Dynamic Responses of Super Rice IIyou602 Plants to Different Nitrogen Levels and Configuration Modes

[Objective] The paper was to study the dynamic responses of super rice Ilyou602 plants to different nitrogen levels and configuration modes. [Method] With super rice Ilyou602 as test material, the dynamic changes of total N content in functional leaves, leaf sheaths and stems under different, application amount of nitrogen and configuration modes were analyzed. [Result] The highest total N content of functional leaves under different N levels appeared in the different periods, which was the highest during rehydration period in A3 level. The total N content in various plant positions during full heading stage and maturity stage showed fertilization treatments 〉 CK, functional leaves 〉 leaf sheaths 〉 stems. The total N content in different plant positions showed obvious difference in different treatments. When the super rice Ilyou602 was planted in Chengdu plain, the proper application level of N and configuration mode was as follows： 165 kg/hm2, fertilizer： topdressing = 6：4. [Conclusion] The study provided theoretical basis for nitrogen regulation of high yield cultivation of super hybrid rice.

Influence of Nitrogen Levels and Application Methods on Yield and Quality of Sorghum

A field study was conducted for two years at the Arid Zone Research Institute, Dera Ismail Khan, Pakistan, to determine the optimum level of nitrogen and efficient application method in the production of sorghum （Sorghum bicolor L.）. Using four levels of nitrogen, i.e., 0, 60, 90, and 120 kg ha^-1, and two different application methods （soil application and foliar spray）, the experiment was laid out in a split-plot design, where the main plots were used to determine the effective method of application and the subplots were used to detect the influence of N levels on the grain yield. The average data obtained after two years of study indicated an increase in the grain yields with an increase in N levels irrespective of the method used of N application. The grain yield increased from 2.92 to 5.61 t ha^-1 in the plots that were treated with 90 kg N ha^-1 compared with the control plots. Quadratic regression analysis showed that the increase in the yield was higher at the lower levels of N compared with the succeeding higher levels. The soil application method, producing an average grain yield of 4.79 t ha^-1, was found to be superior to the foliar spray method with an average grain yield of 4.56 t ha^-1. The protein content of the grain showed a linear increase with N application, attaining the maximum at 120 kg N ha^-1 in both the methods of N application. In addition, compared with the method of soil application, higher crude protein contents were observed using the method of foliar spray at all N levels.

Combined effect of shading time and nitrogen level on grain filling and grain quality in japonica super rice

There is limited information about the combined effect of shading time and nitrogen （N） on grain filling and quality of rice. Therefore, two japonica super rice cultivars, Nanjing 44 and Ningjing 3, were used to study the effect of shading time and N level on the characteristics of rice panicle and grain filling as well as the corresponding yield and quality. At a low N level （150 kg N ha^-1, 150N）, grain yield decreased （by 21.07-26.07%） under the treatment of 20 days of shading before heading （BH） compared with the no shading （NS） treatment. These decreases occurred because of shortened panicle length, decreased number of primary and secondary branches, as well as the grain number and weight per panicle. At 150N, in the treatment of 20 days of shading after heading （AH）, grain yield also decreased （by 9.46-10.60%） due to the lower grain weight per panicle. The interaction of shading and N level had a significant effect on the number of primary and secondary branches. A high level of N （300 kg N ha^-1, 300N） could offset the negative effect of shading on the number of secondary branches and grain weight per panicle, and consequently increased the grain yield in both shading treatments. In superior grains, compared with 150N NS, the time to reach 99% of the grain weight （T99） was shortened by 1.6 to 1.7 days, and the grain weight was decreased by 4.18-5.91% in 150N BH. In 150N AH, the grain weight was 13.39-13.92% lower than that in 150N NS due to the slow mean and the maximum grain-filling rate （GRmean and GRmax）. In inferior grains, grain weight and GRmean had a tendency of 150N NS〉150N BH〉150N AH. Under shaded conditions, 300N decreased the grain weight due to lower GReen both in superior and inferior grains. Compared with 150N NS, the milling and appearance qualities as well as eating and cooking quality were all decreased in 150N BH and 150N AH. Shading with the high level of 300N improved the milling quality and decreased the number of chalky rice kernels, but the eating and cooking quality was reduced with increased chalky area and overall chalkiness. Therefore, in the case of short term shading, appropriate N fertilizer could be used to improve the yield and milling quality of rice, but limited application of N fertilizer is recommended to achieve good eating and cooking quality of rice.

