Anatomical differences of poplar (Populus × euramericana clone I-214) roots exposed to zinc excess

Biologia ◽  
2012 ◽  
Vol 67 (3) ◽  
Author(s):  
Miroslava Stoláriková ◽  
Marek Vaculík ◽  
Alexander Lux ◽  
Daniela Baccio ◽  
Antonio Minnocci ◽  
...  

AbstractPoplar is one of the suitable candidates for phytoremediation due to extensive root system, fast growth rate, easy propagation and high biomass production. Zinc (Zn) is an essential element, but at high concentration becomes toxic to plants, similarly like cadmium (Cd). In order to evaluate the effect of Zn on root tissue development we conducted experiments with poplar (Populus × euramericana clone I-214) grown in hydroponics. Plants were treated with low (control) and excess level of Zn (1 mM). Changes in the development of apoplasmic barriers — Casparian bands and suberin lamellae in endodermis, as well as lignification of xylem vessels have been investigated. We found that both apoplasmic barriers developed closer to the root apex in higher Zn-treated root when compared with control root. Similar changes were observed in lignification of xylem vessels. For localization of Zn within root tissues, cryo-SEM/EDXMA analyses were used. Most of Zn was localized in the cortical tissues and four-time less Zn was determined in the inner part of the root below the endodermis. This indicates that endodermis serves as efficient barrier of apoplasmic Zn transport across the poplar root.

1999 ◽  
Vol 77 (1) ◽  
pp. 113-121
Author(s):  
James L Seago, Jr. ◽  
Carol A Peterson ◽  
Daryl E Enstone

Tissues in adventitious roots of Hydrocharis morsus-ranae L. developed from a four-tiered apical meristem. A set of periclinal divisions in the outermost layer of the ground meristem produced a hypodermis, which was normally uniformly biseriate. Aerenchyma formed from the adjacent inner layer of the cortex by a series of cell divisions and cell lyses; three- to five-celled, radial aerenchyma strands formed by periclinal divisions in radial cell files 0.3-5 mm behind the apex. Intervening cells underwent anticlinal and periclinal divisions followed by cell lyses within 1 mm of the apex to produce air spaces. Aerenchyma formation in this species is unusual and presents a unique system suitable for a study of developmentally programmed cell death in parenchyma cells. The endodermis formed a complete Casparian band about 10 mm behind the root apex and did not develop further; it had neither suberin lamellae nor secondary walls. The hypodermis was parenchymatous and was without Casparian bands, suberin lamellae, and secondary walls. Following acid digestion, the wavy walls of the endodermis and the walls of the epidermis remained.Key words: aerenchyma, cell death, endodermis, Hydrocharis, hypodermis, root development.


Biologia ◽  
2012 ◽  
Vol 67 (3) ◽  
Author(s):  
Zuzana Vatehová ◽  
Karin Kollárová ◽  
Ivan Zelko ◽  
Danica Richterová-Kučerová ◽  
Marek Bujdoš ◽  
...  

AbstractThe objective of this study was to determine the effect of silicon (Si) and cadmium (Cd) on root and shoot growth and Cd uptake in two hydroponically cultivated Brassica species (B. juncea (L.) Czern. cv. Vitasso and B. napus L. cv. Atlantic). Both species are potentially usable for phytoextraction. Inhibitory effects of Cd on root elongation were diminished by the impact of Si. Primary roots elongation in the presence of Cd + Si compared with Cd was stronger and the number of lateral roots was lower in B. juncea than in B. napus. Cd content per plant was higher in B. napus roots and shoots compared with B. juncea. Suberin lamellae were formed closer to the root apex in Cd + Si than in Cd treated plants and this effect was stronger in B. napus than in B. juncea. Accelerated maturation of endodermis was associated with reduced Cd uptake. Cd decreased the content of chlorophylls and carotenoids in both species, but Si addition positively influenced the content of photosynthetic pigments which was higher in B. napus than in B. juncea. Si enhanced more substantially translocation of Cd into the shoot of B. napus than of B. juncea. Based on our results B. napus seems to be more suitable for Cd phytoextraction than B. juncea because these plants produce more biomass and accumulate higher amount of Cd. The protective effect of Si on Cd treated Brassica plants could be attributed to more extensive development of suberin lamellae in endodermis.


Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 413 ◽  
Author(s):  
Katarzyna Głowacka ◽  
Anna Źróbek-Sokolnik ◽  
Adam Okorski ◽  
Janusz Najdzion

The analysis of the effects of cadmium (Cd) on plant cells is crucial to understand defense mechanisms and adaptation strategies of plants against Cd toxicity. In this study, we examined stress-related enzyme activities after one and seven days of Cd application and the ultrastructure of roots of Pisum sativum L. after seven days of Cd treatment (10, 50, 100, and 200 μM CdSO4). Our results showed that phenylalanine ammonia-lyase (PAL) activity and the amount of Cd accumulated in the roots were significantly positively correlated with the Cd concentration used in our experiment. However, Cd caused a decrease of all studied antioxidative enzyme activities (i.e., catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX)). The analysis of the ultrastructure (TEM) showed various responses to Cd, depending on Cd concentrations. In general, lower Cd concentrations (50 and 100 μM CdSO4) mostly resulted in increased amounts of oil bodies, plastolysomes and the accumulation of starch granules in plastids. Meanwhile, roots treated with a higher concentration of Cd (200 μM CdSO4) additionally triggered protective responses such as an increased deposition of suberin lamellae in the endodermal cell walls. This indicates that Cd induces a complex defense response in root tissues.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Heonsang Jeong ◽  
Jongtaek Park ◽  
Hyunook Kim

Nitrogen is an essential element in the environment. If excess nitrogen includingNH4 +is present in water, however, it can result in algae blooming and eventually the destruction of the aquatic ecosystem. Therefore, the determination ofNH4 +in streams, lakes, and effluents of the treatment facilities has long been carried out. The Nessler method is the most common spectrophotometric method to measureNH4 +in water. However, the result of the method becomes inaccurate if there are interfering substances such as Cl2, Cl−, hardness-causing compounds (e.g., Mg2+), and Fe2+in target water samples. In this study, therefore, the traditional Nessler method has been modified to eliminate the effects of interfering substances; the so-called MS was added to water samples. In addition, the polyvinyl alcohol reagent as a dispersing agent was added to water samples to increase the sensitivity and reproducibility of the method. The modified method could successfully analyzeNH4 +of water samples even with the interfering substance at high concentration.


2001 ◽  
Vol 79 (5) ◽  
pp. 621-634 ◽  
Author(s):  
Fengshan Ma ◽  
Carol A Peterson

The cytological events of wall modification in the endodermis and exodermis of Allium cepa L. roots were examined with fluorescence and transmission electron microscopy. In the endodermis, Casparian bands, suberin lamellae, and tertiary walls developed in succession. At the site of the future Casparian band, the plasma membrane was bound to the wall before deposition of detectable hydrophobic components in the radial wall. Suberin lamellae were deposited on the inner faces of the primary walls, first along the outer tangential walls and then the inner tangential walls. On both walls, segments of the lamellae were formed earlier in primary pit fields than at nonprimary pit field regions. Suberin lamellae then extended to the radial walls. When they reached the Casparian bands, the lamellae intruded between the bound plasma membranes and the walls, so that the cells' plasma membranes remained intact. In this way, suberin lamellae that were continuous around the cells were laid down. Later, tertiary walls were deposited internal to the suberin lamellae. None of the wall modifications interrupted the symplastic connections of the endodermis. During suberin lamella and tertiary wall formation, more dictyosomes and ER profiles appeared than during Casparian band development. In the exodermis, although Casparian bands were readily detected with fluorescence microscopy, they were rarely detected with electron microscopy. Suberin lamellae were formed in long cells severing their plasmodesmata. As in the endodermis, dictyosomes and ER were prominent during suberin lamella formation. Tertiary walls were not formed in the exodermis.Key words: Allium cepa, Casparian band, endodermis, exodermis, suberin lamella, ultrastructure.


