not turned on so gravity is only applied to one
what was darwins experiment
confirmed that the shoot tip was responsible for phototropic responses.
for example, covering tip with an opaque shield and transparent shield
what is the boysen jenson experiment
he confirmed that water and solutes need to be able to move backwards from the shoot tip for phototropism to occur. therefore he experimented with a impermeable mica block and permeable gelatin block. The one with the gelatin block showed phototropism, the mica block showed no phototropism
