Mechanism of Effect of Lanthanum Nitrate on Vigor of Aged Rice Seeds

The effect of La(NO3)(3) on natural or artificial aged rice seeds vigor was studied. The results show that the germination rate, germination index and vigor index of aged rice seed increase. Activities of superoxide dismutase, catalase and peroxidase are enhanced. . O-2(-) and malond ialdehyde contents decrease in germinating stage of aged rice seed, and cell membrane permeability of aged rice seeds reduces by treating with La(NO3)(3). The vigor increase of rice natural aged seed is greater than that of artificial aged rice seeds by treating with La(NO3)(3).

Utilization of nuclear magnetic resonance (NMR) in the determination of water status on rice seeds

The relation between seed viability and waterstatus in seed was studied.The experimentwas carried out at Zhongshan University.Seeds of hybrid rice Shanyou 63 were collectedfrom Guangdong Academy of Agriculture Sci-ences in 1993 and then stored for one year inopen air or with silica gel.Before and afterstorage,the relative content of free water andbound water in seeds were measured with

Study on mutagenic effects of rice seeds irradiated by CO_2 laser

Seeds of japonica rice (cv. Zhenuo 2) at twodifferent physiological states (dry seeds withwater content 13% and wet seeds soaked inthe water for 36 h) were irradiated by COlaser in four different power-densities. Theseeds irradiated by 200GY ofCo γ rays andno radiated seeds were used as the controls.Results showed that the biological effects

Amplification and sequencing of a sulfur-rich 10kd prolamin gene from rice seeds

Nutritious value of seed storage protein is low due to deficiency in essential amino acid contents. Cereals are mainly deficient in lysine and legumes in sulfur-containing amino acids (methionine and cysteine). So far, several sufur-rich seed protein genes have been isolated and the essential amino acid contents of seed proteins were increased in transgenic tobacco and Brassica napus. In this paper we report the isolation and sequencing of the 10kd prolamin gene from seeds. Poly(A) RNA were prepared from the immature endosperms of japonica rice, Sachiminori, 10 d after flowering. Complementary DNAs were synthesized according to Promega Instruction Manual. Two primers were synthesized and their sequences were Primer Ⅰ: CGTCTACACCATCTGGAATC, Primer Ⅱ: GTGTTTGCAGATAGTATGC. The amplified fragraents were inserted into the Sma I site of pGEM-7zf(+) and was used to transform E. coli JM101 after PCR reaction. DNA sequence were determined by Sanger’s Chain-termination method. Synthesis of cDNA. Using mRNAs as

Isolation and Identification of Burkholderia glumae from Symptomless Rice Seeds

A survey on isolation and detection of the casual organism of bacterial grain rot of rice was conducted during 1997-2006. In 2006, six pathogenic bacterial strains were isolated from two symptomless seed samples of rice （Oryza sativa L.） originally produced in Hainan Province and then planted in Zhejiang Province, China. They were identified as Burkholderia glumae which is the causal organism of bacterial grain rot of rice by physiological characteristics, colony morphology, pathogenicity test, Biolog, fatty acid methyl ester （FAME） analysis and RAPD-PCR compared with the four standard reference strains. It is confirmed that there is the infection of B. glumae in so-called ＇health looking seeds＇.

Rice seeds identification based on back propagation neural network model

Rice quality directly affects the final rice yield.In order to achieve rapid,non-destructive testing of rice seeds,this paper combines the three-dimensional laser scanning technology and back propagation(BP)neural network algorithm to build a rice seeds identification platform.The information on rice seed surface is collected from four angles and processed using Geomagic Studio software.Based on the noise filtering,smoothing of the point cloud,vulnerability repair,and downsampling,the three-dimensional(3D)morphological characteristics of a rice seed surface,and the projection features of the main plane cross-section are obtained through the calculation of the features.The experiments were performed on five rice varieties,including Da Hua aromatic glutinous,Hong ShiⅠ,Tian You VIII,Xin Dao X,and Yu Jing VI.The resulting input vector consisted respectively of:(1)nine 3D morphological surface features,(2)nine projection features of the main cross-section plane of rice,and(3)all of the above features.The results showed that for an input vector consisting of nine surface 3D morphological features,the recognition rate of the five rice varieties was 95%,96%,87%,93%,and 89%,respectively;for an input vector consisting of nine projection features of the main cross-section plane of rice seeds,the recognition rate was 96%,96%,90%,92%,and 89%,respectively;and lastly,for an input vector consisting of all the features,the highest recognition rate of 96%,97%,91%,94%,and 90%,respectively,was achieved.The analysis showed that rice varieties could be identified by using 3D laser scanning.Therefore,the proposed method can improve the accuracy of rice varieties identification.

