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April 21

Do all flowers need sunlight to blossom?

Having located the linked article my wife and I have had a heated debate concerning flowers. We would like the following question answered.

Do all flowers require sunlight in order to bloom? Clearly not all flowers need sunlight to develop, and not all plants need sunlight in order to survive. Our question relates specifically to the opening and blooming of flowers.

https://news.mongabay.com/2019/08/new-orchid-species-from-japan-lives-on-dark-forest-floor-never-blooms/amp/

Thank you — Preceding unsigned comment added by 2A00:23C6:6888:C600:28F4:D64D:6F71:62B8 (talk) 20:57, 21 April 2022 (UTC)[reply]

There are a lot of plants that bloom at night (see Category:Night-blooming plants) I don't know what triggers them to bloom ("when it's dark" vs "when it becomes no-longer-light"). So I'm not sure if that does or doesn't qualify for your interest. DMacks (talk) 21:50, 21 April 2022 (UTC)[reply]

BTW, all plants need some sunlight, even if not directly - see photosynthesis. Alansplodge (talk) 22:43, 21 April 2022 (UTC)[reply]

Tell it to Gastrodia kuroshimensis. (That one doesn't bloom, which is the key to the question.) --jpgordon^{𝄢𝄆𝄐𝄇} 23:04, 21 April 2022 (UTC)[reply]

This being the Science Desk and all, I think some precision is required here. Is the question asking about direct sunshine on the flowers being required for them to bloom, or just daylight? If it's the former, the answer is obviously no. Many flowering plants in deep mountain valleys never experience direct sunlight. HiLo48 (talk) 00:07, 22 April 2022 (UTC)[reply]

OP here, different computer. Without being in a cave it would be well nigh impossible to have no sunlight. The question relates to the plant receiving direct sunlight in order for the flower to bloom. Deep valleys may have flowers but they are not dark to the point of near 0 sunlight such as experienced in deep jungle floors where the flower in question grows. Thanks — Preceding unsigned comment added by 62.252.54.42 (talk) 11:04, 22 April 2022 (UTC)[reply]

Flowering room plants often do not need (and do not receive) direct sunlight. For a few examples, see here. --Lambiam 14:21, 22 April 2022 (UTC)[reply]

OP again. Thank you, and if the flowers do not receive any sunlight such as those that exist in caves...those never bloom because they never receive sunlight? Is that accurate without deviation and exception? Thanks — Preceding unsigned comment added by 62.252.54.42 (talk) 15:24, 22 April 2022 (UTC)[reply]

There are parasitic plants that don't do their own photosynthesis, and only emerge above ground or out of the trunk of the host plant to flower and set seed. The fact that the sun shines on them at that point is probably of only indirect interest to them. Abductive (reasoning) 07:37, 23 April 2022 (UTC)[reply]

It is disappointing that the original questioner seems to have a better grasp of the issue than most of those who have responded! One study has shown that in the parasitic plant Dodder the cue to initiate flowering comes from the FT protein generated by the host and used by the host plant to initiate its own flowering. The trigger for flowering in the host plant is in most cases photoperiod, so still you need to have light in the system, although not directly illuminating the Dodder plant itself. The same article points out that "very little is known about how flowering of parasitic plants is regulated". Jmchutchinson (talk) 09:16, 23 April 2022 (UTC)[reply]

That's what I alluded to by indirect interest. Even holoparasites have to engage with the pollinators and seed dispersers, and know what season it is. An example is beechdrops (interesting that both it and dodders have an always-plural name.) Dodders is an aboveground plant and only hemiparasitic. Abductive (reasoning) 16:19, 23 April 2022 (UTC)[reply]

Dodder, singular. Bazza (talk) 09:05, 24 April 2022 (UTC)[reply]

In any case, no evidence has been presented that the light plants may need for flowers to open and bloom has to be, specifically, sunlight. Here Corydalis lutea is reported to be a blooming perennial that thrives even in dense shade. --Lambiam 10:01, 23 April 2022 (UTC)[reply]