Photosynthetic pigments content, δ-aminolevulinic acid dehydratase and acid phosphatase activities and mineral nutrients concentration in cadmium-exposed Cucumis sativus L.

Biologia ◽  
2009 ◽  
Vol 64 (2) ◽  
Author(s):  
Jamile Gonçalves ◽  
Fernando Nicoloso ◽  
Alexssandro Becker ◽  
Luciane Pereira ◽  
Luciane Tabaldi ◽  
...  

AbstractIn this study, the effects of cadmium chloride (CdCl2) on plant growth, histology of roots, photosynthetic pigments content, δ-aminolevulinic acid dehydratase (ALA-D; E.C. 4.2.1.24) and acid phosphatase activities (AP; E.C. 3.1.3.2), soluble phosphorus (Pi) measurement and mineral nutrients content in cucumber seedlings (Cucumis sativus L.) were investigated. Cucumber seedlings were grown in vitro in an agar-solidified substrate containing four CdCl2 treatments (0, 100, 400, and 1000 μM) for ten days. Cd was readily absorbed by seedlings and its content was greater in the roots than in the shoot. Cd reduced shoot and root length, and fresh and dry biomass of seedlings. Inhibition of root cell elongation in Cd-treated seedlings was observed by the increase of the mean radial size of cells belonging to three zones of the root tip. The highest level of Cd reduced in a similar manner chlorophyll a, chlorophyll b and total chlorophyll contents. Increasing concentrations of Cd resulted in a linear decrease in carotenoids levels of cotyledons. Interestingly, the ALA-D activity in cotyledons was inhibited only at the highest level of Cd. Root and shoot AP activities were, respectively, activated and inhibited at all CdCl2 concentrations. Root Pi concentration was increased in all Cd treatments and it was not altered in the shoot tissues. Moreover, in general, the nutrient contents were increased in the root and decreased in the shoot. Therefore, we suggest that Cd affects negatively growth, photosynthetic pigments, ALA-D and AP activities and partition of mineral nutrients in cucumber seedlings.

2008 ◽  
Vol 20 (4) ◽  
pp. 285-294 ◽  
Author(s):  
Etiane C. Skrebsky ◽  
Luciane A. Tabaldi ◽  
Luciane B. Pereira ◽  
Renata Rauber ◽  
Joseila Maldaner ◽  
...  

Pfaffia glomerata (Spreng.) Pedersen plantlets were grown under different cadmium (Cd) concentrations (0, 20, 40, 60 and 80 μM) in a hydroponic system during 7 d. Plant growth, micronutrient, chlorophyll and carotenoid concentrations, as well as δ-aminolevulinic acid dehydratase (ALA-D; E.C.4.2.1.24) and acid phosphatase (AP; E.C.3.1.3.2) activities were then analysed. Cadmium concentration in both shoots and roots increased with increasing external Cd levels. Metal concentration was on average 12-fold greater in root than in shoot tissues. Root length was unaffected by Cd treatments. In contrast, dry weight of both shoot and roots increased significantly upon addition of 20 and 40 μM Cd. Moreover, shoot and total plant dry weight was only reduced in plants treated with 80 μM Cd. Conversely, root dry weight decreased significantly upon addition of Cd concentrations above 40 μM. A micronutrient- and organ-dependent response to Cd toxicity was observed. Zinc and Cu concentrations in both shoot and roots did not alter upon treatment with Cd. Cadmium stress reduced Mn uptake but not its translocation within the plant. A synergistic effect of Cd on Fe concentration in root at 20 μM and 80 μM Cd levels was observed. The activity of AP, and especially that of ALA-D, was reduced with increasing Cd levels. At those these Cd levels, chlorophyll concentration was also reduced. There was a positive correlation between concentrations of carotenoids and chlorophylls. Our results indicate that P. glomerata seems to have some degree of Cd tolerance.


