GreenLab Course
Production-Expansion
Biomass Allocation. Plant Demand.
Biomass allocation, plant demand
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Biomass allocation.
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Biomass allocation is driven by the sinks of all expanding organs.
We have seen that, on a given date t, the biomass increase q(t) is defined from the total available biomass Q(t),
and the relative ratio of the organ sink φo / Σjφj,
with j respectively standing for all the different organ types (all roots, all leaves, etc.);
the sum of all organ sinks ( Σjφj ) builds plant demand D(t).
Considering now the period of a growing cycle n, the biomass allocated to organ o, of physiological age p, can be written as follows:
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qo,p(n) = Q(n-1) . φo,p(i) / D(n) (equation 2)
where
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n is the current growing cycle
o stands for the organ type
p stands for the physiological age
i stands for the organ age (expressed in cycles since the beginning of expansion)
φo,p defines the sink function of organ o at physiological age p
D(n) is the total plant demand at cycle n (the sum of all sinks of organs in expansion)
Q(n-1) is the available biomass in the common pool. By definition Q(0) defines the seed biomass.
Plant demand
Plant demand, at a given cycle n, called D(n), can be computed from the sum of all cohort demands:
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D(n) = Σo,p Do,p(n)
where
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Do,p(n) is the demand of organ o, at physiological age p.
Do,p(n) = Σt1=n-l;n No,p(t1) . φo,p(t1-n+l)
giving the expression of demand:
D(n) = Σo,p Σt1=n-l;n No,p(t1) . φo,p(t1-n+l) (equation 3)
where:
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n is the current cycle
o is the organ type (internode, leaf, fruit, ring, root, etc.)
p is the physiological age
t1 stands for the different appearance cycles of cohort Co,p
t1 stands for the different appearance cycles of cohort Co,p
t1-n+l is therefore the age of the organ (belonging to [0..l])
No,p(t1) stands for the number of organs appeared at cycle t1