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71.
Summary Two municipal sludges, one from a highly industrialized city, Chicago, Il, and another from a little industrialized, highly agricultural area, Tucson, AZ are compared for winter barley production on Pima c 1 (Typic torrifluvent). Both sludges were responsible for highly significant additions of Zn, Cu, Ni, Cd and P to the soil each year when applied at the rates of 100 mt/ha singly and 20 mt/ha each year for 4 years. Nitrogen responses for barley straw and grain were observed from both sludges. Tucson sludge appears to be attractive as a potential fertilizer, not only as an NPK source, but also for its organic matter and minimal amounts of heavy metals. The Chicago sludge with relatively high levels of heavy metals, particularly Cd, appears poorly suited as a fertilizer, if used for an extended period of time, because of the plant's tendency to take up elevated levels of certain heavy metals. Some parts of barley plants proved to be a better indicator of heavy metal uptake and concentration than others. The diagnostic-tissue test promises to be a useful tool to warn against undesirable accumulation of heavy metals. Fortunately, when compared with other plant parts, the heavy metal in grain was the least altered as a result of continued sewage sludge use on arid land. The soil's neutral to slightly alkaline pH and the presence of lime throughout the soil profile appeared to be critical factors in keeping plant uptake of heavy metals relatively low as compared with soils of other climates.  相似文献   
72.
A combined method is described for the determination of various metabolites from a single tissue sample of the brain. It comprises a quick inactivation of cerebral enzymes by microwave irradiation, easy separation of the desired brain regions, and perchloric acid extraction of tissue substances, which are assayed either by specific enzymatic techniques or by HPLC with electrochemical detection. The obtained values of most energy and neurotransmitter metabolites in the brain are in agreement with those reported using other methods. However, this technique, in contrast to the brain freezing in vitro or freeze-blowing, provides a more efficient procedure for rapid arrest of cerebral metabolism even in the deep brain structures and is therefore suitable for detection of early changes particularly those occurring in experimental pathological conditions such as ischemia.  相似文献   
73.
Two groups ofAvahi laniger were studied in the Forêt de Analamozoatra near Perinet in the eastern rainforest of Madagascar from August to October 1984. Overlap between the home ranges of neighbouring groups ofA. laniger was minimal. Group size ranged from one to four individuals with a median group size of two. In four out of ten groups a baby was born between August and September.A. laniger were most active after dusk and before dawn. They had an extended resting period around midnight. Their diet consisted mostly of leaves from at least 17 different plant species. They also ate flowers. Fruit eating was recorded twice. Leaves eaten had high contents of protein and sugar but did not contain alkaloids. The concentration of condensed tannins did not differ between food items and non-food items. There was no indication of competition with other prosimians that might explain their nocturnality.  相似文献   
74.
Regeneration of peach plants from callus derived from immature embryos   总被引:9,自引:0,他引:9  
Summary Peach plants were repeatedly regenerated from immature embryos but not from callus derived from mature embryos. A white, nodular, highly regenerative callus was obtained when friable, primary callus from immature embryos was transferred from medium containing 4.5 M 2,4-dichlorophenoxyacetic acid and 0.44 M benzyladenine (BA) to media containing 0.27 M -naphthaleneacetic acid (NAA) and 2.2 M BA. This callus retained its morphogenetic potential for a minimum of three subcultures. Green nodular callus, that lacked regenerative capacity, was produced from primary callus derived from mature embryos. Maximum regeneration of shoots occurred when highly regenerative callus was transferred to a medium in which the NAA concentration was reduced five times and the BA concentration was increased two times. Regenerated shoots were rooted in the dark on a medium containing 28.5 M indoleacetic acid. Cytogenetic analysis of regenerated plants indicated that all plants were diploid, 2n = 2x = 16. Phenotypic evaluation of regenerated plants, grown under field conditions, is now in progress.  相似文献   
75.
Summary Agrobacterium strains harbouring the T-region and the virulence-region of the Ti plasmid on separate replicons still display efficient T-DNA transfer to plants. Based on this binary vector strategy we have constructed T-region derived gene vectors for the introduction of foreign DNA into plants. The vectors constructed can replicate in E. coli, thus the genetic manipulations with them can be performed with E. coli as a host. They can be transferred to Agrobacterium as a cointegrate with the wide host range plasmid R772. Their T-regions are transferred to plant cells from Agrobacterium strains conferring virulence functions.The plasmid pRAL 3940 reported here is 11.5 kb large, contains a marker to identify transformed plant cells and unique restriction sites for direct cloning of passenger DNA, flanked by the left- and right-hand border fragments of the T-region (including the 25 bp border repeats). The plasmid is free of onc-genes. Therefore, is does not confer tumorigenic traits on the transformed plant cells and mature, fertile plants can thus be regenerated from them.  相似文献   
76.
The genomic sequences of several RNA plant viruses including cucumber mosaic virus, brome mosaic virus, alfalfa mosaic virus and tobacco mosaic virus have become available recently. The former two viruses are icosahedral while the latter two are bullet and rod shaped, respectively in particle morphology. The non-structural 3a proteins of cucumber mosaic virus and brome mosaic virus have an amino acid sequence homology of 35% and hence are evolutionarily related. In contrast, the coat proteins exhibit little homology, although the circular dichroism spectrum of these viruses are similar. The non-coding regions of the genome also exhibit variable but extensive homology. Comparison of the brome mosaic virus and alfalfa mosaic virus sequences reveals that they are probably related although with a much larger evolutionary distance. The polypeptide folds of the coat protein of three biologically distinct isometric plant viruses, tomato Bushy stunt virus, southern bean mosaic virus and satellite tobacco necrosis virus have been shown to display a striking resemblance. All of them consist of a topologically similar 8-standard β-Barrel. The implications of these studies to the understanding of the evolution of plant viruses will be discussed.  相似文献   
77.
