3.3 Carbohydrate accumulation promoted by the
eCO2
Under the ambient CO2 condition, soluble sugar content
reduced significantly when N application rate increased from N0 to N5
and N10. Further enrichment to N15 significantly increased the soluble
sugar content. However, the starch content was relatively stable (Fig.
3A, B, C and D). Likewise, under the eCO2, enrichment of
N from N0 to N5 reduced soluble sugar, but further N enrichment to N10
or N15 increased soluble sugar content. In contrast, the starch content
under the eCO2 was consistently high under all N
application rates (Fig. 3E, F, G and H). The new-born tillers under the
eCO2 had higher contents of both soluble sugar and
starch than the ambient CO2, implying that relative
higher distribution of N content in them was not a result of
carbohydrate drainage. Overall, under the eCO2condition, all tissues contained higher carbohydrate content than the
ambientCO2, regardless of N application rate.