SECOND DRAFT

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A parasitic plant is a plant that derives some or all its nutritional requirements from another living plant. They make up about 1% of angiosperms and are in almost every biome in the world. All parasitic plants have modified roots, named haustoria (singular: haustorium), which penetrate the host plants, connecting them to the conductive system – either the xylem, the phloem, or both. This provides them with the ability to extract water and nutrients from the host. Parasitic plants are classified depending on where the parasitic plant latches onto the host and the amount of nutrients it requires. Some parasitic plants can locate their host plants by detecting chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plant in approximately 20 families of flowering plants are known.[1][2]


Peer Review

I really like how well your article flows. It is very clear and straightforward with neutral tone. Are you planning on including a title for the second draft? Also I think that it was a great idea to include various examples of seed dispersal along with a subsection on mechanism. I think that the first paragraph provides the reader with a clear summary and understanding of a parasitic plant. I think you also have sufficient amount of sources that are reliable. Something that I think could be useful is to possibly making the title subsections more descriptive rather than then simply "mechanism". Also possibly defining some key terms that may not be familiar to a non-expert. Overall, I think that you are doing a great job, and on the right track!

-Jason Faghih

Peer Review

I really like how well your article flows. It is very clear and straightforward with neutral tone. Are you planning on including a title for the second draft? Also I think that it was a great idea to include various examples of seed dispersal along with a subsection on mechanism. I think that the first paragraph provides the reader with a clear summary and understanding of a parasitic plant. I think you also have sufficient amount of sources that are reliable. Something that I think could be useful is to possibly making the title subsections more descriptive rather than then simply "mechanism". Also possibly defining some key terms that may not be familiar to a non-expert. Overall, I think that you are doing a great job, and on the right track!

-Jason Faghih

Mechanism

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The parasitic plant has many obstacles to overcome in order to attach to the host. Distance from the host and stored nutrients are only some of the problems, the host's defenses are an obstacle to overcome itself. The first hurdle is penetrating the host, the host has systems to reinforce the cell wall by protein cross-linking so that it stops the parasitic progress at the cortex of the host's roots. The second hurdle is the host's ability to secrete germination inhibitors. This prevents germination of the parasitic seed. The third hurdle is the host's ability to create a toxic environment for where the parasitic plant attaches to. The host secretes phenolic compounds into the apoplast the creates a toxic environment for the parasitic plant eventually killing it. The fourth hurdle is the host's ability to ruin the tubercle using gums and gels or injecting toxins into the tubercle.[3]

Seed dispersal

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There are several ways of seed dispersal, but all the strategies aim towards the same goal of putting the seed in direct contact to or within a critical distance to the host.

  1. The Cuscuta seedling can live for 3-7 weeks and extend out 35 cm in search of the host before it dies. This is because the Cuscuta seed is large and has stored nutrients to sustain its life. This is also useful for seeds that get digested by animals and excreted out.
  2. Mistletoe use a sticky seed for dispersal. The seed sticks to nearby animals and birds and then come into direct contact with the host.
  3. Arceuthobium seeds have a similarly sticky seed as the mistletoe but they do not rely on animals and birds, they mainly disperse by fruit explosiveness. Once the seed makes contact with the host rain water can help position the seed into a suitable position.
  4. Some seeds detect and respond to chemical stimulations produced in the host’s roots and start to grow towards the host.[4]

Communication

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Importance

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Some parasitic plants are destructive while some have positive influences in their communities. Some parasitic plants damage invasive species more than native species. This results in the reduced damage of invasive species in the community.[5]

References

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  1. ^ Heide-Jørgensen, H., & Heide-J²rgensen, Henning S. (2008). Parasitic flowering plants. Leiden: BRILL.
  2. ^ http://ebookcentral.proquest.com.offcampus.lib.washington.edu/lib/washington/reader.action?docID=589241
  3. ^ Walters, D. (2010). Plant Defense Warding off attack by pathogens, herbivores and parasitic plants. Hoboken: Wiley.
  4. ^ Heide-Jørgensen, H., & Heide-J²rgensen, Henning S. (2008). Parasitic flowering plants. Leiden: BRILL.
  5. ^ http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0034577