N is the total inorganic nitrogen (including both nitrate and ammonium) supply rate, P is the phosphorus supply rate, and K is the potassium supply rate.
Phosphorus-use efficiency was negatively correlated with the abundance of arbuscular mycorrhizas, suggesting higher efficiency of these fungi than of ectomycorrhizas for phosphorus supply to the host.
This result corroborates with the data presented by Meena and Biswas (2014a), which verified improvements at the phosphorus supply capacity when organic sources were applied concomitantly with phosphorus powder rock.
Eleven diets were optimised so that 70% of the phosphorus supply was provided by one of the following oilseed meals: untreated (UT) linseed, groundnut, soybean, rapeseed, sunflower meals, formaldehyde-treated (FT) soybean, rapeseed, sunflower meals, the FT oilseed diets being with or without phytase supplementation (FTP).
In three out of four species we found contrary reactions to light depending on phosphorus supply.
We observed significant changes of sterol contents with light intensity and phosphorus supply.
By analysing both conditions simultaneously we were able to detect interactive effects of the two factors light intensity and phosphorus supply, i.e. phosphorus supply influenced the reaction of algal sterol contents to varying light intensities.
However, not all of the analysed sterol contents showed the same reaction to light intensity and phosphorus supply.
For example, in contrast to the other species, in C. ovata no accumulation of storage lipids was found at high light intensities or low phosphorus supply (unpubl. data).
Consistent with the results obtained for S. quadricauda we found interactive effects of the two factors light and phosphorus supply on both sterols in C. meneghiniana (Table 1).
As a result, phosphorus supply might indirectly limit sterol synthesis by reducing the amount of membranes and so the enzymes needed for sterol synthesis.