Litter decomposition and C and N dynamics as affected by N additions in a semi-arid temperate steppe, Inner Mongolia of China

Litter decomposition is the fundamental process in nutrient cycling and soil carbon（C） sequestration in terrestrial ecosystems. The global-wide increase in nitrogen（N） inputs is expected to alter litter decomposition and,ultimately, affect ecosystem C storage and nutrient status. Temperate grassland ecosystems in China are usually N-deficient and particularly sensitive to the changes in exogenous N additions. In this paper, we conducted a 1,200-day in situ experiment in a typical semi-arid temperate steppe in Inner Mongolia to investigate the litter decomposition as well as the dynamics of litter C and N concentrations under three N addition levels（low N with 50 kg N/（hm2？a）（LN）, medium N with 100 kg N/（hm2？a）（MN）, and high N with 200 kg N/（hm2？a）（HN）） and three N addition forms（ammonium-N-based with 100 kg N/（hm2？a） as ammonium sulfate（AS）, nitrate-N-based with 100 kg N/（hm2？a） as sodium nitrate（SN）, and mixed-N-based with 100 kg N/（hm2？a） as calcium ammonium nitrate（CAN）） compared to control with no N addition（CK）. The results indicated that the litter mass remaining in all N treatments exhibited a similar decomposition pattern： fast decomposition within the initial 120 days, followed by a relatively slow decomposition in the remaining observation period（120–1,200 days）. The decomposition pattern in each treatment was fitted well in two split-phase models, namely, a single exponential decay model in phase I（〈398 days） and a linear decay function in phase II（≥398 days）. The three N addition levels exerted insignificant effects on litter decomposition in the early stages（〈398 days, phase I; P〉0.05）. However, MN and HN treatments inhibited litter mass loss after 398 and 746 days, respectively（P〈0.05）. AS and SN treatments exerted similar effects on litter mass remaining during the entire decomposition period（P〉0.05）. The effects of these two N addition forms differed greatly from those of CAN after 746 and 1,053 days, respectively（P〈0.05）. During the decomposition period, N concentrations in the decomposing litter increased whereas C concentrations decreased, which also led to an exponential decrease in litter C：N ratios in all treatments. No significant effects were induced by N addition levels and forms on litter C and N concentrations（P〉0.05）. Our results indicated that exogenous N additions could exhibit neutral or inhibitory effects on litter decomposition, and the inhibitory effects of N additions on litter decomposition in the final decay stages are not caused by the changes in the chemical qualities of the litter, such as endogenous N and C concentrations. These results will provide an important data basis for the simulation and prediction of C cycle processes in future N-deposition scenarios.

Nitrogen Fertilizer Optimization and Cultivar Selection for Rice Grown near Mountainous Slopes in Orissa,India—A Field Experiment and Simulation Model Study

Degradation of the natural resource base has led to decline in crop yields or stagnation that caused food shortages at varying degrees among mountain families. Rice, the major staple food in Asia, is suffering from lack of suitable cultivar and N fertilizer management, when grown near mountainous slopes under rain-fed agro-ecosystem. An investigation through a field experiment and simulation study was conducted at United Nations University, Tokyo to select suitable rice cultivars and N fertilizer level for the rice grown near mountainous slopes in Orissa, India. The field experiment was conducted during wet season （June to November） of 2001 at Kasiadihi village of Dhenkanal district, Orissa, India with eight popular rice cultivars of medium （120～130 d） and long duration （135～150 d） group and four N levels （0, 40, 80 and 120 kg·ha^-1）. Highest grain yield of 5,680 kg·ha^-1 was obtained from cultivar Ranjit of long duration group followed by 4,730 kg·ha^-1 from cultivar Mahamaya of medium duration group, across N levels. CERES-Rice model was used to simulated grain yield of these two selected cultivars using historical weather data of the past 18 years （1983～2000）. Long duration cultivar Ranjit registered higher yield with lower stability as compared medium duration cultivar Mahamaya over the past 18 years. An optimum N fertilizer level of 80 kg·ha^-1 was recommended for rice grown under rain-fed ecosystem near mountainous slopes in Orissa, India to attain optimum yield potential of cultivar.

