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Modeling final leaf length as a function of carbon availability during the elongation period

Auzmendi, I., Hanan, J., Da Silva, D., Favreau, R., DeJong, T. M.
Acta horticulturae 2017 no.1160 pp. 75-82
branches, carbon, leaf area, leaf development, leaves, mechanistic models, peaches, shoots, temperature
Each leaf is both a sink and a source of carbon that determines the growth of plant structure. Therefore, simulation of individual leaf expansion is essential in modeling plant structural growth. Leaf expansion has been often fitted to logistic sigmoidal functions that require initial and final leaf length, and duration of elongation to be known. A different method, based on the compound interest law, determines leaf length using initial length, relative elongation rate and duration of elongation. We aimed to evaluate which factors are most important in explaining final leaf length variability. Elongation of individual leaves on peach shoots was monitored over 21 days. Individual leaf lengths were fitted to logistic functions to determine their initial and final lengths, and durations of elongation in growing degree hours. Parameters that could affect final leaf length were evaluated: shoot characteristics below the leaf, initial length, duration of elongation, and temperature during the initial days after leaf appearance. Final leaf length had significant relationships with leaf area and length of the shoot axis excluding sylleptic branches, but it was not significantly related to initial length or duration of elongation. Total shoot leaf area and temperature during the initial days after leaf appearance also affected final leaf length. Our results showed that final leaf length is mainly determined by factors acting during leaf elongation. Based on these data, we used compound interest law and carbon availability concepts to develop a mechanistic model of final lengths of individual leaves.