Effect of soil water content, intercepted radiation and temperature on sugar cane sucrose balance and partition

Changes in the sugar and structural (non-sugar) components in cane stalks of seven crops grown under artificial water stress and a reduction in the photosynthetic source by defoliation were determined. Under non-limiting conditions, changes in these components were similar and linked with stalk dry weight, explaining the distribution between structural material and sugar. Sugar production and the fraction of the total dry matter in the millable stalk which is sugar can be predicted simply from the stalk dry weight. Where water and radiation are limited, the trends in the proportions of these components diverge strongly. Pronounced water stress, a low radiation/temperature ratio or recovery of stalk turgidity after stress are the main significant environmental factors causing these divergences. These factors, interacting in a complex manner, modify the simple partition calculated from the millable stalk dry weight. (Résumé d'auteur