intrinsic root growth rate under idealised conditions?

you might want to check out allometric analysis for studying partitioning between different plant carbon pools (shoot, root, but also stem / leaf / symbiotic fungi / flowering / fruiting..)

You may want to check out our review, availabe here on RG: Lambers, H. & Poorter, H. 1992. Inherent variation in growth rate between higher plants: A search for physiological causes and ecological consequences. Adv. Ecol. Res. 22: 187‑261.

For questions regarding biomass allocation, I would think Shoot:Root ratios, based on biomass measures, would be the most appropriate measure. Other than for leaves, it would be more difficult for roots to calculate specific root masses/areas: you would have to know the total root length which can be measured with specific scanners plus software. I always wonder how 'functional' these measures are. Regarding water/nutrient uptake, 1 mm of hair root may be more functional than 1 cm of tap root. The latter of course, is very important for keeping the plant upright and is an important transport route of water and nutrients. It would be possible to also separate root biomass/length into different classes and look at the relative distribution of the biomass over these classes between treatments (e.g. sun vs shade). The reviews suggested above are a great resource.

Hi Adrian!! Thank you very much for the references. Will go through the PJ-GUESS model for sure...! The question that I actually wanted to address is actually 'how' to measure the root growth whether under any condition or stress (light as I said and water as you mentioned).

Also, as of leaf and root relation I referred to a ratio of Root Length/Leaf Area (Körner and Renhardt 1987, Oecologia; 74(3): 411-418), but again I found it to be a relative terms of leaf. What if I do not want to relate it to the Leaf area (though may be I should)?

Are L:R and Root Length:Leaf Area same parameters? Shall check in the references provided...

Thank you..!! :-)

Hi Staddon Sir! The inquisition that I had was actually for manipulated situations (basically garden experiments). Can we monitor plant roots in terms of their growth rate (may be by harvesting the plants over time)?

For allocation between different plant parts I am trying to chalk out the different suites of the traits pertaining to different organs including stem, leaf, roots and reproductive organs).

Thank you very much Sir! :-)

Respected Lambers Sir, Thank you very much for the response...!

Sir, I have read your paper (very explicitly explained traits and simple to understand; one of my key paper to understand traits and plant physiology), and surprisingly, its after this paper only that I have this inquisition. Sir, in this paper, in section VII (page 297), the importance of roots (as in root weight ratio) in determining the relative growth rate (of the plant) is discussed.

I was wondering if we can have a measure to understand how efficiently does a root grow under different conditions (may be through a harvest garden experiment). Can we (or do we) have a ratio like Relative Root Growth Rate = [ln (Specific Root Length after time 2) - ln(Specific Root Length after time 1)] / (time 2 - time 1) ???

In place of Specific Root Length, may be we can use Specific Root Area or Root Weight Ratio, depending on the question we are addressing?

Sir, will this be correct trait? Will this be logical to understand how the roots change in their parameters irrespective of above-ground scenario?

Thank you very much Sir! :-)

Hello van Dam Sir! Sir, I did read about Shoot:Root ratios and their importance in the allocational strategies of plants. Moreover, fine roots (

You're Welcome Adrian! 

I actually am reading about L:R ratio. Surely is of help, so, thanks to you!

Dear Ankita,

Thanks for your clarification and explaining in more detail what exactly you were after.

I believe it is perfectly valid and very interesting to compare RGR for shoots with that for roots, and to explore which traits correlate with differences in RGR.  You can then start exploring if traits such as SLA and LDMC correlate with their belowground counterparts.  It may be the case in some comparisons, e.g., for the grasses compared in Lambers & Ryser  (1995) (on RG), but for other comparisons, e.g., of species naturally occurring in P-limited environments, you likely end up with rather different above- and belowground functional traits.

In summary, I believe what you're aiming for is perfectly valid and interesting, and I look very much forward to seeing the results of your analyses.

Regards,

Hans 

Respected Lambers Sir!

Thank you very much for the appreciation. That was the exact thought, I was wondering if such shoot and root co-relations already exist. With a dose of appreciation from you, I shall work and produce the results asap now.

Sir, there is one more doubt that I would want to request for clarification - Is the "root length or root area or root weight" in Specific Root Length or Specific Root Area or Root Weight Ratio (respectively), signifies: (1)  fine roots (2mm diameter, or (3) all the roots irrespective of diameter ??

Unfortunately I haven't read the article you referred. Shall go through it now!!

Thank you Sir! :-)

Dear Ankita,

You make a very important point when splitting up your three categories.  That is essential.  When we deal with SLA, we focus on shoot parts (leaves) that are important in carbon assimilation.  If you were to include ALL roots, it would be like including the entire shoot, in which case you end up with LAR, not SLA.  Both ratios are important, byt they gice you different information.  You will find that this point has been made very strong by Dave Eissenstat.  I suggest you check out some of his excellent papers.

Regards,

Hans 

Respected Sir!

Oh, That's so true! The difference as is between LAR and SLA (for shoots) shall hold for belowground root traits too. I should be careful while using these parameters in the study.

Also, I shall go through the papers by Eissenstat Sir as suggested!

Thank you Sir!! :-)

Dear Lambers Sir!!

You were so right!!     Eissenstat sir has brilliant papers. And to my surprise the Root Growth Rate that I was searching for has already been thought of and performed by him back in 1988 (though the purposes are different, but still). I came across one of his papers (Eissenstat and Caldwell 1988; Ecology 69(3): 870-873) in which Rate of Root Growth was calculated as RGR = [ln(Root length at time t2) - ln(Root length at time t1)] / (time t2 - time t1). This is exactly what I was curious to know. :)

Thank you so very much Sir!!

I am glad I could be of some help.  Good luck.  Regards, Hans 

Sir, you are THE HANS LAMBERS. THE ECOPHYSIOLOGIST I know... who else could have been of more help!

Its a pleasure! Thank you... :-)

:-)

Ankita,

it seems the recommendations by Hans put you on the right track. As you pursue your research let me note a very relevant effort lead by Christian Wirth at the Max Planck Institute  in biogeochemistry at Jena, Germany. They have generated an impressive database of plant functional traits, including some of the root ones you were thinking about. The link for TRY (the name of the database) is

http://www.try-db.org/TryWeb/Home.php

and they are searching for meaningful data on roots. Keep them in mind as you progress with your research.

Miquel 

Dear Miquel Sir, Thank you very much for the kind appreciation. I will be really honored if the data set that I work on could be of some worth to further researches.

I read about TRY database while going through a review article by Kattge et al. (2011) (A generic structure for plant trait databases; Methods in Ecology & Evolution; 2(2): 202 - 213) where they compiled 'current major compilatons of plant trait data'.

Shall definitely keep your appreciation in mind during the work!

Thank you Sir!! :)

great!

good luck with your experiments

Thank you Sir.. :)

well, the length of root also can effected by type of soil and irrigation system.from that the best method to analysis growth rate of root or any plant via Dry matter and C/N ratio. from my research in this area you get negatively and positively rate that according to the plant growth stage. good luck , I look forward to your success