Talk:Plant defense against herbivory

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To-do list for Plant defense against herbivory: edit · history · watch · refresh

Here are some tasks you can do:
  • Expand:
    • By region: tropical vs. temperate variations in terrestrial plants and seaweeds.
    • More on mimicry, also need to create mimicry in plants.
    • Signalling between plants (mentioned at the bottom of alarm signal)
    • See also these articles.
    • Decomposers and plant defenses - decomposition can sometimes be detrimental to plants
    • Other:
    • What to do with this redirect?
    • Scope? Taxonomic scope (limited to the taxonomic definition of plants?) and ecological scope (see above redirect)
Priority 4  

Contents

[edit] Constitutive vs. Induced Defense

I´d like to add something to "Constitutive vs. Induced Defense"

"Why these defenses are inducible rather than constitutive?"

By "choosing" induced defense over constitutive defense, the plant will only allocate resources to defense that originally were supposed to go to growing, flowering (...), when strictly necessary, rather then allocating every time a part of the resources to constitutive defence. The disadvantage of induced defence is that it requires a certain period of time to take place after the attack begins. Depending on this period, the plant can be in risk while waiting for the substances to be synthesized and transported. In sum, the reliability of the INDUCED DEFENCE will depend on the plant´s chance of being attacked by herbivores and the time duration between the attack and the defense response.

As a general rule, the type of defense depends on the cost-benefit relatioship. To better understand the cost-benefit relationship we must consider the Optimal Defense Theory (that is further metioned), which is based on three factors:

1 - All plant defence has a cost, and resources used for plant defence cannot be used to others functions (as growing, flowering, seeding) at one time;

2 - The impact of a plant´s tissue loss depends on the significance of the affected plant tissue in a specific phenophase,physiological stage of development(exemple: During flowering phenophase, the most important part of the plant would be the flower);

3 - Some parts and tissues of plants has a greater chance to be attacked by herbivores than others (it reffers to the Apparency Theory).

So, we can assume that, the type of defense will be ruled by the plant´s chance of being attacked by herbivores, the physiological stage of development of the plant and the plant strategy to allocate resources.

e-mail: joaninha_sem_lacinho@yahoo.com.br

Go for it! (Please add citations)--Franciepants18 19:25, 30 March 2006 (UTC)
If anyone has pictures to add, please do so! --Franciepants18 21:39, 27 February 2006 (UTC)

[edit] footnotes references

I begin to reorganize references in footnotes (easier to read). I'm waiting for some feedback before to continue, because there are a lot of them! (maybe too much, citing sources is good policy but cutting some recent scientific research may help the standard reader). Besides that, i'm not a good english writer and some sentences must be modified if we replace the name if scientist by a footnote number. --alink 14:48, 4 July 2006 (UTC)

[edit] indirect defence

There is no mention in this article about indirect defence, where plants emit Volatile Organic Compounds to attract parasitoids of their herbivores. I am quite familiar with this subject, but I find it difficutl to embed it in this article. Maybe we can discuss?—Preceding unsigned comment added by Jeroenemans (talk • contribs) 16:45, 2 February 2007 (UTC)

Seems like the section in the article called Indirect defenses would be a good place to include information on ....indirect defenses.--DO11.10 20:16, 2 February 2007 (UTC)

[edit] GA on hold failed

Since this page appears to be undergoing significant editing I'm placing it on hold until the content stabilises as per criterion 5.

I've failed the article for now - but please do relist it once it's been re-written! I'd be happy to review it if you let me know. Verisimilus T 16:37, 20 May 2007 (UTC)

[edit] Article title

How did the article get its title ? Is the phrase in wide use ? The term "Host-plant resistance" HPR is very well established in agricultural research parlance. Also HPR is a little wider in that it includes herbivores as well as fungal and viral pathogens. Unless there is a plan for Plant defense against pathogens, which would have similar content, it would be useful to move to 'Host plant resistance', or perhaps just 'Plant defense' or 'Plant resistance'. Shyamal 02:38, 19 May 2007 (UTC) --Actually, yes, there are a number of articles that could be incorporated into a broad topic page called Plant defense against pathogens. Here are a few:

