Tolerance to Cadmium of Agave lechuguilla (Agavaceae) Seeds and Seedlings from Sites Contaminated with Heavy Metals

Figure 6

Transverse sections of Agave lechuguilla seedlings of Villa de la Paz site. (a), (b), (c) 0 ppm; (d), (e), (f) 60 ppm; (g), (h), (i) 100 ppm. Epidermal cells showing irregular form and periclinal cell walls (arrow) with (a) and (d) normal thickening; (g) thinner. Vascular bundle with xylem vessels (arrow) (b) normal; (e) and (h) premature lignified. Cortex parenchyma cells with starch grains (arrow) (c) and (f) scarce; (i) abundant with a breakdown of the cells. v = vacuole; p = procambium. The analysis of this section was made with a light microscope (Leica DM 2000). Bars = 20 μm.