EmeraldCropSci
Member
- Location
- Cheltenham, Glos.
Several things making my head spin! Why don't roots grow upwards, sidewards? Gravity? So with seed dressings isn't the root always growing away from its nutrients? What decides the path the roots take? Osmosis? least resistance? Or magnetism? (manganese of course being one of the few magnetic elements) Is gravity simply a mass pull or do we move into the realms of quantum fields and the higgs bosun? buy me a drink and I won't mention it again.
You're right. Gravity is the driver and roots can detect the pull of gravity and react accordingly. There are vesicles within each plant cell that detect gravity. Experiments by NASA and others in free fall orbital experiments (which is not gravity free, but where everything is falling at the same rate together around the Earth in orbit) have shown that plant roots and shoots grow erratically unless given some other stimulus like light (for shoots) or spin (roots). Even so, growth tends to be spindly.
In soils roots also take paths dictated by soil structure and nutrient availability. It appears that some roots are more involved in scavenging nutrients, whilst others more involved in obtaining water. Negative influences like salinity, compaction, low oxygen or pathogens can further prevent root exploration.