Fig. 2

Photosynthesis capacity is controlled by light intensity. A and B represent the photosynthesis parameters and photosynthetic pigment content; C and D represent chlorophyll fluorescence under different light intensities. E is the score plot of PCA, and 150,250,350,450,550 represents the treatment of 150, 250,350,450,550 μmol·m^− 2·s^− 1 light intensity. F is the loading plot of PCA,and the corresponding indexes of the numbers are as follows: 1 = Pn, 2 = Tr, 3 = Gs, 4 = Ci, 5 = Chla, 6 = Chlb, 7 = Car, 8 = Chla+b, 9 = Chla/b, 10 = Fo, 11 = Fm, 12 = NPQ, 13 = qP, 14 = 1-qP, 15 = ETR, 16 = Fv/Fm, 17 = Fm′, 18 = Fo’, 19 = Fv’/Fm′. G represents photosynthesis capacity