Changes of photosynthetic rate and respiration rate of leaves at different leaf ages

1. Photosynthetic rate and respiratory rate: the photosynthetic rate of leaves in one and two years was similar, and the photosynthetic capacity was the strongest, and the photosynthetic rate of three-year-old leaves decreased obviously. The respiration rate also had the same change rule, only the respiration of three-year-old leaves decreased lower.

2. Other aspects of physiological changes: the activity of rubpc in biennial leaves was slightly higher than that in annual leaves, but decreased significantly in three-year-old leaves; glycolate oxidase activity was similar in one-year-old and two-year-old leaves, and decreased significantly in three-year-old leaves; protein content in annual leaves was higher than that in biennial leaves, and that in biennial leaves was higher than that in third-year leaves; chlorophyll content increased at any time.

The results showed that the annual and biennial leaves were functional leaves, and the three-year-old leaves began to senescence. (Ye Qingsheng, Pan Ruichi)