Photosynthetic Response of Maize Plants Against Cadmium and Paraquat Impact   总被引：1，自引：0，他引：1  

Ganka Chaneva  Petya Parvanova  Nikolina Tzvetkova  Alexandra Uzunova 《Water, air, and soil pollution》2010,208(1-4):287-293

The effects of cadmium (Cd) and/or paraquat (PQ) toxicity on photosynthesis in maize leaves were examined by measurement of gas exchange and chlorophyll content in hydroponically cultured plants. It was found that growth rate was distinctly influenced only by 100 µM Cd treatment. Chlorophyll a and chlorophyll b decreased along with the increase of Cd concentration, while PQ spraying, alone and combined with Cd, increased chlorophyll a content on the third and seventh experimental days. Generally, carotenoid content increased in response to Cd and PQ and reached the highest levels at 100 µM Cd. Rate of photosynthesis in maize decreased after Cd treatment. CO₂ assimilation was approximately 60% reduced at 50 µM Cd and 70% reduced in the presence of 100 µM Cd. PQ toxicity was partly overcome after the third day of exposure. Transpiration and stomatal conductance in maize leaves decreased on the third day along with Cd concentration and PQ spraying, except for the 25-µM Cd-treated plants. On the tenth day, the 25-µM Cd-treated plants and those from PQ-treated variants showed an increase of transpiration and stomatal conductance. Maize exhibited an ability to accumulate Cd in high quantities, especially in the roots—over 4,500 mg Cd/kg dry weight.  相似文献   

Exogenous succinate increases resistance of maize plants to copper stress     

Snejana Doncheva  Zlatimira Stoyanova  Katya Georgieva  Dimitrina Nedeva  Rumyana Dikova  Grigor Zehirov  Ana Nikolova 《植物养料与土壤学杂志》2006,169(2):247-254

The effect of copper (Cu) excess (1.5, 4.7, 31, 78, 156 μM) and exogenously supplied succinate on plant growth, chlorophyll content, chlorophyll fluorescence, and isoenzym profiles of some antioxidant enzymes in maize plants was studied. Excessive Cu supply led to a reduction in the relative growth rate (RGR), tolerance index (TI), chlorophyll a and chlorophyll b contents, and the quantum yield of PSII electron transport in the light‐adapted state (ΦPSII). Copper treatment induced several changes in the anionic and cationic peroxidases (PODs), as well as superoxide dismutase (SOD) isoenzyme profiles. After 8 d of 78 μM–Cu treatment, two new anionic and two new cationic peroxidase isoenzymes in the roots were registered. Copper applied at concentrations above 31 μM resulted in higher levels of manganese superoxide dismutase (Mn‐SOD) in the roots and Cu,Zn‐superoxide dismutase (Cu,Zn‐SOD) in the leaves. However, the addition of Na‐succinate (200 μM) to the root medium prior to Cu treatment increased the capacity of the plants to partially overcome Cu toxicity.  相似文献   

Silicon‐induced cadmium resistance in rice (Oryza sativa)     

Chika C. Nwugo  Alfredo J. Huerta 《植物养料与土壤学杂志》2008,171(6):841-848

Silicon (Si)‐induced cadmium (Cd) tolerance in rice (Oryza sativa L.) was investigated by analyzing Cd uptake, growth, and physiological parameters. Silicon treatments (0.0, 0.2, or 0.6 mM) were added to 6 d–old seedlings, and Cd treatments (0.0 or 5.0 μM) were added to 20 d–old seedlings. Parameters determined included: maximum net CO₂ assimilation (A_max), stomatal conductance (g_smax), and transpiration (E_max) rates at varying intercellular CO₂ concentrations (C_i). Also measured were chlorophyll fluorescence, growth, and Cd‐uptake parameters. Results showed a Si‐induced inhibition of Cd uptake. However, 0.2 mM or 0.6 mM Si treatment concentrations did not differentially inhibit Cd uptake or differentially alleviate Cd‐induced growth inhibition, despite a significant increase in tissue Si concentration due to 0.6 mM Si treatment compared to 0.2 mM Si treatment. Additionally, photosynthesis and chlorophyll‐fluorescence analysis showed that treatment with Cd significantly inhibited photosynthetic efficiency. Interestingly, the addition of 0.2 mM Si, more so than the addition of 0.6 mM Si, significantly alleviated the inhibitory effects of Cd toxicity on photosynthesis and chlorophyll‐fluorescence parameters. Our results suggest that 0.2 mM Si could be close to an optimum Si‐dose requirement for the alleviation of toxicity symptoms mediated by moderate (5 μM) Cd exposure.  相似文献   

