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Overexpression of Proline Transporter Gene Isolated from Halophyte Confers Salt Tolerance in Arabidopsis

Proline is one of the most important and widespread osmolyte which functions in adaptation to adverse environmental stresses in many organisms. Also it is an important carbon and nitrogen resource in higher plants. Metabolism of proline has been elucidated in many plant species. However, transport of proline was poorly characterized although transport system plays an important role in proline distribution in different tissues. We isolated one full_length cDNA encoding proline transporter from the typical halophyte: Atriplex hortensis L. through cDNA library screening and 5′_RACE. The deduced amino acid sequence had eleven transmembrane domains, showed 60%-69% similarities to other ProTs and the gene was designated AhProT1. In the phylogenetic tree, higher plants' ProTs, e.g. AhProT1, showed more similar to ProP from microorganisms than ProT from mammalians. AhProT1 gene was transformed into Arabidopsis thaliana under 35S promoter. In MS medium containing [U_ 14 C] proline, AhProT1 + plants were able to accumulate much more radiolabeled proline in the roots than control plants. In MS medium containing different concentrations of NaCl, AhProT1 + plants could endure 200 mmol/L NaCl and keep development and biomass increase with proline supply, whereas control plants died back at 150 mmol/L NaCl.

Effects of Ag-carrying Zirconium Phosphate on the Kinetics of Growth of the Roots of Culture Artemisia annua

在植物组织和细胞培养过程中 ,尤其是在生物反应器培养中的染菌问题 ,一直是制约植物细胞培养工业化的难题。通过比较各种防腐剂的抑菌效果 ,确定银型磷酸锆盐抗菌粉为青蒿根培养的最佳防腐剂。银型磷酸锆盐抗菌粉在浓度为 30mg/L时 ,既能降低培养液的染菌几率 ,又不明显抑制青蒿根的生长及青蒿素的生物合成。在添加 30mg/L抗菌粉的培养液中进行的青蒿根生长、pH值变化以及残糖、铵离子和硝酸根离子消耗的动力学研究表明 ,在 4 0d内青蒿根在培养液中生长良好 ,营养成分的消耗和对照呈相似的趋势。

Responses of Halophyte Salicornia bigelovii to Different Forms of Nitrogen Source

Salt-affected soils are agricultural and environmental problems on a global scale. Plants suffer from saline stresses in these soils and show nitrogen （N） deficiency symptoms. However, halophytes grow soundly under saline conditions. In order to clarify the N nutrition of the halophyte Salicornia bigelovii, it was grown at several N levels （1, 2, 3, and 4 mmol L-1）, supplied in the form of NO3 or ammonium （NH4＋）, under high NaCl conditions （200 mmol L-l）. NH4^＋- fed plants showed better growth than NO3-fed plants at 1-3 mmol L-1N, and plants in both treatments showed the same growth at 4 mmol L-1 N. Nitrogen contents in NO3-fed plants increased with the N concentrations in solution; competitive inhibition of NO3- absorption by Cl- was observed under lower N conditions. In addition, shoot dry weight was significantly correlated only with shoot N content. Therefore, growth of NO3-fed plants was regulated by N absorption. In contrast, N contents of shoots in NH4＋-fed plants did not change with N concentration. Shoot Na content decreased with increasing N concentration, while K content increased. Dry weight was highly correlated only with K content in NH4＋-fed plants. These observations indicated that growth of NH4＋-fed plants was mainly regulated by K absorption.

COMBINED EFFECTS OF TEMPERATURE, IRRADIANCE AND SALINITY ON GROWTH OF DIATOM SKELETONEMA COSTATUM

factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatom Skeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32℃), irradiance ((0.02, 0.08, 0.3, 1.6)×10 16 quanta/(s·cm 2)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition for S. costatum was temparature of 25℃, salinity of 18-35 and irradiance of 1.6×10 16 quanta/(s·cm 2). The results indicated S. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall. It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities.

