Physiological aspects of willows (Salix spp.) in citric acid assisted phytoremediation of cadmium

U radu je analiziran  uticaj limunske kiseline na morfološke, fiziološke i  biohemijske karakteristike  odabranih  klonova  vrba  (Salix  spp.)  gajenih  u  zemljištu  umereno zagađenom  kadmijumom  (Cd).  Definisanjem  parametara  akumulacije,  otpornosti  i tolerantnosti različitih klonova vrba na prisustvo kadmijuma u podlozi, kao i uspešnosti primene  limunske  kiseline  kao  helatora  u  procesu  asistirane  fitoremedijacije,  mogao  bi se  identifikovati  klon  (ili  klonovi)  pogodan  za  dekontaminaciju  zemljišta  zagađenog kadmijumom. Da  bi  se  postigao  cilj  istraživanja biljke su gajene u polu-kontrolisanim uslovima tokom 3 meseca. Eksperiment je podeljen u dve faze (dve godine istraživanja),zasnovane  na  razlikama  u  metodološkom  pristupu.  Tokom  prve  godine  limunska kiselina je dodata jednom, dok je tokom druge druge godine aplikacija ovog helatora vršena  u  tri  ponavljanja.  U  radu  je  analizaran  sadržaj  i  distribucija  Cd  u  zemljištu  i različitim  biljnim  organima  (koren,  izdanak,  mladi  i  stari  listovi);  uticaj  Cd i  limunske kiseline na morfometrijske parametre: visina i prečnik izdanka, masa i površina listova, broj  listova,  masa  i  zapremina  korena;  na  fotosintetičke  karakteristike:  intenzitet fotosinteze,  intenzitet  transpiracije,  stomatalnu  provodljivost,  intercelularnu koncentraciju  CO2,  efikasnost  korišćenja  vode,  koncentraciju  fotosintetičkih  pigmenata; na mineralnu ishranu i distribuciju makronutrijenata u biljkama (sadržaj azota, fosfora i kalijuma);  na  sadržaj  aminokiseline  prolina  i  cisteina;  na  aktivnost  antioksidativnih enzima  (katalaza,  askorbat-peroksidaza,  gvajakol-peroksidaza),  kao  neezmiskih antioksidanata poput sadržaja redukovanog glutationa i tiola. Dobijeni  rezultati  su  ukazali  na  genotipsku  specifičnost  analiziranih  klonova  vrba  u procesu  fitoremedijacije  u  zavisnosti  od  primenjenog  tretmana,  doze  Cd  i  prisustva limunske kiseline. Toksično dejstvo nije bilo jasno uočljivo na morfološkom nivou, dok su  primenjeni  tretmani  signifikantno  uticali  na  fiziološko-biohemijske  procese  u biljkama.  Sa  povećanjem  sadržaja  Cd  u  biljkama  je  utvrđena  tendencija  smanjenja intenziteta fotosinteze, transpiracije, kao i efikasnosti  koršćenja vode, dok je primena limunske  kiseline  ublažila  štetan  efekat  ovog  teškog  metala,  što  je  registrovano  na kombinovanim tretmanima.  Kao odgovor na akumulaciju Cd u biljnom tkivu utvrđena je  promena  aktivnosti  antioksidativnih  enzima,  kao  i  neezimskih  komponenti odbrambenog  sistema  zaštite.  Pored  toga,  u  radu  je  utvrđeno  da  primena  limunske kiseline  utiče  na  usvajanje,  akumulaciju  i  toleranciju vrba na prisustvo Cd,  te  rezultati ove  studije  imaju  praktičan  značaj  u  usavršavanju  tehnika  fitoremedijacije  i dekontaminacije zagađenih područja.The role of citric acid on morphological, physiological and biochemical characteristics of selected willow clones (Salix spp.) grown in soil with moderately polluted cadmium (Cd)  was  presented.  The  aim  of  this  study  was  to  determine  the  Cd  accumulation, translocation  and tolerance of different willow clones, as well as the influence of citric acid as a chelator in the assisted phytoremediation process.  In order to achieve this goal, plants  were  grown  in  semi-controlled  conditions  for  3  months.  The  experiment  was divided  into  two  phases  (two  years  of  research),  based  on  differences  in  the methodological approach, regarding the application of citric acid. During the first-year experiment, citric acid was added once, while in the second year the application of this chelator was performed in three repetitions.  The analyses included:  the accumulation and distribution of Cd in soil and various plant organs (root, stem, young and old leaves); influence of Cd and citric  acid on morphometric parameters: stem hight and diameter, number  of  leaves,  biomass  and  area  of  leaves,  biomass  and  volume  of  the  root;  on  photosynthetic  characteristics:  net  photosynthetic  and  transpiration  rate,  water  use efficiency, stomatal conductance, intercellular concentration of CO2, concentration of photosynthetic  pigments;  on  mineral  nutrition  and  distribution  of  macronutrients  in plants (nitrogen, phosphorus and potassium content); on the content of the amino acid proline  and  cysteine;  on  the  activity  of  antioxidant  enzymes  (catalase,  ascorbate peroxidase,  guaiacol  peroxidase),  as  non- enzymatic  components  such  as  reduced glutathione and thiol content. The obtained results indicated the genotypic specificity of the analyzed willow clones in the phytoremediation process, depending on the treatment applied, the Cd dose, and the presence of  citric acid.  The toxic effect was not evident on the morphological  level, while  the  applied  treatments  showed  a  significant  influence  on  the  physiologicalbiochemical processes in the willows. The net photosynthetic rate, transpiration rate, as well as,  water use eficiency  showed decreasing with increasing Cd concentration in plant tissue,  while  the  application  of  citric  acid  mitigated  the  harmful  effect  of  this  heavy metal, which was registered on combined treatments. In response to the accumulation of Cd in plant tissue, a  change in the  activity  of  anti-oxidant enzymes,  as  well as nonenzymatic  components  of  the  defense  system  has  been  established.  In  addition,  the application of citric acid showed the promotion role on the  absorption, accumulation and tolerance of willows grown in moderately polluted soil cadmium, which has a practical significance in the improvement of phytoremediation techniques and decontamination of polluted soil

