THE RELATIONSHIP BETWEEN PHOTOSYNTHETIC CHARACTER AND ADVENTITIOUS ROOTS IN FLOODED CLEISTOCALYX OPERCULATUS SEEDLINGS

Flooding induced the changes in net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of 17-month-old seedlings of Cleistocalyx operculatus. Pn, Gs and Tr began to decline progressively after 5 days of flooding. However, a few seedlings which developed adventitious roots (AR) on submerged portion of the stem starting on the 35th day of flooding showed a gradual increase in Pn, Gs and Tr, and maintained a higher level of Pn, Gs and Tr by the 80th day of flooding. The daily courses of Pn, Gs and Tr of seedlings with AR showed a pattern of two peaks, and the regression analysis indicated that Pn was positively correlated with Gs (r=0.69, P0.05).