Difference in system of current photosynthesized carbon distribution to carbon and nitrogen compounds between rice and soybean

¹⁴CO₂ was assimilated during 10 min in leaf of rice and soybean under 21 kPa O2 (21% O₂ treatment) and 2 kPa O₂ (2% O₂ treatment) at the vegetative growth stage and flowering stage. The ¹⁴C distribution ratio to respired CO₂ and crude chemical components (sugars, polysaccharides, amino acids, organic acids, and proteins) was determined. In this paper, since emphasis was placed on the ¹⁴C distribution mechanism to carbon compounds and nitrogen compounds, the terms carbon metabolism pool (C-pool) composed of sugars and polysaccharides, and nitrogen metabolism pool (N-pool) composed of organic acids, amino acids and proteins were used. The results obtained were as follows.

¹⁴C distribution ratio to N-pool at 0 min after ¹⁴C assimilation was higher in soybean than in rice regardless of the treatments and stages, and that at 30 min after ¹⁴C assimilation under light condition markedly decreased both in rice and soybean. Therefore, especially in soybean, a large amount of photosynthesized ¹⁴C was once distributed to the N-pool, then ¹⁴C compounds in the N-pool were reconstructed into the C-pool. During this reconstruction process, ¹⁴C compounds in the N-pool were actively respired.

¹⁴C distribution to N-pool at 0 min after ¹⁴C assimilation changed slightly or did not change by the N treatment. ¹⁴C distribution to N-pool in the - N treatment of soybean (13–29 mg N g^-1 content in leaves) was higher than that in the + N treatment of rice (31–48 mg N g^-1 content in leaves). Photosynthesized carbon distribution to N-pool in rice decreased with growth, while it remained constant in soybean. Accordingly, in soybean, photosynthesized carbon was predominantly distributed to the N-pool through photorespiration and/or Calvin cycle (supplying triose-P), which was less affected by nitrogen nutrient and aging. Thus, the mechanism of photosynthesized carbon distribution to carbon and nitrogen compounds was basically regulated by inherited characters of each plant more than by the nitrogen status of leaves.

By the 2% O₂ treatment, ¹⁴C distribution to N-pool decreased in both crops regardless of N treatment, indicating that photorespiration plays an important role in the supply of the preliminarily photosynthesized carbon compounds to N-pool. In the 2% O₂ treatment, ¹⁴C distribution to N-pool was higher in soybean than in rice, indicating that triose-P transported from chloroplast was preferentially distributed to N-pool in the case of soybean.     

Efficacy of single application ammonium sulfate in suppressing potato common scab

Abstract

The objective of this study was to suppress potato common scab by lowering the soil pH and increasing the concentration of water-soluble aluminum (Al) in soil with a single application of ammonium sulfate into each row. Superphosphate (P) and potassium sulfate (K) were applied to the surface soil horizon and ammonium sulfate (N) was applied only into the rows along which potato plants were to be planted. By this application method, the soil pH was lowered and the concentration of water-soluble Al was increased in the soil of the rows where potato tubers were grown. Potato common scab was suppressed in the soil containing water-soluble Al in concentrations of 0.2 to 0.3 mg L^?1 or higher. The pH of the soil fertilized as indicated above remained lower than that of the control soil to which the mixture of N, P, and K was uniformly applied. In soil types such as Haplic Andosols containing allophane at high concentrations of 71 g kg^?1 in Memanbetsu, the suppression of potato common scab by this single application of ammonium sulfate was less effective due to the low soluble Al concentration. In other soil types, the soil pH was easily controlled and common scab was suppressed by this method. The advantages of this method are that (a) it minimizes the use of fertilizers, thus reducing the adverse effects of unnecessary fertilizers on the soil; and (b) it lowers the cost by eliminating additional agricultural chemicals and extra fertilizers.     

