Abstract
The time courses of the chlorophyll contents, apparent photosynthetic rates (Pn), and dark respiration rates (R) in the leaves of Betula maximowicziana infected with Taphrina butulina and in healthy early-leaves were studied. The Pn in the infected leaves was higher than that in the healthy ones by 15 days after leaf emergence, and then it decreased rapidly. The chlorophyll content and R in the infected leaves were higher than those in the healthy leaves until 23 days after bud opening, after that they decreased rapidly. All infected leaves were shed during the 39 days after unfolding, whereas the healthy ones developed to maturity. The early falling of the infected leaves was attributed to the exhaustion of reserve substances and photosynthates.
