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1.
LIU Kai-qi XIANG Mei-mei LIU Ren ZENG Yong-san YANG Yong YU Jin-feng JIANG Xin-yin ZHANG Yue-li 《浙江大学学报(农业与生命科学版)》2004,30(4):429-429
The pectin is a backbone of the plant cell wall, its network structure will systemicly resolve when the plant cell splits up and forms. The pectinase produced by Rhizoctonia mainly acts on the pectin of cell wall, and causes the maceration of tissue and the death of protoplast. Polygalacturonase (PG) can decompose the galacturonic acid of disease tissue. The research defined the PG activities of extracellular metabolite of the different virulence Rhizoctonia isolates, and testifid the e… 相似文献
2.
苹果(品种“Quettaamri,“Kulu”,“Kashmiriamri”)幼芽(茎)培养在含不同水平(0~2.0mg/L)IBA,NAA或IAA的1/2MS培养基上时,可以分化出根.与其它品种相比,“Kashmiriamri”最易生根.各品种在低浓度生长素水平下的生根效果较好.IBA比NAA和IAA对生根的促进作用大,在不含生长素的培养基上幼芽(茎)不能生根 相似文献
3.
FENGKai-lin YANGWei-min CHENkang-ning 《东北农业大学学报(英文版)》2003,10(2):156-160
The working principle of radio remote controlling of construction machinery should be that signals of the radio wave from the transmitter obtained in the receiver were controlled and then changed into electronic analog or digital signals which can be used to drive different actuators and mechanisms of the vehicle. The vehicle could be acted by following the controlling instructions sent by the operator. The best operation mode of construction machinery is suitable not only to manual operating but also to remote controlling in the same vehicle. The design methods of the hydraulic system used for the radio remote controlling of construction machinery are discussed. The design methods of hydraulic circuits for the actuators controlled by solenoid on-off type valves ,hydro-electronic multi-way proportional valves,closed loop proportional servo driver or threeway proportional reducing valves are discussed in detail (with real example). The design methods of the power shift transmission of electro-hydraulic controlling,the devices of braking and the directional streering are discussed in this paper. 相似文献
4.
F.S. Hamid Tahira Ahmad 《农业科学与技术》2006,7(1):14-22
Field experiment was conducted on mature tea bushes of Qi-Men variety at two different altitudes from sea level i.e. at National Tea Research Institute Shinkiari (1000 m) and on farmer's field in Konsh valley at village Battal (1500 m). Different levels of nitrogen with constant dose of phosphorus and potassium were applied to observe the optimal dose of nutrients for highest yield under local edaphic conditions. The experiment was repeated for three consecutive years. The highest yield of fresh tea leaves were obtained by the application of 420 kg ha^-1 N followed by the application of 360 kg ha^-1 N at 1000 masl. The highest dose of nitrogen also reduced significantly the soil pH in the upper (0-15cm) layer depth during 1998 and 1999. During the year 2000, the reduction in soil pH was observed by the application of highest dose of nitrogen but was non-significant at 5% level. The lower soil depth (15-30 cm) showed the reduction in pH with the highest dose of nitrogen during the experimental year but was statistically non significant.
At the higher altitude of 1500 masl the highest yield of fresh tea leaves was obtained by the application of 420 kg ha^-1 during the experimental years but the increase was significant during the year 1999 and 2000. The yield of the fresh tea leaves was positively correlated with the amount of nitrogen application at both the altitudes. The increasing amount of nitrogen decreased the soil pH at both the depths of 0-15cm and 15-30cm. Unlike the lower altitude (1000 m) there was no any significant reduction in the soil pH during 1998 and 1999. A significant reduction in soil pH was found in the year 2000. 相似文献
5.
SongRen-xue YangYun-qing 《东北农业大学学报(英文版)》1999,6(2):158-160
The even degree of animal population is generlay measured by the coefficient of variation of major economic characters.Facing the coefficient of variation,a statistic with complex properties,we achieved indirectly the determination of confidence interval for even degree of an animal population by analysing the reciprocal of the statistic.The sample size which is suitable to the determination of the even degree of an animal population was probed into within the extent of permissive estimation error. 相似文献
6.