Responses of wheat (Triticum aestivum L.) and maize (Zea mays L.) plants to cadmium toxicity in relation to magnesium nutrition

The influence of cadmium (Cd) on physiological processes in wheat (Triticum aestivum L.) and maize (Zea mays L.) plants exposed to either optimal mineral nutrition or the absence of magnesium (Mg) as well as the accumulation of cadmium and magnesium in plant organs were studied using the method of water culture in a greenhouse. Cd treatment reduced shoot fresh mass more strongly in Mg-supplied than in Mg-deficient plants. Negative effect of Cd on photosynthetic activity was more pronounced in T. aestivum than in Z. mays plants. Cd treatment decreased leaf chlorophyll and carotenoid concentration in both Z. mays and T. aestivum, irrespective of the Mg supply. Cd was preferentially accumulated in the roots of both species. Catalase activity in T. aestivum leaves and roots was unaffected by Cd and Mg supply. Cd treatment did not affect Fe accumulation in the leaves of either species, while in the roots a considerable increase occurred, irrespective of the Mg nutrition. Higher tolerance of Z. mays and T. aestivum plants to Cd toxicity exposed to Mg deficiency could partly be ascribed to the preservation of Fe nutrition

Essential-oil composition of parsley and celery conventionally and organically grown in Vojvodina

Celery (Apium graveolens L.) and parsley (Petroselinum crispum L.) are aromatic umbelliferous plants widely used as spices in the human diet due to the presence of essential oils. The chemical composition of the essential oils of aromatic plants can vary depending on the geographical origin, type of soil and agricultural practices [1,2].                In the present study, the influence of location (type of soil) and agricultural practices on the chemical composition of essential oils of parsley and celery leaf was investigated. The samples of both organically and conventionally grown plants were collected from different locations in the province of Vojvodina. The essential oil was isolated by hydrodistillation and then subjected to GC-MS analysis. Identification of chemical constituents was based on a comparison of their retention indices and mass spectra with spectral libraries and literature data. The main components of the essential oils obtained from parsley leaves were 1,3,8-menthatriene (22.8-50.9%), myristicin (12.8-36.8%), β-phellandrene (14.1-29.0%), and β-myrcene (1.4-12.7%). Celery leaf essential oils were mainly composed of β-phellandrene (41.7-72.6%), limonene (10.2-31.1%), and β-pinene (4.8-19.3%). The results obtained showed that there was no significant difference in the qualitative composition between the samples from different locations as well as between those grown in the conventional or organic way. On the other hand, the relative amount of particular compounds significantly varied between the samples in general, thus the correlation between their content and cultivation conditions or soil type could not be established.                In conclusion, the way of production has no specific effect on the qualitative composition of parsley and celery essential oils, although it can affect the relative quantity of their constituents

