Anthesis is the period or action of a flower opening, and this post will document two Ta-Jan flowers doing exactly that.
Firstly, a refresher on the parts of a jujube flower to make this easier to follow along:
Stamens and anthers are mentioned a few times in this post as, unlike the style and stigmata, they are somewhat mobile during anthesis. The stamen, the complete male organ of a flower, is not marked as such on the above photo, but is simply a word that refers to the anther and filament together. Pollen (the sperm equivalent) is produced by the anther. The filament is a stalk that attaches the anther to the flower.
Did you know jujube flowers are of one of two types? Some cultivars are morning blooming, and some are afternoon blooming. Morning blooming flowers begin anthesis in the morning, with peak nectar production that afternoon, while afternoon blooming flowers begin anthesis in the afternoon with peak nectar production the following morning.
I chose Ta-Jan flowers to photograph, as these are morning blooming. These also have a vivid yellow nectary disc! (The discs in some cultivars are less bright.)
The photos below are of the same two flowers — the top views (left) are of the same flower each time (Flower 1), and the side views (right) are of a second, same flower each time (Flower 2). The white twist ties visible were there to help me identify the same flower on the same fruiting branchlet each time — it can be hard to keep track when there are branchlets and flowers everywhere, and even more disorientating with buds turning into flowers and flowers changing form all around and all at the same time!
A flower’s bloom time is just 24 hours, but this isn’t too noticeable to a casual observer, as the flowers are both small and numerous — along any one fruiting branchlet will be many flowers representing all stages of anthesis, and a single flower tends to get drowned out in the noise! If you revisit the Photo Journal: Different Flower Stages post after reading this post, you may well see the photos on that page with new eyes, and will definitely see your own flowers in a new light!
Anthesis of a jujube flower could be broken down into several stages:
- flower bud changes from green to yellowish
- sepals separate
- sepals flatten, petals and stamens (anthers + filaments) upright
- petals and stamens separate
- petals flatten and stamens upright
- stamens flatten
- nectary disc lightens
1. Flower Bud Changes Colour
The 25th November photo for Flower 1 is more yellow in tone overall compared to the 24th November one (this is especially noticeable in the stem the twist tie is on). This is probably the camera adjusting white balance based on the more yellow bud at centre that it was focusing on. However, it’s still apparent that the bud has changed colour when compared to the smaller still developing bud to its right. (My excuse is that I’m not expert enough to adjust for white balance in the field, and it would take too long to do that in software!)
The two photos for Flower 2 are more uniform in tone, and the change in colour of the bud is more apparent. The darker background of the second image may suggest this was taken at night, but this is just an artifact of partial shadow at that time of day popping the flash. (I have everything set to auto as I trust the camera to take better photos than me — one day that will change!)
2. Sepals Separate
The more yellow hue of Flower 1’s sepals is more evident here, when compared to the buds to its right.
And here’s Flower 1 a little later, at 9:59am:
3. Sepals Flatten, Petals and Stamens (Anthers + Filaments) Upright
The glistening you can see on the nectary disc of Flower 1 is nectar production. You may just be able to see the bright yellow disc on Flower 2 too.
If you look really closely, and compare this photo immediately below to the very first photo at top of page (’Jujube flower anatomy’), you’ll note that the petals and stamens here appear combined. The stamens’ filaments are actually tucked into the ‘handle’ part of the little green spoon-like petals — and once you know that you might be able to make out the anthers as the whitish, pointed tips that extend from the ’spoon bowl’ part of the petals further back. The next photo will make this clearer.
4. Petals and Stamens Separate
5. Petals Flatten and Stamens Upright
Here the petals are now in the same plane as the sepals while the stamens remain upright, the whitish anthers shining like little beacons atop the green filaments. The nectar produced by the nectary discs of both flowers is already attracting ants.
6. Stamens Flatten
I missed when this actually happened for Flower 2, but the photo of it the morning after still makes the point!
7. Nectary Disc Lightens
The nectary disc lightens as anthesis progresses, to become the same colour as the sepals:
To wrap up, here’s a photo of Flower 1 and some neighbours, just to illustrate how as some flowers advance through anthesis, others are at their end of life (perhaps having never been pollinated), others are just beginning, and attracting pollinators, and others still are yet to move from the bud stage:
And this is along just two centimetres of one fruiting branchlet!
For a bit of relaxing quiet time, why not grab a magnifying glass (or loupe if you have one) and peruse your own flowers? You may even enjoy watching pollinators moving about — hopefully pollinating as they go! Speaking of pollination, ongoing flower evolvement post-pollination into fruit development is another post I will be covering in due course!
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