Chlorophyll a fluorescence in two varieties of sugar cane subjected to aluminum and water stress

Soils of open pasture in the Cerrado (brazilian savanna) have farming limitations related to the high content of aluminum and water restrictions in the superficial horizons, due to easy drainage and large exposure to high levels of irradiance. Aiming to assess chlorophyll a fluorescence’s responses in two varieties of sugar cane in the State of Mato Grosso do Sul subjected to water restriction and different aluminum contents, an experiment was conducted in a controlled environment. The experimental lineation consisted of random blocks in a factorial scheme (2 varieties x 2 levels of water available in the soil based on field capacity [cc] and 3 contents of Al +3 ), with 15 replications. Significant differences were observed throughout and at the end of the experiment between the averages of some parameters of chlorophyll a fluorescence for treatment EH1 and between varieties. Results obtained by means of the OJIP test were the most efficient for variety distinction. RB1 (RB 8555536) proved to be more responsive to treatments, variety RB2 (RB867515) did not present significant alterations between treatments; its suggests that most part of the radiation was efficiently used in the photochemical stage of photosynthesis, that makes it more tolerant to the subjected stresses.