Analysis of Triticum aestivum seedling response to the excess of zinc

Abstract

The effects of 50 and 300 mg L−1 Zn2+ (50 Zn and 300 Zn) were investigated in Triticum aestivum (cv. Żura) grown hydroponically for 7 days. Although wheat treated with 50 Zn took up relatively high amount of the metal (8,943 and 1,503 mg kg−1 DW in roots and shoots, respectively), none of the morphological and cytological parameters were changed. After 300 Zn, the metal concentration increased to 32,205 and 5,553 mg kg−1 DW in roots and shoots, respectively. It was connected with the depletion of shoot and root growth, their fresh and dry weight, water content and mitotic index of root meristematic cells. Microelement contents (Cu, Mn and Fe) after 50 Zn were changed only in roots, while 300 Zn disturbed ion balance in whole plants. The most evident ultrastructural alterations of root meristematic cells caused by both tested Zn2+ doses included increased vacuolization, accumulation of granular deposits inside vacuoles and cell wall thickening. The effect of 300 Zn on root cell ultrastructure was greater that of 50 Zn. The majority of mitochondria had condensed matrix and swollen cristae, plastids contained plastoglobuli, nucleoli were ring-shaped, thinned down cytoplasm with lipid droplets and swollen endoplasmic reticulum cisternae appeared. In mesophyll cells, 50 Zn caused slight reorganization of chloroplast thylakoids and formation of condensed mitochondria. Three hundred Zn triggered more extensive, but not degenerative, changes: plasmolysis of some cells; chloroplasts with protrusions, changed thylakoid organisation and often large starch grains; irregular, condensed mitochondria. The results indicate that T. aestivum cv. Żura is relatively tolerant to Zn stress.

Ecotype-Specific Pathways of Reactive Oxygen Species Deactivation in Facultative Metallophyte Silene vulgaris (Moench) Garcke Treated with Heavy Metals

“…Adverse effects of metallic stress on plant morphogenesis have been demonstrated not only in the presented research, but also in other species belonging to various taxa. For example, the research of Malar et al [39] on sensitive Eichhornia crassipes specimens revealed the negative impact of Pb ions at the concentration of 100 mg L −1 on shoot and root growth, while Glińska et al [40] observed Triticum aestivum growth inhibition when 300 mg L −1 of Zn was used. Therefore, our results confirmed the sensibility of the NM ecotype, whereas the reaction of the SER one was quite interesting since SER specimens were found not to be fully adapted to the applied HMs.…”

“…Similarly, their roles in plant cells remain still quite enigmatic, despite numerous studies being conducted. Stromules were found to be involved in facilitating the transport of macromolecules or signals such as proteins, salicylic acids, or H 2 O 2 , which must pass from one location to another [40,55,56]. In this context, stromules may reduce the diffusion distance between cell compartments that exchange substrates and products for another metabolic pathway.…”

“…Taking into account that stress conditions induce ROS generation, for which internal changes in chloroplast were proven to participate in stromule formation [58], their frequency often increases in response to various abiotic stresses, such as drought, salt, and cold treatment [53,59]. In turn, Glińska et al [40] noticed the protrusion of Triticum aestivum chloroplasts resulted from degradation processes under an excess amount of Zn. However, in this case, disturbances of cell ultrastructure were also manifested by membrane disintegration or mitochondrion alternations.…”

Additive interactions of nanoparticulate ZnO with copper, manganese and iron in Pisum sativum L., a hydroponic study

“…S1). The latter may be induced by defence mechanisms which are responsible for the Zn immobilization in vacuoles or cell walls [56][57][58][59] .…”

Fluorescent Protein Aided Insights on Plastids and their Extensions: A Critical Appraisal

“…This has led to an erroneous impression in the mind of the non-specialist that mesophyll chloroplasts do not exhibit stromules while the most extensive and numerous stromules are observed in non-green plastids (Köhler and Hanson, 2000 ). Stromule formation has been observed in response to alteration in plastid redox status (Itoh et al, 2010 ; Brunkard et al, 2015 ), elevated temperatures (Holzinger et al, 2007a ), symbiotic interactions (Fester et al, 2001 ; Hans et al, 2004 ; Lohse et al, 2005 ), virus and bacterial infection (Caplan et al, 2008 ; Krenz et al, 2012 , 2014 ; Erickson et al, 2014 ) and growth regulator and mineral nutrient stress (Gray et al, 2012 ; Glińska et al, 2015 ). Stromule formation is also attributed to changes in plastid size and density within a cell (Pyke and Howells, 2002 ; Waters et al, 2004 ).…”