Seasonal changes in photosynthesis of the non-astringent persimmon cultivar Fuyu in subtropical Australia

Abstract

Seasonal changes in net carbon dioxide assimilation (A) were measured over 2 season in a high-yielding ‘Fuyu’ orchard at Palmwoods, Queensland, Australia. Similar patterns of A were recorded in both seasons with only one peak, occurring between 8-11 weeks after full bloom. The peak in A appears to coincide with the period of maximum root growth and stage II of fruit growth. A rates were positively correlated with leaf N (r = 0.85, P<0.05), and moderately negatively correlated with leaf starch (r = -0.82, P <0.05) and specific leaf weight (r = -0.58, P<0.05), indicating an inhibitory feedback mechanism. Specific leaf weight and leaf starch were highly positively correlated (r=0.92, P<0.05). The study suggests that maintaining leaf N within a desirable critical range may be important for maximising fruit growth and for the accumulation of starch reserves for next season crop.