Moisture : Dew v Rainfall – Part 3

In my last blogs I’ve written about dew point and 2018 v 2019. I have one thing left to go into before I give up on leaf moisture. The more time I spend looking at this, the more I believe it is the biggest driver of autumn disease pressure.

Guttation

Last time I spoke about condensation element of Dew formation, this is driven by canopy temperature, air temperature and humidity. Guttation is something slightly different.

Guttation occurs when water pressure builds up in the roots causing internal plant water to exude out of the Hydathodes. These are specialised pores that enable a plant to release water from the plant. Guttation occurs when water pressure builds up in the roots causing internal plant water to exude out of the Hydathodes. These are specialised pores that enable a plant to release water from the plant.

They don’t play any role in transpiration are situated at the end of veins and are always open.

Related image
Image result for hydathodes meaning
Whilst not turf, I love these images showing guttation fluid at the end of the plants vascular system

The guttation fluids contain high levels of organic compounds including amino acids and has in the past been associated with increased levels of disease activity as it’s contents have been considered a food source for unwanted pathogens.

Whilst this is probably a contributing factor, I feel the picture is far blurrier than that implies, after all you’ll only get guttation during growth periods so is it the temperature or guttation fluid causing the bigger challenge? High levels of nutrition in guttation fluid would indicate high levels of nutrition in the plant which would generally mean thinner cell walls and a plant more susceptible to pathogen attack? I don’t know – you can go round in circles on this stuff!!

Missed parts one and two of Glenn’s blogs – read them here.

Leave a Reply