Hi,
I would worry about differences in the relative water content of your
starting tissue (rhizome) vs. your end tissue (whole plant). If different
tissue types have different WC, then growth rate estimates based on fresh
weights alone will be biased. If you measure the dry weights for a subsample
of your rhizomes (per treatment, as suggested by an earlier post), and the
regression is good, then you could convert the rest of your rhizome wet
weight measurements to estimates of dry weight, and compare those to the dry
weights at the end of the experiment to get your RGR.
Steve
On Tue, 4 Aug 2009 19:11:03 -0400
Ted Turluck <[email protected]> wrote:
Hello,
I've posted before with questions about other methods and got a lot of
responses. Thank you to all who responded before.
I'm going to be starting an experiment in which I plan to measure growth
rates of two different haplotypes of Phragmites australis under varying
water depths and salinities. I plan to use change in height and number of
shoots over time as a measure of growth. I'm planting rhizome fragments.
I'll measure length, diameter, number of nodes, and number of buds before
planting. I'll try to make the fragments as similar in size as possible.
I would like to measure biomass before and after as well (or maybe
instead). But I don't know if measuring fresh biomass before planting and
after harvest is a legitimate method.
Would there be a chance that there would be a difference in moisture
content between each rhizome fragment that could mess up my data?
Is height change a good way of measuring growth in grasses?
Is fresh biomass a good thing to measure before and after a growth
experiment?
Thanks for any advice.