My suggestion would be to:
  1. Create a page called Plant defense against pathogens incorporating these and linking these topics (or rename, or redirect to Phytopathology)
  2. Remove the redirect from HPR, and discuss the term in more detail linking to these two other pages.
As an aside, I personally feel that Plant defense against pathogens and Plant defense against herbivory are more descriptive and probably more intuitive titles for the general public than are the fairly specialized terms "Host plant resistance" and "Phytopathology".
What do you think?--DO11.10 03:06, 19 May 2007 (UTC)
I am not too strong about titles, but only so far as it affects the scope of the article. Can we move our discussion to the talk page of the article. Shyamal 03:20, 19 May 2007 (UTC)
I am not sure what you mean, are the titles I suggested okay?--DO11.10 04:39, 19 May 2007 (UTC)
HPR is mostly about insect herbivory and only marginally about disease resistance, so the current state can hold. The article on Disease resistance in fruit and vegetables should perhaps become more generic and be renamed to Plant defense against pathogens or Disease resistance in plants. Phytopathology and (economic) entomology are fields of study that deal among other things in these aspects. The other immunity related articles seem not to be directly related to plants. So, the title and current redirects for this article can stand for the moment. Shyamal 08:46, 19 May 2007 (UTC)
Systemic acquired resistance and the Hypersensitive response (Innate immune system#Other forms of innate immunity is a summary of these responses) are the plant specific mechanisms of HOW plants resist pathogens, they are essentially the plant's immune system.
A common problem I have encountered in several "plant disease" articles is that they are usually pretty focused on WHO discovered the disease, WHERE it is found and WHY it is important to agriculture, but fail to mention much of anything about WHAT the disease does to the plant and HOW the disease infects the plant (an example is Sudden oak death). In my opinion the latter two are as, if not more, important aspects of an encyclopedia article than are the first three. Therefore, I feel it is of the utmost importance to include some of the information in these three articles in any Plant defense against pathogens article. Sorry for the rant there, cheers--DO11.10 17:19, 19 May 2007 (UTC)

[edit] Article structure

The article structure may need some slight modifications, here is a proposal

  • Introduction - what it is and a preview of subsequent parts
  • Evolutionary perspective (value to plant )
    • coevolution
  • Classification and kinds of resistance
    • induced - constitutive
    • antixenosis - antibiosis - tolerance
    • chemical - mechanical and life history strategies (r K selection)
  • Historic perspective and application (value to humans)
    • use of varietal traits
    • measurement of resistance
    • transgenic resistance
    • benefit to agriculture
  • references

Shyamal 02:48, 19 May 2007 (UTC)

Could you be more specific? Roughly, where would the sections in the current article go in your proposal? I don't really know a whole lot about this subject, (although I have learned a fair amount editing this article) so you might have to "dumb it down" a bit for me. What about the study of defense section, and the section on induced defenses, where would they go? --DO11.10 04:46, 19 May 2007 (UTC)

Here it is in a little more detail (with some of the current sections indicated):

  • Introduction

What is plant defense ? why has it arisen ? what are the forms of defense in brief and how is it important to humans ? For instance how human crop breeding often makes plants more susceptible to pests. How we are able to use many plant products that have toxic substances by the innovation of cooking.

  • Evolution
    • The rise of plants, the role of insect herbivory in the diversification of plant strategies. The role of secondary metabolites. The evolution of different forms of herbivory in insects - biting, sucking (the rise of vascular plants), seed eating, root eating, leaf, stem, gall forming. Evolution of Mixed Function Oxidases (MFOs). Co-evolution. (Ehrlich and Raven go here, so also Herbivore response)
    • Forms of defense
      • Constitutive and induced (include role of ethylene in communication)
      • Functional classification - antibiosis, antixenosis, tolerance
      • Direct
        • Chemical (Secondary metabolites, Lectins, Tannins, ..., qualitative and quantitative ...)
        • Mechanical
      • Indirect
      • Mutualistic associations (ants, extra floral nectaries)
    • Defense strategies

(Here goes the current content)

      • Optimal Defense Hypothesis
      • Carbon:Nutrient Balance Hypothesis
      • Growth Rate Hypothesis
      • Growth-Differentiation Balance Hypothesis
  • History and application
    • Agriculture, selection and varietal differences, eg: Grape phylloxera, role of cooking (Trypsin inhibitors etc)
    • Formal study - R H Painter and the later works (this is from the application / agricultural perspective)
    • Applications in plant breeding (classical)
    • Molecular techniques, use of transgenics (include Bt story and link suitably)
  • See also
  • References
  • External links

Shyamal 08:37, 19 May 2007 (UTC)

That is fine with me, I don't think that that is too radical and most of that information is already in the article (I assume you will not be removing anything?), a few thoughts though:

  1. "Introduction" should not be a section title (FAC has taught me this) or is this the article's WP:Lead? "How is it important to humans" should be really a tiny part early on in this article, the vast majority of information at the beginning should focus on the plant itself. Most of this should go at the end in "History and applications".
  2. Both the "Evolution" and the "Introduction" sections should be short (a few paragraphs each) it is important to get to the "meat" of the article (HOW plants defend themselves) as soon as possible.
  3. I would not make the "types" a subheading of evolution since the material in the section is really the "meat" of the article.
  4. I assume that most of the "History and application" section would be new stuff that you are planning to add? I think that these additions will really help round out the article a bit.

