Lead-Induced Histological and Ultrastructural Changes in the Leaves of Soybean (Glycine max(L.) Merr.)

Abstract

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 dm−3. 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.

Comparative phytotoxicity of ZnO NPs, bulk ZnO, and ionic zinc onto the alfalfa plants symbiotically associated with Sinorhizobium meliloti in soil

“…Leaf area can be a good indicator of plant health (Gutierrez-Boem and Thomas, 2001;Weryszko-Chmielewska and Chwil, 2005). In this study, alfalfa leaf area significantly increased (p ≤ 0.05) in plants treated with 500 mg bulk ZnO/kg, compared to NP, ionic, and control treatments ( Fig.…”

Soybean susceptibility to manufactured nanomaterials with evidence for food quality and soil fertility interruption

“…Similar concentrations of these nanoparticles affect hydroponic plants (24,27) and microorganisms (25,28), but the effects on soilcultivated food crop plants are heretofore unknown. Plant growth was monitored by measuring stem length, leaf count, and leaf cover; the latter estimates total leaf area, can indicate plant health, and is affected by water stress (29) and metal exposure (30). Final growth and biomass measurements were made after pod formation and before plant senescence.…”

Oxidative stress potential of Lead-Zinc mining on selected plants growing in Ishiagu, Nigeria

“…Heavy metal presence has various effects on plant leaves including reduction in leaf area, stomata closure; low stomata index and pore diameter (Sayed, 1997;Perfus-Barbeoch, 2002;Weryszko-Chmielewska and Chwil, 2005). Stomata closure may have contributed to the observed high RWC in plants at the study area since reduced stomata pore diameter implies tendency towards closure.…”