GAS EXCHANGE AND GROWTH OF TRITICALE SEEDLINGS UNDER DIFFERENT NITROGEN SUPPLY AND WATER STRESS     

T. Loboda 《Journal of plant nutrition》2013,36(3):371-380

The effect of nitrogen (30 and 120 mg N per cuvette) on photosynthetic rate of four cultivars of triticale (‘Bolero’, ‘Grado’, ‘Largo’, and ‘Lasko’) grown 14 days in phytotron was strongly modified by water content (75, 45 and 35% of full water capacity). For plants grown under 35% of full water capacity, it was higher when they were grown under 30 than under 120 mg N/cuvette (9.88 and 8.76 μmol CO₂ m^?2 s^?1, respectively) but for plants grown under 45 and 75% of full water capacity there were not significant differences. Transpiration, stomatal conductance, photosynthetic water use efficiency, and internal water use efficiency were not influenced by nitrogen doses independently of water content. Photosynthetic rate, transpiration, stomatal conductance, photosynthetic water use efficiency, and dry matter of studied cultivars of triticale grown under 45 and 35% of full water capacity and both nitrogen doses were lower than for plants grown under 75% of full water capacity. With lowering of water content stomatal conductance was decreasing similarly as photosynthetic rate e.g. for plants grown under 35% of full water capacity as compared with those grown under 75% of full water capacity average stomatal conductance decreased from 0.209 to 0.138 mol H₂O m^?2 s^?1 and photosynthetic rate from 13.69 to 9.32 μmol CO₂ m^?2 s^?1 and as a result there were not significant differences in internal water use efficiency for all studied combinations (67.09 μmol CO₂ mol^?1 H₂O) which shows that stomatal factors were mainly responsible for changes of photosynthetic rate. With lowering of water content from 75 to 35% of full water capacity the decrease of photosynthetic rate and stomatal conductance was much higher than the decreases of transpiration (from 3.57 to 3.02 mmol H₂O m^?2 s^?1) what shows not direct dependence of transpiration on stomatal conductance (water use efficiency decreased from 3.87 to 3.10 μmol CO₂ mmol^?1 H₂O). The effect of nitrogen on dry matter production was strongly modified by water availability e.g. for plants grown under 35% of full water capacity, dry matter was similarly independent of nitrogen dose but for plants grown under 45 and 75% of full water capacity dry matter was significantly higher than when they were grown under 120 (79.05 and 86.75 mg, respectively) or with 30 mg N/cuvette (74.03 and 80.30 mg, respectively).  相似文献   

Responses of cucumber grown in recirculating nutrient solution to gradual Mn and Zn accumulation in the root zone owing to excessive supply via the irrigation water     

Constantinos Tzerakis  Dimitrios Savvas  Nick Sigrimis 《植物养料与土壤学杂志》2012,175(1):125-134

A standard and a high manganese (Mn) level (10 and 160 μM) were combined with a standard and a high zinc (Zn) level (4 and 64 μM) in the nutrient solution supplied to cucumber in closed‐cycle hydroponic units to compensate for nutrient uptake. The concentrations of all nutrients except Mn and Zn were identical in all treatments. The objectives of the experiment were to establish critical Zn and Mn levels in both nutrient solutions and leaves of cucumber grown hydroponically, to assess the impact of gradual Zn and/or Mn accumulation in the external solution on nutrient uptake and gas exchange, and to find whether Mn and Zn have additive effects when the levels of both ions are excessively high in the root zone. The first symptoms of Mn and Zn toxicity appeared when the concentrations of Mn and Zn in the leaves of cucumber reached 900 and 450 mg kg^–1 in the dry weight, respectively. Excessively high Mn or/and Zn concentrations in the leaves reduced the fruit biomass production due to decreases in the number of fruits per plant, as well as the net assimilation rate, stomatal conductance, and transpiration rate, but increased the intercellular CO₂ levels. Initially, the Mn or Zn concentrations in the recirculating nutrient solution increased rapidly but gradually stabilized to maximal levels, while the corresponding concentrations in the leaves constantly increased until the end of the experiment. The uptake of Mg, Ca, Fe, and Cu was negatively affected, while that of K and P remained unaffected by the external Mn and Zn levels. The combination of high Mn and Zn seems to have no additive effects on the parameters investigated.  相似文献   