Effect of placement of coated urea fertilizer on root growth and rubidium uptake activity in soybean plant

Abstract

We reported in the previous paper (Takahashi et al. 1991) that the deep placement of slow release N fertilizer (coated urea) contributed to a stable increase of soybean (Glycine max L. Merr.) yield. In the previous study we observed that the deep placement of coated urea did not depress appreciably the nitrogen fixation by root nodules although fertilizer N was efficiently utilized. We assumed that the N absorbed from the roots in the deep layers did not cause nodule senescence, contributed to the maintenance of the leaf activity during the maturation stage, and that the increase in the availability of carbohydrate and N improved seed production. In the current report the effects of placement of coated urea fertilizer on the root growth and activity were studied by measuring the root dry weight and Rb absorption activity.     

Relationship between the Placental Retention Time and the Reproductive Performance at the Foal Heat in Thoroughbred and a Comparison with Heavy Draft

The aim of this study was to clarify the relationship between the placental retention time (PRT) and the reproductive performance following mating at the foal heat in Thoroughbreds. For this purpose, we interviewed 292 farmers over a period of 3 years with questionnaires evaluating foaling, expulsion of placenta and reproductive performance at the foal heat in 1,432 mares. The obtained data were later compared with a previous study of heavy draft mares. The average of the PRT of the 1,432 Thoroughbred mares was 58 ± 88 min (mean ± SD). The mean PRT of Thoroughbreds was significantly shorter than that of the148 min of heavy draft mares. The incidences of retained placenta (RP) occurring in the Thoroughbred mares were 5.2 and 4.0%, for over 3 and 4 hr after foaling, respectively. The incidence of RP over 4 hr was significantly lower than that of 25% in heavy draft mares. The pregnancy rate at foal heat of the mares in which PRT was less than 3 hr was 37%, and it significantly decreased to 11% for those with PRT of more than 3 hr. In the comparison of the reproductive performance between Thoroughbred and heavy draft mares, the pregnancy rate of Thoroughbreds dropped drastically to 10% when PRT exceeded 40, and in consequence, the pregnancy rate of Thoroughbreds was significantly lower than the 30% of heavy draft mares, which had a PRT of over 4 hr. In conclusion, the Thoroughbred mares had a low incidence of RP, however, a PRT exceeding 3 hr severely affected the reproductive performance at the foal heat.     

Use of the RothC model to estimate the carbon sequestration potential of organic matter application in Japanese arable soils

We estimated the carbon (C) sequestration potential of organic matter application in Japanese arable soils at a country scale by applying the Rothamsted carbon (RothC) model at a 1-km resolution. After establishing the baseline soil organic carbon (SOC) content for 1990, a 25-year simulation was run for four management scenarios: A (minimum organic matter application), B (farmyard manure application), C (double cropping for paddy fields) and D (both B and C). The total SOC decreased during the simulation in all four scenarios because the C input in all four scenarios was lower than that required to maintain the baseline 1990 SOC level. Scenario A resulted in the greatest depletion, reflecting the effects of increased organic matter application in the other scenarios. The 25-year difference in SOC accumulation between scenario A and scenarios B, C and D was 32.3, 11.1 and 43.4 Mt C, respectively. The annual SOC accumulation per unit area was similar to a previous estimate, and the 25-year averages were 0.30, 0.10 and 0.41 t C ha⁻¹ year⁻¹ for scenarios B, C and D, respectively. The system we developed in the present study, that is, linking the RothC model and soil spatial data, can be useful for estimating the potential C sequestration resulting from an increase in organic matter input to Japanese arable soils, although more feasible scenarios need to be developed to enable more realistic estimation.     

The biological activities of cardenolide triglycosides from stems, twigs, and leaves of Nerium oleander

