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1.
The root of Alnus sibirica is rich in tissue type,Phloem fibers are obvious and Plasmodesmas are well developed.The number of primary xylem bunches are not stable,there are triarch,tetrarch and pentarech types.The perforation plate of vessel is scalariform,The rays types are radial in shape and unicellular in structure,In root nodule,cortex is the best developed structure,the stele is small.The root nodule is branched.In root nodule tissues,actinomyces proliferate luxuriently,the actinomyces body is in different shapes.  相似文献   

2.
Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.  相似文献   

3.
In order to investigate the effect of water channel blocker HgCl2 on the hydraulic resistance in roots of maize seedlings, a xylem pressure probe was used to monitor the changes in root xylem pressure in response to NaCl- or mannitol-induced osmotic stresses before and after the application of HgCl2. When the maize roots were subjected to 500 umol L-1 HgCl2 in root bathing solution, not only a considerable decline in xylem pressure （increase in xylem tension） was observed, but the loss of responsiveness of the plant to both salt- and mannitol-induced osmotic stresses in terms of xylem pressure change was seen as well when the transpiration rate of the plant was not significantly changed. The results are similar but different from the reversed osmosis by the Fenton reaction in the internodes of Chara coralline, showing that the mechanisms of water transport across cell membrane in plant roots are far more complicated than expected.  相似文献   

4.
Xiangxiang 2A has an evident drawback,i.e.instability in male sterility under higher temperature conditions resulting from the existence of minor restoring genes in it ,which greatly hampered the extension of its elite hybrid Xiangyou 63with both high yield and fine auality in commercial production.To improve Xiangxiang 2A,the hybridization of Xiangxiang 2B with V20 Bwas made again in 1990.A new aromatic CMS line Xinxiang A was successfully developed in 1994.It not only retains the favorable characteristics of Xiangxiang 2A in grain quality and combining ability.but also expresses complete and stable male sterility and high seed production yield potential.Up to now,by using it as female parent.a series of quasi-aromatic hybrids have been developed.Some of them have been released to farmers.Because such hybrids can not only yield higher or as high as but also possess a better grain quality than the current common high-yielding hybrid rice varieties.so that they are preferred and well welcome by the farmers in China.The planting area under these hybrids is increasing rapidly in China.  相似文献   

5.
The beneficial applications of Trichoderma spp. in agriculture include not only the control of plant pathogens, but also the improvement of plant growth, micronutrient availability, and plant tolerance to abiotic stress. In addition, it has been suggested that these fungi are able to increase plant disease resistance by activating induced systemic resistance (ISR) . The mode of action of these beneficial fungi in the Trichoderma -plant-pathogen interaction are many, complex and not comple…  相似文献   

6.
Plant diseases heavily affct plant growth and crop yield even in modern agriculture. Control its difficult because pathogens mutate frequently, and this leads in frequent breaking of disease resistance in commercial cultivars. The excessive application of chemical pesticides is not only producing pesticide-resistant pathogens, but it is harming the environment threatening the health of human beings. Therefore, the use of biological control agents (BCA) may provide an environmental friendly al…  相似文献   

7.
The basic principles of the partial and multiple coherence ananlysis and their utilization on vibration source idenfification are discussed in detail in this paper,The partial coherence analysis is the effective method of vibration source identification in multiple input-single output systems.Formerly,there was not any this kind of unction in the signal processor,and there was not and special software too.The software which we developed and used in the 7T 17S signal processor has this function.This software can be used not only for the parial and multiple coherence analysis of signal,but also for the correlation analysis,power spectrum analysis,transfer function analysis et al.We used this software to make the identifcation of the vibration source of the car floor board of electrical measuring vehicle,and to find the main factors which effect the vibration of the ear board.The excellent result was obtained.This method can also be used for making the identifications of noise source and other sources.  相似文献   

8.
42 isolates of P. sojae were obtained from diseased soybean plants in 9 counties of Heilongjiang Province and 1 county of Jilin Province in Northeast of China. 11 isolates were classified into 3 races ;the rest that could not be classified due to intermediate reactions were classified into 12 virulence types, suggesting virulence diversity of P. sojae in China. Isolates represented race 1,3 and 8. Race 1 was the most prevalent one.and races 3 and 8 were the first report in China. Our results suggest P. sojae is aboriginal in China.  相似文献   

9.
1 1ntroductionSelenium(Se)was found as an eIPment by Sweden chemist J. J. Berzelius in 1817. It isknown as a rare element in terms of its content,which is mere 10--'% in earth curst. Duringsome 100 years after its founding,Se and Se--containing compounds had been described astoxic to organisms till 1957. This is true,but not completely true. Since Shwarz(l957)report-ed that Se is an essential element for animals,its importance in animal nutrition and its bio-logical functions have been st…  相似文献   

