脱毒马铃薯种薯增产效果研究

本试验通过对青薯168脱毒种薯产量性状的研究。结果表明；脱毒种比未脱毒种生育期长18天，单株结薯数增加1.91个，平均薯重提高了20g，商品率增加22％，产量增加16674kg/hm^2，增产率为72.9%。     

不同氮肥用量和氮钾配比对济源烤烟生长和品质性状的影响

采用田间试验与室内分析相结合的方法,以‘中烟100’为供试材料,研究了不同氮肥用量和氮钾配比对济源烤烟生长、单叶质量、中部叶有机钾指数及致香物质的影响.结果表明:1)当施氮量相同(施用氮肥75kg/hm2)时,随氮钾比例的升高成熟期叶干质量、单叶质量、中部叶致香物质均呈先增加后减少趋势,中部叶有机钾指数则随氮钾比例的升高先减小后增加;当氮钾比例相同(N∶K=1∶5)时,随氮肥施用量增加单叶质量、中部叶有机钾指数及致香物质呈先增加后减少的趋势,成熟期叶干质量随氮肥施用量的增加而增加.2)施用纯氮60kg/hm2,N∶K2O=1∶5与施用纯氮75kg/hm2,N∶K2O=1∶5处理能显著提高烤烟单叶质量、中部叶钾含量及致香物质含量,施用纯氮60kg/hm2,N∶K2O=1∶5处理能显著提高中部叶有机钾指数.3)济源王屋烟区生产上保持氮钾比不变,适量减少氮素的施用量(施氮量由75kg/hm2降至60kg/hm2),能够起到控氮、稳钾、降硫、稳产、提高烟叶品质的作用.     

Optimize nitrogen fertilization location in root-growing zone to increase grain yield and nitrogen use efficiency of transplanted rice in subtropical China

The optimized nitrogen fertilization location differs in different rice-growing regions. We optimized nitrogen deep-point application in root-growing zone(NARZ) for transplanted rice in subtropical China. Field plot experiments were conducted over two years(2014–2015) in a double-rice cropping system to evaluate the effects of nitrogen(N) fertilizer location on grain yield and N use efficiency(NUE). Four different nitrogen deep-point application methods(DN) were compared with traditional broadcast application(BN) using granular urea. The results showed that grain yield, recovery efficiency of N(REN), agronomic efficiency of N(AEN), and partial factor productivity of N(PFP_N) significantly increased 10.3–63.4, 13.7–56.7, 24.7–201.9 and 10.2–63.4%, respectively, in DN treatment compared to BN, respectively. We also find that DN treatments increased grain yield as well as grain N content, and thus grain quality, in comparison with conventional BN treatment. Correlation analysis indicated that significant improvement in grain yield and NUE mainly resulted from increases in productive panicle number and grain N content. In our proposed NARZ method, granular urea should be placed 0 to 5 cm around the rice seeding at a 12-cm depth druing rice transplanting. In NARZ, balanced application of N, P and K further improved grain yield and NUE over treatments with a single N deep-point application. High N uptake by the rice plant did not cause significant soil fertility depletion, demonstrating that this method could guarantee sustainable rice production.     

Oxygen consumption and cellular ion transport: evidence for adenosine triphosphate to O2 ratio near 6 in intact cell

Oxygen (O2) consumption and net K+ uptake were measured simultaneously upon reintroduction of K+ into a K+-depleted suspension of renal tubules. The K+/O2 stoichiometries of 11.8 +/- 0.2 and 8.4 +/- 0.6 were obtained for reduced nicotinamide adenine dinucleotide- and flavoprotein-linked substrates, respectively. These values complement classical K+ to adenosine triphosphate (ATP) and ATP/O2 stoichiometries, thereby demonstrating a remarkably efficient coupling between the processes of Na+- and K+-dependent adenosinetriphosphatase-mediated ion transport and oxidative phosphorylation within the intact cell.     

Solar neutrinos: proposal for a new test

The predicted flux on the earth of solar neutrinos has eluded detection, confounding current ideas of solar energy production by nuclear fusion. The dominant low-energy component of that flux can be detected by mass-spectrometric assay of the induced tiny concentration of 1.6 x 10(7) year lead-205 in old thallium minerals. Comments are solicited from those in all relevant disciplines.     

Venus was wet: a measurement of the ratio of deuterium to hydrogen

The deuterium-hydrogen abundance ratio in the Venus atmosphere was measured while the inlets to the Pioneer Venus large probe mass spectrometer were coated with sulfuric acid from Venus' clouds. The ratio is (1.6 +/- 0.2) x 10(-2). The hundredfold enrichment of deuterium means that at least 0.3 percent of a terrestrial ocean was outgassed on Venus, but is consistent with a much greater production.     

