MicrobeHunter.com Microscopy Forum

Hello everyone,

I am new to this forum and was hoping you all might be able to provide some insight into identifying epiphytic microbes occurring on plant leaves. Attached are some photos of what I think might be a type of diatom occurring on leaf tissue. These photos were taken at 400x total magnification (from my recollection) and show spheroid structures of about 15-18 um in diameter occurring in clusters or along on the surface of the plant leaves. Has anyone else seen these structure and have any idea what they might be?

Thank you in advance, and I apologize for the poor quality of the images.

Hi, intriguing but we need more info my friend. What plant is it? Is it a moss, or a water plant or a land plant for example. They may very well be part of the life-cycle of the plant rather than separate organisms.

Can you give a little more info and some extra images? As 'brown spheres' they may be just about anything. Perhaps isolate several the squash them between a slide and cover-slip - or without cover-slip if you don't have any, to see if they contain any discreet parts...

Good luck and welcome to the forum, John B.

p.s.
A guess, looking at the last image, may be a fern spore.
From the first image where they look more spherical they may be cysts containing cyanobacteria or reproductive structures if the leaf is that of a moss.
The leaf-edge visible with 'jagged edges' looks a lot like a moss leaf.
Squashing them and 'seeing what comes out' will very likely help.

Thank you for the advice, and I’ll work on getting you all more photos. The plant the structures are on is a moss, but it is being grown in controlled conditions so these structures should not be fern spores. Additionally, the moss is not reproductive, so I think that rules out moss spores as well. Cyanobacteria cyst is a good guess as the plants are often covered in Cyanobacteria as well.

I’ll try the squashing and to get better visuals to you!

Curioustiny wrote:Thank you for the advice, and I’ll work on getting you all more photos. The plant the structures are on is a moss, but it is being grown in controlled conditions so these structures should not be fern spores. Additionally, the moss is not reproductive, so I think that rules out moss spores as well. Cyanobacteria cyst is a good guess as the plants are often covered in Cyanobacteria as well.

I’ll try the squashing and to get better visuals to you!

Could well be, here are a few images I took of some I found last year - I couldn't pm them as you're a new member and would be unable to retrieve the pm I think. link to images from Sept 2016

Very interested to see what appears!

Thanks for the interesting post my friend.

John B

Hi John,

What microscope are you using? Your micrographs are great!

Here are more photos of the moss-dwelling "brown spheres": https://photos.app.goo.gl/S4Y8xwhM4PxyrE2S2. I attempted to squash some of the samples in isolation, but didn't get high quality visuals of those squashes. On this moss stem, however, I was able to eventually find a ruptured "cyst" among one of the clusters occurring on the moss leaf. It looks to me like it might be a sack of cyanobacteria. It's difficult to tell at 400x magnification, however, but that is the highest power objective I have available at the moment.

My initial thought was these might be some type of Phoma, but seeing as no spores were exuded from the structures when I pressed them with forceps, I highly doubt they're a Phoma after all.

Hmm, had a look at your images and from what I can see they don't look like cysts of cb - but there's very little detail. I agree that they don't look or indeed 'react' like Phoma may be expected to when 'squashed' and ruptured....
What we need is greater detail, not necessarily magnification - I think x400 is easily enough for the purposes of ID.

Basically try to separate some of the spheroids from the moss with dissecting needles - easily done under a stereo 'scope but not otherwise unfortunately. Then squash them as evenly and thinly as possible between slide and cover-slip and use as any water-mount.
It may be possible that they are moss propagules rather than sexually-reproductive structures (propagule here being clonal of course) also. Their position on both stem and leaf I think rules out reproductive organs. Their apparent lack of damage or effect on the tissue adjacent I suspect precludes their being Phoma or similar.

As seen the images are the limiting factor - have a few more tries to improve them if you can - it only takes one good image to give a whole host of clues!

Interesting indeed.

John B.

Oh yes, the images were not with my current Orthoplan, rather they were with a very nice Chinese generic infinity 'scope with Plan objectives sold as the 'SP200' by the folk at Brunel Microscopes. But then along came the mighty Orthoplan and then a nice little SM-LUX and my conversion to Leitz began!

Hi,
I think it is moss spores, not necessarily coming from this particular plant. If this moss (not fertile as you write) has once been standing in open nature, it may have gathered spores of other mosses. Spores when ripe fly through the air and are deposited somewhere. Also to be noted is that 1 spore capsule of a moss contains many thousands of spores and hence these can be found almost everywhere. A dimension of 15 - 18 µm is plausible. Squeezing wil not give you more detail.

Thank you both!

If these are moss spores, I think the best course of action is to try germinating the spores. I’ll let y’all know if it looks like protonema that emerges (if anything emerges at all...)!