10.
A cotton cultivar Xinluzao 8 was grown under four levels of water stress treatments （normal irrigation, slight, mild and severe water stress） from the initial reproductive growth stage in Shihezi, Xinjiang, China, in 2002, to evaluate the growth and eco-physiological performances. Under water stress conditions, the transpiration ability decreased while the leaf temperature increased. Although the relative leaf water content decreased as water stress increased, the differences among the treatments were small, indicating that cotton has high ability in maintaining water in leaf. The stomatal density increased as water stress increased, while the maximum stomatal aperture reduced only in the severest stressed plants. The time of the maximum stomatal aperture was delayed in the mild and severe stressed plants. When severe stress occurred, the stomata were kept open until the transpiration decreased to nearly zero, suggesting that the stomata might not be the main factor in adjusting transpiration in cotton. Cotton plant has high adaptation ability to water stress conditions because of decrease in both stomatal conductance and hydraulic conductance from soil-to-leaf pathway. The actual quantum yield of photosystem Ⅱ （PS Ⅱ） decreased under water stress conditions, while the maximum quantum yield of PS Ⅱ did not vary among treatments, suggesting that PS II would not be damaged by water stress. The total dry weight reduced as water stress increased.  相似文献   

11.
The even degree of chicken population could be estimated by the coefficient of variation or the percentage of the chicken whose body weights were not higher and lower than average body weight by 15% in the sampling population.In fact,the two indexes were relative to each other.On the basis of analyzing the relationship between the two expectations,the expectations which had been worked out independently were corrected in this paper.  相似文献   

12.
Many animal feed grains contain high β-glucan in the cell wall. Pigs do not secret β-glucanase to degrade the β-glucan in their feed. The indigestible β-glucan not only blocks the release of nutrients from the grain cell wall, but also increases the digesta viscosity in the gastrointestinal tract of pigs. Therefore, dietary β-glucan significantly inhibits nutrient digestion and absorption in pigs. Transgenic expression of β-glucanase in the digestive tract of pigs may offer a solution to solve this problem. In the current study, four artificial codon-optimized β-glucanases genes was prepared and expressed in porcine cells. Only p Bg A and p Egx showed high activity in transfected pig kidney cells. To improve the p H range and p H stability of β-glucanase, the two β-glucanases, p Bg A and p Egx, were co-expressed in pig kidney cells and salivary gland cells by Linker A3 or 2A peptide. The resulting dual enzymes of p Bg A3 p Eg and p Bg2 Ap Eg showed significantly enlarged p H range and significantly increased p H stability, as compared to parental enzymes. These results provide useful data for future study on increasing the feed digestibility of pigs by transgenic expression of β-glucanase in their salivary glands.  相似文献   

13.
It is not reasonable to estimate the average relationship degree in statistics by using the mean of relationship coefficients between the individuals in a animal population.According to diferent usage of relationship coefficient,the estimation method of average relationship coefficient in animal population was disscussed by using Z transformation or CSC transformation,respectively,when relationship coefficient shows relationship degree or probability.  相似文献   

14.
The maize population Csyn 4 was improved for three cycles with three recurrent selection methods MS1, MS1-HS, and MHSRRS in northern China. A total of 40 NC Ⅱ testcrosses were made by four testers with Csyn 4 and 10 improved populations, which were evaluated in four environments in the cropping season of 2005. Analysis of variance indicated a significant progress （P〈 0.05） in yield and other chief agronomic traits in the improved populations and testcrosses, demonstrating that the three recurrent selection methods were effective for increasing grain yield of testcrosses and improvement of general combining ability in maize population. The average grain yield increase of population Csyn 4 in MS1, MS1-HS, and MHSRRS recurrent selections was 266.7 kg ha^-1 （5.3%）, 288.0 kg ha^-1 （5.7%）, and 231.3 kg ha^-1 （4.6%） per cycle, while the grain yield of S 1 progeny of population for Csyn 4 was increased by 420.0 kg ha^-1 （10.9%）, 376.0 kg ha^-1 （9.8%）, and 414.7 kg ha^-1 （10.8%） per cycle in MS1, MS1-HS, and MHSRRS recurrent selections, respectively. Linear responses （b） in the MS1, MS1-HS, and MHSRRS recurrent selections were the same as the realized responses of the selection （G） for grain yield increase of Csyn 4 and S1 progeny of the populations. The grain yield of testcrosses increased by 3.3-5.2% on average per cycle. The value of heterosis did not display any differences amongst the different cycles of selections. The GCA for yield component traits of population Csyn 4 was improved significantly by means of three selection methods, whereas the GCA for plant height, ear height, days to silking, and days to pollen did not show significant increase in the recurrent selections. GCA for the number of tassel branches were decreased in the selections, while GCA for the number of plant leaves were increased, but the difference was not significant.  相似文献   