Edit away! Cheers,--DO11.10 17:36, 19 May 2007 (UTC)

Yes, the introduction is not a titled section. Currently the article has many examples which are scattered. Evolution unfortunately is not going to be short because plant-herbivore interactions have a very interesting evolutionary background. Ok, forms of defense can be elevated and not below evolution. There is perhaps very little that is going to be entirely new. Only filling some gaps and reorganizing. Shyamal 02:19, 20 May 2007 (UTC)
That looks great! My only complaint is that the lead is a little short. Could it be expanded a bit? Maybe add a sentence about indirect defenses, and a sentence or two on importance to humans?--DO11.10 16:49, 20 May 2007 (UTC)
Another thing, the evolution section seems to exclusively devoted to insect herbivory, what about herbivory by mammals? It seems like they have driven a lot of plant defenses as well.--DO11.10 17:12, 20 May 2007 (UTC)
A fresh eye will find more things to do and add, so do take a go at it. I was mostly looking at how the parts fit in, I will take a look at content again later. Shyamal 01:28, 21 May 2007 (UTC)
The breadth of the article is now better. Formatting of references needs to be made consistent. Shyamal 04:38, 21 May 2007 (UTC)
I have formatted the refs that had PMIDs or ISBNs with Diberri's template filler. But some journals don't appear to be associated with PubMed (I couldn't find the articles there) so they will probably have to be converted by hand.--DO11.10 17:25, 22 May 2007 (UTC)
Great ! That was quite some work. Thanks. Shyamal 01:35, 23 May 2007 (UTC)

[edit] Problems with this article

1. Allelopathy is used incorrectly--it is about plant defenses against other plants. Maybe it is used for herbivory also, in which case, cite a current article that discusses plant allelopathic chemical defenses against herbivores.
2. Chemical defenses list only allelopathy, not the well known relationships between various herbivores who have adapted to chemicals that plants use as defenses, such as glucosinolate-myrosinase, and what about swallowtails, aren't the plants themselves toxic to other organisms, isn't that part of the evolutionary relationship, the plant's defense against herbivores, a single herbivore's adaptation to the defense and use of it? The glucosinolate-myrosinase is easy and well researched, see [1].
3. Don't reach for a 1975 book on ecology, when there are tons of well-researched articles directly about chemical defenses that plants have against herbivores. I'm concerned about the scope of the article in general, that it's not overall well-developed, but rather put together in pieces. The one article on line you cite in the allelopathy section does not use that term at all, the other books are old. It's not my area, so I could be wrong, but please find a recent article to show me allelopathy used in this way, and write about plant secondary metabolites as defenses against herbivores, not about allelochemicals. KP Botany 17:55, 21 May 2007 (UTC)

