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1.
Yali Zhang Huajun Lv Dongsheng Wang Jingchao Deng Wenjing Song Kousar Makeen Qirong Shen Guohua Xu 《Plant Growth Regulation》2011,63(3):235-242
Partial nitrate nutrition (PNN) was found to improve rice (Oryza sativa L. var. japonica) growth. However, how PNN is related to photosynthesis in rice cultivars with different nitrogen use efficiency (NUE) is
still not clear. Two rice cultivars, Nanguang (high NUE) and Elio (low NUE), were grown under sole NH4
+ and PNN at a total nitrogen concentration of 2.86 mM. The dry weight, leaf area, ribulose-1,5-bisphosphate carboxylase/oxygenase
(Rubisco) and gas exchange parameters were measured. Nitrogen and Rubisco contents in the newly expanded leaves of cv. Nanguang
were similar to those of cv. Elio when only NH4
+ was supplemented in the nutrient solution. However, in cv. Nanguang, nitrogen and Rubisco contents increased under PNN than
under sole NH4
+ nutrition. Higher nitrogen and Rubisco contents were recorded in cv. Nanguang than in cv. Elio under PNN. The ratio of carboxylation
efficiency (CE) to Rubisco content in cv. Nanguang was 11 and 14% higher than that in cv. Elio under NH4
+ and PNN, respectively. CE was 14% higher in cv. Nanguang than that in cv. Elio. The results suggest that PNN causes an increase
in photosynthesis in cv. Nanguang. It is concluded that differences in Rubisco activity, rather than stomatal limitation,
are responsible for the differences in photosynthesis between the two cultivars. The presence of nitrate increases Rubisco
content in rice with a high NUE, which leads to faster biomass accumulation at later growth stages. 相似文献
2.
Alteration of nitrogen metabolism in rice variety 'Nipponbare' induced by alkali stress 总被引:1,自引:0,他引:1
Huan Wang Jianaer Ahan Zhihai Wu Decheng Shi Bao Liu Chunwu Yang 《Plant and Soil》2012,355(1-2):131-147
Aims
Alkali stress (AS) is an important agricultural contaminant and has complex effects on plant metabolism, specifically root physiology. The aim of this study was to test the role of nitrogen metabolism regulation in alkali tolerance of rice variety 'Nipponbare'.Methods
In this study, the rice seedlings were subjected to salinity stress (SS) or AS. Growth, the contents of inorganic ions, NH 4 + -nitrogen (free amino acids), and NO 3 ? -nitrogen in the stressed seedlings were then measured. The expression of some critical genes involved in nitrogen metabolism were also assayed to test their roles in the regulation of nitrogen metabolism during adaptation of rice variety 'Nipponbare' to AS.Results
AS showed a stronger inhibiting effect on rice variety 'Nipponbare' growth than SS. AS may have more complex effects on nitrogen metabolism than SS.Conclusions
Effects of AS on the nitrogen metabolism of rice variety 'Nipponbare' mainly comprised two mechanisms. Firstly, in roots, AS caused the reduction of NO 3 ? content, which caused two harmful consequences, the large downregulation of OsNR1 expression and the subsequent reduction of NH 4 + production in roots. On the other hand, under AS (pH, 9.11), almost all the NH 4 + was changed to NH3, which caused a severe deficiency of NH 4 + surrounding the roots. Both events might cause a severe deficiency of NH 4 + in roots. Under AS, the increased expression of several OsAMT family members in roots might be an adaptative response to the reduction of NH 4 + content in roots or the NH 4 + deficiency in rhizosphere. Also, the down-regulation of OsNADH-GOGAT and OsGS1;2 in roots might be due to NH 4 + deficiency in roots. Secondly, in shoots, AS caused a larger acuumulatiuon of Na+, which possibly affected photorespiration and led to a continuous decrease of NH 4 + production in shoots, and inhibited the expression of OsFd-GOGAT and OsGS2 in chloroplasts. 相似文献3.
