Roundup was Cardamine hirsuta

Christian Lachaud
Thu, 04 Apr 2013 14:00:43 PDT
Lou : why is this effect not occurring in areas cleaned manually ? Manually
removing weeds (1) brings light the same way as having weeds killed by
glyphosate and (2) also suppresses roots inhibitory secretions, which is
alledged to impact negatively on the germination of Cardamine seeds as well
as seeds from other plants.

If these were true however, Cardamine would not be the only weed to benefit
from this new situation, since light and suppression of inhibition must
logically promote germination whatever the species.

I have observed that areas cleaned with roundup show little colonisation by
seedlings from other species. It takes more time, as if seeds had been
killed by roundup or if their vitality was lower. But Cardamine is growing
mad like nowhere else.

On the contrary, in areas cleaned manually, a mix of plants colonise back,
including very few cardamine individuals in the mix.

I already thought about all you say Lou, it is not that simple. For
instance, the effect can also come from chemical interactions between
glyphosate or whatever other components in roundup and soil components, the
dead plants can release components promoting Cardamine's germination,
eventually through fungi developping on plants cadaver, and so on.

If anyone is interested in seriously building an experimental design for
running it in controlled conditions, I will help if you want. I can even
collect Cardamine seeds of my strain for this purpose and send it to anyone
willing to investigate further this issue.

There may be many factors involved, but to start with the purpose of
validating my observations, Nhu's type of design is appropriate. I was only
mentionning that I don't need it myself, I have enough observations in the
field and local people testimonies showing consistency. This is only
appropriate for a third party willing to start a scientific investigation.

Aaron : do you have any references to advise ?

Dr. Christian M. Lachaud, PhD*

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