Photosynthetic responses of the riparian plant Arundinella anomala Steud. in Three Gorges reservoir region as affected by simulated flooding EFFECTS OF EXOGENOUS ETHYLENE ANDα-NAPHTHALENE ACETIC ACID ON AERENCHYMA FORMATION IN THE STEM OF TWO RIPARIAN PLANT SPECIES ARUNDINELLA ANOMALAAND SALIX VARIEGATAIN THE THREE GORGES RESERVOIR REGION OF CHINA The effects of flooding on aerenchyma formation in the stem of Arundinella anomala var. depauperata Keng, a riparian plant in Three Gorges reservoir area 水淹对三峡库区两种岸生植物秋华柳(Salix variegata Franch.)和野古草(Arundinella anomala Steud.)水下光