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51.
52.
Transections of the brain of rabbit reveal that electroencephalographic arousal produced by injections of adrenaline takes place at the midbrain level, while mescaline and 3,4-dimethoxyphenylethylamine induce such arousal lower in the brainstem, at the medullary level.  相似文献   
53.
54.
祁门红茶的香气特征   总被引:26,自引:7,他引:26  
通过对祁红当家品种——槠叶群体种及其适制绿茶的亲缘种——安徽7号(对照)在加工红茶的过程中香气形成的动态分析和比较研究表明,在祁红检出的110多种香气成分中,己醛,1-戊烯-3-醇、反-2-己烯醛、顺-3-己烯醇、芳樟醇氧化物Ⅱ、芳樟醇、香叶醇、橙花叔醇等含量较高。在相同的祁红加工过程中,槠叶群体的香气物质形成总量高于对照,且形成高峰超前,其中香叶醇含量在揉捻阶段剧增;与安徽7号相比,香叶醇含量高出30倍以上,而其他香气成分含量则无明显差异。实验还发现,两品种茶叶在加工过程中,儿茶素的减少与茶叶香气总量及其中的萜烯醇类的增长均具有很好的对应关系,槠叶群体中有关香气配糖体的含量高于安徽7号,文中对此作了讨论。  相似文献   
55.
We investigated the effects of poultry manures (PM) and cow manures (CM) using estimated mineralizable nitrogen (EMN) method on nitrate, nutrient content and growth parameters of komatsuna and compared with chemical fertilizer (CF) in an abandoned soil. We applied manures as EMN based on their total N content. The 100% of EMN by PM or CM enhanced dry matter (DM) but depressed nitrate content. The PM-Keifun (PMK) with total N (4.87%) produced greater growth parameters, DM, nutrient content and lower nitrate content but manures with total N (<2%) could not. The solo CF150 did not promote leaf number but increased nitrate and Na content. In conclusion, a higher total N (>4%) concentration of manure led to increase availability and nutrient contents, DM, and depressed nitrate content of komatsuna, comparable with solo CF in an abandoned soil.  相似文献   
56.
The carbohydrates in soil organic matter seem to be derived from undecomposed or partially decomposed plant and microbial residues, In soil, these carbohydrates exist chiefly in such from as polysaccharide hemicellulose, and their polyuronide has been the chief object of investigation1)-3). In various soil, the polyuronide is found in a large quantity in fulvic fraction of soil organic matter and has been considered as important in connection with the physical structure of soil4),5). According to Lynch 5), the carbohydrate content of humic acid is markedly smaller than that of fulvic acid. His work also indicates that a' considerable change is noted in the content and composition of the carbohydrate in humic acid because of the addition of some organic substances to the soils, or of the cultivation of virgin soils. Further, some investigators7) believe that uronic acid is introduced into the aromatic structure of the humic acid by changing into pentose and furan. Accordingly, it seems that the role of carbohydrate in the formation of soil humic acid should not be overlooked.  相似文献   
57.
Five barley cultivars were grown together in complete, low-P·low-pH and high-Al medium containing only NO3, only NH4 or both NO3 and NH4 as N sources, respectively using an automatic control system of pH for water culture, and the relationship between the differential Al tolerance and the plant-induced pH change of medium among the barley cultivars was investigated.

The pH of the medium containing only NO3 as N source tended to increase, whereas the pH of the other media containing only NH4 or both NO3 and NH4 as N sources tended to decrease, but the fluctuations of the medium pH could be maintained within the value of 0.2 pH in the complete medium and within the value of 0.1 pH in the high-Al medium.

Barley cultivars still differed in their Al tolerance in the medium which was continuously stirred and circulated at a constant pH. The pattern of Al tolerance was not affected by the N sources in the medium. The plant-induced pH change of medium for each cultivar was influenced by the N sources in the medium, and was not correlated positively with Al tolerance. The contents of Al and Ca or other nutrient cations in roots were positively correlated with Al tolerance and positive correlations were recognized also between the contents of Al and Ca or some other nutrient cations in the roots.

