Hydathodes can have guard cells, but their presence depends on the type of hydathode.
Hydathodes are specialized plant structures involved in guttation, the process where plants release water droplets from their leaves. There are two main types:
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Epithelial Hydathodes (Passive Hydathodes): These hydathodes lack guard cells and consist of a cluster of loosely arranged parenchyma cells (the epithem) located near the end of a vein. Water is forced out through these structures via root pressure, and the release is not regulated by guard cells.
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Open Hydathodes (Active Hydathodes): These hydathodes are modified stomata, and thus do possess guard cells. This means they can regulate the opening and closing of the pore through which water is released. The opening is structurally similar to a stoma, hence the presence of guard cells. These are often found on leaf margins.
Essentially, if the hydathode is a modified stoma, it will have guard cells. If it's a simpler structure made up of just parenchyma cells, it will not. The reference suggests guard cells are present, likely referencing the open type of hydathode.