Characterization of ammonium and nitrate uptake and assimilation in roots of tea plants 总被引:3,自引:0,他引:3
Y. Y. Yang X. H. Li R. G. Ratcliffe J. Y. Ruan 《Russian Journal of Plant Physiology》2013,60(1):91-99
It has been pointed out that tea (Camellia sinensis (L.) O. Kuntze) prefers ammonium (NH 4 + ) over nitrate (NO 3 ? ) as an inorganic nitrogen (N) source. 15N studies were conducted using hydroponically grown tea plants to clarify the characteristics of uptake and assimilation of NH 4 + and NO 3 ? by tea roots. The total 15N was detected, and kinetic parameters were calculated after feeding 15NH 4 + or 15NO 3 ? to tea plants. The process of N assimilation was studied by monitoring the dynamic 15N abundance in the free amino acids of tea plant roots by GC-MS. Tea plants supplied with 15NH 4 + absorbed significantly more 15N than those supplied with 15NO 3 ? . The kinetics of 15NH 4 + and 15NO 3 ? influx into tea plants followed a classic biphasic pattern, demonstrating the action of a high affinity transport system (HATS) and a low affinity transport system (LATS). The V max value for NH 4 + uptake was 54.5 nmol/(g dry wt min), which was higher than that observed for NO 3 ? (39.3 nmol/(g dry wt min)). KM estimates were approximately 0.06 mM for NH 4 + and 0.16 mM for NO 3 ? , indicating a higher rate of NH 4 + absorption by tea plant roots. Tea plants fed with 15NH 4 + accumulated larger amounts of assimilated N, especially glutamine (Gln), compared with those fed with 15NO 3 ? . Gln, Glu, theanine (Thea), Ser, and Asp were the main free amino acids that were labeled with 15N under both conditions. The rate of N assimilation into Thea in the roots of NO 3 ? -supplied tea plants was quicker than in NH 4 + -supplied tea plants. NO 3 ? uptake by roots, rather than reduction or transport within the plant, seems to be the main factor limiting the growth of tea plants supplied with NO 3 ? as the sole N source. The NH 4 + absorbed by tea plants directly, as well as that produced by NO 3 ? reduction, was assimilated through the glutamine synthetase-glutamine oxoglutarate aminotransferase pathway in tea plant roots. The 15N labeling experiments showed that there was no direct relationship between the Thea synthesis and the preference of tea plants for NH 4 + . 相似文献
4.
5.
O. G. Polesskaya E. I. Kashirina N. D. Alekhina 《Russian Journal of Plant Physiology》2006,53(2):186-192
In plants of wheat (Triticum aestivum L.) grown in the media with nitrate (NO 3 ? plants), ammonium (NH 4 + plants), and without nitrogen (N-deficient plants), the response to oxidative stress induced by the addition of 300 mM NaCl to the nutrient solution was investigated. Three-day-long salinization induced chlorophyll degradation and accumulation of malondialdehyde (MDA) in the leaves. These signs of oxidative stress were clearly expressed in NO 3 ? and N-deficient plants and weakly manifested in NH 4 + plants. In none of the treatments, salinization induced the accumulation of MDA in the roots. Depending on the conditions of N nutrition, salt stress was accompanied by diverse changes in the activity of antioxidant enzymes in the leaves and roots. Resistance of leaves of NH 4 + plants to oxidative stress correlated with a considerable increase in the activities of ascorbate peroxidase and glutathione reductase. Thus, wheat plants grown on the NH 4 + -containing medium were more resistant to the development of oxidative stress in the leaves than those supplied with nitrate. 相似文献
6.
Wenjing Song Huwei Sun Jiao Li Xianpo Gong Shuangjie Huang Xudong Zhu Yali Zhang Guohua Xu 《Annals of botany》2013,112(7):1383-1393
Background and Aims
Although ammonium (NH4+) is the preferred form of nitrogen over nitrate (NO3−) for rice (Oryza sativa), lateral root (LR) growth in roots is enhanced by partial NO3− nutrition (PNN). The roles of auxin distribution and polar transport in LR formation in response to localized NO3− availability are not known.Methods
Time-course studies in a split-root experimental system were used to investigate LR development patterns, auxin distribution, polar auxin transport and expression of auxin transporter genes in LR zones in response to localized PNN in ‘Nanguang’ and ‘Elio’ rice cultivars, which show high and low responsiveness to NO3−, respectively. Patterns of auxin distribution and the effects of polar auxin transport inhibitors were also examined in DR5::GUS transgenic plants.Key Results
Initiation of LRs was enhanced by PNN after 7 d cultivation in ‘Nanguang’ but not in ‘Elio’. Auxin concentration in the roots of ‘Nanguang’ increased by approx. 24 % after 5 d cultivation with PNN compared with NH4+ as the sole nitrogen source, but no difference was observed in ‘Elio’. More auxin flux into the LR zone in ‘Nanguang’ roots was observed in response to NO3− compared with NH4+ treatment. A greater number of auxin influx and efflux transporter genes showed increased expression in the LR zone in response to PNN in ‘Nanguang’ than in ‘Elio’.Conclusions
The results indicate that higher NO3− responsiveness is associated with greater auxin accumulation in the LR zone and is strongly related to a higher rate of LR initiation in the cultivar ‘Nanguang’. 相似文献7.
