permaculture

[João Pedro Moreira Gonçalves <joaovox@gmail.com>]

always great inspiration to read about it.

where
 in "human-medium/ecosystem" do we see this symbiotic pattern or something
related to it?
thinking of nomads herding animals in dry lands, always on the move ...

Abstract:
In this paper, we describe a mechanism for the transfer of nutrients from
symbiotic microbes (bacteria and fungi) to host plant roots that we term
the ‘rhizophagy cycle.’ In the rhizophagy cycle, microbes alternate between
a root intracellular endophytic phase and a free-living soil phase.
Microbes acquire soil nutrients in the free-living soil phase; nutrients
are extracted through exposure to host-produced reactive oxygen in the
intracellular endophytic phase. We conducted experiments on several
seed-vectored microbes in several host species. We found that initially the
symbiotic microbes grow on the rhizoplane in the exudate zone adjacent the
root meristem. Microbes enter root tip meristem cells—locating within the
periplasmic spaces between cell wall and plasma membrane. In the
periplasmic spaces of root cells, microbes convert to wall-less protoplast
forms. As root cells mature, microbes continue to be subjected to reactive
oxygen (superoxide) produced by NADPH oxidases (NOX) on the root cell
plasma membranes. Reactive oxygen degrades some of the intracellular
microbes, also likely inducing electrolyte leakage from
microbes—effectively extracting nutrients from microbes. Surviving bacteria
in root epidermal cells trigger root hair elongation and as hairs elongate
bacteria exit at the hair tips, reforming cell walls and cell shapes as
microbes emerge into the rhizosphere where they may obtain additional
nutrients. Precisely what nutrients are transferred through rhizophagy or
how important this process is for nutrient acquisition is still unknown.



On Thu, Oct 4, 2018 at 6:49 PM Lawrence London <lfljvenaura@gmail.com>
wrote:


Microorganisms | Free Full-Text | Rhizophagy Cycle: An Oxidative Process in
> Plants for Nutrient Extraction from Symbiotic Microbes | HTML
> https://www.mdpi.com/2076-2607/6/3/95/htm





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-- 
João Gonçalves
Agroecologia e Permacultura
Poceirão, Lisboa e Chão Sobral
t. 96 98 80 009
http://ecotrabalho.com
http://www.finca-equilibrium.com/
http://artepro.org/
http://chaosobral.org/index_pt.htm