Effect of the Heavy Metals on Developmental Stages of Ovule, Pollen, and Root Proteins in Reseda lutea L. (Resedaceae)

Laboratory of Plant Cell Developmental Biology, Department of Biology, Bu-Ali Sina University, Hamedan, Iran.
Biological trace element research (Impact Factor: 1.75). 03/2011; 143(3):1777-88. DOI: 10.1007/s12011-011-9009-x
Source: PubMed

ABSTRACT Heavy metals are some of the most important environmental pollutants. Excessive amounts of heavy metals adversely affect plant growth and development. Also, the presence of elevated levels of heavy metal ions triggers a wide range of cellular responses including changes in gene expression and synthesis of metal-detoxifying peptides. The overall objective of this research was to elucidate some microscopic effects of heavy metals on the formation, development, and structure of pollen, ovule, and embryo and also root proteins in Reseda lutea L. For this purpose, the vicinity of Ahangaran lead-zinc mine (Hamedan, Iran) was chosen as a polluted area where amount of some heavy metals was several times higher than the natural soils. Flowers and young buds were collected from non-polluted and polluted plants, fixed in FAA(70), and studied during developmental stages by light microscopy. The results showed that heavy metals can cause some abnormalities during the pollen and ovule developmental process. The number of pollen grains was decreased, and their shape was changed. Increasing in thickness of the callosic wall and stabilizing of tapetum layer were observed in polluted plants. Asymmetrical formation of ovular integuments, degradation of egg apparatus, irregular formation of embryo sac, considerable vacuolation of embryonic cells, and degeneration of embryo in the late stage of heart-shaped embryo are the results of heavy metal pollution. For protein studies, young roots were harvested from plants exposed to pollution and non-exposed to pollution at the same time. Root proteins were extracted and studied by electrophoresis. The results revealed that some new proteins were synthesized in polluted samples that probably elevate plant tolerance to heavy metals.

