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I have an avocado plant that I grew from a pit. I have noticed that in the evening the leaves begin to droop down, and then in the morning and day they come back up to where they normally are. Is this normal behavior?

Here's a picture of the plant during the day: enter image description here

During the night the leaves go down towards the plant, I guess you could say that they curl in towards the plant.

Mihkel
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  • I know this is a couple years old but I just had to correct Aleksander on Sunflowers drooping.Yes Sunflowers very well do droop at night. I don’t know where you live Sunflowers stay up right 24/7 but it must be a magical place... – Keith May 11 '20 at 02:16

1 Answers1

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Yes this is normal behavior for many plants. It is caused by phototropism. During the day, when light shines, the plant will grow towards the light. This is caused by auxins, which are phytohormones. The most common method used by plants is that these auxins stimulate growth, but are degraded by light. This causes the effect that parts of the plant in shade grow harder than parts in light, and hence they bend towards the light. During night this effect stops and therefore the leaves will droop.

benn
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  • Ok, do normal outdoor trees like oaks or maples do this aswell? – Mihkel Jul 06 '18 at 07:38
  • It is not always obvious for outdoor plants, because the light is not like indoor just from one direction. But sunflowers are a nice extreme example. – benn Jul 06 '18 at 07:39
  • I just found on [internet](http://plantsinmotion.bio.indiana.edu/plantmotion/movements/leafmovements/bean/beansleep.html) that plants can also adapt to this behavior even in absence of day/light change. In the video you can see a bean plant that was used (trained) to stretch during day light and droop over night. And when the day/night rhythm stopped the plant continues this behavior. So phytohormones involved in circadian rhythm are also involved. – benn Jul 06 '18 at 10:25
  • They just had an episode podcast on radiolab involving this topic, plants in general the whole episode but talking in this case about plants going to sleep or drooping at night. Its an npr program should be able to look it up if youre interested – user22106 Jul 06 '18 at 15:48
  • The OP asks about drooping. Your answer is about growth. These are two different things. For example, do sunflowers droop? No. – Aleksandar M Jul 30 '18 at 10:06
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    Do sunflowers droop? Sure there are situations where they droop, but that's not the point here. Sunflowers are a nice example of phototropism. I don't know what level in biology you have, but in biology we have different kinds of growth. Cell growth is well known, but swelling: filling tissue with fluids is another way of growth. In plants they use this kind of growth a lot (they don't have muscles you see). This kind of drooping happens when there is lack of this turgor growth and is regulated by reaction to light. – benn Sep 04 '18 at 09:52