Autor(es)

Cruz, Larissa P. ; Pissolato, Maria D. ; Almeida, Rafael L. ; Machado, Eduardo C. ; Ribeiro, Rafael V.

• Tipo de documento: Artigo Científico
• Fonte: TROPICAL PLANT BIOLOGY; v. 18, n. 1, p. 13-pg., 2025-11-03.

Resumo

Energy cane (Saccharum spp. hybrid) is a sustainable feedstock for the sucroenergetic sector due to its capacity of producing more biomass than sugarcane (Saccharum spp. hybrid). As biomass is formed by carbohydrates, photosynthesis is a key physiological process to understand the biomass production by plants. Herein, one sugarcane (IACSP95-5000) and two energy canes (Vertix 2 and Vertix 3) genotypes were cultivated under greenhouse conditions to evaluate the photosynthetic capacity of top leaves and to measure the actual photosynthesis of all green leaves of the main tiller. Such evaluation consisted of measurements of leaf CO2 assimilation rate, maximum and effective quantum efficiencies of photosystem II, chlorophyll fluorescence quenchings and the relative abundance of PEPC and Rubisco, as well as leaf chlorophyll and nitrogen contents. All genotypes showed similar maximum and actual photosynthesis in the top leaves, which was not correlated to their biomass production. In fact, the effects of leaf aging on canopy CO2 uptake and the differential tillering seem to explain biomass production. IACSP95-5000 showed a sharp decrease in several photosynthetic traits and in abundance of key photosynthetic enzymes along the canopy profile, resulting in the lowest biomass yield. Vertix 2 and Vertix 3 exhibited a canopy with higher photochemical activity and lower variation in abundance of key photosynthetic enzymes with leaf aging, as well as more well-developed tillers as compared with IACSP95-5000. Moreover, Vertix 2 - bred for high fiber content - exhibited a more homogeneous photosynthesis with leaf aging, a physiological trait associated with the highest biomass production among genotypes evaluated. Our findings indicate that visible signs of leaf aging - or its absence - do not necessarily correspond to a decline - or maintenance - of photosynthetic activity, which highlights the relevance for physiological parameters to guide agronomic and breeding strategies to improving biomass yield. (AU)

• Processo FAPESP: 19/27106-0 - Alterações no transcriptoma, metaboloma e respostas fisiológicas associadas à memória à seca em cana-de-açúcar
• Beneficiário: Maria Dolores Pissolato
• Modalidade de apoio: Bolsas no Brasil - Doutorado