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    • "In areas rich in nickel, various abnormalities of vegetative growth such as necrosis and chlorosis of leaves, reduction of biomass were also found (Yusuf et al. 2011). Nickel and other heavy metals can also affect plant reproduction because of anomalies in gamete development, embryogenesis, seed production (Mohsenzadeh et al. 2011) and polar cell growth (Breygina et al. 2012). "
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    ABSTRACT: Pollen morphology of seven Alyssum L. taxa growing on serpentine soils in different places in the European Mediterranean macrobioclimate territory were studied, described and compared. Cluster analysis was performed to show similarity between species and their populations. The shape of the pollen grains varies among the species and among the grains within the same anther. The pollen grains are 3-colpate, prolate, with long and narrow colpi reaching the poles. The ornamentation of the exine varies from micro-reticulate to reticulate between the species. Pollen sterility/fertility was also calculated. The highest percentage of sterile pollen (73.76%) was calculated for Alyssum murale subsp. murale and the lowest (9.54%) for A. bertolonii subsp. bertolonii. All species are representatives of sect. Odontarrhena (C.A.Meyer) Koch well known as Ni-hyperaccumulators. Nickel and other elements present in pollen and stamen were studied by inductively coupled plasma-mass spectrometry (ICP-MS). The stamen parts of all species were micromorphologically analyzed by scanning electron microscopy (SEM) coupled to an Energy-Dispersive X-Ray Probe (EDX). Accumulation of Ni was detected in the stamens of all studied species and rarely in the pollen grains. The distribution patterns of Ni were similar among species examined.
    Plant Biosystems 12/2014; DOI:10.1080/11263504.2014.989284 · 1.92 Impact Factor
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    • "Furthermore, it is unknown whether most serpentine plants accumulate Ni into pollen grains, despite evidence that plants growing in soils contaminated by metals via human activities can accumulate them into pollen (Moronét al. 2012). Metals in pollen could reduce germination (citations above; Mohsenzadeh et al. 2011; Yousefi et al. 2011a) or pollinator attraction (Meindl and Ashman 2014), and Ni accumulation in nectar can affect pollinator foraging (Meindl and Ashman 2013, 2014). Thus, a first and necessary step towards understanding the reproductive consequences of growth on serpentine soil is documenting metal concentrations of reproductive organs and floral rewards of non-hyperaccumulating serpentine plants, as well as determining whether or not nonhyperaccumulating endemic species are better able to avoid potentially deleterious effects of metals by excluding them from reproductive organs than nonendemics . "
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    ABSTRACT: Serpentine soils are edaphically stressful environments that host many endemic plant species. In particular, serpentine soils are high in several heavy metals (e.g. nickel, cobalt, and chromium) and these high heavy metal concentrations are thought, in part, to lead to varying levels of plant adaptation and soil affinities (i.e. endemic vs. non-endemic plant species). It is unclear, however, whether serpentine endemics vs. non-endemics differ with respect to heavy metal uptake into either vegetative or reproductive organs. Here, we use nickel as a model to determine whether plant heavy metal uptake varies with level of endemism in several non-hyperaccumulating species. Under controlled greenhouse conditions, we grew seven plant species from the Brassicaceae family that vary in their degrees of affinity to serpentine soil from low (indifferent) to medium (indicator) and high (endemic) in soil that was nickel-supplemented or not. We quantified nickel concentrations in leaves, pistils, anthers, pollen and nectar. While nickel concentrations did not vary across organs or affinities when grown in control soils, under conditions of nickel-supplementation endemic species had the lowest tissue concentrations of nickel, particularly when considering leaves and pistils, compared to indifferent/indicator species. Species indifferent to serpentines incorporated higher concentrations of nickel into reproductive organs relative to leaves, but this was not the case for indicator species and endemics where nickel was similar in these organs. Our findings suggest that endemic species possess the ability to limit nickel uptake into above-ground tissues, particularly in reproductive organs where it may interfere with survival and reproduction. Indifferent species accumulated significantly more Ni into reproductive organs compared to leaves, which may limit their reproductive potential relative to endemic species when growing on serpentine soils. Additional work determining the fitness consequences of these differences will further our understanding of edaphic endemism.
    AoB PLANTS 06/2014; 6. DOI:10.1093/aobpla/plu036 · 2.27 Impact Factor
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    • "chlorosis of leaves, reduction in biomass, etc. (Yusuf et al. 2011). Excessive amount of heavy metals can also affect plant reproduction: they cause anomalies in gamete development, embryogenesis and, consequently, a decrease in seed production and loss of biodiversity (Mohsenzadeh et al. 2011; Sabrine et al. 2010). The mechanisms of nickel toxicity have been studied mainly in mammalian cells and microorganisms (Macomber and Hausinger 2011); much less studies have been carried out on plants. "
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    ABSTRACT: To investigate the mechanisms of Ni(2+) effects on initiation and maintenance of polar cell growth, we used a well-studied model system-germination of angiosperm pollen grains. In liquid medium tobacco pollen grain forms a long tube, where the growth is restricted to the very tip. Ni(2+) did not prevent the formation of pollen tube initials, but inhibited their subsequent growth with IC(50) = 550 μM. 1 mM Ni(2+) completely blocked the polar growth, but all pollen grains remained viable, their respiration was slightly affected and ROS production did not increase. Addition of Ni(2+) after the onset of germination had a bidirectional effect on the tubes development: there was a considerable amount of extra-long tubes, which appeared to be rapidly growing, but the growth of many tubes was impaired. Studying the localization of possible targets of Ni(2+) influence, we found that they may occur both in the wall and in the cytoplasm, as confirmed by specific staining. Ni(2+) disturbed the segregation of transport vesicles in the tips of these tubes and significantly reduced the relative content of calcium in the aperture area of pollen grains, as measured by X-ray microanalysis. These factors are considered being critical for normal polar cell growth. Ni(2+) also causes the deposition of callose in the tips of the tube initials and the pollen tubes that had stopped their growth. We can assume that Ni(2+)-induced disruption of calcium homeostasis can lead to vesicle traffic impairment and abnormal callose deposition and, consequently, block the polar growth.
    Biology of Metals 09/2012; 25(6). DOI:10.1007/s10534-012-9584-0 · 2.50 Impact Factor
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