太空生存太空生存太空生存 (28).pdf

《太空生存太空生存太空生存 (28).pdf》由会员分享，可在线阅读，更多相关《太空生存太空生存太空生存 (28).pdf（9页珍藏版）》请在得力文库 - 分享文档赚钱的网站上搜索。

1、Influence of nitrogen source and concentrations on wheat growth andproduction inside“Lunar Palace-1”Chen Donga,b,d,e,1,Zhengpei Chua,b,c,1,Minjuan Wange,1,Youcai Qina,b,c,Zhihao Yia,b,c,Hong Liua,b,c,*,Yuming Fua,b,c,*aSchool of Biological Science and Medical Engineering,Beihang University,Beijing 1

2、00191,ChinabInstitute of Environmental Biology and Life Support Technology,Beihang University,Beijing 100191,ChinacInternational Joint Research Center of Aerospace Biotechnology&Medical Engineering,Beihang University,Beijing 100191,ChinadHigher Education Evaluation Center of the Ministry of Educatio

3、n,Beijing 100081,ChinaeCollege of Information and Electrical Engineering,China Agricultural University,100083,Beijing,ChinaA R T I C L E I N F OKeywords:NO3-NH4Spring wheatNutrient solutionBiomass yieldA B S T R A C TMinimizing nitrogen(N)consumption and maximizing crop productivity are major challe

4、nges to growing plantsin Bioregenerative Life Support System(BLSS)for future long-term space mission.Plants cultivated in thecontrolled environments are sensitive to the low recyclable N(such as from the urine).The purpose of this study isto investigate the effects of nitrogen fertilizer(NH4-N and N

5、O3?-N)disturbance on growth,photosynthetic effi-ciency,antioxidant defence systems and biomass yield and quality of wheat(Triticum aestivum L.)cultivars duringontogenesis.Experiments were divided into 4 controlled groups,:NO3?-N:NH4-N 7:1mmol L?1;:NO3?-N:NH4-N 14:0.5 mmol L?1;:NO3?-N:NH4-N 7:0.5 mmo

6、l L?1and CK:NO3?-N:NH4-N 14:1 mmol L?1,andother salt concentrations were the same.The results showed that heading and flowering stages in spring wheat aresensitive to low N concentration,especially NO3?-N in group and.NO3?is better to root growth than to shootgrowth.The plants were spindling and the

7、 output was lower 21.3%when spring wheat was in low N concen-tration solution.Meanwhile,photosynthetic rate of low N concentrations is worse than that of CK.The solublesugar content of the edible part of wheat plants is influenced with NO3?:NH4ratio.In addition,when N con-centration was lowest in gr

8、oup,the lignin content decreased to 2.58%,which was more beneficial to recyclesubstances in the processes of the environment regeneration.1.IntroductionHumanitys plans to further explore space strongly suggest thedevelopment of bioregenerative life support systems(BLSS)fully incor-porated into space

9、 stations,transit vehicles and eventually in habitats onthe Moon and Mars 1,2.These concepts aim to decrease the(re-)supplymass by(re-)generating essential resources for humans through biolog-ical processes.Within a BLSS,the cultivation of higher plants takes acrucial role as they can contribute to

10、all major functional aspects(e.g.food production,carbon dioxide reduction,oxygen production,waterrecycling and waste management)3.As a primary input source,nutrient solution is one of the most important environmental factors forplant growth.In particular,wheat(Triticum aestivum L.),which is a corecr

11、op in BLSS 4,is often restricted in growth by nitrogen fertilizerdisturbance from urine treatment module 5.Thus,enhancing the cropyield/quality and nitrogen fertilizer recycled are matters of interest forresearchers in both space and urban agriculture settings 6.Mineral metabolism plays a significan

12、t role in photosynthesis,respi-ration and carbohydrate accumulation of wheat plants.Ammonium N(NH4-N)and nitrate N(NO3?-N)are the main inorganic N absorbed andutilized by wheat roots.Root uptake of NH4-N and NO3?is an activeprocess and it can be blocked by metabolic inhibitor.As assimilation ofNH4re

