Species specific physiological responses of Pinus densiflora and Larix kaempferi seedlings to open-field experimental warming and precipitation manipulation

AbstractPhysiological responses of 1-year-old Pinus densiflora and Larix kaempferi seedlings were measured under open-field warming and precipitation manipulation. Air temperature of warming plots was 3 °C higher, while precipitation manipulation plots received ±40% of the precipitation than control plots. Seedlings were planted in May, and temperature and precipitation were manipulated from June 2017. Total chlorophyll content (Chlt), net photosynthetic rate (Pn), transpiration rate (E), and stomatal conductance (gs) were measured between July and September 2017. For P. densiflora and L. kaempferi, Chlt increased by 11.75% and 11.64%, and Pn decreased by 9.14% and 2.17% under warming, respectively. E and gs were lower under warming in P. densiflora, but higher in L. kaempferi. The lower Pn in P. densiflora resulted from stomatal closure, while that of L. kaempferi resulted from reduced vitality. Lower precipitation increased Chlt and Pn by 11.64% and 2.66% for P. densiflora, and by 6.40% and 4.32% for L....