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Author Topic: What purpose do thorns serve on berry bushes and roses other then protection?  (Read 20131 times)

Offline Karen W.

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Well I was wondering this as I was chipping up dead Himalayan blackberry briars in my wood chipper

today?

Do they serve any other purpose nutritional water wise or other beneficial service to the plant?

Oh Yes... and what exactly is The thorn part made of.. is it like a fingernail only on a plant?

I would be interested in knowing if someone else knows!


 

Offline neilep

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this is a kewl kwestion..

Can I ask wot ewe do with the chipping after ewe have made chips ?
 

Offline Karen W.

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Thank you... I thought so! *smiles*

I believe I will burn them  or dump them over the bank to compost there.. they are mostly dried up, the green ones,must be careful as they will re-root in my yard if I am not careful.. They have grown over my entire barn and are taking over the property!

I love the berries but hate the briars.. Thinking about a new goat again!
« Last Edit: 02/04/2009 16:36:02 by Karen W. »
 

Ethos

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Well I was wondering this as I was chipping up dead Himalayan blackberry briars in my wood chipper

today?

Do they serve any other purpose nutritional water wise or other beneficial service to the plant?



I'm not a Botanist, but it seems to me they probably serve as a defense mechanism.
 

Offline Karen W.

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Yes thats what I mentioned in the title!
 

Ethos

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Yes thats what I mentioned in the title!
Ahhh yes, I seemed to have missed that detail in my haste to post my answer.

One must consider the selective nature of this defense mechanism however. The berries and pollen are attractive to many species as a food source, thereby insuring that the pollen and seed will be carried to new locations. The function of the thorns must inhibit damage caused by larger and more clumsy creatures in favor of the smaller and more agile ones, thereby increasing the likelyhood for less damage while still insuring the pollination process and dispersion of seed.
« Last Edit: 02/04/2009 04:09:42 by Ethos »
 

Offline Don_1

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Thorns are a means of defense against herbivorous animals and are found on plants such as the Pyracantha, Berberis and Acacia. They are not always effective. Giraffe and some deer and antelope are able to eat these plants despite the thorns. The thorn is a modified stem.

Your Blackberry, like roses, has prickles, which are an outgrowth of the epidermis. They serve the same purpose as thorns, but in addition can help such plants support themselves.
 

Offline Karen W.

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Thanks DON 1. What do you mean by supporting itself?

What makes the thorn so much harder and stiffer then the stem itself?
 

Offline Karen W.

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Yes thats what I mentioned in the title!
Ahhh yes, I seemed to have missed that detail in my haste to post my answer.

One must consider the selective nature of this defense mechanism however. The berries and pollen are attractive to many species as a food source, thereby insuring that the pollen and seed will be carried to new locations. The function of the thorns must inhibit damage caused by larger and more clumsy creatures in favor of the smaller and more agile ones, thereby increasing the likelyhood for less damage while still insuring the pollination process and dispersion of seed.

I can agree with that! It makes good sense.
 

Offline Don_1

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There are very few genuine 'climbing' plants, most of those we have as climbers are in fact ramblers. Today's climbing, tea, floribunda and bush roses are hybrids of the natural ramblers. These ramblers like the brambles (blackberry) use the prickles on individual stems to help interlock the stems to each other and to the stems of other bushes to keep them off of the ground. This way the new growth can get high up to where there is the most sunlight without the need to expend to much energy on the growth of a rigid trunk. From this high vantage point, they can then spread over greater distances. As I am sure you will be aware, trying to pull out a single stem of bramble is virtually impossible.

As to your question 'What makes the thorn so much harder and stiffer then the stem itself?' I'm afraid I cannot help on that point (no pun intended). I'm not even sure the reasons are known to botanists. Perhaps someone should ask David Belamy.
 

Offline Bored chemist

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I'm not David Bellamy, but I do have a bushy beard so perhaps I can anaswer this.
Anyone who has got a splinter from a piece of rough timber will know that wood is hard enough to make spikes that can puncture skin. My guess is that the thorns (and BTW, I tought they were modified leaves, but I may be getting them muddled with needles) are made essentially of celulose and lignin. The reason that they are stiffer than the stem is because it's expensive for the plant to make lots of lignin and cellulose so, for the stems, it doesn't make much but, if the thorns are not rigid then there's no point having them (no pun intended).
 