等渗Ca(NO₃)₂和NaCl胁迫对番茄光合作用的影响   总被引：34，自引：3，他引：34  

史庆华  朱祝军  钱琼秋 《植物营养与肥料学报》2004,10(2):188-191

研究了番茄的光合作用对等渗Ca(NO3)2和NaCl处理的响应。在等渗条件下120mmol.LNaCl和80mmol.LCa(NO3)2胁迫后,番茄叶片的叶绿素a、叶绿素b、总叶绿素含量、Chl.a/Chl.b比值、净光合速率(Pn)、气孔导度(Gs)、原初光能转换效率(Fv.Fm)、光合电子传递量子效率(ΦPSII)、Fv.Fo、光化学猝灭系数(qP)均呈下降趋势,以NaCl处理的下降幅度大于Ca(NO3)2处理;而Ca(NO3)2处理的胞间CO2浓度(Ci)呈下降趋势,NaCl处理的Ci呈升高趋势。因此,两种盐处理均对番茄植株光合作用造成了伤害,NaCl造成的伤害较Ca(NO3)2较为严重,Ca(NO3)2胁迫净光合速率下降可能是气孔限制所引起的,而NaCl胁迫净光合速率下降可能是由非气孔因子限制引起的。  相似文献   

Effect of salinity on growth,photosynthesis and mineral composition in leguminous plant Alhagi pseudoalhagi (Bieb.)     

Halil Kurban  Hirofumi Saneoka  Kunito Nehira  Rahmutulla Adilla  Gnanasiri S. Premachandra  Kounosuke Fujita 《Soil Science and Plant Nutrition》2013,59(4):851-862

Leguminous plant Alhagi pseudoalhagi was subjected to 0 (control), 50, 100, and 200 mM NaCI treatments during a 30 d period to examine the mechanism of tolerance to salinity. Plant dry weight, net CO₂ assimilation rate, leaf stomatal conductance, intercellular CO₂ concentration, and solute concentration in leaves, stems, and roots were determined. Total plant weight in the 50 mM treatment was 170% of that of the control after 10 d of treatment. Total plant weight was lower in the 100 and 200 mM treatments than in the control. The leaf CO₂ assimilation rate was approximately 150% of that of the control in the 50 mM treatment, but was not affected significantly by 100 mM of NaCI, while it was reduced to about 60% of that the control in the 200 mM treatment. Similarly stomatal conductance was consistent with the CO₂ assimilation rate regardless of the treatments. Intercellular CO₂ concentration was lower in the NaCI-treated plants than in the control. Changes in CO₂ assimilation rate due to salinity stress could be mainly associated with stomatal conductance and the carboxylation activity. Although the leaf Na⁺ concentration increased to 900 mmol kg^-1 dry weight in the 200 mM treatment compared to 20 mmol kg^-1 in the control, the plants did not die and continued to grow at such a high leaf Na⁺ concentration. Uptake and transportation rates of Na+, Ca²⁺, Mg²⁺, and K⁺, and the accumulation of N were promoted by 50 mM NaCI. Na⁺ uptake rate continued to increase in response to external NaCI concentration. However, the uptake and transportation rates of Ca²⁺, Mg²⁺, and K⁺ behaved differently under 100 and 200 mM salt stress. The results suggest that A. pseudoalhagi is markedly tolerant to salinity due mainly to its photosynthetic activity rather than to other physiological characteristics.  相似文献   

Effect of water stress on growth,photosynthesis, and photoassimilate translocation in soybean and tropical pasture legume siratro     