EXAMINATION OF SILICATE LIMITATION OF PRIMARY PRODUCTION IN JIAOZHOU BAY, CHINA I. SILICATE BEING A LIMITING FACTOR OF PHYTOPLANKTON PRIMARY PRODUCTION

Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO - 3 N, NO - 2 N, NH + 4 N, SiO 2- 3 Si, PO 3- 4 P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq.(1) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temperature; that the main factor controlling the primary production is Si; that water temperature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecological niches for C , the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D , the coefficient of water temperature’s effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay, the biogeochemical sediment process of the silicon, the phytoplankton predominant species and the phytoplankton structure. The authors considered silicate a limiting factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and uptake by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrinsic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high plant nutrient concentrations but low phytoplankton biomass in some waters is reasonably explained in this paper.

Characteristics of the δ15NNO3 distribution and its drivers in the Changjiang River estuary and adjacent waters

In this study, we conducted investigations in the Changjiang （Yangtze） River estuary and adjacent waters （CREAW） in June and November of 2014. We collected water samples from different depths to analyze the nitrogen isotopic compositions of nitrate, nutrient concentrations （including inorganic N, P, and Si）, and other physical and biological parameters, along with the vertical distribution and seasonal variations of these parameters. The compositions of nitrogen isotope in nitrate were measured with the denitrifier method. Results show that the Changjiang River diluted water （CDW） was the main factor affecting the shallow waters （above 10 m） of the CREAW, and CDW tended to influence the northern areas in June and the southern areas in November. 615Nrqo~ values in CDW ranged from 3.21%o-3.55%o. In contrast, the deep waters （below 30 m） were affected by the subsurface water of the Kuroshio Current, which intruded into the waters near 3 I^N in June. The ~iI^NNo3 values of these waters were 6.03%0-7.6%0, slightly higher than the values of the Kuroshio Current. Nitrate assimilation by phytoplankton in the shallow waters of the study area varied seasonally. Because of the favorable temperature and nutrient conditions in June, abundant phytoplankton growth resulted in harmful algae blooms （HABs）. Therefore, nitrate assimilation was strong in June and weak in November. The ~15NNo3 fractionations caused by assimilation of phytoplankton were 4.57%0 and 4.41%o in the shallow waters in June and November, respectively. These results are consistent with previous laboratory cultures and in situ investigations. Nitrification processes were observed in some deep waters of the study area, and they were more apparent in November than in June. The fractionation values of nitrification ranged from 24%0-25%o, which agrees with results for Nitrosospira tenuis reported by previous studies.

Production of DMS and DMSP in different physiological stages and salinity conditions in two marine algae

Dimethylsulfide(DMS) and dimethylsulfoniopropionate(DMSP) production by Scrippsiella trochoidea and Prorocentrum minimum was investigated to characterize the effects of physiological stage and salinity on DMS and DMSP pools of these two marine phytoplankton species.Axenic laboratory cultures of the two marine algae were tested for DMSP production and its conversion into DMS.The results demonstrated that both algal species could produce DMS,but the average concentration of DMS per cell in S.trochoidea(12.63 fmol/L) was about six times that in P.minimum(2.01 fmol/L).DMS and DMSP concentrations in algal cultures varied significantly at different growth stages,with high release during the late stationary growth phase and the senescent phase.DMS production induced by three salinities(22,28,34) showed that the DMS concentrations per cell in the two algal cultures increased with increasing salinity,which might result from intra-cellular DMSP up-regulation with the change of osmotic stress.Our study specifies the distinctive contributions of different physiological stages of marine phytoplankton on DMSP and DMS production,and clarifies the influence of salinity conditions on the release of DMS and DMSP.As S.trochoidea and P.minimum are harmful algal bloom species with high DMS production,they might play an additional significant role in the sulfur cycle when a red tide occurs.

