Assessment of leaf ultrastructure offers insights into mechanisms regulating sugarcane performance under low-phosphorus stress

Autor(es)

Zambrosi, Fernando C. B. ^[1] ; Mesquita, Geisa L. ^[2] ; Tanaka, Francisco A. O. ^[2]

Afiliação do(s) autor(es)

^[1] Inst Agron IAC, Ctr Solos & Recursos Ambientais, POB 28, BR-13020902 Campinas, SP - Brazil

^[2] Univ Sao Paulo, Dept Fitopatolgia, POB 09, BR-13418900 Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ACTA PHYSIOLOGIAE PLANTARUM; v. 42, n. 4 MAR 31 2020.
• Citações Web of Science: 0

Resumo

Detailed studies of plant responses to phosphorus (P) deficiency might reveal opportunities to improve sugarcane performance under nutrient stress, termed as P use efficiency. Then, we aimed through transmission electron microscopy to offer insights into the effects of varying P supply on leaf ultrastructural traits influencing photosynthesis and leaf area formation. Plants of the genotype RB86-7515 were cultivated under varying nutrient supply (0.0125, 0.05, 0.2 and 0.8 mM P) for 4 months. Diagnostic mature leaves were sampled to evaluate ultrastructural organization and P concentration. Leaf area and plant dry mass responded positively to increasing P rates and maximum values were attained at 0.55 mM P. Leaf P concentration increased as a function of nutrient supply, and the greatest area of diagnostic leaf and whole plant growth was associated with 1.80 g kg(-1) P. Under severe deficiency (relative growth <= 30% and leaf P <= 0.90 g kg(-1)) generated with 0.0125- and 0.05-mM P, transmission electron microscopy revealed pronounced damages to leaf ultrastructure. In mesophyll cells, the changes were more intense under the lowest P rate, and included disintegration of the middle lamella, collapse of plasma membrane and distortion of thylakoids. Bundle sheath chloroplasts of the severely P-deficient plants exhibited, compared with those under 0.2- and 0.8-mM P, disorganization of lamellar membrane system. Collectively, these ultrastructural alterations offer insights into how P deficiency affects whole plant photosynthetic capacity and provide possible target traits at canopy level related to sugarcane P use efficiency. (AU)

• Processo FAPESP: 16/14058-9 - Variação no estado nutricional por manganês afeta a resistência da cana-de-açúcar à ferrugem alaranjada?
• Beneficiário: Francisco André Ossamu Tanaka
• Modalidade de apoio: Auxílio à Pesquisa - Regular