Measurement of morphological growth traits

On each sampling date, the harvested plant was divided into leaves, stems and roots, washed with tap water and dried with absorbent paper. The biomass of each plant component, the height and ground diameter of the main stem, and the elemental composition and CC of the mature leaves were determined. The RGR_Biomass, RGR_Height and RGR_Diameter were calculated according to the following equations:

where W₁, H₁ and D₁ were the initial biomass, height and ground diameter, respectively, W₂, H₂ and D₂ were the respective values at the next harvest, and t was the interval time (days) between the two harvests.