Feasibility of terahertz spectroscopy for hybrid purity verification of rice seeds

The purity of hybrid rice seeds reflects the typical consistency of seed varieties in characteristics.The accuracy and reliability of seed purity detecting are of great significance to ensure the quality of seeds.In this study,the feasibility of identifying the purity of hybrid rice seeds,Xinong 1A/89,by terahertz(THz)time-domain spectroscopy system combined with chemometrics was explored.Three quantitative identification models for testing the purity of Xinong 1A/89 hybrid rice seed were developed and compared by THz absorption spectroscopy with extreme learning algorithm(ELM),Principal cComponent Regression(PCR)and Partial Least Squares Regression(PLSR).Experimental results showed that comparing with classical PLSR and PCR models,ELM presents a better feasibility and stability.For the testing set,the quantitative prediction result of ELM(ELoo=2.005×10^(-5),R^(2)=96.75%)is significantly better than those of PCR(ELoo=7.346×10^(-5),R^(2)=88.10%)and PLSR(ELoo=8.007×10^(-5),R^(2)=87.03%).The results highlight the feasibility of THz spectroscopy combined with ELM as an efficient and reliable method for verification of hybrid rice seeds.

Simulation and experiment on prediction of total rice seeds mass in vibrating tray for vacuum plate seeder

To improve the seeds pick-up precision of a vacuum plate seeder,it is important to accurately control the relative distance between suction plate and seeds layer in vibrating tray.Under the excitation of reciprocating vibration with a time varying interference in direction angle,the seeds motion is simulated using the discrete element method(DEM).By analyzing the seeds distribution characteristics,it was found that the seeds-mass-per-unit-area(SMA)was approximately plane distributed in the tray.Then,four square areas on the bottom of rectangular tray were divided symmetrically near the four vertices to measure the corresponding SMA respectively,and a monitoring plane model was established to predict the average SMA and total seeds mass in the tray.The prediction results of DEM simulation showed that the maximum and the mean relative errors were 6.75%and 2.85%.The influences of the normal vector of monitoring plane model and the standard deviation of SMA in four monitoring areas on the prediction errors were analyzed.A method for improving prediction accuracy by using linear regression correction was proposed,and the maximum and the mean relative errors could be reduced to 5.01%and 2.07%.When the tray was vibrated with the frequency of 11 Hz and the amplitude of 4 mm,experiments were carried out on the vacuum plate seeder test-rig.A Kalman filter was adopted to suppress the SMA measurement noise in four monitoring areas.Prediction results indicated that the maximum and the mean relative errors were 10.2%and 3.46%with the average SMA in range of 0.9-1.5 g/cm2,respectively.The paper can provide a basis for further study on the automatic control of suction plate motion according to the variation of seeds mass in the tray.

Determining the effects of LFHV-PEF treatment on the water distribution and vigor of aged rice seeds using LF-NMR

This study aimed to investigate the effect of low-frequency high-voltage pulsed electric field (LFHV-PEF) treatment on the germination of aged rice seeds. Aged rice seeds were subjected to LFHV-PEF treatment with different electric field strengths, and low-field nuclear magnetic resonance (LF-NMR) was performed to acquire the LF-NMR data of rice seeds at different germination periods during a standard seed germination test to analyze their internal patterns of water state and distribution. Optimal treatment conditions were determined based on the physicochemical data collected during germination, and the improvements in seed vigor were verified. The findings indicated that during germination, the contents of bound and semi-bound water within the aged rice seeds initially increased and then decreased, whereas free water and total water contents increased continuously and rapidly. Side peaks were also observed within the seeds. Under the LFHV-PEF treatment, the semi-bound water within the seeds was more easily converted to free water, and the water absorption rate, germination potential, germination rate, germination index, and vigor index of these seeds improved. Further, the optimal electrical field strength was 12 kV. By analyzing the internal patterns of water state and distribution in seeds, the mechanism by which electric field treatment improved seed vigor was elucidated, thus, providing theoretical support and data evidence for research on water absorption during the germination of rice seeds, and methods for improving seed vigor.

