Dynamics of seedling growth acclimation towards altered light conditions can be quantified via GROWSCREEN: a setup and procedure designed for rapid optical phenotyping of different plant species

Abstract

Summary• Using a novel setup, we assessed how fast growth of Nicotiana tabacum seedlings responds to alterations in the light regime and investigated whether starch-free mutants of Arabidopsis thaliana show decreased growth potential at an early developmental stage.• Leaf area and relative growth rate were measured based on pictures from a camera automatically placed above an array of 120 seedlings. Detection of total seedling leaf area was performed via global segmentation of colour images for preset thresholds of the parameters hue, saturation and value.• Dynamic acclimation of relative growth rate towards altered light conditions occurred within 1 d in N. tabacum exposed to high nutrient availability, but not in plants exposed to low nutrient availability. Increased leaf area was correlated with an increase in shoot fresh and dry weight as well as root growth in N. tabacum . Relative growth rate was shown to be a more appropriate parameter than leaf area for detection of dynamic growth acclimation. Clear differences in leaf growth activity were also observed for A. thaliana .• As growth responses are generally most flexible in early developmental stages, the procedure described here is an important step towards standardized protocols for rapid detection of the effects of changes in internal (genetic) and external (environmental) parameters regulating plant growth.

A Journey Through a Leaf: Phenomics Analysis of Leaf Growth inArabidopsis thaliana

“…Pictures can be taken at a single timepoint to measure plant size (Figure 2a) or over time to measure rosette growth (Figure 2b) (Leister et al, 1999;Zhang et al, 2012). Over the last years, several specialized automated growth platforms equipped with imaging systems have been developed (Granier et al, 2006;Walter et al, 2007;Jansen et al, 2009;Arvidsson et al, 2011;Skirycz et al, 2011b;Tisné et al, 2013;Apelt et al, 2015). These setups are often combined with specialized image analysis methods to obtain rosette growth measurements.…”

“…The rosette is isolated from the original images through image segmentation. This can be based on splitting the images in their red, blue and green (RGB) channels (Figure 2a) (Leister et al, 1999) or by the non-linear conversion of RGB: the hue, saturation and value (HSV) color space (Walter et al, 2007), for which the hue is the most important dimension to discriminate plants from a background (De Vylder et al, 2012). Alternatively, in case of gray-scale images, watershed-based segmentation can be performed (Apelt et al, 2015).…”

Diel Growth Cycle of Isolated Leaf Discs Analyzed with a Novel, High-Throughput Three-Dimensional Imaging Method Is Identical to That of Intact Leaves

“…Because images are acquired in near-infrared light, only grayscale images are available. This allows image acquisition throughout day and night but makes segmentation more challenging in comparison with color images (Russ, 2002;Walter et al, 2007). Therefore, the following segmentation procedure is applied (Fig.…”

Leaf segmentation in plant phenotyping: a collation study

“…Biologists grow model plants, such as Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum), in controlled environments and monitor and record their phenotype to investigate general plant performance. While previously such phenotypes were annotated manually by experts, recently image-based nondestructive approaches are gaining attention among plant researchers to measure and study visual phenotypes of plants [24,28,41,55].…”

“…Several specialized algorithms have been developed to measure whole-plant properties and particularly plant size [6,17,25,27,31,40,55,61]. Nondestructive measurement of a plant's projected leaf area (PLA), i.e., the counting of plant pixels from top-view images, is considered a good approximation of plant size for rosette plants and is currently used.…”