The air temperature was controlled at 23/18 &#8451 or 28/23 &#8451 (day/night). Whilst the CO₂ concentration was maintained at 360 or 720 µmol/mol. The temperature and CO₂ treatments were randomly assigned in each of the four groups. One G. pentaphyllum plant (5-foliolate) was obtained from Beishan of Jinhua, Zhejiang Province and then planted in Zhejiang Normal University of botany experimental garden. Reproduction of new plants was used by cutting propagation. After 5 years we obtained sufficient plant material for this study. The seedlings were planted in a temperature-controlled greenhouse (24 &#8451) from October to December (2014). Prior to treatment in a growth chamber, healthy plants were transplanted into pots (18 cm × 16 cm). The pots were filled with 3 kg of red soil combined with organic fertilizer of peat (19:1, w/w; total of organic matter content is approximately 60 g/kg). 50 plants were moved to each growth chamber. All plants were watered sparingly twice a week with 100 mL of modified Hoagland nutrient solution. The plant samples were evaluated at 60 days after treatment.

Elevated CO₂ increased the level of total sugars and gypenoside A, but decreased the total antioxidant capacity and main antioxidant compounds in different organs of G. pentaphyllum. Also, TP content at CT was lower than C. Similarly, TP content of leaves significantly decreased at T compared to CK, with a drop of 25.65%. Furthermore, high temperature and elevated CO₂ level significantly decreased the TP contents of leaves and stems. These results suggest that elevated CO₂ and increased temperature does not favor accumulation of phenolics in G. pentaphyllum organs.