Effects of Nitrogen Amount on the Photosynthesis Parameters of Summer Millet in North China

In this study,effects of nitrogen（ N） amount applied on photosynthesis behaviors of the summer millet in North China was investigated. Photosynthetic rates（ Pn）,chlorophyll contents（ Chl）,photosynthetic active duration（ PAD）,and chlorophyll relative steady phase（ RSP） in flag and the upper third leaves were assessed in cultivars of Baogu 19,Jigu 19,9050,and 60 D under three N treatments [i. e.,0（ control）,75,and 150 kg/hm2]. Results indicated that the photosynthesis parameters were drastically regulated by external N levels,all of them showing elevation along with the increased N input in both assayed leaves.Among the cultivars examined,behaviors of the photosynthetic parameters were much better in Baogu 19 and worse in 60 D. The plant yields in the cultivars under various N treatments were shown to be in consistent with the behavior of the photosynthesis parameters. Correlation analysis revealed that plant yield is positively correlated with Pn and Chl and significantly positively correlated with PAD and RSP,suggesting that longer effective photosynthetic duration of leaves impacts largely on plant biomass production and the yield formation potential. Our investigation indicates that suitable external N applied can increase the yield of summer millet associating with the improvement of photosynthesis behaviors in upper leaves that contribute to plant biomass at the late growth stage. Baogu 19 exhibited higher plant yield together with improved photosynthetic parameters in upper leaves,suggesting its potential as an elite cultivar in planting in the summer season of North China.

Construction of Food Web Model for Liusha Bay-Based on Stable Isotope Analysis

To investigate the food web structure of Liusha Bay,the δ13C and δ15N values of various organisms collected in Liusha Bay were measured via stable isotope technique.Based on the calculated δ15N value,the correlation between stable isotope ratio and trophic level were established to predict the trophic levels of shrimps,crabs,cephalopods and fishes.By comparing the analysis results of stomach contents of 24 organisms,two methods gave a similar consistence in approximately 71% of organisms within a 0.5 trophic level.It is concluded that stable isotope technique could be an effective method for studying ocean food web trophic level.

普通文件和HTML文件及XML文件信息检索过程探析

通过对普通文件(Plain Text)、HTML文件和XML文件结构的分析,以经典的VSM为例,探讨了3种文件在信息检索过程中所采用的不同处理技术。同时针对传统VSM的不足以及HTML文件和XML文件的结构特点,讨论了N-Level VSM对经典VSM的改进。

Expression Patterns of Nine Ammonium Transporters in Rice in Response to N Status

Nitrogen use efficiency （NUE） was very low in China and a loss of as much as 7070 of the applied nitrogen fertilizers was reported in high-yielding rice fields. In order to investigate the molecular basis of high-affinity ammonium transport or uptake into rice （Oryza sativa L.）, we analyzed the expression profiles of nine ammonium transporters （AMT）, three each of OsAMT1, OsAMT2 and OsAMT3, at two different N requirement stages （young seedling stage and tillering stage） of rice growth as well as the changes in these expression patterns according to external N status using real-time reverse transcription polymerase chain reaction （RT-PCR）. The results suggested that the nine OsAMT genes were expressed in different organs of rice plants, including mature roots, new roots, stems, old leaves and new leaves and that the expression patterns were organ specific and independent of the positions of the corresponding proteins in the phylogenetic tree. OsAMT1;1, 3;2 and 3;3 were expressed in the roots and shoots, primarily old leaves, OsAMT1;2 and 1;3 mainly in the roots, and OsAMT2;1, 2;2, 2;3 and 3;1 mainly in the shoots, primarily in new leaves, and relatively more in the stems than other genes. The expression patterns at the two different N requirement stages were the same; however, at the tillering stage with greater N requirements, the OsAMTs transcript levels were greater than those at the young seedling stage with low N requirements. N starvation for 48 h up-regulated OsAMT1;1, 1;2, 3;1, 3;2, 3;3 and down-regulated OsAMT1;3 mRNA abundance. Following N starvation, NH4＋ and NH4NO3 re-supply down-regulated OsAMT1;2 and 3;3 and up-regulated OsAMT1;3, whereas NO3 re-supply down-regulated OsAMT1;1 and 1;2. These suggested that the organ-specific expression pattern of OsAMT could be regulated by N requirement and external N status.

Elliptic genera of level N for complete intersections

We focus on the elliptic genera of level N at the cusps of a congruence subgroup for any complete intersection.Writing the first Chern class of a complete intersection as a product of an integral coefficient c1 and a generator of the 2nd integral cohomology group,we mainly discuss the values of the elliptic genera of level N for the complete intersection in the cases of c_(1)>,=,or<0.In particular,the values about the Todd genus,Â-genus,and A_(k)-genus can be derived from the elliptic genera of level N.