With the aim to investigate the mechanisms of action of nano plastics (nano PS) on plants, seeds of Allium cepa were germinated for 72 h in the presence of polystyrene nano PS (50 nm size, at ...concentrations of 0.01, 0.1 and 1 g L−1) and, subsequently, roots were analysed by a multifaceted approach. No effect was induced by any concentration of nano PS on the percentage of seed germination while root growth was inhibited by 0.1 and 1 g L−1 nano PS. Cytological analysis of the root meristems indicated cytotoxicity (reduction of mitotic index) and genotoxicity (induction of cytogenetic anomalies and micronuclei) starting from the lowest dose. Moreover, the biochemical and histochemical analysis of oxidative stress markers gave evidence of stress induction, especially at the highest doses. Damages reported could be due to mechanical surface contact in root external layers, as evidenced by histological localization, and to the internalization of nano PS in different cellular compartments, observed under TEM. The present research underlines the hazardous nature of nano PS, that for their ability to be internalized into crop plants, can enter into different trophic levels of the food chain.
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•Cyto-physiological traits in onion roots treated by nano-polystyrene were studied.•Nano PS reduced root elongation in onion seedlings during germination.•Nano PS induced cyto/genotoxicity on root meristem.•The highest applied concentrations of nano PS triggered oxidative stress.•Nano PS were internalized in different root cellular compartments.
The effects of different copper concentrations on percentage germination, increase in fresh weight and radicle growth of Vicia sativa L. seeds were studied. Physiological studies showed that the ...germination rate was not affected up to a concentration of 5 × 10−3 M, but already at 10−3 M the copper stopped root elongation. Structural and ultrastructural observations of embryo and cotyledon reserve mobilization showed that inhibition of radicle growth at 10−3 M Cu concentration cannot be ascribed to nutrient shortage but probably to an effect of copper on radicle cell division and elongation. In seeds treated with 5 × 10−3 M CuBr2, the copper completely inhibited cotyledon protein mobilization, so that embryo protein mobilization supported normal growth of the radicle up to 30 h after imbibition. The particular protein content of adjacent cotyledon cells is also discussed.
•The effects of copper on germinative metabolism of Vicia sativa were investigated.•The limit of Cu tolerance for germinative metabolism was between 10−4 and 10−3 M.•Copper excess allowed the germination but arrested the radicle growth.•Ultrastructural studies allowed to determine the possible causes of root growth stop.
Copper excess allowed germination but arrested radicle growth in Vicia sativa L. seeds.
In this work we studied the effect of salinity (ranging from 50 to 500mM NaCl) on the physiological and the antioxidant responses of the local halophyte Limonium delicatulum Kuntze. We based our ...analysis on 12 biochemical assays that are commonly used to measure the antioxidant responses under stress such as oxidative stress markers, enzymes activities and polyphenolic compounds. Our aim was to study parameters that are strongly correlated with the growth response to salinity. Results showed two different growth responses depending on the concentration of NaCl in the medium. Under 50 to 200mM, the growth was stimulated before it decreased significantly at 300â500mM. L. delicatulum revealed a good aptitude to maintain photosynthetic machinery by increasing the concentrations of photosynthetic pigments, which is essential for the stabilisation of photosystems and the photosynthesis process under optimal NaCl concentration. Their breakdown at higher salinity decreased the photosynthetic performance of plants resulting in growth inhibition. Moreover, to reduce the damaging effect of oxidative stress and to tolerate the accumulation of salt ions, L. delicatulum induced the activities of their antioxidant enzymes more than their contents in polyphenolic compounds.
Copper bromide (CuBr2) effects on seed germination and plantlet development of Vicia sativa L. are evaluated through mitotic index, chromosome aberrations, nucleolar activity and mineral profile. ...CuBr2 induces a significant presence of micronuclei, sticky and c-metaphases, anaphase bridges and chromosome breaks. Increased number of nucleoli and scattering of AgNOR proteins from the nucleolus in the nuclear surface at CuBr2 1mM and in the cytoplasm at CuBr2 5mM, goes along with the decrease of root growth. In V. sativa embryo the content of many macro and micronutrients increases up to copper 1mM in agreement with reserve mobilization while at CuBr2 5mM some elements are present in lower amount. We hypothesize that inhibitory effects observed at 5mM are due either to a nutrient shortage or to a direct influence of copper on root cell division, evidenced by low mitotic index, high occurrence of chromosome aberrations and loss of material from the nucleolus.
•Copper effect on Vicia sativa seed germination and plantlet development was analysed.•Genotoxicity and embryo mineral profile were evaluated.•Influence of copper on root cell division and mineral content was observed.•Increased number of nucleoli and scattering of nucleolar proteins were detected.•Major toxic effects were observed at 5×10−3M copper bromide.
Halophytic plants growing in extreme environments have developed morphological, anatomical, biochemical and physiological adaptations. In this research, the effect of salinity (up to 500 mM NaCl) on ...the germination parameters and the antioxidant responses of two halophytic
Limonium
species was evaluated
.
Seed germination parameters (rate, speed), ROS production and the contents of phenolic compounds and antioxidant enzymes of
Limonium delicatulum
and
Limonium vulgare
were investigated, with respect to their tolerance to salt treatments and their ability to recover from salt stress conditions.
