Question

Water drops present on leaf margins of tropaeolum, balsam, and grasses in the early morning are due to
A. Guttation
B. Dew
C. Osmosis
D. Transpiration

Answer 1

Hint: Plants draw water from their roots and circulate it up throughout their system. But they mostly release excess water during the daytime which means that water is taken in without releasing the water at night, and then all that pressure can build up within the plant, especially when temperatures are low and humidity is high.

Complete answer: Water drops present on leaf margins of tropaeolum, balsam, and grasses in the early morning are due to guttation. Guttation is the process in which the loss of impure water can be a dilute solution of different organic and inorganic substances from the plant mostly through the margins of leaves. It occurs when the transpiration rate is very low as compared to the rate of water absorption. Due to the development of root pressure the water is pushed out through specialized pores at vein endings commonly known as hydathodes. Guttation as we know is the elimination of drops of xylem sap on the tips or edges of leaves of some vascular plants which generally include grasses and a number of fungi. So, not confused with dew, which condenses from the atmosphere onto the plant surface. Guttation normally happens during night time.
So, the correct option is option A-Guttation.

Note: Guttation fluid may contain a variety of organic and inorganic compounds, mainly sugars, and potassium. After drying, a white crust is mainly observed on the leaf surface. Girolami et al. in 2005 found that guttation drops from corn plants that germinate from neonicotinoid-coated seeds could contain amounts of insecticide.