缓释尿素对稻田水体氮磷削减和水稻产量的影响

为了减少稻田水体中的氮磷元素含量流失给水环境带来的危害,保护水环境良性循环,研究了缓释尿素对稻田水体氮磷元素及水稻产量的影响.结果表明:不同施肥处理对稻田水体中氮素含量影响较大,在水稻的整个生育期中,分蘖期的全氮含量最高,其中施用普通尿素的处理在分蘖期水体中的全氮含量达24.25 mg/L,超出了农田灌溉水质标准所规定...     

14C-dead living biomass: evidence for microbial assimilation of ancient organic carbon during shale weathering

Prokaryotes have been cultured from a modern weathering profile developed on a approximately 365-million-year-old black shale that use macromolecular shale organic matter as their sole organic carbon source. Using natural-abundance carbon-14 analysis of membrane lipids, we show that 74 to 94% of lipid carbon in these cultures derives from assimilation of carbon-14-free organic carbon from the shale. These results reveal that microorganisms enriched from shale weathering profiles are able to use a macromolecular and putatively refractory pool of ancient organic matter. This activity may facilitate the oxidation of sedimentary organic matter to inorganic carbon when sedimentary rocks are exposed by erosion. Thus, microorganisms may play a more active role in the geochemical carbon cycle than previously recognized, with profound implications for controls on the abundance of oxygen and carbon dioxide in Earth's atmosphere over geologic time.     

Caudate unit responses to nigral stimuli: evidence for a possible nigro-neostriatal pathway

Electrical stimulation of the Substantia nigra evokes depressant and facilitatory responses from individually recorded caudate nucleus neurons. These effects resemble those elicited from caudate cells by microiontophoretic ejections of dopamine. Since histochemical evidence suggests that dopamine-containing fibers link the substantia nigra with the caudate, this pathway may mediate the changes in caudate spike rates produced by nigral stimuli.     

Thyrocalcitonin: evidence for release in a spontaneous hypocalcemic disorder

Thyrocalcitonin content of thyroid gland extracts from normal postparturient cows was 3.9 times greater than in cows with postparturient paresis. The parafollicular cells in diseased cows were less numerous and appeared to have discharged their secretory products. An abrupt release of thyrocalcitonin near parturition may be related to the development of the hypocalcemia and hypophosphatemia in this disorder.     

Ratio of blue to red light: a brief increase following sunset

Visible spectra of solar radiation were recorded during sunset. With the development of twilight, there was an expected decrease in the blue-to-red ratio; but directly upon setting of the sun there was a sharp rise in this ratio (due to the predominance of sky-light) which attenuated rapidly to follow the pattern that it had previously taken.     

Gamma rays: further evidence for lack of a threshold dose for lethality to human cells

In experiments designed to measure human cell survival sith +/- 2 percent accuracy it was found that low doses (21 to 87 rad) of gamma-rays inactivated the colony-forming ability of cultured human cells with a probability of 0.00226 +/- 0.00012 per rad. There appears to be no threshold for the lethality of radiation to human cells in vitro.     

Galactokinase: evidence for a new racial polymorphism

Activities of galactokinase and galactose-1-phosphate uridyltransferase in red cells were assayed in a mixed racial population of 645 pregnant women. The distribution of individual transferase activities for black subjects was the same as that for whites. In contrast, the distributions of individual galactokinase activities differed significantly in blacks and whites, the mean for the black population being 30 percent lower than the mean for the white population. The same racial difference was found when red cell galactokinase activity was examined in males and in newborns. Because low-, intermediate-, and high-galactokinase activities appear to segregate within several black families, this observed difference suggests a new, racially determined enzyme polymorphism.     

拔节与孕穗肥比例对中筋小麦氮营养、产量和品质的调控效应

以中筋小麦扬麦10号为试验材料,探讨拔节与孕穗肥施用比例对氮素吸收利用、籽粒产量和品质的调节效应。结果表明:在中等肥力土壤上,增加拔节期氮肥施用比例,产量提高,蛋白质和面筋含量下降,氮素农学效率、生理效率和运转效率(氮收获指数)均较低,氮素生产效率、吸收效率、利用效率和氮肥表观利用率中等;拔节肥和孕穗肥二次施用有利于产量和品质协调,氮素生产效率、农学效率、吸收效率和氮肥表观利用率最高,但氮素利用效率最低,氮素生理效率和运转效率中等。在土壤肥力中等、施氮量为240kg·hm-2条件下,以基肥、拔节肥、孕穗肥比例为2∶1∶1较为适宜,在土壤后期供肥能力较高、施氮量为150kg·hm-2条件下,则以基肥、壮蘖肥、拔节肥、孕穗肥比例为10∶2∶1～2∶6～7较为适宜。     

