Number of results to display per page
Search Results
552. Effect of ammonium/nitrate ratio on pak choi (Brassica chinensis L.) photosynthetic capacity and biomass accumulation under low light intensity and water deficit
- Creator:
- Shang, H. Q. and Shen, G. M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- biomasa, fotosyntéza, biomass, photosynthesis, chlorophyll fluorescence, electron transport rate, nitrate reductase, NH4+, NO3-, stomatal conductance, water-use efficiency, 2, and 581
- Language:
- Multiple languages
- Description:
- We conducted a hydroponic experiment in order to study effects of the ammonium/nitrate ratio (0:15, 5:10, 7.5:7.5, and 10:5) on photosynthetic characteristics and biomass accumulation in Brassica chinensis under low light intensity and water stress. Results showed that net photosynthetic rate, transpiration rate, intrinsic water-use efficiency, stomatal conductance, intercellular CO2 concentration, effective quantum yield of PSII photochemistry, electron transport rate, and nonphotochemical quenching were lower in the treatment (low light intensity and water deficit) than those in the control, whereas stomatal limitation increased. Minimum fluorescence, maximal quantum yield of PSII photochemistry, and photochemical quenching were largely unchanged. Pigment contents first increased and then decreased as the ammonium/nitrate ratios were altered, with significant differences between treatment and control observed at all ratios except for 10:5. Biomass first increased slightly and then decreased both in treated and control plants. Results suggest that economic losses caused by extreme conditions can be minimized by a proper adjustment of the ammonium/nitrate ratio., H. Q. Shang, G. M. Shen., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
553. Effect of ant attendance on aphid population growth and above ground biomass of the aphid's host plant
- Creator:
- Hosseini, Afsane, Hosseini, Mojtaba, Katayama, Noboru, and Mehrparvar, Mohsen
- Format:
- print, počítač, and online zdroj
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Zoologie, polokřídlí, mšicovití, blanokřídlí, populační růst, Hemiptera, Aphididae, Hymenoptera, population growth, Formicidae, ant-aphid interaction, aphid performance, developmental stage, plant yield, 2, and 59
- Language:
- English
- Description:
- Ant-aphid mutualism is considered to be a beneficial association for the individuals concerned. The population and fitness of aphids affected by ant attendance and the outcome of this relationship affects the host plant of the aphid. The main hypothesis of the current study is that ant tending decreases aphid developmental time and/or increases reproduction per capita, which seriously reduces host plant fitness. The effect of attendance by the ant Tapinoma erraticum (Latreille, 1798) (Hymenoptera: Formicidae) on population growth and duration of different developmental stages of Aphis gossypii Glover (Hemiptera: Aphididae) were determined along with the consequences for the fitness of the host plant of the aphid, Vicia faba L., in greenhouse conditions. The initial aphid density was manipulated in order to study aphid performance due to density-dependent changes in ant attendance. The population growth rate of ant attended aphids was more than that of unattended aphids. However, the ratio of 1st-2nd nymphs to adults in aphid populations attended by ants was lower. The yields of bean plants on which the aphids were attended by ants were significantly greater than those of unattended plants. This study indicates that ants not only increase aphid fitness in terms of their population growth rate, but also benefit the host plant., Afsane Hosseini, Mojtaba Hosseini, Noboru Katayama, Mohsen Mehrparvar., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
554. Effect of bicarbonate treatment on photosynthetic assimilation of inorganic carbon in two plant species of Moraceae
- Creator:
- Wu, Y. Y. and Xing, D. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, bicarbonate-use capacity, carbonic anhydrase, chlorophyll fluorescence, photosynthesis, stable hydrogen isotope, 2, and 58
- Language:
- Multiple languages
- Description:
- Excessive levels of bicarbonate adversely affect the growth and metabolism of plants. Broussonetia papyrifera (L.) Vent. and Morus alba L., belonging to family Moraceae, possess the favorable characteristics of rapid growth and adaptability to adverse environments. We examined the response of these two plant species to bicarbonate stress in terms of photosynthetic assimilation of inorganic carbon. They were exposed to 10 mM sodium bicarbonate in the culture solution for 20 days. The photosynthetic response was determined by measuring the net photosynthetic rate of the leaf, water-use efficiency, and chlorophyll fluorescence on days 10 and 20. The bicarbonate-use capacity of the plants was studied by measuring the carbonic anhydrase activity and the compositions of the stable carbon and hydrogen isotopes. The photosynthetic response to high concentration of bicarbonate varied with plant species and treatment durations. High concentrations of bicarbonate decreased the photosynthetic assimilation of inorganic carbon in the two plant species to half that in the control plants on day 10. Bicarbonate treatment did not cause any damage to the reaction centers of photosystem II in Morus alba; it, however, caused a decline in the quantum efficiency of photosystem II in B. papyrifera on day 20. Moreover, B. papyrifera had a greater bicarbonate-use capacity than M. alba because carbonic anhydrase converted bicarbonate to CO2 and H2O to a greater extent in B. papyrifera. This study showed that the effect of bicarbonate on photosynthetic carbon metabolism in plants was dual. Therefore, the concentration of bicarbonate in the soil should first be considered during afforestation and ecological restoration in karst areas., Y. Y. Wu, D. K. Xing., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