Drought Impact Is Alleviated in Sugar Beets (Beta vulgaris L.) by Foliar Application of Fullerenol Nanoparticles

Over the past few years, significant efforts have been made to decrease the effects of drought stress on plant productivity and quality. We propose that fullerenol nanoparticles (FNPs, molecular formula C-60(OH)(24)) may help alleviate drought stress by serving as an additional intercellular water supply. Specifically, FNPs are able to penetrate plant leaf and root tissues, where they bind water in various cell compartments. This hydroscopic activity suggests that FNPs could be beneficial in plants. The aim of the present study was to analyse the influence of FNPs on sugar beet plants exposed to drought stress. Our results indicate that intracellular water metabolism can be modified by foliar application of FNPs in drought exposed plants. Drought stress induced a significant increase in the compatible osmolyte proline in both the leaves and roots of control plants, but not in FNP treated plants. These results indicate that FNPs could act as intracellular binders of water, creating an additional water reserve, and enabling adaptation to drought stress. Moreover, analysis of plant antioxidant enzyme activities (CAT, APx and GPx), MDA and GSH content indicate that fullerenol foliar application could have some beneficial effect on alleviating oxidative effects of drought stress, depending on the concentration of nanoparticles applied. Although further studies are necessary to elucidate the biochemical impact of FNPs on plants; the present results could directly impact agricultural practice, where available water supplies are often a limiting factor in plant bioproductivity

Heavy metal contamination of vegetables from green markets in Novi Sad

are valuable source of vitamins, minerals and fibers important for healthy human nutrition. However, an increased level of heavy metals in vegetables has been noticed in recent years. This study was conducted with an aim to analyze content of heavy metals, cadmium (Cd), lead (Pb), and chromium (Cr) in 11 vegetable species which are the most common in human diet. Vegetables were collected from three green markets (Limanska, Futoška and Riblja pijaca) in Novi Sad, during September and October, from 2009 to 2011. Heavy metal contents were analyzed in edible parts of tomato, potato, spinach, onion, beetroot, parsley, parsnip, carrot, cauliflower, pepper and broccoli using atomic absorption spectrophotometer (Varian, AAS 240FS). The results showed statistically significant differences in element concentrations among analyzed vegetables. In general, the highest metal pollution was observed in the year of 2011. Spinach was found to contain the highest metals content - 0.89 μg/g for Cd, 5.81 μg/g for Pb, and 3.67 μg/g for Cr. According to Serbian official regulations, 18.18% of all analyzed species exceeded maximum permissible level for Cd, 9.09% for Pb, while for Cr these limits are not defined. Elevated content of heavy metals in vegetables might be related to soil contamination, atmospheric depositions during transportation and marketing. Thus, a continuous monitoring of vegetables on markets should be performed in order to prevent potential health risks to consumers

Photosynthetic response and tolerance of three willow species to cadmium exposure in hydroponic culture

Three willow species (Salix alba, Salix matsudana and Salix nigra) were exposed to very high cadmium (Cd) concentrations in order to define some physiological traits related to high biomass production. Plants were grown hydroponically under semi-controlled conditions (greenhouse). It was assumed that leaves accumulate different amounts of Cd in relation to their age due to the specific occurrence of symptoms generated by Cd accumulation. The rate of photosynthesis and concentration of photosynthetic pigments in young and old leaves was correlated with biomass production in order to ascertain their significance as indicators of plant performance at sites contaminated with Cd. Changes in the photosynthetic parameters induced by treatments depended on the concentration of Cd in the nutrient solution, the species of willow and leaf age. Fv/Fm ratios were not considerably changed in treated plants, indicating preserved activity of PSII. According to results presented in this work, the Fv/Fm ratio was a less sensitive indicator of Cd stress in willows than the rate of photosynthesis and pigment concentration. High tolerance to applied treatments estimated on the basis of biomass production of S. nigra and S. matsudana irrespective of Cd concentration in the growth substrate might indicate their potential in the reclamation of Cd-contaminated sites. [Projekat Ministarstva nauke Republike Srbije, br. No. III 043007

Photosynthetic and transpiration rate of treated plants.

<p>Photosynthetic and transpiration rate of treated plants.</p