To solve this problem, we need to identify the process responsible for the loss of water in liquid form from the tip of grass blades at night and in early morning. Let's analyze each option:$\newline \bullet$Root pressure:$\newline$ - Root pressure is a phenomenon that occurs when water is absorbed by the roots and pushed upwards through the plant.$\newline$ - It is responsible for the exudation of water droplets from the tips or edges of leaves, a process known as guttation.$\newline$ - Guttation typically occurs at night or in the early morning when transpiration is low.$\newline$ - Therefore, root pressure is the correct process responsible for this phenomenon.$\newline \bullet$Imbibition:$\newline$ - Imbibition is the absorption of water by solid particles of a substance without forming a solution.$\newline$ - It is not related to the loss of water in liquid form from plant tips.$\newline \bullet$Plasmolysis:$\newline$ - Plasmolysis is the process in which cells lose water in a hypertonic solution, leading to the shrinkage of the cell membrane away from the cell wall.$\newline$ - It is not related to the exudation of water from plant tips.$\newline \bullet$Transpiration:$\newline$ - Transpiration is the process of water vapor loss from the aerial parts of plants, primarily through stomata.$\newline$ - It does not involve the loss of water in liquid form.$\newline$Therefore, the correct option is Option 1: Root pressure.