The δ^15N response and nitrate assimilation of Orychophragmus violaceus and Brassica napus plantlets in vitro during the multiplication stage cultured under different nitrate concentrations

Natural nitrogen isotope composition(δ^(15)N) is an indicator of nitrogen sources and is useful in the investigation of nitrogen cycling in organisms and ecosystems. δ^(15)N is also used to study assimilation of inorganic nitrogen. However, the foliar δ^(15)N of intact plants, which is a consequence of nitrate assimilation occurring in the roots and shoots, is not suited for studying nitrate assimilation in cases where nitrate is the sole nitrogen source. In this study, Orychophragmus violaceus(Ov) and Brassica napus(Bn) plantlets, in which nitrate assimilation occurred in the leaves, were used to study the relationship between foliar δ^(15)N and nitrate assimilation.The plantlets were grown in vitro in culture media with different nitrate concentrations, and no root formation occurred for the plantlets during the multiplication stage.Nitrogen isotope fractionation occurred in both the Ov and the Bn plantlets under all treatments. Furthermore, the foliar nitrogen content of both the Ov and Bn plantlets increased with increasing nitrate concentration. Foliar nitrogen isotope fractionation was negatively correlated with foliar nitrogen content for both the Ov and Bn plantlets. Our results suggest that the foliar nitrogen isotope fractionation value could be employed to evaluate nitrate assimilation ability and leaf nitrate reductase activity.Moreover, high external nitrate concentrations couldcontribute to improved foliar nitrogen content and enhanced nitrate assimilation ability.

Influence of Mycorrhizal Inoculation on the Salt Tolerance of Artichoke Hybrid Seedlings

The role of mycorrhizal symbiosis in the alleviation of salinity stress induced by sodium chloride （NaCI） was investigated. Three artichoke hybrids, Madrigal F1, Opal FI, and Concerto FI （Nunhems company）, were grown in pot in controlled environment with two different mycorrhizal treatments （with or without Glomus viscosum）. Two months after inoculation, the fungus established well on roots of the Madrigal and Opal plants with higher colonization and dependency values, instead the Concerto plants showed lower mycorrhizal dependency and colonization rate. Mycorrhizal symbiosis generally improved plant vegetative growth and sustained plant physiology increasing stomatal conductance and SPAD values. The root systems of two months old artichoke plantlets, both inoculated and non inoculated, were placed in distilled water enriched with different salt concentrations （0, 100, 150, 200, 250 mM NaCI） to study the wilting response. A visual rating system was developed defining various wilting indexes （TO, no wilting; T1, foliar damage on less than 50% of vegetal tissues of basal leaves; T2, initial wilting and foliar damage on more than 50% of vegetal tissues of basal leaves; T3, foliar damage on the apical leaves; and T4, total wilting）. Mycorrhizal plants reached later the wilting indexes than non-mycorrhizal plants. Electrolyte leakage by leaves after salinity imposition was higher in non-mycorrhizal plants and the vegetal tissues were severely damaged especially in the basal leaves. The greater tolerance observed in the mycorrhizal plants could be in agreement with the improvement in growth stimulated by mycorrhizal symbiosis, which leads to the dilution of toxic ions.

Changes of Biogenic Elements in Phragmites australis and Suaeda salsa from Salt Marshes in Yellow River Delta,China

Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow(Huanghe) River Delta, plant samples were collected from two typical salt marshes(Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis(P < 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences(P > 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.

Effects of Salicylic Acid on the Growth and Some Physiological Characters in Salt Stressed Tomato Plants （ Solanum L ycopersicum）

