The effect of deep placement and surface application of nitrogen fertilizers at different light intensities on growth and yield of wetland rice

Summary Lowland rice (RD 3) was cultivated in containers of clay soil submerged with 5 cm water under controlled conditions in the phytotron. Deep placement of urea supergranules 5 cm in the soil significantly enhanced both plant growth and fertilizer efficiency when the plants were cultivated under high light intensity (70 Wm^–2). At the highest urea level grain yield increased 119% above the control level, while growth and fertilizer efficiency was not as high when deep placement of calcium nitrate was used.The application of urea prills and calcium nitrate (18.4g Nm^–2) in two split doses on the soil surface increased grain yield as much as 91% above the control level. At the lower nitrogen concentration (9.2 g N m^–2), the urea prills were more efficient than calcium nitrate as indicated by the grain yield. The height of those plants fertilized by surface application was affected by the concentration and not the type of fertilizer. The number of tillers, however, was significantly higher on urea fertilized plants.When the rice plants were cultivated under low light intensity 930 Wm^–2), neither the nitrogen fertilizers nor the method of application had a significant effect on growth and yield.     

Furry Protein Promotes Aurora A-mediated Polo-like Kinase 1 Activation

Bipolar mitotic spindle organization is fundamental to faithful chromosome segregation. Furry (Fry) is an evolutionarily conserved protein implicated in cell division and morphology. In human cells, Fry localizes to centrosomes and spindle microtubules in early mitosis, and depletion of Fry causes multipolar spindle formation. However, it remains unknown how Fry controls bipolar spindle organization. This study demonstrates that Fry binds to polo-like kinase 1 (Plk1) through the polo-box domain of Plk1 in a manner dependent on the cyclin-dependent kinase 1-mediated Fry phosphorylation at Thr-2516. Fry also binds to Aurora A and promotes Plk1 activity by binding to the polo-box domain of Plk1 and by facilitating Aurora A-mediated Plk1 phosphorylation at Thr-210. Depletion of Fry causes centrosome and centriole splitting in mitotic spindles and reduces the kinase activity of Plk1 in mitotic cells and the accumulation of Thr-210-phosphorylated Plk1 at the spindle poles. Our results suggest that Fry plays a crucial role in the structural integrity of mitotic centrosomes and in the maintenance of spindle bipolarity by promoting Plk1 activity at the spindle poles in early mitosis.     

Early trajectories of forest understory development on reclamation sites: influence of forest floor placement and a cover crop

We tested whether direct placement of forest floor material (FFM: litter, fibric, humus layers and surface mineral horizons) and sowing of a cover crop (Melilotus officinalis) could facilitate the establishment of native forest understory species at a reclaimed coal mine in Alberta, Canada. FFM was salvaged at two depths (15 and 40 cm) from a recently harvested native aspen forest and immediately placed at the same depths on the reclamation site. Total richness (approximately 61 species in 96 subplots) was similar in each of 3 years post‐placement; total richness for all 3 years combined was 87 including 34 typical boreal forest understory species plus 30 other natives. The deeper treatment reduced cover of all species, native and non‐native species in year 1. In year 3, the deeper treatment still had lower cover of non‐native species but had higher cover of forest understory species in years 2 and 3. The deeper treatment also resulted in lower species richness per plot, but only in year 1. In year 2 (when the biennial clover was at its tall stage), the cover crop treatment was associated with lower cover of non‐native species but did not affect the cover of native forest understory species. Direct placement of FFM can help facilitate establishment of a diverse native boreal forest understory in a reclaimed landscape. Although richness and cover may be initially higher with shallower salvage and placement, deeper salvage may ultimately be better for encouraging establishment of native forest understory species.     

Periplast development in cryptophyceae I. Changes in periplast arrangement throughout the cell cycle

Summary The cell covering (or periplast) of many cryptomonads consists of discrete plate areas precisely arranged over most of the cell periphery. Developmental changes in periplast arrangement that occur throughout the cell cycle are examined here forKomma caudata andProteomonas sulcata [haplomorph]. In both cryptomonads, pole reversal occurs during cytokinesis, necessitating major realignment of the plate areas. Growth of the periplast occurs by addition of new plate areas to specialized regions (termed anamorphic zones) located around the vestibular margins and along the mid-ventral line of cells. Development of the periplast from these regions enables elongation and lateral expansion of cryptomonads throughout cell growth. Observed differences in cell division and periplast development between these genera are closely associated with variations in the arrangement of anamorphic zones.     

A single plant technique for field studies of distribution of32P-labelled phosphate between plant and soil pools

Summary ³²P-labelled monocalcium phosphate solution was supplied to the root system of individual wheat plants within a field crop two weeks after emergence. Three levels of carrier P, equivalent to 2.5, 5, and 10 kgP ha^–1 were used. The distribution of³²P between shoots and the soil inorganic and organic P fractions was measured after a further six weeks growth.There was no evidence for the incorporation of³²P-orthophosphate into soil organic P fractions in the wheat rhizosphere in the period between germination and mid-tillering.The suitability of the single plant technique to measure plant available P in field soils was assessed by calculating A values from plants grown in soil witth different fertilizer P histories. There was a significant linear relationship between A values and the amount of soil P extractable with 0.5M NaHCO₃ from the different fertilizer treatments. Although the technique is unlikely to given an absolute value for plant available nutrient, it can provide quantitative data for comparative trials with different forms of fertilizer, methods of fertilizer application or amounts of available soil water. The values obtained should be termed comparative A values or A^c values.     

