How would you explain to have in a given set of plants more net photosynthesis and less dry biomass in one group when compared to the other? Thank you all.
hi
This is explained with regard to photo-respiration. Probably low concentration of oxygen O2 or high concentration of carbon dioxide CO2, and may be high light lead to increased photo-respiration . which results in waste products of photosynthesis (photo assimilates) and reduction in growth and production. good luky
The carbon is fixed by net photosynthesis during day, but its fate depends on day respiration in roots and other compartements, leaf night respiration and storage strategy. RGR is the exponent of dry mass increase at 2 different times, as ln W2=RGRt2+lnW1; but it relates to net phot. A by RGR=(A F)/d(1-R), where F i the fraction of light on a day, d is the surface carbon density in mol m-2 and R is the decimal respired. In brief you should integrate over 24 hours and observe that plant giants are not with high A, btu they make wood that is not respired
Another possibility (if the plants are in the field) is that one group is being eaten more than the other group, by herbivores.
It was not described what are the two plant groups. Species may differ in allocation of assimilates (carbon) - some species growth fast (biomass production, e.g. ruderals, but only if they have enough nutrients ). Some may allocate huge amount of C to root exudates (competitors that competes for nutrients, i.e. their growth is nutrient-limited).
This is just an example showing that fast photosynthesis does not inherently mean fast growth.
Photosynthesis rate is expressed as micro mol CO2/m2/s which may or may not be positively associated with yield or even biomass. However, the total canopy photosynthesis will be positively associated with biomass production as carbon can enter the plant system only through photosynthesis.
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