Yoshiyuki Ohashi  Hirofumi Saneoka  Kounosuke Fujita 《Soil Science and Plant Nutrition》2013,59(2):417-425

Siratro (Macroptilium atropurpureum) and soybean (Glycine max) were grown in pots with or without irrigation for 3 weeks at the vegetative stage to examine the effect of water stress on plant biomass production, biological N₂ fixation, CO₂ assimilation rate, stomatal conductance, leaf water potential, and the partition of ¹⁴CO₂ to plant parts. Biomass production decreased by water stress and the decrease was less conspicuous in siratro, mainly due to the maintenance of a relatively higher growth rate in stem plus petioles and roots. Siratro maintained a higher stomatal conductance and CO₂ assimilation rate at a lower leaf water potential compared to soybean. Water stress decreased the biological N₂ fixation in both species, and the decrease was more appreciable in siratro than in soybean under stress conditions. Water stress affected the export of photoassimilates from leaves in both species. The translocation of ¹⁴CO₂ photoassimilates to nodules and roots was less substantial in siratro than in soybean under water stress conditions. Translocation of photoassimilates from leaves to stem plus petioles in siratro enables the maintenance of growth of stem and petioles under water stress conditions.  相似文献   

WATER STRESS AND NITROGEN MANAGEMENT EFFECTS ON GAS EXCHANGE,WATER RELATIONS,AND WATER USE EFFICIENCY IN WHEAT     

Ejaz Ahmad Waraich  R. Ahmad  Saifullah  A. Ahmad 《Journal of plant nutrition》2013,36(12):1867-1882

A field experiment was conducted over two years to evaluate the gas exchange, water relations, and water use efficiency (WUE) of wheat under different water stress and nitrogen management practices at Crop Physiology Research Area, University of Agriculture, Faisalabad, Pakistan. Four irrigation regimes and four nitrogen levels, i.e., 0, 50, 100, and 150 kg N ha^?1 were applied in this study. The photosynthetic gas exchange parameters [net carbon dioxide (CO₂) assimilation rate, transpiration rate and stomatal conductance] are remarkably improved by water application and nitrogen (N) nutrition. Plants grown under four irrigation treatments as compared with those grown under one irrigation treatment average stomatal conductance increased from 0.15 to 0.46 μ mol m^?2s^?1mol during 2002–2003 and 0.18 to 0.33 μ mol m^?2s^?1mol during the year 2003–2004 and photosynthetic rate from 9.33 to 13.03 μmol CO₂ m^?2 s^?1 and 3.99 to 7.75 μmol CO₂ m^?2 s^?1 during the year 2002–2003 and 2003–2004, respectively. The exposure of plants to water and nitrogen stress lead to noticeable decrease in leaf water potential, osmotic potential and relative water content. Relative water content (RWC) of stressed plants dropped from 98 to 75% with the decrease in number of irrigation and nitrogen nutrition. The higher leaf water potential, and relative water contents were associated with higher photosynthetic rate. Water use efficiency (WUE) reduced with increasing number of irrigations and increased with increasing applied nitrogen at all irrigation levels.  相似文献   

Foliar Applied Phosphorous Enhanced Growth,Chlorophyll Contents,Gas Exchange Attributes and PUE in Wheat (Triticum aestivum L.)     

Ejaz Ahmad Waraich  Zahoor Ahmad  Rashid Ahmad  Saifullah  M. Y. Ashraf 《Journal of plant nutrition》2015,38(12):1929-1943

