Stomata pores

Stomatal conductance is a measure of the rate of either CO2 entering or water vapour exiting the stomata (pores) of a leaf. It depends on factors such as humidity and light intensity. 

The leaf epidermis has small pores, called stomata, which open up for photosynthetic gas exchange and transpiration. Stomata are scattered throughout the epidermis, but are typically more numerous on the lower leaf surface. Each individual stoma (pore) is surrounded by a pair of specialized epidermal cells, called guard cells. In most species, the guard cells close their stomata during the night to prevent transpirational water loss, and open their stomata during the day so they can take up carbon... 

Stoma (pi. stomata) Small pores in plant leaves or stems through which gases can pass. 

The pathway of least resistance for gases to cross an epidermis—and thus to enter or to exit from a leaf—is through the adjustable space between a pair of guard cells (Fig. 1-2). This pore, and its two surrounding guard cells, is called a stoma or stomate (plural stomata and stomates, respectively). When they are open, the stomatal pores allow for the entry of CO2 into the leaf and for the exit of photosynthetically produced O2. The inevitable loss of water vapor by transpiration also occurs mainly through the stomatal pores, as we will discuss in Chapter 8 (Section 8.1B). Stomata thus serve... 

Lower epidermis of wavy-walled, flattened, chlorophylloid cells with thin cuticle and many stomata (breathing pores). Each stoma is surrounded by a pair of crescent-shaped guard cells which regulate its opening and closing. The upper and lower epidermis are continuous around the laminar margin. 

Epidermis is the outer covering tissue of a plant and is protective in function. Its cells may be brick-shaped, polygonal, equilateral or wavy in outline. Their outer walls are frequently lutinized (infiltrated with a waxy-like substance called cutin). Among the epidermal cells of leaves and young green stems may be found numerous pores or stomata (sing, stoma) surrounded by pairs of crescent-... 

A minute pore in the epidermis of plant leaves or stems. Stoma, which are bordered by guard cells that regulate the size of the opening, function in gas exchange between the plant and the external environment. The stomatal apparatus or stomate consists of the stoma plus guard cells, stratification... 

Fig. 5.29. Transmission electron micrograph of a stoma on stem of Opuntia ficus-indica. V, vacuoles m, mitochondria n, nucleus p, plastids po, stomatal pore (slightly open) sn, nucleus of a subsidiary cell (from Thomson and De Journett, 1970 a, by permission)...

The leaves, with their broad surfaees, are the main parts of the plant where photosynthesis occurs (Fig. 1.1). Avery important featine of the leaf structure is the presence of large numbers of tiny pores (stomata) on the surface of the leaf (Fig. 1.2). There are usually thousands of stomata per square centimetre of leaf surface. Each pore (stoma) is oval-shaped and siuToimded by two guard cells. The carbon dioxide used in photosynthesis diffuses into the leaf through the stomata. Most of the water vapom leaving the plant, as well as the oxygen from photosynthesis, diffuses out through the stomata. 

The cell structure of a typical leaf is shown in Figure 3.5a and Figure 3.5b. Transport takes place mainly through openings termed stomatal pores (stoma Greek for mouth), which are concentrated at the underside of the leaf. Stomata... 

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