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31.
32.
This paper reports the results of wheat plants exposed to SO2. The SO2-treated and control plant samples were periodically analyzed with respect to their carbohydrate content, caloric values, phytomass accumulations and net primary productivity. An initial increase, but later decrease in all these parameters was recorded in SO2-treated plants. These effects in wheat plants have been interpreted in terms of energy budget of plants under SO2-stress condition. 相似文献
33.
The ability of fly ash to remove Omega Chrome Red ME (a chrome dye, mostly used in textile industries) from water has been studied. It has been found that low adsorbate concentration, small particle size of adsorbent, low temperature, and acidic pH of the medium favor the removal of chrome dye from aqueous solutions. The dynamics of adsorbate transport from bulk to the solid phase has been studied at different temperatures in light of the adsorption of dye on the outer surface as well as diffusion within the pores of fly ash. The applicability of Langmuir isotherm suggests the formation of monolayer coverage of dye molecules on the outer interface of adsorbent. The thermodynamics of chrome dye-fly ash system indicates spontaneous and exothermic nature of the process. The pronounced removal of chrome dye in the acidic range may be due to the association of dye anions with the positively charged surface of the adsorbent. 相似文献
34.
Field experiments on cotton with different forms of urea applied at rates of 40 and 80 kg N/ha were carried out. The results indicated that application of nitrogen increased plant height, dry matter accumulation, number of bolls per plant, seed cotton yield and nitrogen uptake. The proportion of dry matter and nitrogen in the stem was increased and that in the leaves was reduced by N application. Sulphur coated urea (all applied at sowing) was about the same in effect as N-Serve treated urea and gave significantly more seed cotton yield than untreated urea, neem cake treated urea and sulphur coated urea (applied in two splits). Nitrogen efficiency as expressed by kg seed cotton production per kg N applied was greater with 40 kg N/ha rate than with 80 kg N/ha. Sulphur coated urea (all applied at sowing) gave the highest nitrogen efficiency followed by N-Serve treated urea. 相似文献
35.
Takashi Ozawa Chandra Prasad Risal Ryoko Yanagimoto 《Soil Science and Plant Nutrition》2005,51(6):917-920
The contribution of an earthworm species ( Amynthas vittatus ) to the increase of the nitrogen content of soil was examined. Three specimens of adult earthworms were introduced into 300 g of soil (Gray Lowland soil, silty clay) supplemented with 1% carboxymethyl cellulose in a container and incubated for 32 d at 22°C in the dark. The contents of total-N, NH4 -N and NO3 -N, and the population of aerobic nitrogen-fixing bacteria in soil significantly increased after incubation with the earthworms, while the natural abundance of 15 N (δ15 N) in soil decreased. The amount of nitrogen in the earthworms did not decrease during the incubation in the microcosm. Both acetylene reduction activity of the microcosm and incorporation of 15 N to soil from atmospheric 15 N2 were significantly enhanced by the introduction of the earthworms into soil, though the observed increment of nitrogen in soil was much higher than the estimated one based on the nitrogen-fixing activity. The results obtained in the present study indicated that the earthworms increased the nitrogen content of soil, presumably due to the enhancement of the nitrogen-fixing activity of the soil from the microcosm by the earthworms. 相似文献
36.
Many farmers in southeast Asia are growing rice on unpuddled soil. This practice does not permit breaking of the deadlock of increase in productivity in spite of using high yielding varieties and practising all known scientific technologies. Furthermore, farmers do dry seeding which leads to heavy infestation of weeds and reduces response to other inputs. Similarly, in rice–wheat belt due to short turn around time farmers resort to broadcast sowing of wheat after rice and no data on benefits or otherwise of tillage are available. A field study was therefore conducted for 3 years (1993–1994 to 1995–1996) at the Indian Agricultural Research Institute, New Delhi to study the effect of tillage and seeding methods in rice–wheat cropping system. Treatments included four combinations of two puddling treatments (puddling and no puddling) and two methods of rice seeding (direct seeding and transplanting) in rice and two tillage treatments (zero and conventional tillage) in wheat. Results indicated that puddling increased grain yield of rice by 0.7–1 t ha−1 and of succeeding wheat by 0.2–0.4 t ha−1, straw yield of rice by 0.8–1.7 t ha−1 and of succeeding wheat by 0.1–1.0 t ha−1.
Puddling reduced water requirement of rice by 75 mm ha and increased net return of rice–wheat system by US $175 ha−1. Transplanted rice gave significantly higher grain and straw yields and net returns than direct seeded rice both on puddled and unpuddled seedbed. Conventional tillage in wheat also increased productivity of rice–wheat cropping system significantly over zero tillage after both puddled and non-puddled rice. Our results thus show that rice should be grown on puddled soil and wheat after rice should be sown after conventional tillage. 相似文献
37.
discharge rats of Purkinje neurons were compared in control and hypothyroid adult rats. Purkinje neurons in hypothyroid rats fired significantly faster and were less sensitive to iontophoretically applied norepinephrine than those in control rats. The subsensitivity of the Purkinje neurons appeared to be primarily due to an alteration in the beta-receptor--adenylate cyclase complex, because the sensitivity of these cells to locally applied N6-monobutyryl adenosine 3'-5'-monophosphate (N6 cyclic AMP) did not change significantly. The sensitivity of the Purkinje neurons to norepinephrine could be restored in hypothyroid rats by administration of triiodothyronine. 相似文献
38.
Expression of lactate and malate dehydrogenases in tumors induced by SV40 and 7,12-dimethylbenz(a)anthracene 总被引:1,自引:0,他引:1
Isozyme patterns of lactate and malate dehydrogenases were studied in tumors induced by SV40 and 7,12-dimethylbenz(a)anthracene and in established cultures of cells from these tumors. The expression of B polypeptide subunits of lactate dehydrogenase is suppressed similarly by both agents. This may be due to inactivation of the gene at the locus determining the B polypeptide subunit. Malate dehydrogenase isozyme patterns are not changed significantly by the virus or the carcinogen. 相似文献
39.
Thallium ion-induced carbonyl carbon chemical shifts were compared for all of the L-residue-peptide carbonyl carbons of the gramicidin A transmembrane channel. Molecular structures were deduced by using the argument that helically equivalent and equally proximal carbonyls would exhibit essentially equivalent ion-induced chemical shifts. The transmembrane channel was found to be a head-to-head dimer with the structure of a left-handed, single-stranded beta-helix. 相似文献
40.
Mangale VS Hirokawa KE Satyaki PR Gokulchandran N Chikbire S Subramanian L Shetty AS Martynoga B Paul J Mai MV Li Y Flanagan LA Tole S Monuki ES 《Science (New York, N.Y.)》2008,319(5861):304-309
The earliest step in creating the cerebral cortex is the specification of neuroepithelium to a cortical fate. Using mouse genetic mosaics and timed inactivations, we demonstrated that Lhx2 acts as a classic selector gene and essential intrinsic determinant of cortical identity. Lhx2 selector activity is restricted to an early critical period when stem cells comprise the cortical neuroepithelium, where it acts cell-autonomously to specify cortical identity and suppress alternative fates in a spatially dependent manner. Laterally, Lhx2 null cells adopt antihem identity, whereas medially they become cortical hem cells, which can induce and organize ectopic hippocampal fields. In addition to providing functional evidence for Lhx2 selector activity, these findings show that the cortical hem is a hippocampal organizer. 相似文献