A pot experiment was conducted to evaluate the foliar applied phosphorous with and without pre-plant dose (50 kg hac.^?1) of phosphorous on growth, chlorophyll contents, gas exchange parameters and phosphorous use efficiency (PUE) of wheat. The experiment was conducted in net house at Department of Crop Physiology, University of Agriculture Faisalabad, Pakistan. Two promising wheat cultivar AARI 2011 and FSD 2008 were used as a test crop with 5 foliar phosphorus (P) rates (0, 2, 4, 6, 8 kg ha^?1). The foliar applied P with pre-plant performed better than without pre-plant and control treatments. Foliar treatment of phosphorus at 6 kg ha^?1 P proved to be the best among other foliar treatments followed by 8 kg ha^?1 P. The foliar application of phosphorous at 6 kg hac.^?1 with pre-plant soil applied P increased the shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight. The chlorophyll contents (Chl. a and b) were increased with the foliar application of phosphorous. The gas exchange parameters (net carbon dioxide (CO₂) assimilation rate, transpiration rate, stomatal conductance and sub-stomatal CO₂ rate) were significantly improved by foliar applied P. The maximum values of net CO₂ assimilation rate (5.27 μ mol m^?2 sec.^?1), transpiration rate (3.44 μ mol m^?2 sec.^?1), stomatal conductance (0.81 μ mol m^?2 sec.^?1) and sub-stomatal CO₂ (271.67 μ mol m^?2 sec.^?1), were recorded in the treatment where P was foliar applied at 6 kg hac.^?1 with pre-plant soil applied Phosphorous. The foliar application of phosphorous with pre-plant soil applied P enhanced Phosphorous use efficiency (PUE) in both varieties. The maximum value of PUE (15.42%) was recorded in the treatment where foliar feeding of P was done at 6 kg hac.^?1 with pre-plant soil applied P in both genotypes.  相似文献   

Combined effects of phosphorus nutrition and elevated carbon dioxide concentration on chlorophyll fluorescence,photosynthesis, and nutrient efficiency of cotton   总被引：2，自引：1，他引：1       下载免费PDF全文

Shardendu K. Singh  Vangimalla R. Reddy 《植物养料与土壤学杂志》2014,177(6):892-902

To examine the combined effects of phosphorus (P) nutrition and CO₂ on photosynthesis, chlorophyll fluorescence (CF), and nutrient utilization and uptake, two controlled‐environment experiments were conducted using 0.01, 0.05 and 0.20 mM external phosphate each at ambient and elevated CO₂ (aCO₂: 400 and eCO₂: 800 µmol mol^?1, respectively). The CF parameters were affected more by P nutrition than by CO₂ treatment. Photoinhibition of photosystem II (PSII) was due to increased minimal CF (Fo′) and decreased maximal CF (Fm′), and efficiency of energy harvesting (Fv′/Fm′). In addition, reduced electron transport rate (ETR), the quantum yield of PSII (Φ_PSII) and CO₂ assimilation ( ), and overall photochemical quenching in the P‐deficient leaves led to reduction in the efficiency of energy transfer to the PSII reaction center. Stimulation in the Φ_PSII/ and photorespiration (ETR/P_net) was found under P deficiency, whereas the opposite was the case under CO₂ enrichment. On average, photosynthetic rate (P_net) and stomatal conductance declined by 50–53% at 0.05 mM P and by 70–72% at 0.01 mM P as compared to the 0.20 mM P treatment. However, P deficiency, especially at eCO₂, tended to increase the intrinsic water‐use efficiency. In the P‐deficient plants, the decline in the P and N utilization efficiency (up to 91%) of biomass production was mainly associated with greater reduction in the biomass relative to the tissue P concentration as the P supply was reduced. However, it was significantly stimulated by eCO₂ especially at higher P supply. The CO₂ × P interaction was observed for some parameters such as Fo′, Fm′, P utilization efficiencies of photosynthesis and biomass production that might be attributed to the irresponsiveness of these parameters to eCO₂ under low P treatment. Thus, P deficiency limited the beneficial effect of eCO₂. A close relationship between total biomass and photosynthesis with the P and N utilization or uptake efficiencies was found. The P utilization efficiency of P_net appeared to be stable across a range of leaf P concentrations, whereas the N‐utilization efficiency markedly increased with leaf P and differed between CO₂ levels. An apparent effect of both the treatments (P and CO₂) on N‐uptake and utilization efficiency also indicated the alteration in N acquisition and assimilation in cotton plants.  相似文献   

Effects of sulfur nutrition on photosynthesis in cadmium‐treated barley seedlings     

