Photo Journal: Anatomy of a Shanxi-Li Fruiting Branchlet
Around 7pm the other evening I was perusing my trees, and — as I often do, gently pulled down a fruiting branchlet above to look more closely with my loupe at the flowers and developing fruits along it. To my absolute horror it came away in my hand! I reconciled myself by thinking that maybe it was structurally weak and always destined to fall off, and decided to make good of the situation by writing about it!
So here it is, the anatomy of a Shanxi-Li fruiting branchlet!
This was a large branchlet, about 385 mm along a straight line, but closer to 405 mm long, as measured by following every bend of the stem with a piece of string and then measuring the string. It was so noticeably large (most in my experience tend to be under 300 mm long) that I really do wonder if it was structurally weak and would have snapped off eventually as the developing fruit on it grew larger and heavier?
As with all new jujube branch growth during a season, the oldest part of this branchlet (which was closest to the fruiting mother branch) was turning red while the youngest part of the shoot was still the bright green of new growth.
The proximal end (of anything) is that closest to the point of origin or attachment. Here, the point of attachment of this fruiting branchlet was the fruiting mother branch. Conversely, the distal end (of anything) is that furthest away from the point of origin or attachment:
Here is where the point of attachment was:
And here is the proximal end of the branchlet, with a transverse (crosswise, cross-sectional) view of the point of detachment:
A node is the point along a branch from which leaves and other branches grow. An internode is the interval between two nodes.
The closest node (and leaf) to the fruiting mother branch was 15 mm away. The largest internode, and the third along from the fruiting mother branch, was 40 mm long. The internodes were then spaced at 30 mm intervals, then 25 mm intervals, and finally the last internode was just 3 mm long, but with still developing leaves, and would have lengthened by season’s end. The penultimate internode was 10 mm long.
The leaves are alternate, meaning there is a single leaf at each node. The leaves alternate sides along the branch, because the nodes alternate sides, hence the name. (The two other leaf arrangements defined in botany are opposite and whorled.)The largest leaf on this branchlet was 90 mm long and 55 mm across the widest part. The smallest leaf was 35 mm long and 15 mm across its widest part. The very small, still developing leaves at the distal end were just 5 mm long.
The flower arrangement (inflorescence) at each node is a simple cyme. A cyme is a group of flowers in which the oldest flower occupies the end of the peduncle (the main supporting stalk, or main axis), and newer shoots come from the sides of that stalk.
As the flowers differ in age within a cyme, so too do the fruits which develop from those flowers:
And as flowers (and fruits) differ in age within a cyme, so too do they differ in age along a branchlet. Those at the fruiting mother branch (proximal) end are oldest and those at the (distal) tip are youngest. Here, these cymes which were closest to the fruiting mother branch have no flowers anymore, but do have the largest fruits. Note too the change in colour of the branchlet when moving from the proximal end towards the distal end:
The cymes at the very tip of the branchlet have the youngest flowers of all — minute buds which have only just begun development:
The cymes between these extremes occupy a gradient of mostly fruit and some flowers, to some fruit and mostly flowers, to mostly flowers and some buds, to mostly buds and some flowers. Note too the colour change along the branchlet. You can tell that the banchlet segment in the top photo below is closer to the fruiting mother branch than the segment in the lower photo below, as it is more red at the proximal end:
Fruiting branchlets are the only branches on a jujube tree to produce flowers and fruits — so writing about one allowed me to slip more botany in than I otherwise could have with another branch type!
To go further and discuss the flowers and fruits on a fruiting branchlet really require their own posts to do those topics justice. I covered Photo Journal: Anatomy of a Jujube Flower earlier, and fully intend to do one on fruit later, but here is a good place to wrap up this post with, I guess, a teaser for what will come!
The following photos are of the largest fruit on the branchlet discussed here. This fruit was the most proximal and 8 mm long.
Do revisit the flower anatomy post — this page may help too — and see if you can work out what the two little brown dots on this fruit’s distal end are. (Distal in this context refers to the end of the fruit furthest away from its point of attachment, and not to be confused with the distal end of the branchlet discussed above.)
What about now?
Yes, those are the two stigmata and the branched style of the original flower! The green fruit you see is the maturing ovary of that flower. But more on that to come later!
The proximal end of the same fruit reveals the sepal remnants:
Let’s (almost) bisect it. I say ‘almost’, as a real bisection would have had two equal halves, each with that delicate little peduncle cleaved cleanly in two along its length. Sorry but that was never going to happen!
Just looking at this you may well be able to make out which parts will become the seeds, the stone that contains the seeds, and the fruit itself? This, and what happens as the fruit grows, is definitely the topic of a future post!
About the Author
BSc(Hons), U.Syd. - double major in biochemistry and microbiology, with honours in microbiology
PhD, U.Syd - soil microbiology
Stumbled into IT and publishing of all things.
Discovered jujube trees and realised that perhaps I should have been an agronomist...
So I combined all the above passions and interests into this website and its blog and manuals, on which I write about botany, soil chemistry, soil microbiology and biochemistry - and yes, jujubes too!
Please help me buy a plant if you found this article interesting or useful!
2 comments
Comment from: jabuticaba Member
Comment from: kristi Member
Thank you so much Farouk, much appreciated!
You’ve done very well in making light of your accident, very well documented, I really enjoyed all the details.