- In the 1st and 2nd steps, the daily photosynthesis and sugar accumulation were transformed into unified unit (mmol C g−1 DM). Then the ratios were quantified in the 3rd step. XY335, DH605 and ZD958 represent the three hybrids used in this study. Abbreviations: DM, dry matter; SLA, specific leaf area; AD, sum of daily photosynthesis, i.e. the net carbon assimilation; NSC, non-structural carbohydrates; TSC, total soluble carbohydrates