Yan Hu Nai Shan Wang Xu Jun Hu Xian Yong Lin Ying Feng Chong Wei Jin 《Plant and Soil》2013,371(1-2):105-115
Background and aims
Nickel (Ni) has become a major heavy metal contaminant. The form of nitrogen nutrition remarkably affects IRT1 expression in roots. IRT1 has an activity of transporting Ni2+ into root cells. Therefore, nitrogen-form may affect Ni accumulation and toxicity in plants. The assumption was investigated in this study.Methods
The Arabidopsis plants were treated in Ni-contained growth solutions with either nitrate (NO3 ?) or ammonium (NH4 +) as the sole N source. After 7-day treatments, Ni concentration, IRT1 expression, Ni-induced toxic symptoms and oxidative stress in plants were analyzed.Results
The NO3 ?-fed plants contained a higher Ni concentration, had a greater IRT1 expression in roots, and developed more severe toxic symptoms in the youngest fully expanded leaves, compared with the NH4 +-fed plants. The Ni-induced growth inhibition was also more significant in NO3 ?-fed plants. Interestingly, Ni exposure resulted in greater hydrogen peroxide (H2O2) and superoxide radical (O2 . ?) accumulations, more severe lipid peroxidation and more cell death in NO3 ?-fed plants, whereas the opposite was true for NH4 +-fed plants. Furthermore, the Ni-enhanced peroxidase (POD) and superoxide dismutase (SOD) activities were greater in NO3 ?-fed plantsConclusion
NO3 ? nutrition promotes Ni uptake, and enhances Ni-induced growth inhibition and oxidative stress in plants compared with NH4 + nutrition. 相似文献8.
9.
Responses of CO2 efflux from an alpine meadow soil on the Qinghai Tibetan Plateau to multi-form and low-level N addition 总被引:1,自引:0,他引:1
Huajun Fang Shulan Cheng Guirui Yu Jiaojiao Zheng Peilei Zhang Minjie Xu Yingnian Li Xueming Yang 《Plant and Soil》2012,351(1-2):177-190
Aims
To assess the effects of atmospheric N deposition on the C budget of an alpine meadow ecosystem on the Qinghai–Tibetan Plateau, it is necessary to explore the responses of soil-atmosphere carbon dioxide (CO2) exchange to N addition.Methods
Based on a multi-form, low-level N addition experiment, soil CO2 effluxes were monitored weekly using the static chamber and gas chromatograph technique. Soil variables and aboveground biomass were measured monthly to examine the key driving factors of soil CO2 efflux.Results
The results showed that low-level N input tended to decrease soil moisture, whereas medium-level N input maintained soil moisture. Three-year N additions slightly increased soil inorganic N pools, especially the soil NH 4 + -N pool. N applications significantly increased aboveground biomass and soil CO2 efflux; moreover, this effect was more significant from NH 4 + -N than from NO 3 ? -N fertilizer. In addition, the soil CO2 efflux was mainly driven by soil temperature, followed by aboveground biomass and NH 4 + -N pool.Conclusions
These results suggest that chronic atmospheric N deposition will stimulate soil CO2 efflux in the alpine meadow on the Qinghai–Tibetan Plateau by increasing available N content and promoting plant growth. 相似文献10.
