Differential Physiological Response of Sugarcane Varieties to Osmotic Pressures of Saline Media1

Abstract

Exposure of sugarcane varieties to different levels of osmotic pressure in nutrient solution (by adding NaC1) emphasizes varietal differences in response to this pressure. Working with varieties H 37‐1933 (known to be sensitive to drought) and H 49‐3533 (known to be tolerant to drought), physiological responses to added amounts of osmotic pressure were measured. Differential responses between these two varieties were shown in growth, flowering (tasseling), formation of joints, uptake of phosphorus, uptake of sodium, and storage of sucrose. These experiments showed that, above a certain pressure, there is a withdrawal of sugars from the basal or older joints. Provided that they have not been exposed to osmotic pressure great enough to cause death, after removal of the added pressure the plants start returning sugar to those joints from which it was withdrawn during the period of osmotic stress.