Leaf protein allocation across the canopy and during senescence in earlier and later senescing maize hybrids, and implications for the use of chlorophyll as a proxy of leaf N.

ANTONIETTA M.; GIRÓN P.; COSTA M.L.; GUIAMET J.J.

ACTA PHYSIOLOGIAE PLANTARUM

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2019

0137-5881

Leaf chlorophyll (chl) and protein distribution were analyzed throughout grain filling in four modern maize hybridswith contrasting senescence behavior, at three different canopy levels and at low-N (LN, 18 kg N ha−1) and high-N (HN,218 kg N ha−1) fertilization levels. Chl content assessed by SPAD resembled protein content only at LN, with delayedsenescing genotypes having more leaf protein content than reference genotypes. Across N levels, relative chl content negatively related to light intensity (r2 = 0.59, P < 0.001), while relative protein content did only for the lowest part of the canopy(r2 = 0.54, P < 0.001), suggesting protein distribution in the canopy could be further improved. Relative Rubisco/LHCIIpartitioning increased from lower to upper leaves (P < 0.09) and differed among genotypes (P < 0.05) with no link to senescence behavior. Photosynthetic electron transport rates were lower at LN and differed between genotypes (P