The picked pear is often ripened naturally or artificially in ethylene solution to put the pear into market earlier.When Qiuxiang pear are ripened,a great deal of ethylene is produced,the content of soluble solid,total sugar and titrable acidity are increased.The flesh is softened,the skin of fruit turns yellow,and the fruits are of aromatic favor.At differnet harvest time,respiration intensity appears different changing trends;the fruit qualities and the storage period are influenced too.Artificial ripening promotes fruit ripe and has a better effect than natural ripening.And Qiuxiang pear ripened artificially in earlier the middle or late of August can achieve better fruit qualities and higher economic value. 相似文献
7.
ZHAO Zhuo XI Geng-si 《中国农业科学(英文版)》2007,6(7):825-831
The aim of this study was to elucidate the expression and regulation of the c.kit protein in spermatogenesis of locusts. Immunohistochemistry and biological statistics were used to investigate the expression of the c-kit protein in four representative phases of spermatogenesis of three dominant species of locusts of Arcypteridae (Orthoptera: Acridoidea), namely, Omocestus viridulus (Linnaeus), Euchorthippus unicolor (Ikonn.), and Euchorthippus vittatus Zheng, and so on, in Siping area of Jilin Province, China. The results revealed the following: (1) There was weak positive expression of the c-kit protein in spermatogonia and the positive granules were thinner; (2) there was a strong positive expression of the c-kit protein in primary spermatocyte and the positive granules became the largest than in all developmental stages; (3) the c-kit protein positive expression became stronger in secondary spermatocyte, while the positive granules became thinner; (4) there was strong positive expression of the c-kit protein and the positive granules were thinner in mature sperm, which were distributed on its head and tail; (5) there were strong positive protein granules massing at the end of spermary; (6) the positive intensity of the c-kit protein in spermatogenesis was significantly different among different species of locusts. The data suggested that the c-kit protein may play a crucial role in spermatogenesis as well as maintain the physiological action of sperms and fertilization, regulate the developmental speed of spermatogenesis, and/or maintain species isolation, etc. 相似文献
8.
ZHANG Ji-yang DUAN Ai-wang MENG Zhao-jiang LIU Zu-gui 《中国农业科学(英文版)》2006,5(5):356-362
Water stress effects on stem diameter variations (SDV) were studied in a pot experiment on cotton (Gossypium hirustum L. Meimian99B). Water restriction was imposed at the flowering stage and were compared with a well-watered control treatment. The volumetric soil water content (0v) and SDV were monitored continuously. The objective was to determine the feasibility of using the parameters derived from stem diameter measurements, including maximum daily stem shrinkage (MDS), maximum daily stem diameter (MXSD), and minimum daily stem diameter (MNSD) as indicators of plant water stress. The different behavior of SDV was founded at different growth stages. At stem-maturing stage, MDS increased and MNSD decreased in deficit-irrigated plants compared with the control plants, therefore, it appeared that MDS and MNSD ccould be used as available indicators of plant water status. At stem growth stage, there were no significant differences in MDS values between treatments but MXSD and MNSD responded sharply to soil water deficits. Thus, for rapidly growing cotton, the course of MXSD or MNSD with time offered a consistent stress indicator. SDV was also closely related to atmospheric factors, solar radiation (Rs) and vapor pressure deficit (VPD) were found to be the predominant factors affecting MDS, followed by the relative humidity (RH), while air temperature (Ta) and wind velocity had the least effect. A good linear relationship was founded (r^2 = 0.921) between MDS and environmental variables (Rs, VPD, RH, and θv), which can be used to establish a reference value for detecting plant water stress based on the MDS patterns. 相似文献
9.
LI Meng LI Qingzhan 《东北农业大学学报(英文版)》2007,14(4):345-348
Leptin,a protein hormone produced and secreted predominantly by white adipose tissue,has a critical role in the regulation and coordination of energy metabolism.Leptin is produced in the mammary gland by the fat tissue or by the mammary epithelium.In vitro study has shown that leptin triggers apoptosis in mammary epithelial cells.Mammary gland involution is characterized by extensive apoptosis of the epithelial cells.At the onset of involution,STAT3 is specifically activated.Various studies show that leptin act as a paracrine and autocrin factor to influence mammary epithelial cell proliferation and differentiation.This paper reviewed the function of leptin to the involution of mammary gland. 相似文献
10.