Sixteen cardenolide triglycosides (1?C16) were isolated from stems, twigs, and leaves of Nerium oleander. Among them, 3??-O-(4-O-gentiobiosyl-d-diginosyl)-7??,8-epoxy-14-hydroxy-5??,14??-card-20(22)-enolide, named cardenolide B-3 (16), was isolated from natural sources for the first time. The in vitro anti-inflammatory activities of compounds 1?C16 were examined on the basis of inhibitory activity against the induction of intercellular adhesion molecule-1 (ICAM-1). Compounds 1?C5 were active at an IC50 value of less than 7 ??M. The cytotoxic activity of isolated compounds was evaluated against three human cell lines: normal human fibroblast cells (W-38), malignant tumor cells induced from WI-38 (VA-13), and human liver tumor cells (HepG2). Compounds 1?C5 were active toward WI-38 cells; compounds 1, 3, and 5 were active toward VA-13 cells; and compounds 1?C5 were active toward HepG2 cells at IC₅₀ values of less than 10 ??M. The multidrug-resistant (MDR) cancer-reversal activity of compounds 1?C16 was evaluated on the basis of the amount of calcein accumulated in MDR human ovarian cancer 2780AD cells in the presence of each compound. Compounds 13 and 14 showed significant effects on calcein accumulation.     

A vaccine prepared from a non-pathogenic H5N1 influenza virus strain from the influenza virus library conferred protective immunity to chickens against the challenge with antigenically drifted highly pathogenic avian influenza virus

Inactivated influenza virus vaccine prepared from a non-pathogenic influenza virus strain A/duck/Hokkaido/Vac-1/2004 (H5N1) from the virus library conferred protective immunity to chickens against the challenge of antigenically drifted highly pathogenic avian influenza virus (HPAIV), A/whooper swan/Hokkaido/1/2008 (H5N1). The efficacy of the vaccine was comparable to that prepared from genetically modified HPAIV strain deltaRRRRK rg-A/ whooper swan/Mongolia/3/2005 (H5N1), which is more antigenically related to the challenge virus strain, in chickens.     

Entorhinal cortex layer III input to the hippocampus is crucial for temporal association memory

Associating temporally discontinuous elements is crucial for the formation of episodic and working memories that depend on the hippocampal-entorhinal network. However, the neural circuits subserving these associations have remained unknown. The layer III inputs of the entorhinal cortex to the hippocampus may contribute to this process. To test this hypothesis, we generated a transgenic mouse in which these inputs are specifically inhibited. The mutant mice displayed significant impairments in spatial working-memory tasks and in the encoding phase of trace fear-conditioning. These results indicate a critical role of the entorhinal cortex layer III inputs to the hippocampus in temporal association memory.     

Fortification of <Emphasis Type="Italic">niboshi</Emphasis> with histidine prepared from <Emphasis Type="Italic">katsuobushi</Emphasis> protein digest

ABSTRACT:   Free and total histidine contents in the muscle of various fishes and invertebrates caught in the Seto Inland Sea were estimated. These contents were higher in the muscles from skipjack, yellowfin tuna, yellowtail and mackerel than in those from lizard fish, sea bream and hairtail. Invertebrate muscles, except squid, contained low free and total histidine. Boiled and dried anchovy ( niboshi ) contained lower free histidine than that of dried anchovy (suboshi). To prepare free histidine-rich extracts, the waste residue of soup stock from smoke-dried and shaved skipjack ( katsuobushi ) was digested with proteases. The extract of the enzyme digest contained high free histidine and was used to fortify niboshi with free histidine. If taken, the fortified niboshi may suppress food intake, and prevent obesity.     

Blood parameters and electrocardiogram in squeezed fish simulating the effect of net damage and recovery

ABSTRACT:   In the present study, rubber bands were tied around the girth of rainbow trout Oncorhynchus mykiss to simulate and assess the physiological damage and survival rates of fish that encounter gill nets. Physiological condition was assessed by analysis of blood lactate, pH, oxygen partial pressure and plasma potassium concentration before and after release from binding. Twenty-four hours after release, half of the test fish had died. Although the binding forces used to hamper fish did not differ significantly, blood lactate levels in the dead fish rose to 10-fold higher than those in the survivors. Consequently, the pH level fell in the group that died, whereas in the surviving group it fell only slightly and soon recovered. Potassium concentration increased after release from binding in fish that died, and the P o ₂ levels in these fish continued to drop until just before death. It was concluded that when fish get entangled in fishing nets, blood lactate accumulates because of physical fatigue and the elevated lactate levels lead to metabolic acidosis. Finally, fatal metabolic conditions could cause higher mortality rates, even in escapees.