Lead-induced histological and ultrastructural changes in the leaves of soybean (Glycine max (L.) Merr.)

• Published in: Soil science and plant nutrition (Tokyo) Vol. 51; no. 2; pp. 203 - 212
• Main Authors: Weryszko-Chmielewska, E. (Agricultural Univ. of Lublin (Poland)), Chwil, M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Taylor & Francis Group 01.04.2005; Blackwell Publishing Ltd
• Subjects: GLYCINE MAX; LEAD; lead toxicity; LEAVES; soybean; structure; TOXICITY; ULTRASTRUCTURE
• ISSN: 0038-0768; 1747-0765
• DOI: 10.1111/j.1747-0765.2005.tb00024.x

The seedlings of the soybean (Glycine max. (L.) Merr.) cv. Polan were investigated by subjecting them to water culture for a period of 14 d. To the Knop nutrient solution, lead was added as PbCl2, at four concentrations: 0, 10, 20 and 40 mg d cubic m. Observations of soybean leaf tissues were carried out by light microscopy, transmission electron microscopy and scanning electron microscopy. The Pb levels used in the present study reduced the area of cotyledons and leaf blades of the soybean plants. Pb-induced changes in the leaf epidermis structure involved a reduction in the cell size, more abundant wax coating, and an increase in the number of stomata and trichomes per unit area with simultaneous reduction in the size of the guard cells. The lead treatment resulted in the reduction in the thickness of the leaf blades, reduction in the area of xylem and phloem in the vascular bundles and in the diameter of the xylem vessels. Under Pb stress, the leaf mesophyll cells were characterized by the presence of altered chloroplasts with a reduced lamellar system and multidirectional pattern of the thylakoid system. Burst stroma of the thylakoid system and cracked chloroplast envelopes were also observed. The importance of the increase in the number of stomata and trichomes for plants under the metal stress was examined.