13、quires less energy than that of NO3?many plants prefer NH4astheir source of N 7.Some studies have shown that particularly plantsgrowing on acid or waterlogged soils,where NH4prevails,prefer NH4overNO3?andhavehigh uptakerates andvigorousgrowthwhensuppliedwith NH48.However,when NH4is supplied as the e

14、xclusive N-sourceat high concentrations,NH4is toxic and impairs plant growth 9.*Corresponding authors.School of Biological Science and Medical Engineering,Beihang University,Beijing 100191,China.E-mail addresses:wenjian_(C.Dong),(Z.Chu),(M.Wang),(Y.Qin),(Z.Yi),LH(H.Liu),(Y.Fu).1These authors contrib

15、uted equally to this work.Contents lists available at ScienceDirectActa Astronauticajournal homepage: 24 July 2016;Received in revised form 17 December 2017;Accepted 29 December 2017Available online 3 January 20180094-5765/2018 IAA.Published by Elsevier Ltd.All rights reserved.Acta Astronautica 144(

16、2018)371379Ion concentration and transpiration rate have an effect on ion ex-change properties of roots and ionic interactions within the root apo-plasm.Plants absorb nitrogen as a mineral nutrient mainly from soil,andit can be become in the form of ammonium(NH4)and nitrate(NO3?),which is fundamenta

17、l for the photosynthesis and respiration process.Considerable variation exists in the reported effects of NO3?and NH4nutrition on photosynthetic activity.Both NO3?and NH4nutrition havebeen severally reported to produce higher photosynthetic rates than usedalone 10 or to have no influence on photosyn

18、thetic rates 11.Previousresearches mainly focused on the impacts of different inorganic N con-centrationsonthegrowthanddevelopment of wheatplantsinthenaturalecosystem 12,13.However,little is known about the effects of nitrogenfertilizerdisturbanceonthecrops in the artificial ecosystem.What effectswi

19、ll have different N forms and concentrations,especially those ofcombined NO3?and NH4nutrition,on the growth and development ofspring wheat plants?And which stage will be more important not onlysuitable to the plants cultivation,but also beneficial to yield and quality?For these reasons,it is necessa

20、ry to investigate the nitrogen availabilityeffects on the space agricultural production and evaluate different con-sequences caused by the nitrogen disturbance in the artificial condition.Hydroponic method of growing plants is the biotechnological processof obtaining the high-quality crops because i

21、t allows rational control ofthe mineralcompositionthroughthe regulation of their mineralnutritionduring ontogenesis 14.Therefore,we cultivated wheat plants in hy-droponics and investigated the influences of different N forms and con-centrationsonthewheatgrowth,photosyntheticcharacteristics,antioxida

22、nt capacity,biomass yield and quality during their life cycle.2.Materials and methods2.1.Plant material and cultivation conditionsSpring wheat plants(Triticum aestivum L)were planted in plant cabinof“Lunar Palace-1”4.The porous tube nutrient delivery system withwater supply on demand was used 15,16.

23、The wheat planting densitywas 800 seeds per m2.The growth period of the wheat was 70 days.Forall treatments lighting was continuous(24/0h light/dark).Photosyn-thetic photon flux density(PPFD)levels were measureddaily at the top ofplant canopy with a quantum sensor(Li-250A,Li-Cor,USA).PPFD wasabout 5

24、00molm?2s?1for all the treatments.The relative humidity wasmaintained at 55?4.6%,with a temperature of 21?1.3?C duringdaytime and night.The modified Hoagland nutrient solution was thebasic culture medium.During the whole life cycle of wheat plants,different N supplies were designed and listed in Tab

25、le 1.2.2.Morphological and physiological analyses2.2.1.MorphologyThe height and root length of wheat plants were measured every twodays by straight scale and vernier caliper.Ten samples of those wheatplants were selected randomly when the measurement was in process17,Wheat plants state was analyzed

