Source - sink differences in genotypes and water regimes influencing sucrose accumulation in sugarcane stalks

Abstract

Relatively little is known about the physiological basis for variation in sucrose content among sugarcane clones despite substantial research at the molecular and biochemical levels. We used irrigation and continuous monitoring of photosynthesis and plant extension rate to modify dry matter partitioning in four clones differing widely in sucrose content. Three pot experiments were conducted on two low sucrose content clones, KQ97-2599 and KQ97-2835, and two high sucrose content clones, Q117 and KQ97-5080, in a temperature-controlled glasshouse. As expected, sucrose content on a dry mass basis of whole stalks was greater in high (55% maximum) than in low sucrose clones (40% maximum), but sucrose content in the two clones selected for low sucrose reached 55% in some internodes. Differences between clones in whole-plant net photosynthesis and aerial biomass accumulation were small. However, biomass was distributed over fewer stalks in the high sucrose clones (4-7 stalks per pot) than in the low sucrose clones (9-11 stalks per pot). The high sucrose clones also allocated a considerably greater proportion of dry matter to the stalk (70% maximum) than the low sucrose clones (60% maximum). It is suggested that the relatively large amount of new leaf tissue produced by the high tillering, low sucrose clones placed an additional demand for structural photo-assimilate in these clones and delayed the accumulation of sucrose in the stalk. The results indicated that there is little direct genetic control on the maximum amount of sucrose that can accumulate in stalk tissue and that genetic contrasts in sucrose content reside more in the morphology of the plant and responses to ripening stimuli such as mild water stress, and how these traits influence supply and demand for photo-assimilate.Additional keywords: dry matter partitioning, water stress, Saccharum spp., photosynthesis, plant extension rate.

The Biotechnology Roadmap for Sugarcane Improvement

“…In addition, little is known about what limits the capacity of sugarcane to store high concentration of sucrose in the parenchyma tissue of the stalk (McCormick et al 2008a). Sucrose content variation depends on the morphology of the plant, such as size of the canopy and responses to ripening stimuli such as mild water stress and how these traits influence the supply and demand for photo-assimilate (Inman-Bamber et al 2009). The photomorphogenic control of sugarcane development can be modified by treatment with gibberellic acid (GA3).…”

Produtividade De Colmos E Rendimento De Açúcares Da Cana-De-Açúcar Em Função De Lâminas De Água

“…Conforme a maturação avança, açúcares simples (monossacrídeos, como frutose e glicose) são convertidos em sacarose (um dissacarídeo). A maturação da cana-de-açúcar procede de baixo para cima e, desse modo, a parte inferior contém mais açúcares do que a porção superior (LISSON et al, 2005;MOORE, 2005;INMAN-BAMBER et al, 2009). Farias et al (2009), em estudo realizado no Tabuleiro Costeiro Paraibano, analisaram o efeito de lâminas de água de irrigação na qualidade industrial da cana-de-açúcar, observando forte correlação entre as variáveis.…”

Process-based simple model for simulating sugarcane growth and production

“…As modeling effi ciency represents how much better the model is compared to the average of observed values, the low effi ciency values are primarily due to the time-stable measurements of sucrose content. In general, modeling sucrose accumulation remains a challenge due to the poor understanding of this variable at the whole-plant level (Inman-Bamber et al, 2009). However, the decreased agreement obtained for sucrose (Figure 9b) may be partially due to the characteristics of the measured data rather than to a weakness in the model algorithm.…”