Guttation is the appearance of drops of vascular plants such as grasses. 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 water potential of roots is lower than soil solution. The water will accumulate in plant, creating a slight root pressure. The root pressure forces some water to exude through special leaf tip or edge structured called hydathodes forming drops. Root pressure provides the impetus for this flow. Transpiration, on the other hand, happens because of transpiration pull.