In conclusion, the following mechanisms are proposed. Al tolerant barley cultivars exclude Al actively outside the plasmalemma of the root cells, and the excluded Al may polymerize and or react with P to form Al precipitates. Consequently, in the Al tolerant barley cultivars the Al content may be low in the root protoplasts, high in the whole root tissues and the contents of Ca or other nutrients may be high in the roots. The plant-induced pH change of medium is not considered to be the cause of the differential Al tolerance among barley cultivars.  相似文献   
58.
Soybean (Glycine max L. Merr.) cvs. Akisengoku and Peking, and cowpea (Vigna unguiculata Walp.) cv. Kegonnotaki were inoculated with Bradyrhizobium japonicum AlO17, Shinorhizobium fredii USDAI93, and B. sp. Vigna MAFF03-03063, respectively and were cultured hydroponically with supply of CO2-free air, 3dm3 m-3 CO2 air, or 25 dm3 m-3 CO2 air to study the effects of the CO2 concentration in the rhizosphere on plant growth, nodulation, and nitrogen fixation. Increase of the CO2 concentration in the rhizosphere led to the increase of the plant dry weight in the symbiosis between Peking and USDAI93, and that between Kegonnotaki and MAFF03-03063. On the other hand, dry matter accumulation in the symbiosis between Akisengoku and AI017 decreased under the supply of 25 dm3 m-3 CO2 air aimed at increasing the CO2 concentration in the rhizosphere beyond the optimum CO2 concentration for growth. Nodule mass and nodule number per plant were highest in Akisengoku, followed by Kegonnotaki and lowest in Peking. Also the increase of the CO2 concentration in the rhizosphere led to the increase of the nodule mass and number in Kegonnotaki, while no changes were observed in Akisengoku and Peking. Biological nitrogen fixation (BNF) was highest in Akisengoku, followed by Kegonnotaki, and lowest or near zero in Peking. BNF in Akisengoku and Kegonnotaki showed a similar tendency to that of dry matter accumulation. BNF of Peking was especially low under the supply of CO2-free air, and it increased with the increase of the CO2 concentration in the rhizosphere. For the symbiosis of Bradyrhizobium strains with soybean and cowpea, the most suitable CO2 concentration for N2 fixation and plant growth was estimated to be about 10 dm3 m-3, while for the symbiosis of S. fredii with soybean, the value was estimated to be above 30 dm3 m-3.  相似文献   
59.
ABSTRACT

When rice is grown under moderate salinity (6?dS m?1), yields are reduced by up to 50%. The development of salt-tolerant varieties is a key strategy for increasing yields. We conducted an experiment using a hydroponic system with ion components similar to seawater to determine useful parameters for assessing salt tolerance. Two-week-old seedlings were grown for 7 days on Yoshida hydroponic solution. The treatment group then additionally received an artificial seawater solution (electrical conductivity, 12 dS m?1). After a 2-week period of salt stress, standard evaluation scores (SES) of visual salt injuries were assessed. The K, Na, Mg, and Ca contents were then determined in the roots, sheaths, and leaves of each plant. Following the SES results, we divided the 37 genotypes into four groups: salt-tolerant groups (STGs), moderately salt-tolerant groups, salt-sensitive groups (HSSGs), and highly salt-sensitive groups (HSSGs). In the control, STGs had the highest sheath K content (30.1 mg g?1 dried weight [DW]), whereas HSSGs had the lowest (21.4 mg g?1 DW). Sheath K was also highly and negatively correlated with SES. This suggests that sheath K may be useful for identifying salt-tolerant varieties under non-saline conditions. Plant growth was significantly affected under salt stress, but STGs had the smallest decrease in sheath DW. SES was significantly correlated with sheath and leaf Na, sheath K and Mg, and sheath and leaf Na/K and Na/Mg ratios. The results suggested that sheath K, Na/K, and Na/Mg may be useful indicators for genetic analyses of salt-tolerant varieties under salt-stress conditions. The salt-tolerant cultivars, KCR20, KCR124, and KCR136, are possible candidates for such studies because they had high sheath K content (31.19, 31.21, 29.44 mg g?1 DW, respectively) under non-saline conditions and low SES (3.3, 3.6, 3.9, respectively), and low sheath Na/K (0.64, 0.52, 0.92, respectively) and Na/Mg ratios (2.96, 2.27, 3.03, respectively) under salt-stress conditions.  相似文献   
60.
Abstract

Caldwell and Vest (1968) planted soybeans (Glycine max L. Merr.) with various genotypes at Beltsville, USA, without inoculating them with Bradyrhizobium japonicum, and showed that soybeans preferred certain serotypes of rhizobial strains for nodulation. Recently, the authors have reported that soybeans carrying nodulation-conditioning genes preferred appropriate strains showing specific behavior for nodulation (Ishizuka et al. 1991). For instance, nodulation of soybean cv. Hardee which carries the nodulation-conditioning genes, Rj 2 and Rj 3, does not occur with B. japonicum USDA122, USDA33, Is-1, etc. Nodulation of cv. Hill which carries the Rj 4 gene, does not occur with B. japonicum USDA61, Is-21, etc. while A62-2 which carries a recessive gene rj 1, does not nodulate with almost any of the strains of B. japonicum. Therefore, the B. japonicum strains can be classified into three nodulation types based on the compatibility with these Rj-cultivars, that is, type A strains which effectively nodulated both Rj 2 Rj 3-cultivars and Rj 4-ones, type B strains which did not nodulate the Rj 2 Rj 3-cultivars and type C strains which did not nodulate the Rj 4-cultivars. When the nodulation types of the isolates from nodules of field-grown soybeans were examined, it was suggested that the Rj 2 Rj 3-cultivars and Rj 4-cultivars preferred the type C and type B strains, respectively (Ishizuka et al. 1991).  相似文献   
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