555. Effect of Ca/Mg ions ratio on copper accumulation, photosynthetic activity and growth of Cu2+-treated Salix viminalis L. ‘Cannabina’
- Creator:
- Borowiak, K., Drzewiecka, K., Magdziak, Z., Gąsecka, M., and Mleczek, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, Ca/Mg ions ratio, copper, net photosythesis rate, phytoremediation, Salix sp., stomatal conductance, transpiration rate, 2, and 58
- Language:
- Multiple languages
- Description:
- The aim of the study was to the assess the influence of Ca/Mg ions ratio on the photosynthetic activity of Salix viminalis L. ‘Cannabina’ plants cultivated in medium enriched with Cu(NO3)2. The experiment was conducted in controlled conditions in a phytotron for 21 days; hence the early plant response was tested. Plants were cultivated with different Ca/Mg ions ratios, i.e. (4:1)l, (4:1)h, and 1:10. Plants were additionally treated with Cu(NO3)2 at 1, 2, and 3 mM concentration in cultivation medium. Net photosynthetic rate, stomatal conductance and transpiration were measured after the first, second and third week of cultivation. Additionally, chlorophyll content, leaf morphology, root biomass and copper accumulation in leaves and roots were investigated. The investigations revealed differences in plant response to particular treatments - differences in Cu accumulation for particular Ca/Mg ions ratios were detected. It seems that plants are adapted to high Cu2+ concentrations, when 1:10 Ca/Mg ions ratio is applied. The highest Cu accumulation in roots was noted for plants fertilized with 1:10 Ca/Mg ions ratio, together with high Cu translocation to above-ground plant organs, which suggests its higher potential in phytoremediation., K. Borowiak ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
556. Effect of chromate on photosynthesis in Cr(VI)-resistant Chlorella
- Creator:
- Yewalkar, S. N., Dhumal, K. N., and Sainis, J. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, algae, chromate-resistant, thermoluminescence, 2, and 581
- Language:
- Multiple languages
- Description:
- Chromate-resistant Chlorella spp. isolated from effluents of electroplating industry could grow in the presence of 30 μM K2Cr2O7. Since photosynthesis is sensitive to oxidative stress, chromate toxicity to photosynthesis was examined in this algal isolate. Chromate [Cr(VI)] up to 100 μM was found to stimulate photosynthesis, while 90% inhibition was found, when the cells were incubated with 1 mM Cr(VI) for 4 h. Photosystem (PS) II was inhibited by 80% and PSI by 40% after such Cr(VI) treatment. Thermoluminescence studies on cells treated with 1 mM Cr(VI) for 4 h showed that S2QA - recombination peak (Q) was shifted to higher temperature, whereas S2/S3QB - recombination peak (B) was shifted to lower temperature. These shifts indicated alga stress response in order to overcome an excitation stress resulting from the inhibition of photosynthesis by Cr(VI). The nontreated Chlorella cells kept in the dark showed periodicity of four for the Q peak (4-8°C) and B peak (34-38°C) after exposure to series of single, turnover, saturating flashes. This periodicity was lost in Cr(VI)-treated cells. Higher concentrations of Cr(VI) inhibited mainly the electron flow in the electron transport chain, inactivated oxygen evolving complex, and affected also Calvin cycle enzymes in the Cr(VI)-resistant isolates of Chlorella. and S. N. Yewalkar, K. N. Dhumal, J. K. Sainis.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
557. Effect of chronic cadmium exposure on antioixdant defense system in some tissues of rats: protective effect of selenium
- Creator:
- Ognjanović, B. I., Marković, S. D., Pavlović, S. Z., Žikić, R. V., Saičić, Z. S., and Štajn, A. Š.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Obecná biologie, experimentální biologie, antioxidanty, kadmium, selen, potkan, experimental biology, antioxidants, cadmium, selenium, Rattus norvegicus, antioxidant defense system, 2, and 57
- Language:
- English
- Description:
- The effects of selenium (Se) on antioxidant defense system in liver and kidneys of rats with cadmium (Cd)-induced toxicity were examined. Cd exposure (15 mg Cd/kg b.m./day as CdCl2 for 4 weeks) resulted in increased lipid peroxidation (LP) in both organs (p<0.005 and p<0.01). Vitamin C (Vit C) was decreased in the liver (p<0.005), whereas vitamin E (Vit E) was increased in the liver and kidneys (p<0.005 and p<0.05) of Cd-exposed animals. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were decreased in both tissues (p<0.05 and p<0.005), whereas catalase (CAT) activity was decreased only in liver (p<0.005). Glutathione S-transferase (GST) increased in both tissues (p<0.005 and p<0.01). Treatment with Se (0.5 mg Se/kg b.m./day as Na2SeO3 for 4 weeks) significantly increased liver and kidneys SOD and GSH-Px activities (p<0.05 to p<0.005), as well as CAT and GST activities only in the liver (p<0.01). In animals exposed to Se, both the concentrations of Vit C (p<0.01) and Vit E (p<0.005) were increased in both tissues. Co-treatment with Se resulted in reversal of oxidative stress with significant decline in analyzed tissues Cd burden. Our results show that Se may ameliorate Cd-induced oxidative stress by decreasing LP and altering antioxidant defense system in rat liver and kidneys and that Se demonstrates the protective effect from cadmium-induced oxidative damage., B. I. Ognjanović, S. D. Marković, S. Z. Pavlović, R. V. Žikić, A. Š. Štajn, Z. S. Saičić., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
