XVI International Botanical Congess

Photosynthesizing leaf is the main source of assimilates for the growth and development of vegetative and reproductive organs in the plant. However, some other chlorophyll-containing organs (stem, bract, green bolls) of the plant may also carry out considerable part of the donor=s functions. In this connection, investigation of the photosynthesis in aphyllous organs in cotton and their contribution into the total photosynthetic productivity of this plant is the aim of our work. Photosynthesis was determined by radiometric method. It is proved that at mid October, by the end of cotton=s vegetation, when leaf's photosynthesis decreases sharply, the intensity of CO2 assimilation in bracts and bolls increases and is to 52-66 percent of total photosynthesis in the plant. The highest assimilating capacity is characteristic to the bract (30-45 percent).