氮在水稻中的行為及其品種間的差別（英文）

1、Behavior of N within Rice Plants, Comparingbetween Japonica and Indica VarietiesS. LON1, CHEN Neng-chang1, 2, N. CHISHAKI1, S. INANAGA11. Lab of Plant Nutrition, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan2. Guangdong Institute of Ecology, Environmental and Soil Sciences,

2、 and Guangdong Key Lab of Integrated Control of Agro-environment, Guangzhou 510650, ChinaAbstract: To investigate the behavior of N within rice plants, Japonica (Hinohikari) and Indica (Hadsaduri) types were grown in the culture solution in a green house. The nitrate nitrogen (NO-3-N) or ammonium ni

3、trogen (NH4+-N) labeled with 15N were supplied to both plants for one week at tillering, panicle initiation and heading stages. The rice plant was harvested immediately after application of 15N at panicle initiation and heading stage respectively. By the determination of NO-3-N and NH4+-N in the sol

4、ution culture, the 15N amount absorbed from the root during one week was calculated. All harvested plants were separated into the roots, vegetative parts or ears. After the total nitrogen in each plant part was determined by the Kjeldahl method, the 15N was analyzed by emission method.By comparing b

5、etween Japonica and Indica plants in all growth stages, it is shown that the 15N amount absorbed with both NH4+-N and NO-3-N remained more in the Japonica than in the Indica, while comparing between NH4+-N and NO-3-N treatments, 15N amount absorbed with NH4+-N remained more in the both plants than t

6、hat with NO-3-N. At maturity stage, 15N amount absorbed with both N forms, observed in ears, remained more in Japonica than in Indica. The result suggests that 15N amount remained in rice plants were different between varieties and supplying N form and among N supplying period.Key words: nitrogen; r

7、ice; variety; N loss; growth stageCLC number: S13 Document code: A Article ID: 1672-2175(2004)04-0646-05Nitrogen nutrition of rice plants has long been a hot research topic because rice is the world's most important cereal crops and nitrogen is the costly fertilizers in rice production. Raun and

8、 Johnson1 estimated current nitrogen use efficiency (NUE) of worldwide cereal production to be near 33%, indicating that much of the applied fertilizer nitrogen (N) is not utilized by the plant and is susceptible to loss from the soil-plant system. There are several mechanisms responsible for the N

9、loss from the soil including ammonia volatilization, nitrate leaching, nitrification and denitrification2. Moreover, Nitrogen can be loss through plant leaves because N budget study35 cannot fully be balanced in solution culture. More recently direct measurement of NH3 from leaves69 have indicated t

10、he directly loss of nitrogen from plant leaves. It is concluded that crops in many areas will represent a significant input of ammonia to the atmosphere and that NH3 losses may become large enough to significantly affect crop N budgets9.Most N losses from various crops such as corn4, barley8, 9, oil

11、seed rape9, pea9, and winter wheat9, 10 and occurred between anthesis and 14 days post-anthesis. In our present study NO-3-N and NH4+-N labeled with 15N were used to investigate the behavior of N absorbed at each growing stage of two rice varieties: Japonica and Indica. 1 Methods and materials1.1 De

12、sign of the trialA pot experiment by solution culture was carried out in a green house at Kagoshima University, Japan, by using 2 rice (Oryza Sativa L.) varieties, namely Hinohikari, a semidwarf japonica rice variety, most widely cultivated in southern Japan, and Hadsaduri, a tall indica variety wit

13、h a week stem as well as long anm slender-awned grain. On June 03, 1998, two one-month seedlings were transplanted into a pot (3.5 L) containing N 20 mg·kg-1 as NH4NO3 (Calendar of transplanting, 15N treatment and sampling is shown in Fig.1). The amount of other nutrients were: w(P) 2.2 mg·

14、;kg-1, w(K) 8.3 mg·kg-1, w(Mg) 7.1 mg·kg-1, w(Ca) 6.0 mg·kg-1, w(Fe) 1 mg·kg-1, w(Mn) 0.3 mg·kg-1, w(B) 0.1 mg·kg-1, w(Zn) 0.01 mg·kg-1, w(Cu) 0.01 mg·kg-1, w(Mo) 0.001 mg·kg-1 and w(Si) 50 mg·kg-1. The detailed chemical compositions of nutrients use

