never seen or heard of this till now, thank you
At night,
transpiration usually does not occur because most plants have their
stomata closed. When there is a high
soil moisture level, water will enter plant roots, because the
water potential of the roots is lower than in the soil solution. The water will accumulate in the plant, creating a slight
root pressure. The root pressure forces some water to exude through special
leaf tip or edge structures,
hydathodes or water glands, forming drops.
Root pressure provides the impetus for this flow, rather than
transpirational pull. Guttation is most noticeable when transpiration is suppressed and the relative humidity is high, such as during the night.
Chemical content
Guttation fluid may contain a variety of organic and inorganic compounds, mainly sugars, and potassium.
[1] On drying, a white crust remains on the leaf surface.