Rapid and non-destructive detection method for water status and water distribution of rice seeds with different vigor

In this study,newly harvested and aged rice seeds were analyzed to determine their aging process,identify the difference between artificially and naturally aged seeds,and develop a rapid,accurate,and non-destructive detection method for water status and water distribution of rice seed with different vigor.To this end,an artificially accelerated aging test was conducted on the newly harvested rice seeds.Then,low-field nuclear magnetic resonance(LF-NMR)technology was applied to test the new(Shennong No.9816,2018),old(Shennong No.9816,2017),and artificially aged seeds(Shennong No.9816,2018).A standard germination test was conducted for three types of seeds.Finally,the differences of water status and distribution between rice seeds of different vigor were analyzed based on the standard germination test results and wave spectrometry information collected using LF-NMR.The results indicated that new seeds,old seeds,and the artificially accelerated aging rice seeds all exhibited two water phases,and the vigor of rice seeds after the artificial accelerated aging test was lower than that of new seeds.There were significant differences between the frequencies of bound water at the time of the peak and the time at the end of the peak for the three types of seeds.The two times showed an increasing trend for rice seeds with poor vigor,indicating that the ability of the water in the rice seeds having poor vigor to combine with other substances was weakened.There were significant differences between the distributions of free water peak end time for the three types of seeds.All the rice seeds with poor vigor exhibited a decreasing trend at this time,indicating that the freedom of free water inside the rice seed samples with poor vigor was weakened.The total water content of the artificially aged seeds and the aged seeds was higher than that of the new seeds,but the free water content increased from artificially aged seeds to new seeds to aged seeds.This indicates that LF-NMR technology is an effective detection method that can simply compare the differences in seed vitality with respect to water distribution as well as differentiate the seed internal water content of artificially aged and naturally aged seeds.

Determination the Vigor of Rice Seed with Different Degrees of Aging with Ultraweak Chemiluminescence During Early Imbibition

用高灵敏度的单光子计数系统探测人工老化 (40℃ ,相对湿度 90 % ) 0、7、14和 2 1d的水稻种子吸胀初期的超弱化学发光强度变化 ,首次观测到水稻 (OryzasativaL .)种子吸胀初期超弱化学发光强度与其老化程度有关。加水激活水稻种子的超弱化学发光 ,其强度依赖于种子的老化程度。实验结果表明水稻种子的人工老化时间越短 ,则吸胀初期 (2 0～ 30min)超弱化学发光的强度越强 ,萌发率越高。水稻种子萌发率与超弱化学发光强度呈显著正相关。观测水稻种子吸胀初期超弱化学发光强度的变化可望成为检测种子老化程度的一种快速、简便、无损伤的新方法。

Effect of Fulvic Acid on Growth and Yield Components of Direct Seeding Rice

ObjectiveThis study aimed to investigate the effect of fulvic acid on the growth and yield components of direct seeding rice （Nanjing 44）. MethodThe rice seeds were soaked in 0 （water as a control）, 1, 2, 4 and 6 g/L fulvic acid （FA） before sowed. Then, the rice morphological indices, leaf chlorophyll content, photosynthesis parameters, root activity and chlorophyll fluorescence parameters were measured in the following field studies. ResultCompared with the control, the leaf area index, chlorophyll content, net photosynthetic rate, stomatal conductance and dry matter weight and some fluorescence parameters such as the maximum photochemical efficiency of photosystem II （PSII） （Fv/Fm）, excitation energy capture efficiency of opened PSII reaction center （Fv’/Fm’） and efficiency of the open reaction centre （ΦPS II） increased by different levels at both jointing stage and heading stage of direct seeding rice, whose seeds were soaked by FA with different concentrations. High FA concentration （4-6 g/L） significantly increased the cultivated rice leaf area index, chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate and dry matter weight by 10.32% -22.88% , 5.88% -13.11% , 12.16% -26.84% , 11.43% -88.46% , 10.63% -21.63% , 18.49% -19.68% , respectively, thereby improving the physiological function and light energy transform efficiency of rice at the growth stage. With FA concentration increasing, the yield, effective panicles, grain number per panicle and seed setting rate were increased significantly compared with the control by 17.52%-18.71%, 3.46%-3.85%, 6.30%- 6.51% and 7.82%-8.69% respectively. ConclusionSoaking rice seed with FA could be considered as an effective way to improve the rice competitiveness at early growth stage.