1994 ◽  
Vol 119 (5) ◽  
pp. 964-970 ◽  
Author(s):  
Eleazar Reyes ◽  
Paul H. Jennings

Roots of `Golden Girl' squash (Cucurbita pepo var. melopepo) and `Encore' cucumber (Cucumis sativus L.), 4- and 3-days-old, respectively, were exposed to 2, 6, 10, and 15C for 24, 48, 96, 144, and 192 hours to compare the sensitivity to chilling temperatures and the subsequent recovery at more favorable temperatures. Seedlings were more sensitive to chilling at 2 and 6C when measured by their ability to resume growth when returned to 26C. Root growth decreased after 48 hours of chilling. Seedlings stressed at 10 and 15C were able to continue root growth at these temperatures and when returned to 26C. However, seedlings at 10C exhibited root-tip browning in both crop species, suggesting disfunction in metabolic pathways that were repressed in seedlings growing at 2C where those symptoms were not present. Effects on root dry weight occurred in the first 24 hours at all temperatures studied. After 96 hours of treatment, seedlings grown at 2 and 6C were irreversibly damaged, as evidenced by their inability to resume growth when returned to 26C. Leakage of electrolytes from squash and cucumber roots increased after 48 hours at 2C. Potassium, Na+, and PO4-2 were lost in greater amounts than Mg+2, Cl-, and SO4-2. No difference in ionic leakage occurred at 10 and 15C, and Ca+2 leakage was not detected at any chilling stress temperature.


2014 ◽  
Vol 54 (1) ◽  
pp. 95-105 ◽  
Author(s):  
Marek Burzyński

Lead uptake by young cucumber (<em>Couches satires</em> L.) seedlings growing in 10<sup>-4</sup> and 10<sup>-3</sup> M PbCl<sub>2</sub> solution caused δ-aminolevulinic acid synthesis inhibition, reduced the activity of δ-aminolevulinic acid dehydratase and the chlorophyll centent in the cotyledons. Lead mainly accumulated in the roots (ca 93-96% of Pb uptake) and hypocotyls (ca 4-6%), whereas only trace Pb amounts were found in the cotyledons when 10<sup>-3</sup> M solution was used. It is supposed that one of the causes of the reduction of chlorophyll synthesis by lead is its influence on tissue hydration which diminished to about 50 per cent as compared with the control. The direct effect of lead on the examined steps of chlorophyll synthesis cannot, however, be ruled out.


2021 ◽  
Vol 23 (1) ◽  
pp. 176
Author(s):  
Lin Chen ◽  
Fenghua Zheng ◽  
Zili Feng ◽  
Yue Li ◽  
Muxuan Ma ◽  
...  

Vacuolar invertase (VI) can irreversibly degrade sucrose into glucose and fructose and involve in plants abiotic-stress-tolerance. Cucumber (Cucumis sativus L.) is susceptible to drought stress, especially during the seedling stage. To date, the involvement of VI in drought tolerance in cucumber seedlings is in urgent need of exploration. In the present study, a cucumber vacuolar invertase gene, CsVI2, was isolated and functionally characterized. The results showed that (1) CsVI2 showed vacuolar invertase activity both in vivo and in vitro; (2) the transcript level of CsVI2, along with VI activity, was significantly induced by drought stress. Moreover, the expression of sucrose synthase 3 (CsSUS3) was increased and that of sucrose phosphate synthase 1 (CsSPS1) was decreased after exposure to drought stress, which was followed by an increase in sucrose synthase activity and a decrease in sucrose phosphate synthase activity; (3) CsVI2-overexpressing transformed cucumber seedlings showed enhanced vacuolar invertase activity and drought tolerance and 4) protein–protein interaction modelling indicated that a cucumber invertase inhibitor, CsINVINH3, can interact with CsVI2. In summary, the results indicate that CsVI2 as an invertase can regulate sucrose metabolism and enhance drought stress in cucumber seedlings.


2014 ◽  
Vol 49 (3) ◽  
pp. 259-267 ◽  
Author(s):  
Józef Buczek ◽  
Ewa Kowalińska ◽  
Krystyna Kuczera

