Biomass-Based Leaf Curvilinear Model for Rapeseed (Brassica napus L.)

Abstract

Leaf is one of the most important photosynthetic organs of rapeseed (Brassica napus L.). To quantifyrelationships between the leaf curve and the corresponding leaf biomassfor rapeseed on main stem, this paper presents a biomass-based leaf curvilinear model for rapeseed. Various model variables, includingleaf length, bowstring length, tangential angle,and bowstring angle, were parameterized based on data derived from the field experiments withvarieties, fertilizer, andtransplanting densities during 2011 to 2012, and 2012 to 2013growingseasons. And then weanalysed the biological significance of curvilinear equation for straight leaves,constructed the straight leaf probabilistic modelon main stem,quantified the relationship between leaf curvature and the corresponding leaf biomass, and constructed the leaf curvilinear model based on the assumption and verification of the curvilinear equation form for curvingleaf. The probability of straight leaf can be quantified with piecewise function according tothe different trend in the normalized leaf ranks ((0, 0.4],and (0.4, 1]). The leaf curvature decreased with the increasing of leaf biomass, and can be described with reciprocal function. The curve of straight leaf and the curving leafcan besimulated by linear equation and thequadratic function, respectively. Our models were validated withthe independent dataset from the field experiment, and the results indicatedthat the model could effectively predict thestraight leaf probability and leaf curvature, which would be useful for linking the rapeseed growth model with the rapeseed morphological model, and set the stagefor the development of functional-structural rapeseed models.