YUE Xia-li YU Xiao-qing LIU Yong-hong DONG Yuan-yan 《中国农业科学(英文版)》2007,6(3):316-321
To study the growth effects of differing concentrations of bensulfuron-methyl on Chlorella pyrenoidosa and to evaluate the ecological risk, the effects of bensulfuron-methyl on the growth and the content change of chlorophyll and protein in Chlorella pyrenoidosa were studied through 96 h acute toxicity tests. Bensulfuron-methyl accelerated the growth of algae at lower concentrations (〈 1 mg L^-1) with content increase of chlorophyll or protein, and it inhibited the growth of algae at higher concentrations (〉 5 mg L^-1). The content of chlorophyll or protein in algae cells reduced with the increasing concentration of bensulfuron-methyl, exhibiting the good concentration-effect relationship. The 96 h-EC50 of bensulfuronmethyl upon the algae was 15.7 mg L^-1 Bensulfuron-methyl has inhibiting effect on the growth of Chlorella pyrenoidosa and is low in toxicity. 相似文献
11.
Analysis of Genetic Diversity of Processing Apple Varieties 总被引:1,自引:0,他引:1
SONG Ye ZHAI Heng YAO Yu-xin LI Ming DU Yuan-peng 《中国农业科学(英文版)》2006,5(10):745-750
Genetic diversity of 18 processing apple varieties and two fresh varieties were evaluated using 12 simple sequence repeats (SSR) primer pairs previously identified in Malus domestica Borkh. A total of 87 alleles in 10 loci were detected using 10 polymorphic SSR markers selected within the range of 5-14 alleles per locus. All the 20 varieties could be distinguished using two primer pairs and they were divided into four groups using cluster analysis. The genetic similarity (GS) of groups analyzed using cluster analysis varied from 0.14 to 0.83. High acid variety Avrolles separated from other varieties with GS less than 0.42. The second group contained Longfeng and Dolgo from Northeast of China, the inherited genes of Chinese crab apple. The five cider varieties with high tannin contents, namely, Dabinette, Frequin rouge, Kermerrien, M.Menard, and D.Coetligne were clustered into the third group. The fourth group was mainly composed of 12 juice and fresh varieties. Principal coordinate analysis (PCO) also divided all the varieties into four groups. Juice and fresh apple varieties, Longfeng and Dolgo were clustered together, respectively, using both the analyses. Both the analyses showed there was much difference between cider and juice varieties, cider and fresh varieties, as well as Chinese crab apple and western European crab apple, whereas juice varieties and fresh varieties had a similar genetic background. The genetic diversity and differentiation could be sufficiently reflected by combining the two analytical methods. 相似文献
12.
ZHANG Ying-jie LIU Yue-qin SUN Hong-xin SUN Shao-hua LI Wu 《中国农业科学(英文版)》2007,6(5):634-640
Forecast of the heterosis of Small Tail Han sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA was done in different sheep breeds. The gene frequency, the polymorphism information contents, the number of effective alleles, the heterozygosity, and the genetic distances were studied in four imported meat sheep and Small Tail Han sheep using five microsatellite loci. The crossing effects on the Small Tail Han sheep with four imported meat sheep were tested. The results indicate that there are genetic polymorphisms at five microsatellite loci in five sheep breeds. Five microsatellite loci can be used for genetic diversity evaluation in sheep breeds. The genetic variability of Dorset is the highest, and that of the Small Tail Han sheep is the lowest in the five sheep breeds. The order of heterosis from large to small in four imported meat sheep by the analysis of genetic relationship is White-Suffolk, Black-Suffolk, Dorset, and Texel. This accords with the testing results of actual heterosis. It is feasible to forecast the heterosis of Small Tail Han sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA, which will have an important value for sheep breeding in the future. 相似文献
13.
LI Jiu-sheng LI Bei SU Mei-shuang RAO Min-jie 《中国农业科学(英文版)》2005,4(9):693-699
Field experiments were conducted to investigate the effects of nonuniformity of sprinkler fertigation and the amount of fertilizers applied through fertigation on nitrogen uptake and crop yield during two growing seasons of winter wheat in 2002-2003 and 2003-2004 at an experimental station in Beijing. In the experiments, the seasonal averaged Christiansen irrigation uniformity coefficient (CU) varied from 72% to 84%. Except for the fertilizer applied before planting, fertilizer was applied with the sprinkler irrigation system with a seasonal averaged CU for fertigation varied from 71% to 85%. Three levels of fertilizer applied varying from 0 to 180 kg N ha^-1 were used in the experiments. The experimental results demonstrated that sprinkler fertigation uniformity had insignificant effects on nitrogen uptake and crop yield for the uniformity range tested. Also, the influence of fertilizer applied through sprinkler fertigation on crop yield was minor, while the total nitrogen content for stem and nitrogen uptake increased with increasing fertilizer applied. 相似文献
14.
