spine formation and nanocrystalline cellulose

[fero]

I think I tumbled down a rabbit hole with this one, I'm really no expert though I found it interesting so thought I'd share.
It started off with some thoughts on how much energy my plants and especially the cactus must use to produce there beautiful spines. how are they formed . what are they made from. what does the plant use to construct such an impressive defence .

this site was useful https://www.google.com/url?sa=t&source= ... 5423064661

I found that they are made from cellulose. and the cellulose is made from glucose. though the cellulose being crystaline was interesting. and the emerging uses for crystaline cellulose in electronics and photovoltaic cell's.though not from cactus as far as I am aware.
using cellulose as a green solution instead of plastics ect.

Quote. .(The unique cellulose-arabinan composite structure of cactus spines, together with high cellulose crystallinity, may explain this finding)
this is quoted from https://www.google.com/url?sa=t&source= ... In5MhDvLsk

and has information about cellulose crystallinity and the bend strength of spines.



this is quoted from https://www.google.com/url?sa=t&source= ... A0553LyKsi
New horizons for cellulose nanotechnology’.
ROYAL SOCIETY PUBLISHING
Quote. ..(The much larger (5–7 nm) microfibrils of the textile fibres [26] and tension wood [48] must be formed by fusion of smaller units near the point of synthesis. Their approximately Iβ monocrystalline form [26] implies that the cellulose synthase complexes that assemble them must be grouped close together and travelling in the same direction along the cell membrane, not in antiparallel directions as observed for primary-wall synthesis in Arabidopsis [49]. The absence of hemicellulosic polymers when these large textile microfibrils are laid down suggests a role for the hemicelluloses, in other cell walls, keeping microfibrils apart as well as bridging between them. Interestingly, cactus spines have equally large microfibrils accompanied by an α(1,5′) L-arabinan [50], a pectic polymer normally associated with non-elongating primary cell walls [51] and incapable of assuming the cellulose-like chain conformations of the hemicelluloses.)

Quote... (Crystalline cellulose nanofibers are obtained from the bark of Cereus Forbesii) from
https://www.google.com/url?sa=t&source= ... UZUo13g-pZ

how the spines on cacti are formed I am still not entirely sure on a cellular, level. though I feel I've now got a somewhat better understanding.
any thoughts would be welcome

[Darren S]

The 'alternatives to plastic' bit made me smile. I used to work in a factory that made (biodegradable) cellulose packaging film - 'cellophane' - until the place closed in the early 90s because it could not compete economically with plastic...

That said - cellulose film manufacture involves a lot of very unpleasant chemicals. We could not wear some man-made fabrics to work as they would disintegrate like soggy tissue paper after a few 12 hour shifts in that atmosphere!

[fero]

Hi Darren
There was mentioned some strong acids used to separate the cellulose nanocrystals.
Doesn't sound like a heathy environment your clothes melting.
I think governments need to lead the change as we become more aware of the damage microplastics are having . The cheapest option isn't always best and once a change is made alternatives usually fill the gap pretty fast.
Big business and profit are unfortunately king. IMO.

It is suprising how fast spines can grow, in ceroids they are often soft for a while when newly grown.
I am just trying to better understand spine growth and how best to promote it.
It seems good light ,air, and water, are the main ingredients.
Does anyone know how the cellulose is created at the base of the spines.
Would each type of cactus have different cellulose nanocrystals.
They are in some respects similar finger nails or hair .

[ralphrmartin]

There's definitely a cost to the plant, as this picture on the web of Browningia candelaris nicely shows.

Up to a certain height, the plant produces dense spines. Above that height it doesn't bother. That height is just about as high as a browsing llama can reach.

[fero]

I was trying to think of other similar examples and thought of the young plants of pachycereus and carnegiea and the older much less spined adults.

I've found a pdf it is mainly about the breakage strength of cactus spines. It's definitely a bit more accessable than the two quite technical articles in my first post.
Quote : (1. Cactus spines had resiliency comparable to low alloy steel and GFRP, and higher than carbon
steel..) from pdf
https://www.google.com/url?sa=t&source= ... ep1HF59T47

It also has some good images of cactus spines cells

[fero]

Cactus spines have numerous adaptations
Shading from the sun protection from cold
Collecting water droplets from mists and dew, water coalesce
Protection from predation
Camouflage
Segment dispersal
And probably many more.
Their are man made material's that are copying the water harvesting abilities of cacti to collect water from mists.
It reminded me of the plight is copiapoa solaris in the dry atacama.
The energy they take to produce is obviously well worth it.

[AndrewB]

I have observed spines appear to grow better, stronger and with more intense colours when cacti are given increased fertiliser, I particularly seemed to notice it with slightly increased potassium. This is short term qualitative, not quantitative observation.

[fero]

I have been reading some articles about the micro scales on some cactus spines and their ability to move droplets of water even up a downward angeled spine.
There are articles on opuntia microdaisys( this one is not one of my favorites I've come into contact with it too many times.)
Gymnocalycium baldianum at
https://www.google.com/url?sa=t&source= ... EwGcDaHN-i
Also Copiapoa cinerea var. haseltoniana, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa . At
https://www.google.com/url?sa=t&source= ... 58ZyB8f5jv
Quoted from above.( C. cinerea showed movement of dew droplets from spine tips to their base, even against gravity. )
There are also some articles on how once the water droplet has moved down to the base of the spine it is absorbed through the trichomes at the base of the spines into directly into the plant body. This was something I was unaware of, I had previously believed the droplets would fall and be absorbed by the roots.
Information on this is at.
https://www.google.com/url?sa=t&source= ... mgSnBRDvW3


Andrew
I agree potash/potassium is a good feed.
I'm going to try using some Rock Phosphate this year
Which is something I haven't used before, any one using it.

[AndrewB]

One word of caution about potassium (potash), if the plant gets too much it’s growth will be seriously stunted and it will go a dark purple. It’s then tricky to get it growing again, but using a higher nitrogen ratio for a while should resolve the imbalance.

[fero]

Hi Andrew
Do you think this neoporteria is suffering from the same as you suggested. I bought it last year specifically because it had such a purple epidermis.
The rock phosphate I mentioned has limestone in so maybe it would be good for ariocarpus, or aztecium.