Diel leaf growth of soybean: a novel method to analyze two-dimensional leaf expansion in high temporal resolution based on a marker tracking approach (Martrack Leaf)

Abstract

BackgroundWe present a novel method for quantitative analysis of dicot leaf expansion at high temporal resolution. Image sequences of growing leaves were assessed using a marker tracking algorithm. An important feature of the method is the attachment of dark beads that serve as artificial landmarks to the leaf margin. The beads are mechanically constricted to the focal plane of a camera. Leaf expansion is approximated by the increase in area of the polygon defined by the centers of mass of the beads surrounding the leaf. Fluctuating illumination conditions often pose serious problems for tracking natural structures of a leaf; this problem is circumvented here by the use of the beads.ResultsThe new method has been used to assess leaf growth in environmental situations with different illumination conditions that are typical in agricultural and biological experiments: Constant illumination via fluorescent light tubes in a climate chamber, a mix of natural and artificial illumination in a greenhouse and natural illumination of the situation on typical summer days in the field. Typical features of diel (24h) soybean leaf growth patterns were revealed in all three conditions, thereby demonstrating the general applicability of the method. Algorithms are provided to the entire community interested in using such approaches.ConclusionsThe implementation Martrack Leaf presented here is a robust method to investigate diel leaf growth rhythms both under natural and artificial illumination conditions. It will be beneficial for the further elucidation of genotype x environment x management interactions affecting leaf growth processes.

Diurnal Leaf Starch Content: An Orphan Trait in Forage Legumes

“…Alternatively in a starchless mutant, RGR increase in late afternoon when soluble sugars accumulate and carbohydrate availability is high, and decrease at night and dawn [39]. In soy, RGR correlates more directly with carbohydrate concentration, which peaks at ED, and linearly decreases to the lowest level at dawn [40]. Taken together utilization of leaf starch provides flexibility to plant growth strategies during the diel cycle, but how starch concentration and this added flexibility relates to overall biomass potential is still not well understood.…”

Molecular approaches for genetic improvement of seed quality and characterization of genetic diversity in soybean: a critical review

“…Therefore, phenomics integrated with other omics approaches has the most potential in plant breeding. Marker tracking approaches (Martrack leaf) have also been used to facilitate accurate analysis of two-dimensional leaf expansion with high temporal resolution (Mielewczik et al 2013). Alteration in expression of many GmNAC and hormone-related genes Le et al (2012) Affymetrix Soybean Gene Chip…”

Water relations determine short time leaf growth patterns in the mangrove Avicennia marina (Forssk.) Vierh.

“…Relative leaf area change was measured using a custom-made marker tracking software similar to Martrack Leaf (Mielewczik et al, 2013).…”

“…Relative leaf area change was measured using a custom‐made marker tracking software similar to Martrack Leaf (Mielewczik et al, ). We did not use Martrack Leaf because it turned out to be sensitive to movements due to wind.…”

“…A relatively simple method to measure leaf area growth of dicotyledons is to fix a leaf in a plane and observe it through a camera with the image plane parallel to the leaf (Schmundt, Stitt, Jahne, & Schurr, 1998;Walter, Feil, & Schurr, 2002). Relying on this principle, Mielewczik, Friedli, Kirchgessner, and Walter (2013) presented a semiautomated image analysis software based on marker tracking, and they also showed the general feasibility of their method for field studies.…”