1997 ◽  
Vol 75 (7) ◽  
pp. 1188-1199 ◽  
Author(s):  
Daryl E. Enstone ◽  
Carol A. Peterson

The exodermal Casparian band in corn (Zea mays L.) was first seen 10 mm distal to the kernel 4 days after planting. From its inception, the band usually occupied most of the radial wall (as seen in a cross section of the root). Subsequent maturation of the band around the root was asynchronous into the region of emerging lateral roots. Thus, a continuous apoplastic barrier would have been absent over much of the young root surface. Suberin lamellae development was also asynchronous, as these structures formed in those cells which had Casparian bands. Frequently, a lamella was initially deposited in patches, progressing centripetally until a continuous lipid layer was formed around the cell protoplast. Many instances of band plasmolysis (typical of the endodermis) were observed in the developing uniform exodermis. It could occur in cells with no detectable Casparian bands, suggesting that the tight connection between the plasmalemma and the wall that causes this phenomenon is not due to hydrophobic attractions. The results are consistent with the idea that there are strong attractions between proteins of the membrane and wall in the region of the Casparian band. The tight connection between the plasmalemma and the wall was broken during the later stages of suberin lamella development. Key words: Zea mays L., Poaceae, band plasmolysis, exodermis, Casparian band, suberin lamella.


1996 ◽  
Vol 74 (8) ◽  
pp. 1220-1226 ◽  
Author(s):  
Carol A. Peterson ◽  
Janet L. Waite

The onion exodermis is made up of two cell types, i.e., long and short cells. Both form Casparian bands, but suberin lamella development is absent or delayed in the short cells. Long cells did not accumulate fluorescein, a common test for cell vitality, because of reduced wall permeability due to suberin lamella development. Immature, long cells without lamellae stained in 15 min, whereas mature cells with lamellae required a 3.5- to 4-h treatment before staining was visible. Long exposure to fluorescein was needed to show that mature long cells were alive. Their vitality appeared to decline slowly with age but was not affected by drought stress. Fluorescein staining was apparent in the long cells only after treatment of paradermal sections; when dye was applied only externally to root segments, it did not enter the long cells from the epidermis or from the neighbouring short cells. This result indicates that the long cells were connected symplasmically to the cells of the cortex but were either unconnected, or connected by plasmodesmata of small functional diameter, to the epidermal and short cells. If they were unconnected, they would not form part of the symplasmic path of ion transfer into the root. Keywords: Allium cepa L., drought, exodermis, suberin lamella, vitality.


2019 ◽  
Vol 11 (2) ◽  
pp. 575-580
Author(s):  
Seema Tewari ◽  
Sandeep Bajpai ◽  
Madhu Tripathi

Aquatic environment gets polluted by heavy metals because of their environmental persistence and ability to bioaccumulate in aquatic organisms. Cadmium is a ubiquitous toxic heavy metal, biologically non-essential element, it is not biodegradable and has a very long biological half-life. The aim of the present study was to assess the glycogen content in muscle, liver,  gill and kidney of Channa punctatus exposed to sublethal concentrations of cadmium chloride after 4, 7, 15 and 30 days of exposure. The results clearly showed significant decrease in the glycogen levels in the experimental fish C. punctatus. Decrease in muscle glycogen was found highly significant (P<0.001) after 30 days in both low concentration (36.823 mg/L) 6.12±0.41mg/g and in high concentration (73.646 mg/L) 4.04±0.32 mg/g in comparison to control. Decrease in liver glycogen content was found highly significant (P<0.001) after 30 days in high concentration 9.12±0.49 mg/g when compared with control. The decrease in gill glycogen content after 30 days exposure was found highly significant (P<0.001) 1.36±0.13 mg/g in low concentration and in high concentration 0.79±0.25 mg/g in comparison to control. Decrease in kidney glycogen content was found highly significant (P< 0.001) at 30 days in low concentration 3.92±0.05 mg/g  and in high concentration 2.81±0.20 mg/g  in comparison to control. The influence of toxicant cadmium chloride in selected tissues of fish was taken into account in evaluating fish response against stressor. Hence, we can use glycogen content as biomarker of cadmium stress in fish.


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