روزنه آبی

thumb|A section of hydathode in the leaf of Primula sinensis ([[Brockhaus and Efron Encyclopedic Dictionary)]] A hydathode is a type of pore, commonly found in vascular plants, that secretes water through pores in the epidermis or leaf margin, typically at the tip of a tooth or serration. These structures help plants regulate fluid balance and filter nutrients, functioning somewhat like tiny kidneys in leaves. Hydathodes are found in a wide variety of plants, from ferns to flowering trees, but can also serve as entry points for harmful bacteria.