Chlorophyll (Chl) and nitrogen (N) content measurements
Leaf Chl content and Chl a /b ratio were determined as reported previously (Takagi et al., 2019). In brief, leaf segments were incubated in N, N -dimethylformamide at 4 °C overnight and the absorbance values of the aliquot were measured at 750 nm, 663.8 nm, and 646.8 nm to calculate the chlorophyll content (Porra et al., 1989). The total leaf nitrogen content was determined by using the Nessler’s reagent in a digestion solution after the addition of potassium sodium tartrate (KNaC4H4O6) and then measuring the absorbance at 420 nm (Takagi et al., 2017).