15、d in the experiment are shown in Table 1.The solution was renewed once a week and pH was adjusted to 5.5 by adding 1 mol/L NaOH or HCl. At the tillering (which was July 17th), panicle initiation (July 21st) and heading stages (August 21st), plants were transferred to 15N labeled 15NH4N03 (containing

16、 19.25 atom % excess) and NH415NO3 (containing 18.71 atom % excess) solution and fed for one week and then returned to the previous solution. The concentration of other nutrients during 15N feeding was same as previous solution. An amount of 15N nutrient solution before feeding was preserved to dete

17、rmine the exact nitrogen content in the solution. parts of total pots including the solution after feeding were harvested immediately after one week of feeding. Final harvest at maturity occurred on October 2nd. At harvest, plants were separated into roots, vegetative parts and panicles (if present)

18、. All vegetative parts of plants were dried at 20 by using a vacuum drier while roots and panicles were dried at 70 by using a drying oven. After drying, the dry weights of all plant parts were recorded and ground by using a vibrating mill (HEIKO, T-200).Table 1 Chemical compositions of nutrientsEle

19、mentsw/(mg·kg-1)CompoundsN20.0NH4NO3P2.2KH2PO4K8.3KClMg7.1MgSO47H2OCa6.0CaCl2Fe1.0Fe(III)-EDTAMn0.3MnSO46H2OB0.1H3BO3Zn0.01ZnSO47H2OCu0.01CuSO45H2OMo0.001(NH4)4Mo7O244H2OSi0 or 50Na2SiO3The 15N nutrient solution before and after absorbing of rice plant were measured by using a DIONEX Chromatogr

20、aphy instrument to determine the amount of NO3-N and NH4-N absorbed by plant during one week feeding. 1.2 Analysis All plant parts were analyzed to determine the total N and 15N. 1.2.1 Total N A considerable amount of samples from each parts was digested with conc. H2SO4 in a micro Kjeldahl flask, d

21、istillated with w(NaOH) 40% and titrated with 0.025 mol/L H2SO4. Salicylic acid was added to include nitrate-N11. The titrates were preserved to determine 15N. 1.2.2 15N determination The 15N was measured by emission spectrometry. The principle and procedure of 15N determination were as below:1.2.3

22、PrincipleNitrogen gas enclosed in a discharge tube is excited by a height frequency discharge. The spectra of the emitted light are different for three species of molecules (14N14N, 14N15N, and 15N15N). The intensity of the bandheads is proportional to the concentrations of the respective molecular

23、species. In case of equi-librium among the three types of molecules, it is sufficient to determine the concentration ratio of two molecular species.1.2.4 ProcedureAbout 10 ml of the titrate (100200 µg N) was taken into a glass tube. Pyrex capillary tube (15 cm long and 2 mm diameter) containing

24、 50 µl of 0.005 mol/L HCI was inserted into the glass tube. About 2 ml of 0.1 mol/L NaOH was added into the titrate and then the tube was immediately covered by parafilm. The glass tube was kept in drier (37 ) for two days. The capillary tube was then taken out from the glass tube and dried at

25、70 under reduced pressure. The CuO strings (2 to 4 pieces) heated at 560 for one week was inserted into the capillary tube. A constriction was made around 5 cm apart from the sample and three pieces of CaO block heated at 950 for at least 3 hours, were put into the capillary tube. The open end of th

26、e tube was connected to a vacuum line to produce a vacuum below 10-4 torr. After prescribed vacuum had been reached, the capillary tube was cut off by fusing at a point some 10 cm from the end. The tube was then heated at 560 for at least 3 hours to burn the sample with the reagent of N2 gas. After

27、taking out from the furnace, the discharge tubes were cooled at room temperature for several hours so that CO2 and H2O could be absorbed completely within CaO. A portion of the discharge tubes (which were failed to produce emission) were prepared directly from powdered samples.15N atom% excess was c

28、alculated as follows:15N atom% excess = 15N atom% 15N atom% of natural abundance (0.363%)The amount of N derived from fertilizer for each plant part was calculated as follows:Amount of fertilizer N = ( 15N atom% excess of N of each plant part / 15N atom% excess of N applied) × total N content o

