Negative Gravitropism | Demonstration

Negative gravitropism demonstration showing how mustard shoots react to change in pot position.

Gravitropism is growth or movement response to gravity, observed in plants and fungus. Its is also called – geotropism. Just like phototropism, gravitropism can be positive or negative. To put it simply – positive gravitropism makes plants point same direction as gravity is puling – down, while negative gravitropism is directed upwards.

Plants, well, at least mustard, are ridiculously sensitive to light. Before landing on last setup version for this demonstration, I've tried: using direct light from flash, indirect light from flash (both on weakest power setting), indirect light from 3,5 W 2700K light bulb (lowest wattage I could find for wide spectrum light bulb). In all cases plants pointed toward light source. Though, response was a lot weaker, compared to positive phototropism video (   • Positive Phototropism | Demonstration  ). I ended up using indirect light from 3,1 W red light bulb, since phototropic response to red light is normally masked by gravitropic response (https://nph.onlinelibrary.wiley.com/d.... For this reason video is desaturated. Light were places in front of plants but pointed away from them and towards the panel to diffuse light. Exposure times were 1 min 15 s with ISO 200 and f/8. Oh, and yeah, all of this was done in a wardrobe, with all gaps covered to avoid external light. It is a big wardrobe.

Plants on the right are control group.

Most likely reason why all motion ceases in the end – plants ran out of energy.


Sequence of images for this video was edited and exported with Capture One, save up to 10% using coupon code: AMBGPHASE


Music:
Isolated by Kevin MacLeod is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/...)
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