Investigations were conducted on the influence of tungsten (Na<sub>2</sub>WO<sub>4</sub>) and meta-vanadate (NaVO<sub>3</sub>) on uptake and reduction of nitrates by cucumber seedlings. Tungsten and vanadium almost completely inhibited nitrate reductase activity (NR) after treating the plants for 24 hours with nitrates in the presence of 10<sup>-4</sup> M WO<sub>4</sub><sup>-2</sup> and 10<sup>-3</sup> M VO<sub>3</sub><sup>-</sup>. Uptake of NO<sub>3</sub><sup>-</sup> in the presence of WO<sub>4</sub><sup>-2</sup> in this same period of time was lowered by about 50 %, while in the presence of VO<sub>3</sub><sup>-</sup> by seventy percent. The ratio of NO<sub>3</sub><sup>-</sup> absorbed to that reducted in control plants was around 3, whereas in the presence of WO<sub>4</sub><sup>-2</sup> and VO<sub>3</sub><sup>-</sup> 9 and 8 respectively. The effect of NR inhibiting activity by WO<sub>4</sub><sup>-2</sup> and VO<sub>3</sub><sup>-</sup> was significant but somewhat weaker if both inhibitors were applied to the plants 24 hours after formation of the NR system, whereas NO<sub>3</sub><sup>-</sup> uptake was subject to a slight lowering. The above data suggest that WO<sub>4</sub><sup>-2</sup> and VO<sub>3</sub><sup>-</sup> after a 24 hour application of these inhibitors to plants, primary inhibit biosynthesis and activity of NR and to a lesser extent effect NO<sub>3</sub><sup>-</sup> absorption. On the basis of results reached the Butz and Jackson (1977) hypothesis concerning the model of NO<sub>3</sub><sup>-</sup> uptake and reduction by plant tissues is discussed.


Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1145-1152 ◽  
Author(s):  
Shulin Liu ◽  
Yanxia Shi ◽  
Han Miao ◽  
Min Wang ◽  
Baoju Li ◽  
...  

Gummy stem blight (GSB), caused by Didymella bryoniae (syn. Stagonosporopsis cucurbitacearum), is an important disease of cucumber (Cucumis sativus L.) worldwide. To better understand the resistance to GSB in cucumber seedlings, a set of 160 F9 recombinant inbred lines (RILs) and a total of 405 pairs of SSR primers were employed to detect quantitative trait loci (QTLs) conferring the resistance. Genetic analysis indicated that the resistance to GSB in PI 183967 seedlings was quantitative and mainly governed by two pairs of major QTLs and multiple minor QTLs. Six QTLs, gsb3.1, gsb3.2, gsb3.3, gsb4.1, gsb5.1, and gsb6.1, for resistance to GSB in cucumber seedlings were detected. The stable locus gsb5.1 on Chr.5 was repeatedly detected in three seasons. Locus gsb5.1 accounted for the highest phenotypic variation, 17.9%, and was flanked by SSR15321 and SSR07711 within the genetic distance of 0.5 cM. There were 102 candidate genes predicted in the region harboring the stable QTL gsb5.1, of which seven genes were related to disease resistance. These results can provide a good base for further study and molecular markers for fine-mapping the major QTL conferring GSB resistance in cucumber.


2009 ◽  
Vol 21 (3) ◽  
pp. 175-186 ◽  
Author(s):  
Jamile F. Gonçalves ◽  
Alexssandro G. Becker ◽  
Luciane B. Pereira ◽  
João B. T. da Rocha ◽  
Denise Cargnelutti ◽  
...  

In this study, the effects of lead (Pb) on growth, photosynthetic pigments concentration, lipid peroxidation, electrolyte leakage percentage (ELP), protein oxidation, aminolevulinate dehydratase (ALA-D; E.C. 4.2.1.24), ascorbate peroxidase (APX; E.C. 1.11.1.11), catalase (CAT; E.C. 1.11.1.6) and superoxide dismutase (SOD; E.C. 1.15.1.1) activities, and ascorbic acid (AsA), non-protein thiol groups (NPSH) and total soluble protein concentrations in cucumber seedlings (Cucumis sativus L.) were investigated. Seedlings were grown in vitro in an agar-solidified substrate containing three Pb levels as (C2H3O2)Pb.3H2O (0, 100, 400, and 1000 µmol L-1) for 10 d. Increasing Pb concentrations in substrate enhanced Pb concentration in both roots and shoot. Pb accumulated at a higher amount in roots. Root length and total fresh weight were decreased at the two highest Pb concentrations. Cucumber showed no reduction in shoot length and total dry weight at any Pb level. The highest Pb concentration decreased water content and ALA-D activity as well as increased malondialdehyde, carbonyls and total soluble protein concentrations. Carotenoids concentration enhanced at 100 and 400 µmol Pb L-1, while chlorophyll concentration and ELP were not affected by Pb stress. Activity of APX was inhibited while the activities of CAT and SOD were increased at all Pb concentrations. AsA was enhanced at 400 and 1000 µmol Pb L-1 whereas NPSH were increased only at the highest Pb concentration. Therefore, high Pb-exposure caused oxidative stress, and the antioxidant system of the cucumber seedlings was not sufficient to revert it, contributing for growth reduction.


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