26、as precisely as possible 18.2.2.2.Determination of relative water content(RWC)At vegetative growth stage,heading stage,flowering stage andmaturity stage,the RWCs of leaves were separately measured 19.Samples were excised from the leaves of ten wheat plants at the secondleaf at the terminal bud for e

27、ach treatment.The fresh leaves wereweighted about 0.5g(m1)and soaked in double distilled water at roomtemperature for 4h.Then the leaves were weighted as m2and put in thedrying oven(65?C)for 48h.The driedleaves were expressedas m3.RWCwas calculated as according to the following equation:RWC m1?m3m2?

28、m3?100%2.2.3.Determination of membrane stability index(MSI)Samples were excised from the leaves of ten wheat plants at thesecond leaf at the terminal bud for each treatment.To measure the MSI ofleaves at different stages 20,the sample was divided into two equiva-lent parts(about 0.1g for each)and so

29、aked in 10mL double distilledwater.Then one part was heated at 40?C for 30min.ConductivityC1wasdetermined by conductivity meter(HI8733,Hanna instruments,Italy).The other part was heated at 100?C for 10min,and conductivity C2wasdetermined.MSI was calculated as the following:MSI?1?C1C2?100%2.3.Stomata

30、 observationSamples were excised from the leaves of ten wheat plants at a similarposition for each treatment at vegetative growth stage.To observe thestomata,samples were taken from fully expanded leaves in each plant.The slides made by the leaf epidermal fingerprint of cotton with thetransparent na

31、il polish method were observed using an optical micro-scope 21.Slides were analyzed with an Olympus DP71 microscope(Olympus Inc.,Japan).The length,width and frequency of stomata weremeasured with Motic Images Plus 2.0.10 images per leaf,one leaf perplant and 10 plants per treatment were analyzed.2.4

32、.Photosynthetic characteristics analyses2.4.1.Chlorophyll contentsSamples were excised from the leaves of ten wheat plants at thesecond leaf at the terminal bud for each treatment.The content ofchlorophyll a and chlorophyll b was measured with an ultraviolet spec-trophotometer(SP-75,Shanghai spectru

33、m instruments co.,LTD,China)at vegetative growth stage,heading stage,flowering stage and maturitystage,respectively 22.Leaf samples were frozen in liquid nitrogen andstored at?80?C until measured.2.4.2.Photosynthetic efficiencyFrom vegetative growth stage to maturity stage,portable photosyn-thesis i

34、nstrument(Li-6400XT,Li-Cor,USA)was used for the determina-tion of photosynthetic characteristics.Leaf gas-exchange parametersincluded photosynthetic rate(A),stomatal conductance(gs)and inter-cellular CO2concentration(Ci)using the second leaf at the wheat ter-minal bud.Water use efficiencies(A/gs)wer

35、e calculated by dividing A bygs and the instantaneous carboxylation efficiencies(A/Ci)were alsocalculated 23.2.5.Antioxidant capacity analyses2.5.1.Peroxidase(POD)activityPOD activity during vegetative growth stage,heading stage,flower-ing stage and maturity stage was analyzed spectrophotometrically

36、 at470nm using guaiacol as a phenolic substrate with hydrogen peroxide24.Samples were excised from the leaves of ten wheat plants at thesecond leaf at the terminal bud for each treatment.The reaction mixturecontained 0.15mL of 4%(v/v)guaiacol,0.15mL of 1%(v/v)H2O2,2.66mL of 0.1M phosphate buffer(pH7

37、.0)and 40L of enzymeTable 1Major nutrient solution parameters of different treatments.ItemsNO3?KNO3(mmol L?1)NH4NH4H2PO4(mmol L?1)NO3?:NH4Total N(mmol L?1)717:18140.528:114.570.514:17.5CK14114:115C.Dong et al.Acta Astronautica 144(2018)371379372extract.Blank sample contained the same mixture without

