Chlorophyll Pigment and Leaf Macronutrient Trait Variation of Four Salix Species in Elevated CO2, under Soil Moisture Stress and Fertilization Treatments

Leaf chlorophyll pigment and macronutrient concentrations were quantified for four willow species (Salix cordata (COR), S. discolor (DIS), eriocephala (ERI) interior (INT)) while growing under 2 × factorial of ambient elevated CO2 well-watered drought-stressed soil moisture treatments (Expt. 1). After the first year, we saw no difference in stem biomass between treatments. In following a second experiment was conducted on subset willows as atmospheric fertilization (FERT). For both years Expt. 1, a, b, + b (TCC) carotenoids (CAR) significantly downregulated response to (eCO2) upregulated drought (DRT). 2, FERT mitigated downregulation TCC CAR, CAR. Across species, ERI had greatest followed by either COR or DIS. Except one case, INT lowest concentrations. A significant x interaction due magnitude effects. The CHLa:b ratio not affected DRT but did increase FERT. DIS, then COR. TCC:CAR decreased eCO2 increased leaf N only nutrient downregulate eCO2; whereas all other levels remained unchanged. DRT, Mg upregulated; P, K, Ca downregulated. again downregulated; nutrients All Of Ca. Species variation important, so clonal change. Indeed, macronutrients are different segregated from three this may be related evolutionary origins INT, taxonomic section Longifoliae, arid southwest USA Mexico. Furthermore, low conditions, it necessary fertilize plants see eCO2.