X-ray microtomography in comparison to radiographic analysis of mechanically damaged maize seeds and its effect on seed germination

Francisco Guilhien Gomes Junior,Carlos Manoel Pedro Vaz,Silvio Moure Cícero,Paulo Renato Orlandi Lasso

doi:10.4025/actasciagron.v41i1.42608

Francisco Guilhien Gomes Junior, Carlos Manoel Pedro Vaz + Show 2 more

Open Access

https://doi.org/10.4025/actasciagron.v41i1.42608

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Abstract

Among the most relevant aspects of seed production, mechanical damage may affect seed germination and reduce health and vigor. This study introduces a noninvasive high-resolution imaging procedure for evaluating the mechanical damage to maize seeds and the effects on seed germination. Seeds with different levels of mechanical damage were evaluated using a benchtop micro-computed tomography system (micro-CT) and digital X-ray equipment. The two-dimensional transaxial, coronal and sagittal micro-CT sections were used to inspect the seed anatomy and the mechanical injuries in the internal seed tissue. Germination tests were performed using paper towel rolls (25°C for 7 days) in which the seedling length was evaluated on a daily basis, and the seedling dry biomass was measured at the seventh germination day. The micro-CT cross-sectional images allowed an efficient spatial characterization of the mechanical damage inside the seeds. On average, mechanically damaged seeds produced seedlings with a length 24% shorter and a dry biomass 65% less than that of the undamaged seeds. We concluded that the micro-CT technique provides an efficient means to inspect mechanically damaged maize seeds and allows for a reliable association with germination response.

Highlights

Mechanical damage affects seed quality (Bewley & Black, 1994) along with harvesting, transporting, drying and handling (Carvalho & Nakagawa, 2012)
An improvement in the evaluation of mechanically damaged maize seeds occurred in late 1990s when X-ray radiography was introduced as a non-invasive technique for analyzing internal injuries of seeds along with their physiological quality (Cicero, Heijden, Van der Burg, & Bino, 1998; Carvalho, Aelst, Eck, & Hoekstra, 1999)
Research evaluating pre-harvesting cracks on maize seeds using X-ray radiography and low-temperature scanning electron microscopy showed that internal injuries or those perpendicular to the embryonic axis affect seed germination and vigor (Carvalho et al, 1999)

Summary

Introduction

Mechanical damage affects seed quality (Bewley & Black, 1994) along with harvesting, transporting, drying and handling (Carvalho & Nakagawa, 2012). An improvement in the evaluation of mechanically damaged maize seeds occurred in late 1990s when X-ray radiography was introduced as a non-invasive technique for analyzing internal injuries of seeds along with their physiological quality (Cicero, Heijden, Van der Burg, & Bino, 1998; Carvalho, Aelst, Eck, & Hoekstra, 1999). Research evaluating pre-harvesting cracks on maize seeds using X-ray radiography and low-temperature scanning electron microscopy showed that internal injuries or those perpendicular to the embryonic axis affect seed germination and vigor (Carvalho et al, 1999). Because radiographic analysis is a two-dimensional (2D) projection of a seed, it is not effective in determining depth of cracks. Cicero and Banzatto-Junior (2003) showed that 23% of maize seeds with mechanical damage on the embryo produced normal seedlings and concluded that the X-ray radiography technique did not allow for an accurate evaluation of fractures

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