Yichang Chen  Alfredo J. Huerta 《Journal of plant nutrition》2013,36(7-8):845-856

The effects of sulfur (S) nutrition at 0.1 or 1 mM S on cadmium (Cd) toxicity measured by photosynthesis in barley (Hordeum vulgare L. cv. UC 476) seedlings were studied. Eight‐day‐old seedlings were treated with 25 μM Cd by adding cadmium chloride (CdCl₂) to the nutrient solution. Then photosynthetic carboxylation efficiency (ACi curve) and stomatal conductance of the primary and second leaves were measured at four and eight days after Cd treatment. Fluorescence parameters were measured every 24 h for eight days after two days of Cd treatment. At 20 days, plant growth parameters were measured and dry biomass determined. The results showed that ACi was significantly reduced by Cd, but more in the low (0.1 mM) S than in the high (1 mM) S‐treated plants. Stomatal conductance of plants was also decreased by Cd, but more in the low S‐treated plants. Low S‐treated plants exposed to Cd showed an increase in Fo and Fq, and a decrease in Fv/Fm and T_1/2, indicating photoinhibitory damage to PSII. Analysis of the growth parameters showed that Cd decreased plant size and biomass, but the reduction was more severe in the low S‐treated plants. These results support the hypothesis that S is a critical nutritional factor in plants which is important for the reduction of Cd toxicity.  相似文献   

Evaluating the effectiveness of biofertilizer on salt tolerance of cotton (Gossypium hirsutum L.)     

Muhammad Amjad  Javaid Akhtar  Muhammad Saqib Rashid 《Archives of Agronomy and Soil Science》2013,59(8):1165-1177

In the present study, the effectiveness of biofertilizer containing plant growth promoting rhizobacteria was evaluated on growth and physiology of cotton under saline conditions. Cotton plants were exposed to different levels of NPK (50%, 75%, and 100% of recommended levels) along with coating with biofertilizer under saline (15 dS m^?1) and non-saline conditions. It was observed that the biofertilizer seed coating improved growth, physiological (relative water content and chlorophyll content index), and ionic (K⁺/Na⁺) characteristics under saline and non-saline conditions. However, shoot growth (shoot fresh and dry weight) and leaf gas exchange characteristics (CO₂ assimilation rate, A; intercellular CO₂ concentration, C_i; transpiration rate, E; stomatal conductance, g_s) were decreased by biofertilizer coating under saline condition. Increasing levels of NPK fertilizer increased shoot growth, whereas root growth was maximum at 75% NPK level under saline conditions. The results of the study indicate that the biofertilizer application was very effective for cotton plant in non-saline conditions but not very effective in saline conditions.  相似文献   

Absorption of various types of chelated copper in a low concentration range by cucumber     

K. Hino  C. de Kreij  C.W. van Elderen 《Journal of plant nutrition》2013,36(5):1049-1056

Two experiments were conducted to compare absorption of copper (Cu) from cupric chloride (CuCl₂) and various types of chelated Cu in a low concentration range by cucumbers. In the first experiment, two varieties of cucumber were grown on rockwool for 40 days in a glasshouse with standard nutrient solution which contained six different concentrations of CuCl₂ (0, 0.05, 0.10, 0.20, 0.40, and 0.80 μmol/L). Copper deficiency symptoms were examined during the growing period, and the total nitrogen (N), iron (Fe), manganese (Mn), zinc (Zn), and copper contents of young fully grown leaves were measured. There were no differences among treatments in the leaf contents of N and Mn. Copper contents increased and Zn decreased with increasing Cu levels. The content of Cu at the three low Cu treatments (including no Cu addition) were in the deficient range (48–65 μmol/kg dry matter). The zero Cu level had paler green leaves than other treatments. No differences were apparent between varieties. The second experiment was carried out under exactly the same conditions as the first, but on the basis of the results of the first experiment, Cu treatments were 0, Cu‐EDDHA at 0.4, Cu‐DTPA at 0.4, Cu‐EDTA at 0.4, Cu‐NTA at 0.4, CuCl₂ at 0.4 μmo/L as Cu²⁺. After the experiment, the total N, Fe, Mn, Zn, and Cu contents of young, fully grown leaves were measured. There were no differences between treatments in the leaf contents of Cu except zero Cu level. They were in the range of 101–119 μmol/kg dry matter. At no Cu addition treatment, the Cu content was only 31 μmol/kg dry matter which is considered to be the deficiency level. For the other examined elements, there were no differences among the treatments and varieties. From these data it was concluded that the availability of these chelated Cu types were the same as CuCl₂ under the conditions of the experiments conducted.  相似文献   