Excessive soil salinity is an important constraint limiting the distribution of plants in natural habitats, and is an increasingly severe agricultural problem in arid and semi-arid regions. Higher salinity levels caused significant reduction in growth parameters like leaf area, leaf length and root and shoot dry weight. Salicylic acid （SA）, a plant phenolic is now considered as a hormone-like endogenous regulator, and its role in the defence mechanisms against biotic stressors has been well documented. In recent years its role has been widely investigated in abiotic stress （salinity, drought, water deficit and so on）. The aim of the present work was to study the effects of salicylic acid on growth and some physiological characters of salt stressed tomato plants. The presence of salicylic acid at low concentration （0.01 mM） in culture medium riched with NaCl 100 mM （6 g·L^-1） improves the tolerance of tomato cv. Golden Sunrise to salinity. This amelioration results in stimulation of growth and development of plants. The applied of SA in saline medium induce： （i） an increase in chlorophyll content; （ii） a better supply of essential elements in plant growth, such as K＋; （iii） a decrease in toxic ions such Na＋ and CI in aerial organs; and （iv） an additional synthesis of organic solutes and osmoprotectors like proline and proteins. All these results suggest that salicylic acid could be successfully used in alleviating depressive effects of salt on the productivity of the cultivated tomato.

Effect of Salinity on Reeds in the Treatment of High Salinity LandfilI-Leachates Using HFs

The growth of reeds was impeded remarkably under a salinity of 15.0±3.4 g CI·L-1 in the first year of this experiment, recovered in the second year and then increased year-by-year afterward. The growth of reeds under a salinity of 9.3±1.9 g CI·Ll was much better than those under 15.0 ± 3.4 g CI·L1. The stress effect was significant for shoot extension but not for the quantity of shoots increase. The dense vegetation bed during the vegetation period （June-October） provided a high rate of evapotranspiration and water loss from HFs （horizontal subsurface flow constructed wetlands）, which made large contributions to reducing pollutant load. The HFs with die-back reeds in the non-vegetation periods （November-March） provided slight evapotranspiration and water loss and made less of a contribution to reducing pollutants removal compared to HFs with the dense vegetation bed in the vegetation periods. However, the HFs with die-back reeds in the non-vegetation periods had higher removal performance than the HF without reeds. This indicated that the rhizosphere of HFs with reeds might play important roles, such as that the microbes around rhizomes might have a higher amount of pollutant-removing microbe activity than those in the HF without reeds during the non-vegetation period.

An Ecological Survey of Limoniastrum guyonianum： A Halophyte Native Tree in Arid Zones of Algeria

In arid and semi-arid regions soil salinity is a constraint for the development of plants and a threat to balance food in these soils some species are threatened with extinction. Two natural constraints drought and salinity have altered the ecosystem stability, but it has always conditions more or less favorable to the existence of a spontaneous flora adapted to the climatic and edaphic stress. The aim of this study is to describe a halophyte native tree and its climatic and edaphic requirements, it is a case of Limoniastrum guyonianum. According to this survey L. guyonianum, grows well under high temperature, insolation and evaporation and low rainfall and humidity. The species tolerate the soil basic pH, salinity, calcareous and do not need the organic matter and chlorure ions There are some morphological adaptations in the L. guyonianium to the several conditions as the length of the root and cylindrical shapes of the leaves and their extraction of salt.

Salt Stress Effects on Germination, Plant Growth and Accumulation of Metabolites in Five Leguminous Plants

The investigation was conducted to determine physiological criteria of early selection for salt tolerant leguminous plants. Plants were subjected to 5 levels of salt stress at the roots （0, 50, 100,150 and 200 mM NaCI）. Results showed that sodium chloride had an underrating effect on growth of stems and seed germination of the species studied. The germination rates of seeds of Glycine max and Phaseolus vulgaris （sensitive glyeophytes） were affected from 3 g/L of NaCl, with critical thresholds at 9 and 12 g/L respectively. In contrast, critical thresholds with Mucunapoggei （facultative halophyte）, Vigna unguiculata （moderately tolerant glycophyte） and P. adenanthus （natural halophyte） was found to be above 21 g/L. The reduction of stems growth rate were not significant in P. adenanthus whereas in M. poggei and V. unguiculata this inhibition was observed just when nutritive solutions were enriched with 200 mM. The lipid contents were reduced in all the species under salt stress, whereas proteins and proline contents in the leaves were substantially increased in tolerant species （M. poggei, P. adenanthus and V. unguiculata）. In contrast, proteins and leaf proline contents were negatively affected by salt concentration to G. max and P. vulgaris. Seed germination, proteins and proline could be used as physiological criteria of early selection for salt tolerant leguminous plants.

