Appearance time, expansion rate and expansion duration for leaves of field-grown maize (Zea mays L.)

Abstract

Date of appearance and expansion duration of leaves are critical parameters for calculating leaf area of a canopy, which is, in turn, an important component of growth. In this study, a three-line function and a logistic function were both fitted to normalized leaf area data of individual leaves from field-grown plants. Algorithms were developed relating leaf appearance time, expansion rate and expansion duration to growing degree days (GDD) from emergence. Leaf appearance time was a nonlinear function of leaf number. Both leaf expansion rate (RN) and leaf expansion duration (LN) were bell-shaped functions of leaf number (N) with RN skewed toward a lower value and LN skewed toward a higher value of N. These algorithms were used to develop a model of leaf area development detailed in a companion paper. Key words: Temperature, water stress, leaf area