Isolated stem culture
Uniform stems of the invasive and native species were detached from plants cultivated in a garden. The stems were washed with tap water and cut into 10-cm-long segments. Five or 6 segments were placed into a 9 cm petri dish that contained two pieces of filter paper and 8 mL of distilled water and cultured in an RXZ growth chamber (Jiangnan Equipment Factory, Ningbo, China). The cultures were maintained at 28°C/25°C (day/night) under a light/dark photoperiod of 14:10 h, irradiation of ~40 μmol photon m–2s–1 and 70% relative humidity for 20 days. The survival rate, root length and electron transport rate (ETR) of the stems in the isolated cultures were then investigated.