The effect of nitrogen starvation on the NO3-dependent induction of nitrate reductase (NR) and nitrite reductases (NIR) has been investigated in the halophilic alga Dunaliella salina. When D. salina cells previously grown in a medium with NH 4 + as the only nitrogen source (NH 4 + -cells) were transferred into NO 3 ? medium, NR was induced in the light. In contrast, when cells previously grown in N-free medium were transferred into a medium containing NO 3 ? , NR was induced in light or in darkness. Nitrate-dependent NR induction, in darkness, in D. salina cells previously grown at a photon flux density of 500 umol · m?2 s?1 was observed after 4 h preculture in N-free medium, whilst in cells grown at 100 umol · m?2 s?1 NR induction was observed after 7–8 h. An inhibitor of mRNA synthesis (6-methylpurine) did not inhibit NO 3 ? -induced NR synthesis when the cells, previously grown in NH 4 + medium, were transferred into NO 3 ? medium (at time 0 h) after 4-h-N starvation. However, when 6-methylpurine was added simultaneously with the transfer of the cells from NH 4 + to NO 3 ? medium (at time 0 h), NO 3 ? induced NR synthesis was completely inhibited. The activity of NIR decreased in N-starved cells and the addition of NO 3 ? to those cells greatly stimulated NIR activity in the light. The ability to induce NR in darkness was observed when glutamine synthetase activity reached its maximal level during N starvation. Although cells grown in NO 3 ? medium exhibited high NR activity, only 0.33% of the total NR was found in intact chloroplasts. We suggest that the ability, to induce NR in darkness is dependent on the level of N starvation, and that NR in D. salina is located in the cytosol. Light seems to play an indirect regulatory role on NO 3 ? uptake and NR induction due to the expression of NR and NO 3 ? -transporter mRNAs. 相似文献
11.
Growth of 2-month-old nonnodulatedHippophaë rhamnoides seedlings supplied with combined N was compared with that of nodulated seedlings grown on zero N. Plant growth was significantly better with combined N than with N2 fixation and, although not statistically significant for individual harvests, tended to be highest in the presence of NH 4 + , a mixture of NH 4 + and NO 3 ? producing the highest yields. Growth was severely reduced when solely dependent on N2 fixation and, unlike the combined-N plants, shoot to root ratios had only slightly increased after an initial decrease. An apparently insufficient nodule mass (nodule weight ratio <5 per cent) during the greater part of the experimental period is suggested as the main cause of the growth reduction in N2-fixing plants. Thein vivo nitrate reductase activity (NRA) of NO 3 ? dependent plants was almost entirely located in the roots. However, when grown with a combination of NO 3 ? and NH 4 + , root NRA was decreased by approximately 85 per cent.H. rhamnoides demonstrated in the mixed supply a strong preference for uptake of N as NH 4 + , NO 3 ? contributing only for approximately 20 per cent to the total N assimilation. Specific rates of N acquisition and ion uptake were generally highest in NO 3 ? +NH 4 + plants. The generation of organic anions per unit total plant dry weight was approximately 40 per cent less in the NH 4 + plants than in the NO 3 ? plants. Measured extrusions of H+ or OH? (HCO 3 ? ) were generally in good agreement with calculated values on the basis of plant composition, and the acidity generated with N2 fixation amounted to 0.45–0.55 meq H+. (mmol Norg)?1. Without acidity control and in the presence of NH 4 + , specific rates of ion uptake and carboxylate generation were strongly depressed and growth was reduced by 30–35 per cent. Growth of nonnodulatedH. rhamnoides plants ceased at the lower pH limit of 3.1–3.2 and deterioration set in; in the case of N2-fixing plants the nutrient solution pH stabilized at a value of 3.8–3.9 without any apparent adverse effects upon plant performance. The chemical composition of experimental and field-growing plants is being compared and some comments are made on the nitrogen supply characteristics of their natural sites. 相似文献
12.
Peter E. Mortimer Marcellous R. Le Roux Maria A. Pérez-Fernández Vagner A. Benedito Aleysia Kleinert Jianchu Xu Alexander J. Valentine 《Plant and Soil》2013,366(1-2):229-241
Background and aims
Acacia cyclops is an invasive species within Mediterranean ecosystems, characteristically low in soil nutrients. Thus associations with nitrogen-fixing bacteria (NFB) and arbuscular mycorrhiza (AM) may provide an advantage to these legumes. This study investigated the role of AM and NFB in the growth and nutritional physiology of A. cyclops.Methods
Seedlings were inoculated with?naturally occurring?NFB, Glomus mosseae or both, and grown under glasshouse conditions for 5 months. Plants were cultivated in sand and supplied with a 20 % strength nutrient solution.?Xylem sap nutrients, photosynthetic rates, biomass and chemical compositions, were recorded.Results
The dual inoculation decreased the colonization of both symbionts, compared to a single symbiosis with either symbiont. Despite low colonization levels, the dual symbiosis increased host biomass and relative growth rates. This was associated with increased photosynthetic rates and enhanced nutrition. Additionally, dual symbiotic plants had enhanced N and P acquisition and utilization rates. Xylem sap analysis showed higher levels of NH 4 + being exported from the roots to the shoots in the dual symbiotic plants compared with other treatments.Conclusions
These findings suggest the dual symbiosis is an important factor in the growth and development of A. cyclops under nutrient limiting conditions. 相似文献13.
Labeled nitrogen (15?N) was applied to a soil-based substrate in order to study the uptake of N by Glomus intraradices extraradical mycelium (ERM) from different mineral N (NO 3 ? vs. NH 4 + ) sources and the subsequent transfer to cowpea plants. Fungal compartments (FCs) were placed within the plant growth substrate to simulate soil patches containing root-inaccessible, but mycorrhiza-accessible, N. The fungus was able to take up both N-forms, NO 3 ? and NH 4 + . However, the amount of N transferred from the FC to the plant was higher when NO 3 ? was applied to the FC. In contrast, analysis of ERM harvested from the FC showed a higher 15?N enrichment when the FC was supplied with 15NH 4 + compared with 15NO 3 ? . The 15?N shoot/root ratio of plants supplied with 15NO 3 ? was much higher than that of plants supplied with 15NH 4 + , indicative of a faster transfer of 15NO 3 ? from the root to the shoot and a higher accumulation of 15NH 4 + in the root and/or intraradical mycelium. It is concluded that hyphae of the arbuscular mycorrhizal fungus may absorb NH 4 + preferentially over NO 3 ? but that export of N from the hyphae to the root and shoot may be greater following NO 3 ? uptake. The need for NH 4 + to be assimilated into organically bound N prior to transport into the plant is discussed. 相似文献
14.
Jailson L. Cruz Alfredo A. C. Alves Daniel R. LeCain David D. Ellis Jack A. Morgan 《Plant and Soil》2014,374(1-2):33-43
Aims
This study evaluated how different nitrogen forms affect growth and photosynthetic responses of cassava to CO2 concentration.Methods
Cassava was grown in 14-L pots in a greenhouse at 390 or 750 ppm of CO2. Three nitrogen treatments were applied: (a) 12?mM NO3 ?, (b) 6?mM NO3 ??+?6?mM NH4 +, and (c) 12?mM NH4 +.Results
Thirty-six days after treatments began, plants grown under elevated CO2 and fertilized only with NO3 ? (750_NO3 ?) had photosynthetic rates similar to plants grown under 390_NO3 ?, indicating significant photosynthetic acclimation to CO2. In contrast, photosynthetic rates at elevated CO2 increased as NH4 + increased in the nutrient solution, such that photosynthetic acclimation was reduced for plants fertilized with only NH4 +. However, this positive effect of NH4 + on photosynthesis was not observed in more advanced growth stages, and the toxic effects of NH4 + severely reduced total dry mass for these plants measured at the end of the experiment.Conclusions
Our results indicate that cassava will respond with increased biomass accumulation in response to raising atmospheric CO2 levels, and that N form can have an important impact on the photosynthetic response. However, the positive effect of NH4 + fertilization on cassava photosynthetic CO2 response eventually led to a toxicity problem that reduced biomass production. The challenge is to determine how to manage NH4 + fertilization so that the photosynthetic benefit observed in the initial phase may persist throughout the crop cycle. 相似文献15.