This might be sort of a nit-pick, and I don't really know how much this field has changed since 1975, or what kinds of articles you have in mind (for example, review articles versus articles on specific mechanisms), but there is nothing wrong with citing secondary sources (in fact, most of the time it works better than citing primary sources, in the sense that there is less need to pick and choose which information is worth presenting: Wikipedia:No original research#Primary, secondary, and tertiary sources). Kingdon 18:55, 21 May 2007 (UTC)
I looked around a bit and found that KP Botany is correct, alleochemicals is used incorrectly. I have to say that I came to this article with the intention of footnoting the referencing, then I stayed on to copyedit it and add images. So most of the references were here when I got here. I don't know a lot about this subject either, but I have learned a lot. I found a good source for information about chemical defenses, if you give me some time (a few hours for a rough draft) I will update the page with the correct information. --DO11.10 19:04, 21 May 2007 (UTC)
Kingdon, the issue isn't with secondary sources, even tertiary sources would be better for most articles on Wikipedia--in fact, I'd vote that Wikipedia editors should go to college textbooks on a subject first (not other encyclopedias), then work out from there. The issue is researching a specific subject, plant chemical defenses against herbivory, out of an old and general book (ecology). If you'd rather use books, that's fine. But use something more recent, that shows the relationship of the evolutionary dance between species as evidenced by genetic studies, and use something more on topic, the ecology of plants, or the ecology of plant insect relationships. However, much more readily available than these books, and available to the style of editing prevalent on Wikipedia (web only), are the many review articles and the introductions of non-review articles in peer reviewed journals that are on line. KP Botany 19:46, 21 May 2007 (UTC)
DO11.10, I'm impressed by how quickly you steared the article's section on chemical defenses towards the right direction. KP Botany 21:26, 21 May 2007 (UTC)
Thank you! I did not realize it was wrong, or I would have changed it much sooner. If you would like to have a go at copyediting, or have anything to add please feel free to do so.--DO11.10 21:46, 21 May 2007 (UTC)
K P Botany, do you have any specific suggestions on the scope of the article ? It was indeed filled with disconnected trivia and I have specifically tried to find a coherent thread to connect it. Unfortunately I do not have access to any recent review articles, but someone with access to Ann.Rev.Ent.Syst. chould be able to compare the structures and find gaps. Thanks for pointing out the allelochemicals bit. And thanks DO11.10, the article looks enormously better. I guess it can soon be renominated for GA. Shyamal 01:46, 22 May 2007 (UTC)
My suggestion is to get a book on the topic, again, those secondary and tertiary sources, and look at the table of contents, even looking online at Amazon or BN might be enough, to see how they organize the topic, then see how that organization scheme compares with ours and tweak ours in any way you see necessary. Once you get the organization down, then let's figure out what else is needed. I think we should go for FA, too, as the topic is great. Lots of work left to do, and I'm busy this week. KP Botany 03:30, 22 May 2007 (UTC)

[edit] Communication ethylene - Tannins

There was a paper on how browsing of Acacia caused a release of ethylene leading to (rapid) tannin increases in neighbouring plants (this was, perhaps, during the "group-selection" era). While it was tempting to add it, I suspect that there has been no subsequent confirmation. Shyamal 01:46, 22 May 2007 (UTC)

I think that this is the bit you are talk about:

There are several alternative explanations for the presence of allelochemicals in plants. Evidence suggest that flavonoids and cuticle waxes absorb between 90 – 99% of incoming ultraviolet (UV) radiation in cucumbers and maize, effectively acting as UV shields.[1][2] [uncommented]Allelochemicals, particularly cuticle waxes, may also prevent undesired water loss and maintain sufficient amounts of water in plants during periods of plant stress and drought. (Question : Need citation of reference that terms cuticle wax as an allelochemical[/uncommented] Additionally, some allelochemicals act as storage compounds for essential plant nutrients such as nitrogen and phosphorus.[3]

Sorry, I had meant to move it here, but forgot. I couldn't find any good place to put it. But feel free to add it back, if you know where it should go.--DO11.10 02:11, 22 May 2007 (UTC)
The section you have placed above is actually more about protection against UV and I commented out the bit about cuticle wax being called allelochemicals. I think this bit can be removed with no ill effects to the article. But the topic I was thinking about was [2]. Shyamal 02:32, 22 May 2007 (UTC)

[edit] GA on hold

I have reviewed this article according to the GA criteria and have put the article on hold until the following issues are addressed:

  1. In the second paragraph in the intro, reword some of the sentences so they don't all start with "By".
  2. The definition of co-evolution in the Coevolution section uses the hyphen, so the heading should also.
  3. "When an herbivore eats a plant it selects for plants that can mount a defensive response." Remove "for".
  4. "Over 3000 known alkaloids exist, examples include nicotine, caffeine, morphine, colchicine, ergolines, strychnine, and quinine." Add an inline citation for the 3,000 fact. Same for "There are over 10,000 known types of terpenoids."
  5. "Phenolics, sometimes called phenols, contain a fully saturated 6 carbon ring linked to an oxygen." Linked to an oxygen what?
  6. Fix the link for goat to direct to the correct page instead of a dab page in "Plant structural features like spines and thorns reduce feeding by large ungulate herbivores (e.g. kudu, impala, and goats)..."
  7. "Some plants prevent the laying of eggs by insects species by mimicking the presence of insect eggs on their leaves." Either remove species or I think it should be "insect species".
  8. "Because female butterflies are less likely to lay their eggs on plants that already have butterfly eggs, some species of neotropical vines of the genus Passiflora (Passion flowers) containing physical structures resembling the yellow eggs of Heliconius butterflies on their leaves, and discouraging oviposition by butterflies." Rewrite to "Because female butterflies are less likely to lay their eggs on plants that already have butterfly eggs, some species of neotropical vines of the genus Passiflora (Passion flowers) contain physical structures resembling the yellow eggs of Heliconius butterflies on their leaves, which discourage oviposition by butterflies."
  9. "The formal study of plant resistance to herbivory was first covered extensively in 1951 by Reginald (R.H.) Painter, who is widely regarded as the founder of this area of research, in his Plant Resistance to Insects." State if this is a book, journal article; assume reader may not know.

