Talk:Plant root exudates

Wiki Education Foundation-supported course assignment

This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Kzlatkin.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 18:00, 18 January 2022 (UTC)

Carbon content

Invasive Spices copied this from User talk:Patrickmckennaniab#Plant root exudates.

Hello and welcome to Wikipedia. Hopefully you'll continue editing. My apologies for reverting your first edit – you made a small mistake. Invasive Spices (talk) 23 June 2022 (UTC)

Hello, thank you for your message. I have followed your new link, I believe the problem remains. The article is claiming 5-21% of all fixed carbon is transferred to the rhizosphere via exudates. You reference the review paper by Walker, linked here...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1540314/

This article makes the 5-21% claim and refers to another paper by Marschner et al (1995), linked here...

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1399-3054.1987.tb02861.x

This article concerns phytosiderophore activity in barley roots, which concerns iron uptake. The article makes no reference to carbon rhizodeposition, and the claim of 5-21% of photosynthetic carbon being exuded is absent. The best estimates we have of this are in the paper by Jones et al, linked here...

https://link.springer.com/article/10.1007/s11104-009-9925-0

The most accurate estimate is ~5% of fixed carbon is rhizodeposited, given the difficulties in assessing, as the article describes. I hope you will include this in this article, many thanks for reading.

I reverted my reversion of Patrickmckennaniab's version. I am uncertain about what text belongs here but after further examination I agree that his vaguer text and more recent citation is preferable.

My reasoning for my first reversion to the Walker version was as follows. When claiming 5-21% Walker refers to Marchner 1995. (You are correct that Marschner et al. 1987 is about barley and iron but the 5-21% claim comes from the 1995 book.)

There are nonetheless several problems with the Walker version.

I am unable to find the 5-21% number in the book. Walker does not provide a page number.

There are many more recent publications we might use.

The more recent Jones you cite gives a 5% number.

However Jones also has downsides. That statistic is for all soil residues, pertains to shoot stage plants and is the result of tests in CO2 injected chambers.

I think the Walker version attempted to extract too much specificity out of too little available data. I am far from an expert in this exact statistic but I am certain none of these sources is perfectly satisfactory for exactly what % of photosynthetically fixed carbon is transferred from plants to the rhizosphere via root exudates. Your text reflects that and so I reverted my reversion. Invasive Spices (talk) 24 June 2022 (UTC)

References