Identification of rice seed varieties using neural network

A digital image analysis algorithm based color and morphological features was developed to identify the six varieties （ey7954, syz3, xsl 1, xy5968, xy9308, z903） rice seeds which are widely planted in Zhejiang Province. Seven color and fourteen morphological features were used for discriminant analysis, Two hundred and forty kernels used as the training data set and sixty kernels as the test data set in the neural network used to identify rice seed varieties. When the model was tested on the test data set, the identification accuracies were 90.00%, 88.00%, 95.00%, 82.00%, 74.00%, 80.00% for ey7954, syz3, xsl1, xy5968, xy9308, z903 respectively.

Study on Cadmium Tolerance of Seed Germination and Seedlings Growth of Different Rice Varieties

The research used bioassay method to explore seed tolerance of Cd in terms of seed germination and seedling growth. Specifically, 12 rice varieties of three types were investigated under Cd stress, covering germination rate, shooting index, vigor index, seedling and shoot lengths, and fresh weights. The results showed that as Cd concentration grew, seed germination and seedling growth kept increasingly inhibited; germination index, vigor index, root length, shoot length and fresh weights went down; inhibition effects on seed germination and seedling growth were conventional rice〉two-line hybrid rice〉three-line hybrid ,rice. Shanyou 9588, Tianyou 998, Chuanxiang 8, and Y Liangyou 1 performed ~rongly in Cd tolerance; C Liangyou 651, Nei 5 You 263, Xiangwanxian 16, Huanghuazhan, Xiangwanxian 13, and Zhunliangyou 527 performed poorly in Cd tolerance, and Cd tolerance of rest treatments were moderate.

The Development and Application of 2BDQ-8 Rice Direct Sowing Machine

[Objective] The aim was to introduce the development and application of 2BDQ-8 rice direct sowing machine and provide a theoretical basis for rice mechanization production. [Method] 2BDQ-8 rice direct sowing machine was used for the promotion test in field of several cities and counties in Jiangsu Province,and artificial rice planting and mechanization rice planting were compared to explore the production and economic situation. [Result] 2BDQ-8 rice direct sowing machine had advantages such as high efficiency and low cost,the rice direct sowing machine saved about 30% compared to the artificial rice planting and mechanization rice planting,and the overall efficiency was significant. [Conclusion] 2BDQ-8 rice sowing machine was a production technology that had low cost and high efficiency,which should be widely applied.

Assessment of Seed-Borne Plant Pathogenic Fungi Associated with Rice Crop in South-Eastern Nigeria

This study was conducted to assess the incidence of seed-borne fungi on rice seeds sourced from the major rice growing areas of South-Eastern Nigeria. The rice seeds were collected during the dry seasons between 2009 and 2010. Four hundred rice seeds randomly collected and surface sterilized by washing in 3% sodium hypochlorite and rinsed two times with sterile distilled water were placed in three circular rings inside the Petri dishes. The incubation was done one after the other for each variety from all the locations. Ten fungi species from eight genera were isolated from the rice seeds in all the rice growing areas of South-Eastern Nigeria. The fungi pathogens vary from one locality to another, as well as the frequency of occurrence. The pathogens isolated include： Fusarium moniliforme, F. solani, F. oxysporium, Aspergillus spp., Botridiploidia spp., Helminthosporium spp., Penicillium spp., Trichoconis padwickii, Curvularia oryzae and Phoma oryzae. Though, there was the presence of some seed-borne fungi in the rice seeds from the areas studied, most of the cultivars experienced up to 90% germination. But some cultivars had very low germination. IR 1416 from Arochukwu and GB90 from Arondiuzogu had less than 1% germination. This study shows that seed-borne organisms are major constraint in rice production in the South-Eastern states of Nigeria as a result of low seed germination stemmed from infestation of fungi organisms in the seeds.