The estrous cycles of 23 Holstein heifers were synchronized with three prostaglandin F2α (PG) injections at 0600 h 11 d apart, designated as Days ?11, 0 and 11. Twelve of the animals were randomly assigned to receive no solid food (Group F) from Day 6 to 14, while the other animals remained on full feed to serve as controls (Group C). Jugular blood samples were collected at 6-h intervals beginning with PG injection at 0600 h on Day 0 until 1800 h on Day 4 and at 0600, 1200 and 1700 h on Day 8 through 10. Samples were collected again at 6-h intervals from PG Day 11 (0600 h) until 1800 h on Day 15. Period 1 was defined as those samples collected from Day 0 through 4.5, Period 2 from Day 7 through 10, Period 3 from Day 11 through 14.25, and Period 4 from Day 14.5 through 15. Plasma growth hormone concentrations were increased (P<0.01) in F as compared with C animals during Periods 2, 3 and 4. Plasma concentrations of prolactin (P<0.01) were decreased in F as compared with C animals during Periods 2 and 3. Plasma urea concentrations were increased (P<0.01) in F as compared with C animals during the first 3 d of the fast (Period 2) but were decreased (P<0.01) during the remainder of the experiment (Periods 3 and 4). Thus, fasting was effective in altering several metabolic parameters. Although plasma progesterone and luteinizing hormone (LH) concentrations remained similar (P>0.05) between F and C animals, plasma estradiol-17β concentrations decreased in F as compared with C animals during Periods 2, 3 and 4. No differences (P>0.05) between F and C animals were found in duration to LH peak after PG injection, estrous behavior, or pregnancy rates. Results from this study indicate that fasting reduced plasma estradiol-17β concentrations during estrus but did not alter occurrence of estrus or pregnancy rate.  相似文献   
78.
This paper is a survey of the vegetation of the southeastern departments in the Province of Santa Fe (Argentina). The vegetation was analyzed following Braun-Blanquet's approach modified by Mueller-Dombois & Ellenberg (1974). The most relevant species of the region were placed in 25 groups according to their requirements or general behaviour. Most of the communities are herbaceous, and apart from the woody and some other miscellaneous ones they were grouped into three ecologically and floristically defined sets. The first set, the Stipa grasslands and related communities, which are characterized by the more or less abundant presence of Stipa hyalina, Stipa neesiana and Stipa papposa, comprises five different communities. The second, the halophilous communities, comprises five communities, the two Spartina ssp. grasslands, the halophilous prairies of Distichlis spicata, the short sedge Scirpus americanus communities and the ‘pela-dales’. The third, the hygrophilous communities, comprises nine communities which are not so well defined as the ones in the other sets. Besides, two further communities have been included, the Paspalum quadrifarium and the Melica macra tall grasslands.  相似文献   
79.
A direct radioimmunoassay for measuring urinary 20-hydroxyprogesterone cross-reactivity to monitor and assess luteal function and detect pregnancy in the lion-tailed macaque (Macaca silenus) is described. Urine samples were collected daily during ten nonconceptive and five conceptive ovarian cycles of five dult female lion-tailed macaques. Urine was analyzed for concentrations of 20α-hydroxypro-gesterone cross-reactivity, estrone conjugates, and creatinine. The strength of the luteal phase in normal nonconceptive cycles (n = 8) is characterized by a maximum sevenfold increase (day 9) in mean 20α-hydroxyprogesterone cross-reactivity over follicular phase levels; the duration, by a 13-day sustained elevation of mean 20α-hydroxyprogesterone cross-reactivity levels. Pregnancy is detectable from 20α-hydroxyprogesterone cross-reactivity values approximately 20 days after the periovulatory estrone conjugate peak (n = 4). Apparent anovulation (n = 1), extended follicular phase (n = 1), and early abortion (n = 1) also are detectable using 20α-hydroxyprogesterone cross-reactivity measurements.  相似文献   
80.
Evidence from morphology and anatomy (including embryology), as well as from palynology, chemistry and cytology, indicates thatHydrastis is quite divergent from Ranunculaceae (in which the genus has been most often included) as well as from both Glaucidiaceae and Berberidaceae. Distinctive features ofHydrastis, which demarcate it from Ranunculaceae but which are sometimes shared by Berberidaceae, are: the unique mode of origin of the vascular supply to stamens and carpels; the micropyle being formed by both integuments; the xylem not V-shaped in cross section; scalariform vessel perforations present; haploid chromosome number 13; pollen tectum consisting of a compound layer of striae; leaf mesophyll not differentiated; the unique course of stem medullary bundles; D-galactose present. Its distinctive higher haploid chromosome number, as well as its many less-specialized character states (in floral structure, leaf anatomy, and xylem and vessel morphology), suggest thatHydrastis is a relictual primitive group which diverged early from a common ancestral stock of Ranunculaceae, Berberidaceae and probably of Circaeasteraceae; at least some of the features shared byHydrastis and one or another of the families concerned seem to be a heritage from their common ancestor. We propose a reestablishment of a monotypic family, Hydrastidaceae.  相似文献   
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