Effect of the Chemical Mutagens Sodium Azide on Plant Regeneration of Two Tomato Cultivars under Salinity Stress Condition in vitro

The study was carried out to induce variations and stimulate callus induction, plant regeneration from different explants of two tomato （Lycopersicon esculentum Mill.） cultivars Trescantos and super Regina by using tissue culture technique and Sodium azide as a chemical mutagens at concentrations （0.0, 2.0 and 4.0） mM under salinity stress condition at the levels（3.0, 6.0 and 9.0） dS/m. Different plant growth regulators were tested for their potentials in callus induction. The results revealed that treated seeds with SA （sodium azide） at concentration （2.0） mM increased seed germination percentage, seedling height and root length as compare to control treatment. While （4.0） mM concentration cause a reduction in all parameters mentioned above. Concerning to callus induction both cultivars showed a different response against different tested media with varying concentrations of plant growth regulators and despite their variable response to all tested media a combination of （2.0） mg from Kinetin （KIN） and lndol acetic acid （IAA） was found to be the most effective as compare to other treatments. Moreover, when callus transferred to a stressed media the variation was observed in explants fresh weight, and high reduction with the increment of salt level were recorded. Similarly the regeneration efficiency from stressed callus were observed at the level 3.0 and 6.0 dS/m while 9.0 dS/m the callus failed to regenerate plants for all three explants of both tomato cultivars.

Enhancement of Superoxide Dismutase and Catalase Activities and Salt Tolerance of Euhalophyte Suaeda salsa L. by Mycorrhizal Fungus Glomus mosseae

Arbuscular mycorrhizal （AM）-mediated plant physiological activities could contribute to plant salt tolerance. However, the biochemical mechanism by which AM fungi enhance salt tolerance of halophytie plants is unclear. A pot experiment was conducted to determine whether salt tolerance of the C3 halophyte Suaeda salsa was enhanced by the AM fungus Glomus rnosseae. When 60-day-old S. salsa seedlings were subjected to 400 mmol L-1 NaC1 stress for 35 days, plant height, number of leaves and branches, shoot and root biomass, and root length of G. mosseae-colonized seedlings were significantly greater than those of the nonmycorrizal seedlings. Leaf superoxide dismutase （SOD） activity at all sampling times （weekly for 35 days after salt stress was initiated） and leaf catalase （CAT） activity at 2 and 3 weeks after salt stress was initiated were also significantly enhanced in G. mosseae-colonized S. salsa seedlings, while the content of leaf malondialdehyde （MDA）, a product of membrane lipid peroxidation, was significantly reduced, indicating an alleviation of oxidative damage. The corresponding leaf isoenzymes of SOD （Fe-SOD, Cu/Zn-SOD1, and Cu/Zn-SOD2） and CAT （CAT1 and CAT2） were also significantly increased in the mycorrhizal seedlings after 14 days of 400 mmol L-1 NaC1 stress. Our results suggested that G. rnosseae increased salt tolerance by increasing SOD and CAT activities and forming SOD and CAT isoforms in S. salsa seedlings.

Effect of daily salinity fluctuation on the intraspecific interactions of a euhalophyte(Suaeda salsa)along a salinity gradient

Heterogeneity of soil salinity is a prominent environmental characteristic in the intertidal zone of estuaries,affecting the plant growth and the shift of biotic interactions in the salt marsh.This study aims to examine the interactive effects of a salinity gradient and salinity fluctuations on intraspecific interactions of a euhalophyte.We assessed the impact of daily fluctuating salinity on the outcome of intraspecific interactions by cultivating seeds of Suaeda salsa(Chenopodiaceae)in river sand.The experiment was conducted in a greenhouse with three treatments:daily salinity fluctuations(static and fluctuating salinity),a salinity gradient(200 and 400 mmol L^(−1))and three planting densities(1,2 and 4 plants/pot).First,height and biomass of plants were measured at both the start and end of the experiment.Then,the growth indexes and log response ratio of S.salsa were analyzed.The outcome of intraspecific interactions of S.salsa shifted from competition in low salinity to facilitation in high salinity,and high conspecific density strengthened the competition and facilitation intensities.Daily salinity fluctuation did not significantly affect the plant growth and the outcome of intraspecific interactions,but did have a significant influence on belowground biomass.Our results suggest that the stress-gradient hypothesis may apply to predicting the variation of the intraspecific relationship of a salt-tolerant species along a salinity gradient,and the magnitude of this variation is density dependent.These findings help us understand how individuals and populations of a euhalophyte species respond to the natural variation or human modification of salinity conditions.