Practices and Prospects of Super Hybrid Rice Breeding

The great progress in super rice breeding both in China and other countries has been made in recent years. However, there were three main problems in super rice breeding： 1） the super rice varieties were still rare; 2） most super rice varieties exhibited narrow adaptability; and 3） current breeding theories emphasized too much on the rice growth model, but they were unpractical in guidance for rice breeding. According to the authors＇ experience on the rice breeding, the breeding strategies including three steps （super parent breeding, super hybrid rice breeding and super hybrid rice seed production） were proposed, and the objectives of each step and the key technologies to achieve the goals were elucidated in detail. The super parent of hybrid rice should exhibit excellent performance in all agronomic traits, with the yield or sink capacity reached the level of the hybrid rice control in regional trials. The super hybrid rice combination should meet the following criteria： good rice quality, wide adaptation, lodging resistance, resistance to main insects and diseases, and the yield exceeded above 8% over the control varieties in the national and provincial regional trials. To achieve the goal, the technical strategies, such as selecting optimal combination of the parents, increasing selection pressure, paying more attention to harmony of ideal plant type, excellent physiological traits and all the agronomic traits, should be emphasized. The yield of seed production should reach 3.75 t/ha and 5.25 t/ha for the super hybrid rice combinations derived from early-season and middle-season types of male sterile lines, respectively. The main technologies for raising seed production yield included selecting optimum seed production site, using the male sterile line with large sink capacity and good outcrossing characteristics, and improving the amount of the pollen by intensive cultivation of the male parent. According to the technologies of the three-step breeding on super hybrid rice, two super rice parents, including a male parent 996 and a thermo（photo）-genic male sterile [T（P）GMS] line C815S, were bred. Furthermore, a super early hybrid rice combination, Luliangyou 996, which could be used as a double-season early rice variety in middle and lower reaches of the Yangtze River, China, was bred by using the super rice varlet3, 996 as the male parent, and several hybrid rice combinations with higher yield than control variety in regional trials both of Hunan Province and state were bred with the T（P）GMS line C815S as the female parent.

Use of Controlled Release Fertilizer for Increasing N Efficiency of Direct Seeding Rice

Field trials on a silt-loamy paddy soil derived from shallow-sea deposit in direct seeding rice fields were conducted in Zhejiang, China, in 1996 to compare N efficiency of controlled release fertilizers (LP fertilizers) with the conventional urea. Six treatments including CK (no N fertilizer), conventional urea and different types of LP fertilizers at different rates were designed for two succeeding crops of early and late rice. A blend of different types of LP fertilizers as a single preplant "co-situs" application released N in a rate and amount synchronizing with uptake pattern of direct seeding rice. A single preplant application of the LP fertilizers could meet the N requirement of rice for the whole growth period without need of topdressing. Using LP fertilizer blends, equivalent grain yields could be maintained even if the N fertilization rates were reduced by 25%～50% compared with the conventional urea. Agronomic efficiency of the LP fertilizers was 13.6%～ 86.4% higher than that of the conventional urea in early rice and 100%～164.1% in late rice, depending on the amounts of the LP fertilizers applied. N fertilizer recovery rate increased from 27.4% for the conventional application of urea to 41.7%～54.l% for the single preplant "co-situs" application of the LP fertilizers. Use of the LP fertilizers was promising if the increase in production costs due to the high LP fertilizer prices could be compensated by increase in yield and N efficiency, reduction in labor costs and improvement in environment.

Prokaryotic Expression, Purification and Characterization of a Novel Rice Seed Lipoxygenase Gene OsLOX1

Lipoxygenase （LOX, EC1.13.11.12） is a key enzyme during the degradation of lipids in animals and even plants, and also the first key enzyme responsible for the biosynthesis of jasmonate. To purify and characterize the OsLOX1 gene from rice seeds, the entire coding region of the OsLOX1 gene was inserted into an expression vector pET30a（＋） and transformed into Escherichia coil BL21 （DE3）. Expression of the fusion protein was successfully induced by isopropyl-β-D- thiogalactopyranoside （IPTG） and the purified recombinant protein was obtained by His.Bind Kits. Further assay showed that the purified recombinant protein exhibited the LOX activity. The optimum pH was 4.8 （acetate buffer） and the optimum temperature was 30℃ for the above enzyme. Thus, the recombinant might confer an available usage for the synthesis of jasmonate in vitro, and also provides a possibility for elucidating the inter-relationship between the primary structure of the plant seed lipoxygenase protein and its physiological functions.

Diversity of Gram negative bacteria antagonistic against major pathogens of rice from rice seed in the tropic environment

With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference!strains. Sixteen species or types of Pseudomonas and 17 genera of non pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed were P. putida and P. fulva. About 17% of the strains of Pseudomonas and 2% of the non pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents.