I have been consistently observing that corn seedling radicles are much more extensively damaged by pathogens, compared to the seminal roots of the same seedlings. Can anyone point me to some literature on why this might be the case?
Matthew, can be the temperature fluctuations, or more precisely the herbicide injury (this simptom I have in this year in the nursery).
Maybe this link can help you http://www.grains.cses.vt.edu/publications/Diagnosing%20Chilling%20and%20Flooding%20Injury%20to%20Corn%20Prior%20to%20Emergence.pdf
Hypothesis: The answer lies in the functional anatomy. Radicles are softer and fashioned in a way that allows them to extensively pump water, but also nutrient from the environment. This also facilitates the penetration of infectious agents like fungus.
Experiment: Make a cross section of the middle of any radicle (infested or not) and the middle of the seminal root from the same seedling.
Observation: Under the light microscope after coloration and preparation, look at the epidermis and cortical structure. Results: What are the differences that can prove/disprove our hypothesis?
Lucian was right, but even without any injuries, radicles grown in the best condition still represent a gateway to fungal and bacterial infection.