The response of soil respiration to different N compounds addition in a saline-alkaline grassland of northern China

The increase in atmospheric nitrogen(N)deposition has profound effects on soil respiration(SR).However,the responses of SR to the addition of different N compounds,particularly in saline-alkaline grasslands remain unclear.A 3-year controlled field experiment was conducted to investigate the responses of SR to different N compounds(NH,NO,(NH),SO,and NH,HCO,)during the growing seasons in a saline-alkaline grassland located in the agro-pastoral ecotone of northern China.Our results demonstrated that SR showed a bimodal pattern and a significant interannual diference that was regulated by air or soil temperature and precipitation.Nitrogen addition had a significant effect on SR,and the effect of N addition on SR varied yearly,which was related to seasonal precipitation.The mean SR across 3 years(2017-2019)was increased by 19.9%,13.0%and 16.6%with the addition of NH,NO,(NH,),SO,and NH,HCO3,respectively.The highest effect of NH,NO3 addition on SR across 3 years was ascribed to the highest aboveground net primary production,belowground net primary production(BNPP)and soil NO,-concentrations.SR(C loss)was significantly increased while plant productivity(C input)did not significantly change under NH,HCO,addition,indicating a decrease in C sequestration.In addition,BNPP was the main direct factor influencing SR in this saline-alkaline grassland,and soil salinization(e.g.soil base cations and pH)indirectly affected SR through soil microorganisms.Notably,NH,NO,addition overestimated the response of SR to N addition,and different N compounds should be considered,especially in saline-alkaline grassland.

Effects of Soluble Silicate and Nanosilica Application on Rice Nutrition in an Oxisol

Silicon （Si） has been supplied to plants via application of calcium silicate to soil; however, high doses of calcium silicate are required because of its low solubility. Nanoparticles can reduce Si doses and be applied to seeding furrows. This study investigated the effects of liquid Si sources, i.e., highly soluble silicate （115.2 g L^-1 Si and 60.5 g L^-1 Na20） and nanosilica （〈 200 nm）, on Si uptake by rice plants, plant lignification, plant C：N：P stoichiometry, plant physiology, and grain yield using an Oxisol under greanhouse condistions. The treatments included the application of nanosilica and soluble silicate to seeding furrows at Si doses of 0, 605, 1210, and 2 420 g ha^-1. Plant uptake and treatment effects were evaluated by measuring C and lignin contents, Si, N, and P accumulation, physiological characteristics, and grain yield of rice. The deposition of silica bodies and amorphous silica in the flag leaves was analyzed using scanning electron microscopy. Application of liquid Si increased Si accumulation in rice by 47.3% in relation to the control （0 g ha^-1 Si）, regardless of the Si sources used. Nanosilica application increased leaf lignin content by 112.7% when compared to that in the control. Silicon moderately affected the net C assimilation （increased by 1.83%） and transpiration rates （increased by 48.3%）; however, Si influenced neither plant growth nor grain yield of rice. These results are explained by the lack of biotic or abiotic stress in rice plants during the experiment. To the best of our knowledge, in Brazilian agriculture, this is the first report on the use of nanosilica as a Si fertilizer and its effect on plant nutrition. This study provides evidence that rice plants absorb and accumulate nanoparticles; however, further studies are required to investigate the use of nanoparticles in other plant species.