29、f plant part.2 Results and Discussion2.1 Plant weightFig. 2 shows the dry weight of the whole plants of Japonica and Indica. Both varieties had almost same plant biomass until tiller stages, while from panicle stage, Indica grew much more rapidly and had much higher biomass especially at the vegetat

30、ive parts. At maturity, however, Japonica had higher biomass at ear though Indica still showed higher total biomass. Islam et al.12 reported that Indica had much higher absorbing ability than that of Japonica, resulting in higher biomass in the former variety. 2.2 Total N in PlantsFig 2 Changes in d

31、ry weight of Japonica (J) and Indica (I) rice plants at tiller-ing (T), panicle initiation (PI), heading (HD) and maturity (MA) stagesFig 3 Changes in N content of Japonica and Indica rice plants at tillering (T), panicle initiation (PI), heading (HD) and matur-ity (MA) stagesSimilar to plant biomas

32、s, from PI stage, Indica absorbed more N per pot than that of Japonica, The difference became more larger at the HD stage, However, total N in Indica was lower in MA stage per pot, its roots still contained higher N but the ears had much lower nitrogen as shown in Fig. 3. The higher N content in hea

33、ding stage in Indica may be explained by the results obtained by Yoneyama13 that Indica variety has stronger ability in absorption of nutrients than Japonica variety. Islam et al.12 also reported that Indica rice absorbed more nitrogen from soil than Japonica variety, because 15N amount in rice plan

34、t supplied with fertilizer was less in Indica than in Japonica variety. However, the lower N content in ears of Indica than Japonica indicated that it had much lower N translocaton efficiency. Ntanos and Koutroubas14 also found there are difference in cultivar dry matter and N translocation efficien

35、cy between Indica and Japonica, and these differences was related to agronomic characteristics of each cultivar. This result that high Indica cultivar had lower N translocation efficiency was in accordance with that by Ntanos and Koutroubas14. Hayakawa et al.15 reported that NADH-GOGAT favor grain f

36、illing. Thus the reason for lower N translocation in Indica may be that most of the indica cultivars contained less NADH-GOGAT in their sink organ than japonica cultivars as reported by Tomoyuki et al.16.It is very interesting to find that Japonica had higher total N content in heading stage while i

37、t contained lower in maturity, implying that it lost from plant bodies into atmosphere more than that of Japonica. Many results show that nitrogen can be lost as NH3 from leaves8, 9, 17, which is controlled by the ammonia compensation points18. Lower N content in Indica than Japonica implied that th

38、ere have different physiological status at the reproductive stages.N concentrations in Japonica and Indica, however, showed different patterns as shown in Fig. 4. At tillering stage, Indica had a higher N concentration in roots while a bit lower in tops than Japonica, when they grew to PI and HD sta

39、ges, Indica showed lower N contents both in roots and especially in tops, and at maturity stage, Indica had a bit higher N concentration in roots but had much lower N both in tops and ears, further implying that Indica may lost more N from plant bodies. 2.3 15N in Indica and JaponicaFig 6 Changes in

40、 15N amount absorbed in NO3-N from roots of Japonica (J) and Indica (I) at tillering (T), pani-cle initiation (PI), heading (HD) and maturing (MA) stagesThe amount of 15N absorbed with 15NH4 nitrogen and with 15NO3 from culture solution in the whole plants of Indica and Japonica are shown in Fig. 5

41、and Fig. 6 respectively. When 15NH4 was applied at tillering stage for one week, Indica had higher 15N content during the absorption, but from panicle stage, it contained lower 15N than Japonica (Fig. 5A). When 15NH4 was applied at panicle initiation stage for one week, Indica contiained lower 15N t

42、han Japonica and much lower at the later stages. When 15NH4 was applied at heading stage for one week, the 15N in both Indica and Japonca was almost same but Fig 5 Changes in 15N amount absorbed in NH4-N from roots of Japonica (J) and Indica (I) at tillering (T),panicle initiation (PI), heading (HD)

43、 and maturing (MA) stagesa lit lower in Indica at maturity stage. Similar pattern was found for the treatments with 15NO3-N, The difference is that there is a sharp decrease in 15N after the absorption especially in the case of treatments at heading stage (Fig. 6C). More than 40% of applied 15NO3-N

44、was lost one week later from its initial application in Japonica, and the figure for Indica was 60% (Fig. 6C).At the reproductive stage, the organic N compounds began to decompose to inorganic N or low molecular weight compounds such amino acids and re-translocate to reproductive organ, one the othe