Seawater teleosts: evidence for a sodium-potassium exchange in the branchial sodium-excreting pump

The net sodium extrusion rate by the gill of the seawater-adapted euryhaline flounder is identical to the potassium influx. The excretion of sodium is blocked in K(+)-free seawater solutions. The instantaneous sodium outflux readjustment pattern of flounders transferred from seawater to solutions of various sodium chloride or potassium chloride concentrations is consistent with the hypothesis of a linkage between Na(+) outflux and K(+) influx through a common exchange carrier. External Na(+) and K(+) compete for this comnmonz carrier. It is suggested that the exchange diffusion mechanism (linkage of sodium influx and outflux) and the high internal sodium turnover rate which characterizes all seawater teleosts are the results of this competitive process. The sodium-potassium dependent adenosine triphosphatase system occurring in the gill of the seawater teleosts may play a central role in this sodium-potassium exchange pump.     

Shocked quartz in the cretaceous-tertiary boundary clays: evidence for a global distribution

Shocked quartz grains displaying planar features were isolated from Cretaceous- Tertiary boundary clays at five sites in Europe, a core from the north-central Pacific Ocean, and a site in New Zealand. At all of these sites, the planar features in the shocked quartz can be indexed to rational crystallographic planes of the quartz lattice. The grains display streaking indicative of shock in x-ray diffraction photographs and also show reduced refractive indices. These characteristic features of shocked quartz at several sites worldwide confirm that an impact event at the Cretaceous-Tertiary boundary distributed ejecta products in an earth-girdling dust cloud, as postulated by the Alvarez impact hypothesis.     

Social communication in canids: evidence for the evolution of a stereotyped Mammalian display

The variability in the duration and form of the canid play bow was studied in infant coyotes, wolves, wolf-dog hybrids, beagles, and adult free-ranging dogs. Both duration and form showed marked stereotypy. It appears that the role of this context-specific social signal in the communication of play intention has been fostered by selection for "morphological" stereotypy.     

Effects of nitrogen rate and ratio of base fertilizer and topdressing on uptake, translocation of nitrogen and yield in wheat

Application of nitrogen (N) fertilizer is one of the most important measures to increase grain yield and protein content in winter wheat (Triticum aestivum L.) production. However, misuse of N Tertilizer will not only affect gram yield and quality, but also cause the decline of economic benefits and related negative environmental effects. It is essential to study reasonable N application regimes for profitable yields, efficient N utilization and reduction in possible environmental pollution. The objective of this study was to determine the N uptake and translocation in wheat plants by using ¹⁵N isotope tracers in PVC cylinders (2.05 m long, ϕ 0.2 m, without bottom) in seven treatments: without N fertilizer application (N0); N application rate of 168 kg/hm² (0.527 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N1), 1:2 (N2) and 0:1 (N3); N application rate of 240 kg/hm² (0.753 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N4), 1:2 (N5) and 0:1 (N6). The ¹⁵N tracer experiment showed that the main basal N absorbed by plant from sowing to jointing stage accounted for 78.04%–89.67%; fertilizer N use efficiency (FNUE, N fertilizer accumulation in plant/N supplied) of topdressing was significantly higher than that of basal N; reducing basal N amount and increasing topdressing N amount could appropriately promote the plant’s absorption of more N fertilizer and enhance FNUE, of which treatment N2 had the highest values. Under the high-yield condition, when N fertilizer rate was increased from 168 to 240 kg/hm², there were no significant differences in the amount of N accumulation in plants and in grains between treatments with the same ratio of base fertilizer to topdressing; by reducing basal N amount and increasing topdressing N amount accordingly, the translocation efficiency (TE, accumulation amount from vegetative organs to gram/N accumulation in vegetative organs during anthesis) increased, and the amount of N assimilation to grains after anthesis and its contribution proportion (the amount of N assimilation to grains after anthesis/N accumulation in grain) also increased. In other words, grain N accumulation amount increased with increasing amount of topdressing N at the same N fertilizer rate. There were no significant differences among treatments N2, N3, N5 and N6 in grain N accumulation. Appropriate N fertilizer rate with a reduction in basal N amount and an increase in topdressing N amount such as in N2, N5 and N6 increased grain yield and protein content. In conclusion, under conditions used in this experiment, as far as grain yield, protein content and FNUE are concerned, the recommended appropriate N fertilizer application regime is treatment N2, with a N fertilizer rate of 168 kg/hm² and a ratio of base fertilizer to topdressing of 1:2. Translated from Journal of Acta Agronomica Sinica, 2006, 32(12): 1860–1866 [译自: 作物学报]