Altogether, there weren't that many issues, and the article is very well written. Fix these issues within seven days and I'll pass the article. When you are done or if you have any questions, let me know on my talk page and I'll get back to you as soon as I can. --Nehrams2020 23:15, 25 June 2007 (UTC)

In response to ""When an herbivore eats a plant it selects for plants that can mount a defensive response." Remove "for"." - Actually, this sentence is stated correctly. The herbivore selects plants that cannot mount a defensive response, thereby selecting for those that can. Those that mount effective defenses survive (i.e., are selected for). Antelan talk 23:24, 25 June 2007 (UTC)
I believe I have addressed points 2, 3, 5, 6, and 7. Antelan talk 23:34, 25 June 2007 (UTC)
Point 8 also appears fixed. I have made amends for point 9. Regarding 3, I have an additional point that this should be "a herbivore" (Br. E.) and not "an herbivore" (Am. E.), since the British spelling of colour is used. Shyamal 03:27, 26 June 2007 (UTC)
The intro's been reworded, so pt 1 is tackled too.AshLin 17:14, 26 June 2007 (UTC)

(edit conflict) I was finally able to add the references for the numbers in point 4. (I was affected by this yesterday.) It also appears that the remaining points have been addressed. Thank you all!--DO11.10 17:21, 26 June 2007 (UTC)

[edit] GA passed

I have passed this article according to the GA criteria. Good work on fixing the above issues so quickly. The eighth point still needs to be addressed, the main difference between the two sentences is changing "containing" to "contain" and "and discouraging" to "which discourage". If you change it to that, I think the sentence will run more smoothly. Also thank you for describing point three, I didn't read it like that. Anyway, continue to improve the article, making sure that all new information is properly sourced. Maybe consider a peer review and go on to FA if you think you are ready. If you have the time please consider reviewing an article or at GAC to help with the backlog. Make sure to update the article history with its first GA fail, and current pass. Good work, and I hope that you continue to improve the quality of articles on Wikipedia! --Nehrams2020 18:29, 26 June 2007 (UTC)

Agreed and done. Thanks again. Cheers--DO11.10 18:44, 26 June 2007 (UTC)

[edit] Some interesting articles

Some of these may be relevant. Aposematism and mimicry needs more attention, and the first article looks very interesting.

  • Malka Halpern, Dina Raats, Simcha Lev-Yadun (2007) Plant biological warfare: thorns inject pathogenic bacteria into herbivores Environmental Microbiology 9 (3), 584–592. doi:10.1111/j.1462-2920.2006.01174.x
  • SIMCHA LEV-YADUN, MOSHE INBAR (2002) Defensive ant, aphid and caterpillar mimicry in plants? Biological Journal of the Linnean Society 77 (3), 393–398. doi:10.1046/j.1095-8312.2002.00132.x
  • SIMCHA LEV-YADUN, GIDI NE'EMAN (2004) When may green plants be aposematic? Biological Journal of the Linnean Society 81 (3), 413–416. doi:10.1111/j.1095-8312.2004.00307.x

I also recently heard about plants not only communicating with predators of the herbivore, but with other plants. This should also be covered, though I haven't looked into the literature for anything on this yet. Richard001 00:21, 18 August 2007 (UTC)

[edit] Mimicry in plants

I'm considering starting an article on mimicry in plants some day, which I thought I would mention here if anyone is interested. This article could then cover a give a few quick examples and link to the article for those wanting further information. Richard001 01:36, 7 October 2007 (UTC)

[edit] Plant defense

I don't think this should redirect here, as plants have to defend against many things besides herbivores - e.g. pathogenic viruses, bacteria and fungi, parasitic plants, and even, in a broader sense, the elements (e.g. frost). How should we deal with this? Should we perhaps have an article on all these things, with this one being summarized there? Richard001 (talk) 01:07, 21 February 2008 (UTC)

[edit] Scope

What is the working definition of a plant in this article? Does it include seaweeds and such, about which there is some good literature? Richard001 (talk) 07:19, 12 March 2008 (UTC)