Citlivosť vybraných poľnohospodárskych plodín na olovo, kadmium a arzén v skorých štádiách individuálneho vývinu

This paper examines the influence of Pb+2, Cd+2 and As+3 on growth of roots in legumes (broad bean, soybean, pea) and cereals (barley, maize). Roots of germinating plants were exposed to two different levels of Pb+2 (300 and 500 mg*L-1), Cd+2 (100 and 300 mg*L-1) and As+3 (50 and 100 mg*L-1) during four day experiment. During this time, length of roots were daily measured. Toxicity of metal treatment on plant roots was calculated as phytotoxicity index (IP). In all cases, a moderate effect of lead treatment was observed (IP up to 56.67 %) while higher doses of cadmium and arsenic resulted in increase of IP above 50 %. In cases of barley and maize, the toxic effect of almost all test doses of the heavy metals was observed as soon as 24 hours after their application. Generally, a higher tolerance to tested metals showed roots of both bean cultivars (IP 16.27- 69.53 %), while the most sensitive reactions had roots of barley and soybean (IP > 50 %, excluding dose Pb 300).Príspevok sa zameriava na testovanie vplyvu iónov Pb+2, Cd+2 a As+3 na rast koreňov strukovín (bôb, sója, hrach) a obilnín (jačmeň, kukurica). Korene klíčiacich rastlín boli vystavené dvom rôznym dávkam iónov Pb+2 (300 and 500 mg*L-1), Cd+2 (100 and 300 mg*L-1) a As+3 (50 and 100 mg*L-1) počas štyroch dní experimentu, pričom každých 24 hodín bola meraná dĺžka koreňov. Toxicita aplikovaných dávok kovov na korene rastlín bola stanovená indexom fytotoxicity (IP). V prípade všetkých variantov experimentu bol zaznamenaný miernejší účinok olova (IP do 56.67 %). Vplyvom vyšších dávok kadmia a arzénu došlo ku zvýšeniu IP nad 50 %. V prípade jačmeňa a kukurice bol toxický účinok takmer všetkých testovaných dávok kovov pozorovaný už 24 hodín po ich aplikácii. Všeobecne vyššiu toleranciu voči testovaným kovom vykazovali korene odrôd bôbu (IP 16.27- 69.53 %) a najcitlivešie reagovali korene jačmeňa a sóje (IP > 50 okrem dávky Pb 300)

Study on metal-triggered callose deposition in roots of maize and soybean

Abstract: Callose plays important roles in a variety of processes of plant development, and/or in a response to a range of biotic and abiotic stresses. In the current work we have studied and compared the effect of lead, cadmium and arsenic on accumulation of newly formed callose deposits in the roots of maize and soybean. We observed formation of characteristic callose deposits in the root cell walls, probably associated with plasmodesmata, depending on the type of metal and the plant species investigated. Further, the callose turnover was analysed by measuring of total callose content as well as activities of total β-(1,3)-glucanases in roots. The latter enzymes are responsible for callose depletion, and their possible role during metal stress has previously been proposed. However, neither of these biochemical values appeared to be sufficiently reliable for scoring the altered callose turnover (including local deposits) in plant tissue. The microscopical observations are discussed in light of the biochemical data obtained

Effect of Cadmium Chloride and Cadmium Nitrate on Growth and Mineral Nutrient Content in the Root of Fava Bean (Vicia faba L.)

The present study aimed to analyze the differences in the tolerance of fava bean (Vicia faba cv. Aštar) roots to cadmium in nitrate—Cd(NO3)2—and chloride—CdCl2—solutions. The physiological and biochemical parameters were assessed. The tested doses of Cd (50, 100, 150 and 300 mg/L) did not influence the germination of seeds. However, considerable growth inhibition and dehydration were observed after 96 h incubation. The thickness of roots and rupture of cell membranes increased along with the increasing concentration of the metal in the solution. At a Cd dose of 300 mg/L, irrespective of the solution used, increased nitrogen concentration and no change in sodium content were observed. The content of magnesium increased due to the dose of 100 mg/L (cadmium nitrate) and the content of calcium increased due to the dose of 300 mg/L (in either nitrate or chloride). The correlation analyses pointed to a possible effect of nitrates in the applied solutions on the accumulation of Cd and some minerals in the roots of the given variety of fava bean. This may be important for both research and agricultural practice. The identification of crops with high tolerance to cadmium, as well as knowledge about the mechanisms of ion interactions at the soil solution–plant level, is important in terms of such crops’ use in the process of the remediation of cadmium-contaminated soils coupled with food production