Offline Don_1

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I tought they were modified leaves,

If dhis is the Oirish in you coming out, I tort it was spellede loike dhat, big orro (Irish Frankenstein). Or did you just have an attack of slippery finger on keyboard?

Some leaves can be very sharp, but I do not think they are classified as prickles or thorns. Leaves can bear prickles, the rose is a good example of this, or sharp rigid hairs, as on the stinging nettle. Unlike the soft hairs on some plants, these are reinforced with silicates or carbonates.

See this cross section of a rose prickle http://www.biologie.uni-hamburg.de/b-online/e05/stachel.htm
 

Offline stereologist

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Some sharp projections on plants are modified stems, some modified leaves, and some are outgrowths of the epidermis, the 'skin', of the plant.
 

Offline Karen W.

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There are very few genuine 'climbing' plants, most of those we have as climbers are in fact ramblers. Today's climbing, tea, floribunda and bush roses are hybrids of the natural ramblers. These ramblers like the brambles (blackberry) use the prickles on individual stems to help interlock the stems to each other and to the stems of other bushes to keep them off of the ground. This way the new growth can get high up to where there is the most sunlight without the need to expend to much energy on the growth of a rigid trunk. From this high vantage point, they can then spread over greater distances. As I am sure you will be aware, trying to pull out a single stem of bramble is virtually impossible.

As to your question 'What makes the thorn so much harder and stiffer then the stem itself?' I'm afraid I cannot help on that point (no pun intended). I'm not even sure the reasons are known to botanists. Perhaps someone should ask David Belamy.
Thank you Don 1 You make very interesting points about the brambles and their seeking height for light etc.. I like that.. I will post a picture of the ones in question that basically prove your point about the light... My project has been tedious as I cannot stay at it for long periods.. as I become to fatigued trying to clear the stuff by myself with a small pair of snippers and my hands...
 

Offline Karen W.

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I'm not David Bellamy, but I do have a bushy beard so perhaps I can anaswer this.
Anyone who has got a splinter from a piece of rough timber will know that wood is hard enough to make spikes that can puncture skin. My guess is that the thorns (and BTW, I tought they were modified leaves, but I may be getting them muddled with needles) are made essentially of celulose and lignin. The reason that they are stiffer than the stem is because it's expensive for the plant to make lots of lignin and cellulose so, for the stems, it doesn't make much but, if the thorns are not rigid then there's no point having them (no pun intended).
Thanks Bored chemist! what is lignin?
 

Offline Karen W.

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I tought they were modified leaves,

If dhis is the Oirish in you coming out, I tort it was spellede loike dhat, big orro (Irish Frankenstein). Or did you just have an attack of slippery finger on keyboard?

Some leaves can be very sharp, but I do not think they are classified as prickles or thorns. Leaves can bear prickles, the rose is a good example of this, or sharp rigid hairs, as on the stinging nettle. Unlike the soft hairs on some plants, these are reinforced with silicates or carbonates.

See this cross section of a rose prickle http://www.biologie.uni-hamburg.de/b-online/e05/stachel.htm

Interesting link Don.. Now I am going to have to cut one of those bruisers in half to look at it!.. LOL Thanks!
 

Offline Karen W.

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Some sharp projections on plants are modified stems, some modified leaves, and some are outgrowths of the epidermis, the 'skin', of the plant.

Thanks and welcome to the forum!
 

Offline Chemistry4me

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Lignin is a complex polymer in plant cell walls that gives the plant rigidity and strength, and is the major component of wood.
 

Offline Karen W.

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Thank you very much C4M..!
 

Offline Raghavendra

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Offline Karen W.

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Offline Don_1

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OPSS   Ontario Provincial Standard Specification
OPSS   Office of Public Service and Science (United Kingdom)
OPSS   ORCHESTRA Process Support System
 

Offline Chemistry4me

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You forgot:

OPSS Operations Specifications Application
 

Offline Karen W.

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What is the second s stand for in your last one C4M?
 

Offline Chemistry4me

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No idea!
I just saw it in the dictionary. :)

http://acronyms.thefreedictionary.com/OPSS
 

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