Biofortification of rice grain with zinc through zinc fertilization in different countries 总被引:5,自引:0,他引:5
N. Phattarakul B. Rerkasem L. J. Li L. H. Wu C. Q. Zou H. Ram V. S. Sohu B. S. Kang H. Surek M. Kalayci A. Yazici F. S. Zhang I. Cakmak 《Plant and Soil》2012,358(1-2):131-141
Aims and background
The ability to suppress soil nitrification through the release of nitrification inhibitors from plant roots is termed ‘biological nitrification inhibition’ (BNI). Earlier, we reported that sorghum roots release higher BNI-activity when grown with NH 4 + , but not with NO 3 - as N source. Also for BNI release, rhizosphere pH of <5.0 is needed; beyond this, a negative effect on BNI release was observed with nearly 80% loss of BNI activity at pH >7.0. This study is aimed at understanding the inter-functional relationships associated with NH 4 + uptake, rhizosphere-pH and plasma membrane H+-ATPase (PM H+-ATPase) activity in regulating the release of BNIs (biological nitrification inhibitors) from sorghum roots.Methods
Sorghum was grown hydroponically and root exudates were collected from intact plants using a pH-stat system to separate the secondary acidification effects by NH 4 + uptake on BNIs release. A recombinant luminescent Nitrosomonas europaea bioassay was used to determine BNI-activity. Root plasma membrane was isolated using a two-phase partitioning system. Hydrolytic H+-ATPase activity was determined. Split-root system setup was deployed to understand the localized responses to NH 4 + , H+-ATPase-stimulator (fusicoccin) or H+-ATPase-inhibitor (vanadates) on BNI release by sorghum.Results
Presence of NH 4 + in the rhizosphere stimulated the expression of H+-ATPase activity and enhanced the release of BNIs from sorghum roots. Fusicoccin, which stimulates H+-ATPase activity, also stimulated BNIs release in the absence of NH 4 + ; vanadate, which suppresses H+-ATPase activity, also suppressed the release of BNIs. NH 4 + levels (in rhizosphere) positively influenced BNIs release and root H+-ATPase activity in the concentration range of 0-1.0 mM, indicating a close relationship between BNI release and root H+-ATPase activity with a possible involvement of carrier-mediated transport for the release of BNIs in sorghum.Conclusion
Our results suggest that NH 4 + uptake, PM H+-ATPase activity, and rhizosphere acidification are functionally inter-connected with BNI release in sorghum. Such knowledge is critical to gain insights into why BNI function is more effective in light-textured, mildly acidic soils compared to other soil types. 相似文献16.
Xiaodong Ding Li Fu Chenjia Liu Fanjun Chen Ellis Hoffland Jianbo Shen Fusuo Zhang Gu Feng 《Plant and Soil》2011,349(1-2):13-24
To test the hypothesis that rhizosphere acidification would enhance the hydrolyzation of organic phosphates by increasing phosphatase activity. A Petri dish experiment with sterile agar and a pot experiment with a low P soil were used. In the Petri dish experiment, roots of each plant were cultured in two compartments, each of which contained agar with one of three nitrogen combinations: NH 4 + /N0 (N0 = nitrogen free), NH 4 + /NO 3 - , and NO 3 - /N0. Phytin was supplied as the sole phosphorus (P) source to all compartments. In the pot experiment, the soil in each pot was treated with N0, KNO3, or (NH4)2SO4) together with 0 or 75 mg kg?1 phytin-P. Dry weight, P concentration, and P content of roots were highest in the NH 4 + compartments in the Petri dish experiment. In the pot experiment, dry weight, P concentration, and P content of both shoots and roots were higher with NH 4 + than with NO 3 - . NH 4 + treatments reduced rhizosphere pH, promoted the hydrolization of phytin, enhanced acid phosphatase activity in the rhizosphere, and increased phytin-P utilization relative to N0 and NO 3 - treatments. Phosphatase activity was negatively correlated with rhizosphere pH but was positively correlated with plant P content in both experiments. Rhizosphere acidification optimized the activity of acid phosphatase excreted by maize roots and promoted phytin mineralization. NH 4 + -induced acidification in the maize rhizosphere improved the growth of maize roots by improving P uptake from phytin; the improved growth, in turn, increased NH 4 + uptake and acidification. 相似文献
17.