38、 enzymeextract.2.5.2.Catalase(CAT)activityCAT activity was determined according to the method described byKumar and Knowles 25.Samples were excised from the leaves of tenwheat plants at the second leaf at the terminal bud for each treatment.CAT reaction solution consisted of 100mM Na2HPO4-NaH2PO4buf

39、fersolution(pH7.0)and 0.1MH2O2.The optical density was determinedevery 1minat 240nm.2.5.3.Malonaldehyde(MDA)contentSamples were excised from the leaves of ten wheat plants at thesecond leaf at the terminal bud for each treatment.Determination ofMDA depended on the method of Stewart and Bewley 26.Bri

40、efly,atvegetative growth stage,heading stage,flowering stage and maturitystage,10mL 0.1%trichloroacetic acid(TCA)pestled homogenate wasused to centrifuge wheat leaves(0.5g)at 4000rpm for 10min.2mLsupernatant was added to 4mL 5%thiobarbituric acid(TBA)which wasmade up by 20%TCA.The mixture was heated

41、 at 95?C for 30min andthen cooled in ice-bath rapidly.The supernatant was obtained bycentrifuging at 3000rpm for 10min.The absorbency of the supernatantwas recorded at 532nm.The value for non-specific absorption at 600nmwas subtracted.The MDA content was calculated using its extinctioncoefficient of

42、 155mM?1cm?1.2.6.Biomass yield analyses2.6.1.Edible biomassThe thousand-kernel weight(TKW)of wheat seeds was weighedrespectively under 4 different treatments.At maturity,above-groundbiomass(AGB)and grain yield per plant(GY)were also recorded.Har-vest index(HI GY/AGB)was then calculated.2.6.2.Inedibl

43、e biomassFor determination of inediblebiomass components,plant tissues weredried in an oven for 48hat 70?C before weighing.The content of Neutraldetergent solution(NDS),neutral detergent fiber(NDF),acid detergentfiber(ADF),acid detergent lignin(ADL)and acid-insoluble ash(Ash)inwheat straw was determ

44、ined according to Van Soest et al.method 27using FIWEsix rawfiber extractor(VelpScientifica,Italy).Thecontents ofhemicellulose,cellulose,lignin,ash and NDS were analyzed.2.7.Data statisticsThe experiment was setup in a completely randomized design.Allexperiments were performed in triplicate.The aver

45、age value of total 6measurements?standard deviation was regarded as the final result.Allstatistical analyses were performed using SPSS 18.0.Comparison amongmeans performed at significance level P.05.3.Results3.1.The response of wheat growth to different treatmentsIt was found that the morphology of

46、the wheat plants was notewor-thily influenced under different N forms and concentrations of differentgrowth periods(Fig.1A).Particularly at the heading stage of seedling,straw height of wheat under low concentrations was 510cm greaterthan CK.However,after that,the growth momentum of wheat plantsunde

47、r low concentrations had been restricted,which might probably dueto the adaptation to low concentration.The most obvious influence ofdifferent N forms and concentrations on RWC of wheat leaves happenedwhen wheat heading(Fig.1B).With the condition of,and CK,theRWC was the higher at heading stage wher

48、ein the transpirationstrengthened and the plant growth was vigorous.However,the moreRWC existed in leaves,the less reflectivity of leaves was,which wouldaffect the optical property.At flowering stage,RWC of group plantswas at the lowest level of 79%and it is 7%lower than the value for CK.The RWC occ

49、urred lower,which was more beneficial for accumulatingenergy to perform self-pollination.Therefore,photosynthesis,transpira-tion and water-use efficiency are strongly linked to the water regime ofplants.MSI gradually reduced during the development and growth ofwheat plants(Fig.1C).The largest differ

50、ence happened at vegetativegrowth stage and flowering stage.The highest CK value reached 73.2%and the lowest group value was 70.1%at vegetative growth stage.Thegap was larger when flowering,the MSI of group was 4.9%lower thanFig.1.Response of straw height of wheat plants(A),relative water content(B)