Effect of Cadmium on Growth, Photosynthetic Pigments, Iron and Cadmium Accumulation of Faba Bean (Vicia faba cv. Aštar)

The influence of different concentrations of cadmium (Cd) ions (50 and 100 mg/kg soil) on growth, photosynthetic pigment content, Cd, and iron accumulation in faba bean (Vicia faba L. cv. Aštar) was studied under laboratory conditions. No significant changes were observed in the growth parameters of shoots (length, fresh, and dry weight). Both tested Cd doses resulted in decrease in root fresh weight by 31.7% and 28.68% and in dry weight by 32.2% and 33.33%, respectively. Increased accumulation of Cd was observed in roots (125- and 173-fold higher than in control) and shoots (125- and 150-fold higher than in control) as a result of applied doses of Cd. Increased accumulation of iron was detected in roots (1.45- and 1.69-fold higher than in control). Decrease in the content of chlorophyll a (by 25.52 and 24.83%, respectively) and chlorophyll b (by 6.90%) after application of Cd 100 as well as decrease in carotenoids (by 40.39 and 38.36%, respectively) was detected. Weak translocation of Cd from roots to shoots pointed to low phytoremediation potential of the tested bean variety in contaminated soil. However, the high tolerance of this cultivar, its relative fast growth, as well as priority of Cd accumulation in roots presume this plant species for phytostabilisation and revegetation of the Cd-contaminated soils

Assessment of the Hormetic Effect of Arsenic on Growth and Physiology of Two Cultivars of Maize (<i>Zea mays</i> L.)

Although growth stimulation at low arsenic doses was observed in several plants, few studies have focused on this phenomenon in more detail. The effects of different concentrations of arsenic (0–50 mg kg−1 of soil: As0–As50) on the growth and selected physiological parameters of two maize cultivars (Zea mays L. cvs. Chapalu and MvNK 333) were tested. Cultivar MvNK 333 manifested a generally higher tolerance to As than cv. Chapalu, which may be related to the lower content of As in the tissues. The highest stimulatory effect of As was recorded at doses of As1 and As2 (cv. Chapalu), and at the As5 dose (MvNK 333), there was an increase in shoot elongation, biomass, and relative water content (RWC), as well as the content of photosynthetic pigments. The stimulatory effect of lower doses of As apparently represents an adaptation mechanism that is associated with water content regulation in the given conditions. The stomata of the studied cultivars were involved in this regulation in different ways. While cv. Chapalu exhibited increased numbers of stomata on both sides of leaves, cv. MvNK 333 instead responded to the given conditions with decreased stomata size. Although hormetic manifestations closely related to changes in stomatal number and size were observed, a typical stomatal hormetic response was not observed in the given range of As doses

The Cell-Wall &beta;-d-Glucan in Leaves of Oat (Avena sativa L.) Affected by Fungal Pathogen Blumeria graminis f. sp. avenae

In addition to the structural and storage functions of the (1,3; 1,4)-&beta;-d-glucans (&beta;-d-glucan), the possible protective role of this polymer under biotic stresses is still debated. The aim of this study was to contribute to this hypothesis by analyzing the &beta;-d-glucans content, expression of related cellulose synthase-like (Csl) Cs1F6, CslF9, CslF3 genes, content of chlorophylls, and &beta;-1,3-glucanase content in oat (Avena sativa L.) leaves infected with the commonly occurring oat fungal pathogen, Blumeria graminis f. sp. avenae (B. graminis). Its presence influenced all measured parameters. The content of &beta;-d-glucans in infected leaves decreased in all used varieties, compared to the non-infected plants, but not significantly. Oats reacted differently, with Aragon and Vaclav responding with overexpression, and Bay Yan 2, Ivory, and Racoon responding with the underexpression of these genes. Pathogens changed the relative ratios regarding the expression of CslF6, CslF9, and CslF3 genes from neutral to negative correlations. However, changes in the expression of these genes did not statistically significantly affect the content of &beta;-d-glucans. A very slight indication of positive correlation, but statistically insignificant, was observed between the contents of &beta;-d-glucans and chlorophylls. Some isoforms of &beta;-1,3-glucanases accumulated to a several-times higher level in the infected leaves of all varieties. New isoforms of &beta;-1,3-glucanases were also detected in infected leaves after fungal infection