Aim
Our objectives were to compare effects of root charge properties on Al adsorption by the roots of rice that differed in Al-tolerance, and to examine effects of different nitrogen forms on charge properties of rice roots and Al adsorption.Methods
Streaming potential and chemical methods were used to measure root zeta potential and investigate Al chemical forms adsorbed on the roots of rice obtained from solution culture experiments.Results
Rice roots of the Al-sensitive variety Yangdao-6 carried greater negative charge than the Al-tolerant variety Wuyunjing-7, which meant the roots of Yangdao-6 adsorbed more exchangeable and complexed Al. When both rice varieties were grown in NH4 +-containing nutrient solutions, there were less functional groups and lower negative surface charge on their roots, which reduced Al adsorption compared to the rice grown in NO3 ? containing nutrient solutions. The decline in nutrient solution pH due to NH4 + uptake by rice roots was responsible for the reduced numbers of functional groups and the lower negative surface charge on the roots compared to the rice grown in NO3 ? containing solutions.Conclusions
Integrated root surface charge, as expressed by zeta potential, played an important role in Al adsorption by the roots of rice with different Al-tolerance.18.
Chunxia Zhang Sen Meng Yiming Li Li Su Zhong Zhao 《Trees - Structure and Function》2016,30(6):2011-2018
Key message
The total uptake of 15 NO 3 -N was twofold higher than that of 15 NH 4 -N when supplied with ammonium and/or nitrate in different seasons; the seedlings fertilized with NO 3 -N had good growth with high photosynthetic rate and total biomass.Abstract
Appropriate fertilization is crucial for maximum plant growth and improving nitrogen use efficiency. Poplar is an important fast-growing tree species for biomass production, however, little is known about fertilizer management of poplar plantations growing on barren soil in different seasons. To understand nitrogen uptake and allocation of Populus simonii supplied with different forms of nitrogen in different seasons, we determined nitrogen uptake and allocation of P. simonii potted seedlings after a 4-day supply of 15NH4-N, 15NO3-N, 15NH4NO3, and NH 4 15 NO3 in May, July, and September. The total 15N uptake was twofold higher when supplied with sole 15NO3-N compared to sole 15NH4-N in all the investigated seasons. In the presence of ammonium nitrate (15NH4NO3 and NH 4 15 NO3), the total 15N uptake was two times higher when supplied with NH 4 15 NO3 compared to 15NH4NO3. Per unit biomass, the 15N-uptake ability of fine roots was higher in May and July compared to that in September. 15N was present mainly in leaves in May and July, and was mainly stored in roots and stems in autumn. The effect of nitrogen on the growth of P. simonii seedlings was studied by fertilizing with NH4-N, NO3-N, and NH4NO3 for 8 weeks. The seedlings fertilized with NO3-N had good growth with high photosynthetic rate and total biomass indicating that NO3-N is crucial for P. simonii growth. These data contribute to understand the nitrogen uptake in different seasons in trees supplied with different forms of nitrogen. This provides important theoretical bases for fertilizer management of poplar plantations.19.
Fabiano Daniel De Bona Fabiana Schmidt Francisco Antonio Monteiro 《Plant and Soil》2013,373(1-2):201-216
Background and aims
Plant responses to S supply are highly dependent on N nutrition. We investigated the effect of S status on metabolic, nutritional, and production variables in Brachiaria brizantha treated with different N forms. Additionally, 15N and 34S root influx were determined in plants under short- and long-term S deprivation.Methods
Plants were submitted to soil fertilization treatments consisted of combinations of N forms [without N, ammonium (NH4 +), nitrate (NO3 ?) or NH4 ++NO3 ?] at S rates (0, 15, 30, or 45 mg dm?3). N and S influx capacity was determined in hydroponically-grown plants.Results
Shoot production due to S supply increased 53, 145 and 196 % with NH4 +, NH4 ++NO3 ? and NO3 ? treatments, respectively. No or low S impaired protein synthesis and led to high accumulation of N-NO3 ? and asparagine in NO3 ?-fed plants, both alone and with NH4 +. Proline accumulation was observed in NH4 +-fed plants. Short- and long-term S deprivation did not promote considerable changes in 15N influx. 34S absorption decreased depending on the N form provided: NH4 ++NO3 ? > only NH4 + > only NO3 ? > low N.Conclusions
Including both NH4 + and NO3 ? forms in fertilizer increases N and S intake potential and thereby enhances plant growth, nutritional value and production. 相似文献20.