L. vulgare
seeds were less affected by salt treatments than
L. delicatulum
, and consequently recovered more rapidly full germination. Moreover,
L. vulgare
seedlings had more antioxidant phenolics and enzyme activities than
L. delicatulum
. The highest ability of
L. vulgare
to recover from salt treatment might be the result of its adaptation to a highly stressful environment constituted by inland salty soil, whereas
L. delicatulum
grows closer to the sea, thus receiving diluted salt spray. This distinction makes
L. vulgare
a good candidate for biosaline agriculture as edible crop plant.
Graphical abstract
Lentils (
Lens culinaris
L.) are among the most ancient seeds cultivated since prehistory. Several lentil varieties, differing for nutrients and antioxidant compounds, are cultivated in various ...regions of Italy. Seeds of three varieties of
L. culinaris
: Onano, Beluga and Villalba, differing for morphology, colour and size, were studied. Antioxidant activity and the content in total polyphenols, flavonoids and flavonols were evaluated in raw and cooked seeds and in cooking water. The same compounds were quantified in sprouts up to 4 days of germination. The highest content of polyphenols was observed in integument of Beluga seeds, flavonoids in integument of Villalba seeds, while flavonols were particularly abundant in cotyledon of Onano seeds. After seed cooking, a decrease in phytochemicals and antioxidant capacity was observed in tissues but they were partially recovered in cooking water.
Quinoa (
Willd.) is a plant of South American origin recently valorized for its nutritional and nutraceutical properties in human diet. Quinoa is cultivated in many parts of the world, with a ...selection of varieties with good adaptability to extreme climatic conditions and salt stress. The variety Red Faro, native to southern Chile but harvested in Tunisia, was considered for salt stress resistance, considering its seed germination and 10-day seedling growth at increasing doses of NaCl (0, 100, 200 and 300 mM). Seedlings were spectrophotometrically analyzed for antioxidant secondary metabolites (polyphenols, flavonoids, flavonols and anthocyanins), antioxidant capacity (ORAC, oxygen radical absorbance capacity, DPPH*, 2,2-diphenyl-1-pic-rylhydrazyl), antioxidant enzyme activity (superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and catalase (CAT)) and mineral nutrient content in root and shoot tissues. Cytogenetic analysis of root tip was performed to check for meristematic activity and the possible presence of chromosomal abnormalities induced by salt stress. The results indicated a general increase in antioxidant molecules and antioxidant enzymes NaCl dose-dependent, no effects on seed germination but negative effects on seedling growth, and little effect on root meristems mitotic activity. These results indicated that stress conditions can induce an increase in biologically active molecules that could be used for nutraceutical purposes.
In an attempt to alleviate salt-induced damage, the application of ZnO nanoparticles has been suggested. As the use of these particles has also been associated with phytotoxicity, to better clarify ...the effect of zinc and its possible mitigation of salt stress, we treated wheat seedlings with ZnO (nanoparticles or their bulk-scale counterparts, amended either in the growth medium, NPs and B, or sprayed on the leaves, SPNPs and SPB) with or without subsequent treatment with salt. Growth, photosynthetic parameters, zinc and ion concentration, and in situ and biochemical determination of oxidative stress in wheat leaves and/or in roots were considered. Both Zn and NaCl significantly inhibited growth and induced severe alterations in root morphology. Oxidative stress and damage decreased or increased under ZnO treatment and in saline conditions depending on the organ and on the size and mode of application of particles. In spite of the higher stress conditions often recorded in treated leaves, neither pigment concentration nor photochemical efficiency were decreased. A large variability in the effects of ZnO treatment/priming on seedling salt response was recorded; however, the presence of a cumulative negative effect of priming and salt stress sometimes observed calls for caution in the use of ZnO in protection from saline stress.
The present research reports a biochemical and micro-submicroscopic analysis of copper effect on reserve mobilization during germination of
Phaseolus vulgaris
L. var. soisson nain hatif seeds. Dry ...embryonic cells are rich in protein bodies and little starch grains. In Cu-treated embryos copper inhibited 50 % of albumin and globulin mobilization after 72 h imbibition. The severe alterations in treated embryo cells, observed by electron microscope, were probably the cause of the inability to utilize the amino acids freed by protein mobilization and so possibly the cause of the inhibition of
P. vulgaris
embryonic axis elongation.
Seeds of Raphanus sativus L. subjected to accelerated ageing were investigated for reactive oxygen species (ROS) release and for content of vitamin E (tocopherol, TOC, and tocotrienol, TOC-3), fatty ...acids and phytosterols in seed coats, cotyledons and embryonic axes during germination. In unaged seeds, ROS release occurred mainly in seed coats of non-imbibed seeds and in seedlings (48 h of imbibition). TOC and TOC-3 were mainly represented by the γ-isoform, abundant in embryonic axes. Fatty acids were mainly found in cotyledons. In seed coat and embryonic axis, phytosterols consisted mainly of sitosterols. The effects of ageing were mainly visible in embryonic axes at 48 h of imbibition. Deterioration was associated with a decrease in fresh weight increase percentage, germination percentage, α-TOC and total fatty acid content. An increase in ROS release from seed coats and in γ-TOC, δ-TOC, γ-TOC-3 content in embryonic axis was also observed. The use of γ-TOC and total fatty acids in embryonic axis as parameters of seed quality evaluation during storage was suggested.
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