基于结构比较的蛋白质同源模建系统及其评估Ⅱ侧链的安装

至今,有关蛋白质侧链的同源模建,除了在本体模板上安装侧链和少数限制条件下在同源模板上安装侧链的报道外,系统的研究和实施似乎还未见报道。本软件系统ＰＭＯＤＥＬＩＮＧ采用同源移植和“死端排除“相结合的侧链安装策略,对与模板蛋白相应践基具有相似大小和形状的目标残基采用直接移植的方法。其余铡链则用广义“死端排除定则”安装。经众多蛋白的测试,达到了较好的模建品质。     

Molecular phylogeny of icefish Salangidae based on complete mtDNA cytochrome b sequences, with comments on estuarine fish evolution

Phylogenetic relationships among 15 species in the family Salangidae were constructed based on the complete cytochrome b sequence (1141 bp). We confirmed the monophyly of the family Salangidae and defined four primitive lineages within this family: (I) Protosalanx , Neosalanx anderssoni , Neosalanx tangkahkeii , and Neosalanx argentea ; (II) Neosalanx reganius , Neosalanx jordani , Neosalanx oligodontis , and Neosalanx  sp.; (III) Hemisalanx , Salanx , Leucosoma , and Salangichthys ishikawae ; and (IV) Salangichthys microdon . A major finding of our study is the key basal placement of Sg. microdon . According to the tentative estimation, the divergence of the four lineages appears to have been initiated in the early Miocene (21 Mya), with most speciation events occurring 1.05–9.90 Mya. Taxonomic revisions on subfamilial, generic, and specific levels were carried out based on phylogenetic relationships and genetic distance, taking into account some key morphological characters. The speciation mechanism in Salangidae is also discussed, and the evidence shows that geographical isolation, water mass, as well as some ecological factors, may not always play important roles in the speciation of temperate estuarine fish. In the most cases, sympatric salangids are not monophyletic, indicating that their coexistence reflects secondary contact rather than sympatric speciation.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 327–342.     

Follicle cells and germ line cells both affect polarity in dicephalic chimeric follicles of Drosophila

Summary In aberrant egg follicles of the pattern mutant dicephalic (dic) the oocyte is wedged in between two groups of nurse cells, and this condition may give rise to embryos which express anterior traits at both ends. We have analysed the role of the dic genotype of the germ line cells and the surrounding somatic follicle cells in the formation of the dic follicular phenotype. By means of pole cell transplantations into Fs (1) K 1237 hosts (this cell-autonomous mutation causes degeneration of the host's germ line cells early in oogenesis), we constructed chimeras in which either the follicle cells, the germ line cells, or both were homozygous for the dic mutation. In all three combinations the dic phenotype was expressed but not in controls with dic ⁺ in both germ line cells and follicular epithelium. Since follicles with the dic phenotype may be produced if either the germ line cells or the follicle cells lack dic ⁺ gene activity we suggest that cellular interactions between both cell types are required for the correct positioning of the oocyte at the follicle's posterior pole.     

Effect of ATC,N-Serve 24 E and thiourea nitrification inhibitors on yield and N uptake of barley fertilized with fall-applied N1

Solution urea and aqua NH₃ were injected in bands 9 cm deep and spaced 45 cm apart with and without nitrification inhibitors during October in 10 field experiments in north-central Alberta. ATC (4-amino-1,2,4-triazole hydrochloride), N-Serve 24 E (2-chloro-6-trichloromethyl-pyridine) and thiourea were used in two experiments, ATC only in another six experiments, and N-Serve 24 E only in another two experiments. Yield and apparent recovery of applied N in barley grain were determined. In the two experiments where fall treated plots were soil sampled in the following spring, 44% of the fall-applied N was recovered in the soil when inhibitors were not used. But where the inhibitors were added to the fall-applied N as NH₄−N in May was 4% and 31% without and with addition of inhibitors, respectively. Likewise, in experiments where three inhibitors were used, the treatments with inhibitors increased the yield and N recovery in grain by more than 50% compared to fall application without inhibitors. In the other experiments, fall-applied ATC or N-Serve 24 E did not always increase yield or N recovery in grain. Considering all experiments with ATC, the average recovery of applied N in barley grain was 28, 40 and 57% for fall banding, fall banding with ATC and spring application, respectively. In view of this and previous work in north-central Alberta, inhibitors injected in bands in the fall slowed nitrification and improved yield, but nests or large granules of urea were more effective. Scientific paper No 553, Lacomba Research Station, Research Branch, Agriculture Canada.     

Macromolecular refinement of X-ray and cryoelectron microscopy structures with Phenix/OPLS3e for improved structure and ligand quality

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