Abdullah F Ilias G N M 《浙江大学学报(农业与生命科学版)》2004,30(4):391-391
The palm, Elaeis guineensis, has its origins in Africa but is planted on a commercial basis in several countries Statistics for 2002 showed that in the lead for land mass under oil palm cultivation is Indonesia, at 3,769,000 ha, followed by Malaysia at 3,376,000 ha; however, the world‘s leading 相似文献
15.
SHEN Ping GAO Guisheng SHI Qiumei LI Min 《东北农业大学学报(英文版)》2009,16(1):56-58
To investigate the mechanism of action of Chinese herbal medicine, the immunocells of Harder's glands were observed. The healthy Hy-Line Brown chickens of 12-day-old were divided into three groups randomly. The chickens in group 1 and 2 drank the water with 0.5% and 1% Chinese herbal medicine immunopromoter every day. The chickens in group 3 as control drank pure water. The Harder's glands of the chickens from 0.5% group, 1% group and control group at 24, 36 and 48 d after drinking medicine respectively were made into histological section. And then the histological sections were observed histologically. The results showed that Chinese herbal medicine could increase the quantity of the immunocells in glandular organs conspicuously. Immunopotentiator of Chinese herbal medicine could promote the amount and growth of secreted immunoglobuline and elevate the immune level of the orgamsm, and the effect of 1% group was higher than that of 0.5% group. 相似文献
16.
GUI Lian-you CHEN Zong-mao LIU Shu-sheng 《中国农业科学(英文版)》2005,4(9):673-679
The effect of tea plant Camellia sinensis induced by exogenous methyl jasmonate (MJA) on lipoxygenase (LOX), polyphenol oxidase (PPO) and proteinase inhibitor (PI) activity in the leaves of tea plants, as well as the growth and midgut proteinase activity of the geometrid Ectropis obliqua larvae were studied. MJA significantly induced LOX, PPO and PI activity in leaves of tea plants. When geometrid larvae have fed on leaves of tea plants treated with MJA, the activities of the high alkaline trypsin-like enzyme and chymotrypsin-like enzyme in their midgut were significantly inhibited, but the activities of the low alkaline trypsin-like enzyme in their midgut were unaffected, leading to imbalance between different types of proteinase activity in the midgut of the larvae and in turn, the growth were inhibited. These chains of response may be an important mechanism of the direct resistance induced by MJA-treatment of tea plant on geometrid larvae. 相似文献
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Antagnism of three strains of Trichoderma spp. against mycelial growth of Rhizoctonia salani
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ZHANG Jing-ze TU Yan-la 《浙江大学学报(农业与生命科学版)》2004,30(4):411-411
Three strains of Trichoderma spp. TV112, TX003, TY009 obtained from previous experiments could inhibit the sclerotial formation of two strains of Rhizoctonia salani AG1 (-1A) isolated from the rice paddies in Hanzhou of China. However, it is unclear if there are the antagonism and mycoparasitism of the Trichoderma strains tested against the mycelial growth of R. solani . The objective of this research was to evaluate the ability of the Trichoderma strains to inhibit the mycelial… 相似文献
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JIAWen-ming ZHOU Yi-lin DUAN Xia-yu LUO Yong DING Sheng-li CAO Xue-ren Bruce D L Fitt 《中国农业科学(英文版)》2013,(1):87-94
Wheat dwarf bunt, caused by Tilletia controversa Kühn (TCK), is an important quarantine wheat disease throughout the world. Based on published research results of the biology and the epidemiology of the disease, the main factors including temperature, humidity, snow cover, and their parameters relating to teliospore germination, infection and epidemics of TCK were determined. The geophytopathological models for the risk analysis of wheat dwarf bunt establishment were modified. Fifty-year meteorologic data from about 500 weather stations in China were used to calculate the probabilities of TCK establishment in different geographic sites with the models. The map that displays the establishment risk of TCK in winter wheat growing regions in China was generated by using geographical information system (GIS). The zones showing high, moderate, low, and very low, including no risk, of TCK establishment accounted for 27.33, 27.69, 38.12, and 6.86% of total winter wheat growing areas in China, respectively. These results will provide useful information to formulate quarantine regulations and wheat importation policy in China. 相似文献