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结合实际情况,分析香港市区行道树安全管理在综合管理措施、规划设计建设、种植养护技术等方面存在的不足,其管理观念及技术已经不符合当前绿化生态的理念及发展。继而针对性提出健全管理机构、优化技术措施、加强各部门的宏观协作等建议。 相似文献
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P. N. P. CHOW 《Weed Research》1988,28(3):145-150
In field experiments with spring wheat (Triticum aestivum L., cv. Neepawa), the low rate (0·02 kg ha-1) of chlorsulfuron significantly reduced wild oat control from individual applications of only barban and diclofop-methyl. The high rate (008 kg ha-1) affected wild oat control by all four graminicides, including difenzoquat and flam-prop-methyl. In most cases, the graminicides did not affect the broad-leaved weed control of chlorsulfuran. Overall, a low rate of chlorsulfuron in mixture with graminicides did not reduce wheat yield, whereas a high rate of chlorsulfuron in the mixtures gave a significant yield reduction compared with individual graminicides applied alone. All herbicide treatments increased wheat yield over the control. In the glasshouse, reduction in wild oat control by diclofop-methyl was directly related to the rate of chlorsulfuron added to diclofop-methyl. The effect of 0·02 kg ha-1 chlorsulfuron on control of wild oat was decreased when the rate of diclofop-methyl increased from 0·5 to 0·9 kg ha-1 and was completely eliminated when diclofop-methyl reached 1·1 kg ha-1. Conversely, diclofop-methyl (0·7 and 1·1 kg ha-1) gave some reduction of wild mustard (Sinapis arvensis L.) and redroot pigweed (Amaranthus retrofiexus L.) control by chlorsulfuron (0·01 and 0·02 kg ha-1), even though in some cases diclofop-methyl/chlorsul-furon gave better control of these broad-leaved weeds. In the laboratory, the absorption and translocation of [14C]-diclofop-nieihyl in wild oat seedlings were significantly reduced when chlorsulfuron was added, compared with [14C]-diclo-fop-methyl applied alone. Effet du chlorsulfuron sur l'efficacité et l'effet sur le rendement de quatre graminicides Dans des essais de plein champ sur blé de printemps (Triticuni aestivum L., cv. Neepawa), la faible dose (0, 02 kg ha-1) de chlorsulfuron a réduit significativement l'efficacité d'une application séparée de barbane et de diclofop-methyl. La forte dose (0, 08 kg ha-1) a contrarié la destruction de la folle avoine pour les quatre graminicides dont le difenzoquat et le flamprop-methyl. Dans la plupart des cas, les graminicides n'ont pas eu d'incidence sur la destruction des dicotylédones par le chlorsulfuron. Par ailleurs. une faible dose de chlorsulfuron en mélange avec les graminicides n'a pas réduit le rendement en blé, en revanche, une forte dose de chlorsulfuron en mélange a entrainé une baisse significative de rendement en comparaison des graminicides appliqués seuls. Tous les traitements herbicides ont entrainé un gain de rendement par rapport au témoin non traité. En serre, la réduction d'efficacité sur folle avoine du diclofop-methyl était directement correlée à la dose de chlorsulfuron ajouté. Les effets de 0, 02 kg ha-1 sur la destruction de la folle avoine baissaient quand le niveau de diclofop-methyl augmentait de 0,5 à 0,9 kg ha-1 et étaient complètement éliminés quand la dose de diclofop-methyl atteignait 1, 1 kg ha-1. Par ailleurs, le diclofop-méthyl (0,7 et 1,1 kg ha-1) a réduit l'efficacité du chlorsulfuron (0,01 et 0,02 kg ha-1) sur la sanve (Sinapis arvensis L.) et l'amaranthe réflechie (Amaranthus retroflexus L.) même si dans certains cas l'association diclofop-mélhyl-chtorsulfuron a eu une meilleure efficacité sur ces mauvaises herbes. Au laboratoire, l'ab sorption et la translocation du diclofop-methyl C14 dans les plantules de folle avoine ont été réduites significativement par l'addition de chlor-sulfuron en comparaison du diciofop-méthyl C14 appliqué seul. Wirkung von Chlorsulfuron zusammen mil Vier Graminiziden auf die Unkrautbekämpfung und den Ertrag von Weizen In Freilandversuehen mit Sommerweizen (Triticum aesttotm L. ‘Neepawa’) verminderie Chlorsulfuron in niedriger Aufwandmenge (0,02 kg ha-1) den Bekämpfungserfolg gegen Flug-Hafer nur bei Barban und Diclofop-menthyl. Die hohe Aufwandmenge (0,08 kg ha-1)beeinträchtigte die Wirkung aller 4 Graminizide, einschliesslich Difenzoquat und Flamprop-methyl. Die Graminizide beeinfiussten die Wirkung von Chlorsulfuron gegen zweikeimblättrige Arten meistens nicht, Der Weizenertrag blieb bei der Mischung der niedrigen Aufwandmenge von Chlorsulfuron mit den Graminiziden unverändert, die hohe Aufwandmenge führte aber in den Mischungen