45、r hand, plant roots keep absorbing NH4+-N or NO3-N ions, resulting high amount of inorganic N in plant bodies. What is more, during the reproductive stage, both the activities of the glutamine synthetase (GS)19, 20 which is responsible for the assimilation of NH4+-N into amino acids and the activiti

46、es of nitrate reductase which is responsible for the conversion of NO3-N to NH4+-N become decreasing, further resulting higher inorganic N in plant bodies21. Much loss of N from 15NO3-N and in Indica indicated that besides NH3, there exist some physiological pathways for N loss from plant bodies.3 C

47、onclusionThough Indica had much higher plant biomass and had more N content at heading stage, but it had much lower N translocation efficiency to ear, indicating that indica may lost more N from plant bodies than Japonica. Comparison between the aborption of 15NO3-N to 15NH4+-N and between Indica an

48、d Japonica further confirmed that Indica lost more N than Japonica. The results that both varities lost more N from nitrate nitrogen than ammonium nitrogen nitrogen implies that besides NH3, there exist some physiological pathways for N loss from plant bodies. References:1 RAUN W R, JOHNSON G V. Imp

49、roving nitrogen use efficiency for cereal productionJ. Agron J, 1999, 91: 357-363.2 KAKUDA K, H ANDO, T KONNO. Contribution of nitrogen absorption by rice plants and nitrogen immobilization enhanced by plant growth to the reduction of nitrogen loss through denitrification in rhizosphere soilJ. Soil

50、Sci Plant Nutr, 2000, 46: 601-610.3 SHARPE R R, HARPER L A. Apparent atmospheric nitrogen loss from hydroponically grown cornJ. Agron J, 1997, 89: 605-609.4 FRANCIS D D, SCHEPERS J S, VIGIL M F. Post-anthesis nitrogen loss from cornJ. Agron J, 1993, 85: 659-663.5 ASHRAF M, SHAMSI S R A, SAJJAD M I,

51、et al. Nitrogen losses from tops of three rice varieties grown in nutrient culture solutionJ. Pakistan J Bot, 1997, 29: 319-322.6 SEKIMOTO H, KUMAZAWA K. Volatilization of Nitrogen Compounds from Rice LeafJ. Japan J Soil Sci Plant Nutr, 1985, 56: 421-426.7 SEKIMOTO H, ARIMA Y, KUMAZAWA K. The Origin

52、 of Volatilized Nitrogen Compounds from Rice LeafJ. Japan J Soil Sci Plant Nutr, 1985, 56: 427-433.8 MATTSSON-MARIE, SCHJOERRNG-JAN-K. Characteristics of ammonia emission from barley plantsJ. Plant Physiol Biochem, 1996, 34(5): 691-695.9 SCHJOERRING-JAN-K, MATTSSON-MARIE. Quantification of ammonia e

53、xchange between agricultural cropland and the atmosphere: Measurements over two complete growth cycles of oilseed rape, wheat, barley and peaJ. Plant Soil, 2001, 228(1): 105-115.10 KANAMPIU F K, RAUN W R, JOHNSON G V. Effect of nitrogen rate on plant nitrogen loss in winter wheat varietiesJ. J Plant

54、 Nutr, 1997, 20: 389-404.11 JACKSON M L. Soil Chemical AnalysisM. Englewood Cliffs, NJ: Prentice-Hall, 1958.12 ISLAM N, INANAGA S, CHISHAKI N, et al. Absorption and translocation of 15N in Japonica (Hinohikari) and Indica (Hadsaduri) rice varietiesJ. Jpn J Trop Agr, 1997, 41(1): 37-42.13 YONEYAMA T,

55、 SANO C. Nitrogen nutrition and growth of the rice plant: II. Consideration concerning the dynamics of nitrogen in rice seedlingsJ. Soil Sci Plant Nutr, 1978, 24: 191-198.14 NTANOS D A, KOUTROUBAS S D. Dry matter and N accumulation and translocation for Indica and Japonica rice under Mediterranean conditionsJ. Field Crops Research, 2002, 74(1): 93-101.15 HAYAKAWA T, YAMAYA M, MAE T, et al. Changes in content of two glutamate synthase proteins in spikelets of ric