558. Effect of copper oxide nanoparticles on growth, morphology, photosynthesis, and antioxidant response in Oryza sativa
- Creator:
- Da Costa, M. V. J. and Sharma, P. K.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, ascorbate, nanoparticle, proline, superoxide dismutase, thylakoid, 2, and 581
- Language:
- Multiple languages
- Description:
- The physiological and biochemical behaviour of rice (Oryza sativa, var. Jyoti) treated with copper (II) oxide nanoparticles (CuO NPs) was studied. Germination rate, root and shoot length, and biomass decreased, while uptake of Cu in the roots and shoots increased at high concentrations of CuO NPs. The accumulation of CuO NPs was observed in the cells, especially, in the chloroplasts, and was accompanied by a lower number of thylakoids per granum. Photosynthetic rate, transpiration rate, stomatal conductance, maximal quantum yield of PSII photochemistry, and photosynthetic pigment contents declined, with a complete loss of PSII photochemical quenching at 1,000 mg(CuO NP) L-1. Oxidative and osmotic stress was evidenced by increased malondialdehyde and proline contents. Elevated expression of ascorbate peroxidase and superoxide dismutase were also observed. Our work clearly demonstrated the toxic effect of Cu accumulation in roots and shoots that resulted in loss of photosynthesis., M. V. J. Da Costa, P. K. Sharma., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
559. Effect of day/night temperature difference on chlorophyll content, photosynthesis and fluorescence parameters of tomato at fruit stage
- Creator:
- Yuan, X. K.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, nonstomatal limitation, photosynthetic efficiency, 2, and 581
- Language:
- Multiple languages
- Description:
- In order to investigate the effect of day/night temperature difference (DIF) on photosynthetic characteristics of tomato plants (Solanum lycopersicum, cv. Jinguan 5) at fruit stage, an experiment was carried out in climate chambers. Five day/night temperature regimes (16/34, 19/31, 25/25, 31/19, and 34/16°C) with respective DIFs of -18, -12, 0, +12, and +18 were used and measured at mean daily temperature of 25°C. The results showed that chlorophyll (Chl) a, Chl b, net photosynthetic rate (PN), stomatal conductance (gs), maximum quantum yield of PSII photochemistry (Fv/Fm), effective quantum yield of PSII photochemistry (ϕPSII), and photochemical quenching (qp) significantly increased under positive DIF, while they decreased with negative DIF. In contrast, the Chl a/b ratio and nonphotochemical quenching (NPQ) decreased under positive DIF, while increased with negative DIF. Chl a, Chl b, PN, gs, Fv/Fm, ϕPSII, and qp were larger under +12 DIF than those at +18 DIF, while Chl a/b and NPQ showed an opposite trend., X. K. Yuan., and Seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
560. Effect of dietary guild (frugivory and insectivory) and other host characteristics on ectoparasite abundance (mite and nycteribiid) of chiropterans
- Creator:
- Luguterah, Albert and Lawer, Eric Adjei
- Format:
- electronic, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- savci, parazitické organismy, mammals, parasitic organisms, negative binomial, parasitism, Poisson, Zero Inflated Negative Binomial, Zero Inflated Poisson, 2, and 59
- Language:
- English
- Description:
- Ectoparasites are an important factor in bat health due to emergent diseases and their associated threats to global public health. The diverse foraging habits of bats expose them to different surfaces which may influence ectoparasite infestations. In spite of these, most studies often overlook dietary specialisations when observing ectoparasite loads. The present paper quantitatively investigates whether foraging strategies as well as other host characteristics (sex, age, trunk and patagial area) influence ectoparasite (nycteribiids and mites) loads of bats. Ectoparasite counts and morphometric data were taken from mist net captures of bats. We then developed and compared models for modeling bat ectoparasite abundance under various distributions using generalised linear models. The negative binomial distribution consistently proved to be adequate for modeling mite, nycteribiid and total ectoparasite abundance based on information-theoretic approaches. Generally, females and frugivores had higher ectoparasite loads conditional on bat sex and diet, respectively. Contrary to nycteribiid abundance, mite abundance was positively related to patagial area. Thus, our findings suggest that dietary guild, sex and patagia of hosts (as well as age-nycteribiid abundance) are significant determinants of ectoparasite abundance., Albert Luguterah, Eric Adjei Lawer., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public