zu einem signifikaten Abfall des Ertrags, vergli-chen mit dem bei Anwendung der Graminizide allein. Mit allen Herbizidbehandlungen wurden gegenüber Unbehandelt höhere Erträge erzielt. Im Gewächshaus war die Wirkung von Diclofopmethyl gegen Flug-Hafer direkt von der zugefügten Menge an Chlorsulfuron abhängig. Der Einfluss von 0,02 kg ha-1 Chlorsulfuron aif die Bekämpfung von Fiug-Hafer nahm ab. wenn die Aufwundmenge von Diclofop-methyl von 0,5 auf 0,9 kg ha-1 gesteigert wurde; bei 1, 1 kg ha-1 Diclofop-methyl war er aufgehoben. Andererseits trat bei 0,7 und 1,1 kg ha-1 Diclofop-methyl eine Minderung der Wirkung von Chlosulfuron (0,01 und 0,02 kg ha-1) gegen Acker-Senf (Sina-psis arvensis L.) und Zurückgekrümmten Fuchsschwanz (Amarenthus retroflexus L.) ein, wenn auch dise Mischung in einigen Fällen gegen dise Arten starker wirkte. Im Labor wurde einc signifikant geringere Absorption und Trans-lokation von 14C-Diclofop-methyl in Keimpflan-zen des Flug-Hafers beobachtet, wenn Chlorsulfuron zugefügt worden war. 相似文献
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Experimental infection of normal and immunosuppressed pigs with Pseudomonas pseudomallei 总被引：1，自引：0，他引：1
AD THOMAS JC FORBES-FAULKNER TL D''ARCY JH NORTON D HOFFMANN 《Australian veterinary journal》1990,67(2):43-46
A single dose of 5 x 10(8) bacilli of Pseudomonas pseudomallei by intratracheal injection resulted in acute (21 cases) or chronic (19 cases) melioidosis in 40 of 48 pigs. Fifteen (10 acute and 5 chronic) had been immunosuppressed by cyclophosphamide before inoculation. The major clinical signs were initial fever, marked neutrophilia and, in the acute cases, respiratory distress. There were no signs of the nasal and ocular discharge, paresis or diarrhoea seen in acute cases in south-east Asia. The cyclophosphamide treatment caused a significant decrease in the neutrophil count by 7 d after inoculation in all 15 immunosuppressed pigs, and all were culture positive at necropsy. Eight of the 33 non-treated pigs were culture negative at necropsy. Pigs overcoming the initial phase of infection had more abscess-like nodules that were bacteriologically sterile at necropsy than the pigs with acute cases of melioidosis. P. pseudomallei was isolated predominantly from the spleen, lungs and the injection site. Although only one strain was used in this study, it is likely that Australian strains of P. pseudomallei are not as virulent as the south-east Asian isolates. 相似文献
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RL Westemeier JD Brawn SA Simpson TL Esker RW Jansen JW Walk EL Kershner JL Bouzat KN Paige 《Science (New York, N.Y.)》1998,282(5394):1695-1698
Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens. 相似文献
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Long‐term Effects of Pyrethrin and Cyfluthrin,a Type II Synthetic Pyrethroid,Insecticide Applications on Bull Reproductive Parameters 
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下载免费PDF全文 JL Stewart CF Shipley FA Ireland VL Jarrell CL Timlin DW Shike TL Felix 《Reproduction in domestic animals》2016,51(5):680-687
The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin‐ and cyfluthrin‐based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks. 相似文献
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P. N. P. CHOW 《Weed Research》1977,17(1):55-60
Five field experiments were conducted from 1972 to 1975 to evaluate weed control in flax (Linum usitatissimum L.) using post-emergence treatments of asulam [methyl (4-aminobenzenesulphonyl) carbamatel alone and in combination with other herbicides. The 14C-asulam absorption by leaf segments and roots of glasshouse grown wild oats (Avena fatua L.) was also investigated. Asulam at 1.12 kg/ha gave good wild oat control and acceptable control of green foxtail (Setaria viridis (L.) Beauv.). However, wild oat control was poorer when asulam was combined with other herbicides: on a 3-year average, as compared with asulam alone at equal rates, the asulam+MCPA mixture resulted in a greater antagonism and a significant 6% reduction in flax seed yield, whereas the asulam+bromoxynil/MCPA mixture gave the least antagonistic effect, improved broadleaf weed control and increased yield by 13%. In mixtures, the potassium salt of MCPA was more compatible with asulam for weed control than the amine form. Both leaf segments and roots of wild oats absorbed and distributed less 14C-asulam from solutions containing MCPA than from those containing bromoxynil or bromoxynil/MCPA. 相似文献