Comparison of the Vegetative Growth,Eco-Physiological Characteristics and Mineral Nutrient Content of Basil Plants in Different Irrigation Ratios of Hydroponic:Aquaponic Solutions     

Hamid R. Roosta 《Journal of plant nutrition》2014,37(11):1782-1803

Aquaponics is the combined culture of fish and plants in recirculating systems. This experiment was conducted to evaluate the production of basil out of the aquaponic system by irrigation of the plants with different ratios of hydroponic and aquaponic solutions. Basil seedlings were irrigated three times day^?1 with 200 mL aquaponic-aquaponic-aquaponic (AAA), aquaponic-hydroponic-aquaponic (AHA), hydroponic-aquaponic-hydroponic (HAH), and hydroponic-hydroponic-hydroponic (HHH) solutions, respectively. Fresh and dry mass of shoots and roots of basil decreased at AAA treatment significantly. The plants were slightly less green at AHA treatments, and a visible chlorosis appeared in the leaves of AAA-treated plants. This chlorosis resulted lower net carbon dioxide (CO₂) assimilation rate, transpiration rate, and stomatal conductance in AAA treatment. Iron (Fe), manganese (Mn), and potassium (K) concentrations in leaves decreased and zinc (Zn) concentration increased in higher ratios of aquaponic:hydroponic solution. Lower Fe, Mn, and K concentrations in aquaponic solution may be a main part of the reason for growth reduction.  相似文献   

GROWTH AND PHYSIOLOGICAL RESPONSE OF HYDROPONICALLY-GROWN SUNFLOWER AS AFFECTED BY SALINITY AND MAGNESIUM LEVELS     

A. R. Rivelli  S. De Maria  S. Pizza  P. Gherbin 《Journal of plant nutrition》2013,36(9):1307-1323

The effects of NaCl and magnesium levels (Mg²⁺) on the physiological response of sunflower were investigated. Plants were grown for 54 days in hydroponic culture with NaCl (100 mM) or without NaCl and four concentrations of Mg²⁺: 0, 0.4, 1.0 and 5.0 mM. At the end of the vegetative growing cycle of sunflower, salt stress reduced leaf area development by 51% and dry matter accumulation by 37% as compared to non saline-treated plants; at this stage, considering the percent reduction of partitioned plant dry matter, roots (42%) and leaves (35%) showed to be more salt-sensitive than stem. Growth reduction was related to the drop in net CO₂ assimilation rate and stomatal conductance, which started declining later during the vegetative growth period when leaf ion concentration started increasing. The investigated genotype was unable to exclude ions and significant amounts of Cl^? (about 1700 μmol g^?1 DW) and lesser Na⁺ (700 μmol g^?1 DW) accumulated in the leaves. The decline in net CO₂ assimilation was well correlated to the increase in leaf Cl^? concentration (r² = 0.71) and not to leaf Na⁺ concentration (r² = 0.33). The results suggest that, though sunflower develops an endogenous protection system by which it redistributes this ions in the whole plant, with more ions accumulating in roots and older leaves, growth reduction may be attributed to specific toxic effects of Cl^? on photosynthetic functionality. In both saline and non saline conditions, little or no significant differences in growth parameters of plants exposed to a range from 0.4 to 5 mM of Mg²⁺ were observed. Whereas, its deficiency caused a drastic reduction of dry matter accumulation up to 90%, due to progressive decline in CO₂ assimilation rate and chlorophyll content, with imbalances in Ca²⁺, Mg²⁺ and K⁺.  相似文献   

Aluminum toxicity in tomato. Part 2. leaf gas exchange,chlorophyll content,and invertase activity     