15.
Hoagland＇s solution was used as water culture medium to study the effect of CO2 concentration on nitrate metabolism of wheat under natural light and light-shaded conditions. NO3^-N, NH4^＋-N, nitrate reductase activity, total uptake N by wheat plants during solution cultural period and total N in plants were determined for comprehensive evaluation of the effect. Results showed that under both natural light and light-shaded conditions, addition of CO2 increased NO3^-N uptake and its assimilative capabilities by plants. However, there were some difference between shoots and roots. With increase of CO2 concentration, the concentration of NO3^-N and NH4^＋-N as well as nitrate reductase activity were all decreased for shoots while the difference was not so distinct in roots, and the nitrate reductase activity was not decreased, but increased. Since NO3^-N uptake by plants from the solution and the total N in plants were much higher by CO2 addition, it may be concluded that addition of CO2 has resulted in rise of nitrate absorption, assimilation and metabolism of wheat.  相似文献   

16.
Experiments with tecyclacis applied as a seed-dressing carried out with triticale cv.Lasko in pots in the glasshouse and in hand-sown plots in the field.The sesults showed that tetcyclacis significantly delayed seedling emergence and inhibited the elongating growth in plant seedling stage,but not affected the growth and development of the adult plant during the late stage of stem extension and the stage of grain expansionl.No significant difference was found in fertile stem number,grain quality and yield between the treated plants with tetcyclacis and control.  相似文献   

17.
To improve grain quality of the high-yielding hybrid rice in China, we introduced the aromatic rice MR365, an improved Indian cultivar, from IRRI in 1984 and began to transfer its aroma and good quality characters into the existing maintainer lines. In the meantime, the research on the inheritance of aroma for increasing the breeding efficiency was also conducted.It was found that the inheritance of aroma in MR 365 and its derivatives was controlled by one pair of recessive major genes based on the KOH-soaking method. There existed disparity in aroma degree among different grains of F2 generation, and different aromatic CMS lines derived from the same aromatic donor had also a little difference in the degree of aroma, which implies that, besides the major genes, aroma may also be affected by the genetic backgrounds or minor genes.Xiangxiang 2A, developed from the cross of V20A//V20B/MR365, is the first aromatic CMS line bred in China. It is not only aromatic but also has good grain quality and combining ability. Using it as female parent, Xiangyou 63 (Xiangxiang 2A / Minghui 63), the first quasi-aromatic hybrid rice combination in China, was developed, and released to farmers in 1995. Xiangyou 63 is characteristic of quasi-aromatic or partially aromatic (because only a portion of or not all grains are aromatic), good grain quality, high-yielding ability, good blast resistance and wide adaptability.  相似文献   

18.
Chemical Composition of Bovine Colostrum   总被引：2，自引：0，他引：2  
Chemical compositions of bovine colstrum and their change after parturition were studied.Fat,total protein,whey proteins,ash and total solid were higher than those in milk and decreased as lactation time was increased.Lactose was lower than that in milk and incresed with the increase of lactation time,whey proteins of colostrum such as Ig,β-Lg,BSA,Lf and Lp were obviously higher than those in milk and decreased as lactation time was increased.There were high unsaturated fatty acids in colostrum compared with bovine milk.Na,Cl,Fe,Zn,Cr and Mg in colostrum were giher than those in milk.They fell as lactation time was increased.I,K,P,Mn and Cu increased with the increase of lactation time.Co,As and Pb were not detecred by ICP method.  相似文献   

19.
1　Introduction　　 Relationship is not respective for traits,it shows the genetic relationship between thesame trait in different individuals.The relationship degree is measured by its coefficient.Ifcertain animal population is made up of n individuals,then Cn2 =12 n(n - 1 ) kinds ofrelationships and 12 n(n - 1 ) relationship coefficients are included in this population.Inpractice of animal breeding,except the calculating relationship coefficients between theindividuals in population,it will…  相似文献   

20.
Information on the center of genetic diversity of soybean(Glycine max) will be helpful not only for designing efficient strategies for breeding programs, but also for understanding the domestication and origin of this species. Here, we describe an analysis of genetic diversity based on simple-sequence repeat(SSR) variations within a core collection of 2 111 accessions of Chinese soybean landraces. Prior to the diversity assessment, the geographic origin of each accession was mapped. The map was then divided into grids each 2.5° in latitude and 5° in longitude. We found two regions that had higher number of alleles(NA) and greater polymorphic information content(PIC) values than the others. These regions are adjacently located within grid position of 30°–35°N×105°–110°E, which includes the valley of the middle and lower reaches of the Wei River, and the valley of the upper reaches of the Hanjiang River. It was also observed that in many regions, genetic diversity decreased with the increase in distance from the center. Another region, in northern Hebei Province(115°–120°E×40°–42.5°N), was observed having higher diversity than any surrounding regions, indicating that this is a sub-center of soybean diversity. Based on the presented results, the domestication and origin of soybean are also discussed.  相似文献   

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