Figure 4

Photosynthesis index statistics of four-week-old seedlings. (A) Photosynthetic indices under the condition the condition of carbon starvation conditions at 56 μmol·m−2·s−1. (B) (Yong leaf), (C) (Old leaf), Photosynthetic electron transfer rate (ETR) under different photosynthetically active radiation (0 μmol·m−2·s−1–1251 μmol·m−2·s−1). PPF refers to the photosynthetic photon flux. (D) (yong leaf), (E) (old leaf), and ΦPSII under different photosynthetically active radiation treatments. (F) Determination of chlorophyll content. G The chlorophyll fluorescence images. The red circle indicates the site where NPQ occurs occurred.