The two structures that Ilmit transpiration are known as Guard cells and xylem stomata and phloem xylem and phloem Stomata and guard cells

## Step 1<br />Transpiration is the process by which water is carried through plants from roots to small openings on the leaves where it changes to vapor and is released into the atmosphere. This process is regulated by two structures: stomata and guard cells.<br /><br />## Step 2<br />Stomata are small openings or pores, mostly found on the epidermis of leaves and stems. They allow for the exchange of gases, including water vapor, between the plant and the atmosphere.<br /><br />## Step 3<br />Guard cells are specialized cells in the epidermis of leaves, stems, and other organs that are used to control the opening and closing of stomata. They regulate the size of the stomatal opening, thus controlling the rate of transpiration.<br /><br />## Step 4<br />The xylem and phloem are vascular tissues in plants that are involved in the transport of water, nutrients, and food. However, they do not directly limit transpiration.