L. Simon  M. Kieger  S. S. Sung  T. J. Smalley 《Journal of plant nutrition》2013,36(2-3):307-317

The effect of aluminum (Al) toxicity on leaf gas exchange, leaf chlorophyll content, and sucrose metabolizing enzyme activity of two tomato cultivars (Lycopersicon esculentum Mill. ‘Mountain Pride’ and ‘Floramerica') was studied to determine the mechanism of growth reduction observed in a related study (Simon et al., 1994, Part 1). Plants were grown in diluted nutrient solution (pH 4.0) with 0, 10, 25, or 50 μM. Al for 16 days. Leaf gas exchange was reduced 2–3 fold in both cultivars as Al concentration increased. Gas exchange of ‘Mountain Pride’ was more sensitive to Al toxicity than ‘Floramerica’, agreeing with growth responses observed. Reductions in carbon dioxide (CO₂) assimilation rate appeared to be due to nonstomatal factors in ‘Floramerica’, but stomatal and non‐stomatal limitations in ‘Mountain Pride’. Chlorophyll content of leaves was not affected by Al. Acid invertase (AI) and neutral invertase (NI) activity of roots responded consistently to Al concentration in both cultivars. Root AI and NI activity decreased to a greater extent for ‘Mountain Pride’ than for ‘Floramerica’.  相似文献   

Changes in micronutrient availability and plant uptake under simulated climate change in winter wheat field     

Jianqing Wang  Xuhui Zhang  Lianqing Li  Kun Cheng  Jufeng Zheng  Jinwei Zheng  Mingxing Shen  Xiaoyu Liu  Genxing Pan 《Journal of Soils and Sediments》2016,16(12):2666-2675

  相似文献   

Environmental Limitations to O3 Uptake - Some Key Results from Young Trees Growing at Elevated Co2 Concentrations     

M.S.J. Broadmeadow  J. Heath  T.J. Randle 《Water, air, and soil pollution》1999,116(1-2):299-310

Elevated carbon dioxide concentrations and limited water supply have been shown to reduce the impact of ozone pollution on the growth and physiology of Quercus petraea in a long-term factorial experiment. These responses can be explained by observed reductions in stomatal conductance, and thus potential ozone exposure of 28% and 40% for CO₂ and drought treatments respectively. However, parameterisation of a stomatal conductance model for Quercus robur and Fagus sylvatica grown under ambient and elevated CO₂ concentrations in a separate experiment has demonstrated that elevated CO₂ also reduces the responsiveness of stomata to both saturation deficit (LAVPD) and soil moisture deficit (ψ) in beech, and to a lesser extent, in oak. Season-long model simulations of ozone fluxes suggest that LAVPD and ψ conductance parameters derived at ambient CO₂ concentrations will lead to these fluxes being underestimated by 24% and 2% for beech and oak respectively at 615 ppm CO₂.  相似文献   

Effects of Nitrogen Deficiency on Leaf Chlorophyll Fluorescence Parameters in Two Olive Tree Cultivars ‘Meski’ and ‘Koroneiki’     

O. Boussadia  K. Steppe  M.-C. Van Labeke  R. Lemeur  M. Braham 《Journal of plant nutrition》2015,38(14):2230-2246

Effects of nitrogen (N) deficiency on photosynthetic carbon dioxide (CO₂) assimilation, photosystem II (PSII) photochemistry and photoinhibition were investigated in young trees of two olive cultivars ‘Meski’ and ‘Koroneiki’ grown in a greenhouse under controlled conditions. The trees were subjected to four different levels of N supply. N deficient trees had a significantly smaller CO₂ assimilatory capacity, but showed little changes in maximum quantum efficiency of PSII photochemistry. However, modifications in PSII photochemistry induced by N deficiency were observed. This was reflected in decreases in quantum yield of PSII electron transport (Φ_PSII) and efficiency of excitation energy capture by open PSII reaction centres (F_v’/F_m’) and in an increase in non-photochemical quenching (NPQ). These results suggest that modifications in PSII photochemistry might be a mechanism to down-regulate photosynthetic electron transport so that production of adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH). would be in equilibrium with the decreased demand in the Calvin cycle in the N deficient trees. Therefore, both CO₂ assimilation rate and total electron flow (J_t) with its compound electron flows devoted to either carboxylation (J_c) or oxygenation (J_o) can be considered as useful tools to assess the N nutrition status of the trees. Clear relationships were found between A_max and the nitrogen nutrition index (NNI) on the one hand, and between J_t and NNI on the other hand. The results demonstrate that ‘Meski’ is more efficient than ‘Koroneiki’ when subjected to N deficiency.  相似文献