Effects of photoperiod on leaf greenness of four bedding plant species     

F. A. Langton  K. E. Cockshull 《The Journal of Horticultural Science and Biotechnology》2013,88(3):400-404

Summary

Short-day (SD) and long-day (LD) photoperiodic treatments were compared, at equal light integral, for their effects on the seedling growth of four bedding plant species: geranium, impatiens, pansy and petunia. Total leaf area was frequently increased by LD given either by day-extension lighting or night-break lighting, but this response was inconsistent and varied greatly between species and experiments. In contrast, leaf greenness measured using a SPAD-502 meter, a measure of chlorophyll content per unit area of leaf, was consistently and significantly increased in LD in all four species. However, night-break lighting may have been somewhat less effective than day-extension lighting. Increasing the day-extension lighting from 16 h to 24 h gave no further intensification of greenness. Consistent with increases in leaf greenness, total dry weight was generally increased in LD, and increases were of a similar magnitude to those given by doubling the daily light integral. The promotional effect of LD on chlorophyll content appears to have been largely ignored or overlooked in recent years, but this may be because simple methods for measuring ‘greenness’ have only recently become widely available.  相似文献   

Effectiveness of different sources of manganese foliar sprays in alleviating manganese deficiency of Lupinus angustifolius L. grown on manganese deficient soils in western Australia     

R.F. Brennam 《Journal of plant nutrition》2013,36(2):293-304

Responses of narrow‐leafed sweet lupins (Lupinus angustifolius L.) to foliar sprays of different sources of manganese (Mn) were compared in field experiments in three years at six sites in Western Australia. The relative effectiveness of manganese chelate (EDTA; 14% Mn) and manganese sulfate (25% Mn) applied as foliar sprays for alleviating Mn deficiency of lupins was assessed. Each source was sprayed at six levels of Mn (0, 0.125, 0.250, 0.50, 1.0, and 2 kg Mn/ha) when pods on the main stem were 2–3 cm long to define the relationship between seed and the amount of foliar Mn applied for lupins grown on Mn‐deficient soil. Manganese chelate, manganese sulfate, and the Mangasol sprays were equally effective. For all sources, 1.0 kg Mn/ha sprayed on the foliage was required to produce maximum seed yield and reduce split seed to an acceptable level (<4%). In all years, manganese sulfate banded with the seed produced similar seed yields as Mn sprayed on the foliage.  相似文献   

Impact of organic residues and mineral fertilizer application on soil–crop system: II soil attributes     

F.A.M. Rezig  E.A. Ehadi 《Archives of Agronomy and Soil Science》2013,59(9):1245-1261

The effects of crop residues alone (Cr⁺) or combined with inorganic fertilizer (FCr⁺) sewage sludge (SS) and humentos (H) on soil properties were studied in a five-season wheat–guar rotation. Incorporation of Cr⁺ and SS significantly decreased pH by 5–9%. Highest organic carbon (OC) was observed in SS plots, whereas Cr⁺ resulted in values threefold that of the control. The added effect of Cr⁺ (46%) combined with fertilizer on total nitrogen (TN) was greater than Cr⁺ by 28%. The fraction of total residue N mineralized was 71%, whereas net N mineralized in Cr⁺, SS, H and FCr⁺ plots at 0–20 and 20–40 cm depths were 39.8, 52.3, 11.4, 66.7 mg kg^?1 and 21.2, 27.9, 8.2, 41.2 mg kg^?1, respectively. Integrated application of Cr⁺ with fertilizer had a synergistic effect on P content (3.49–3.69 units), but soil levels has never exceeded 13 mg P kg ^?1. Sole Cr⁺ significantly increased topsoil cation-exchange capacity (CEC) compared with the control treatment (9.39–21.59%). Application of SS, FCr⁺ and Cr⁺ significantly increased water-holding capacity and decreased bulk density by 9–15% and 8–9%, respectively, suggesting that such practice can restore the productivity of degraded soils and improve crop yields.  相似文献   

Inflammation and wound healing in cats with chronic gingivitis/stomatitis after extraction of all premolars and molars were not affected by feeding of two diets with different omega‐6/omega‐3 polyunsaturated fatty acid ratios     

R. J. Corbee  H. E. Booij‐Vrieling  C. H. A. van de Lest  L. C. Penning  M. A. Tryfonidou  F. M. Riemers  H. A. W. Hazewinkel 《Journal of animal physiology and animal nutrition》2012,96(4):671-680

Feline chronic gingivitis/stomatitis (FCGS) is a painful inflammatory disease in cats. Extraction of teeth, including all premolars and molars, has been shown to be the therapy of choice in cats not responding sufficiently to home care (e.g. tooth brushing) and/or medical treatment (corticosteroids and/or antibiotics). In this study, we hypothesize that a cat food with an omega‐6 polyunsaturated fatty acid (ω6 PUFA) to ω3 PUFA ratio of 10:1 reduces inflammation of the FCGS and accelerates soft tissue wound healing of the gingiva after dental extractions, compared to a cat food with a ω6:ω3 PUFA ratio of 40:1. The cats were fed diets with chicken fat and fish oil as sources of fatty acids. In one diet, part of the fish oil was replaced by safflower oil, resulting in two diets with ω6:ω3 PUFA ratios of 10:1 and 40:1. This double‐blinded study in two groups of seven cats revealed that dietary fatty acids influence the composition of plasma cholesteryl esters and plasma levels of inflammatory cytokines. The diet with the 10:1 ratio lowered PGD₂, PGE₂ and LTB₄ plasma levels significantly, compared to the diet with the 40:1 ratio (p = 0.05, p = 0.04, and p = 0.02 respectively). However, feeding diets with dietary ω6:ω3 PUFA ratios of 10:1 and 40:1, given to cats with FCGS for 4 weeks after extraction of all premolars and molars, did not alter the degree of inflammation or wound healing.  相似文献   

Effects of Kocide 101® on the bean (Phaseolus vulgaris L.)‐Rhizobium symbiosis     

F. P. Baijukya  E. Semu 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):175-183

A glasshouse study was undertaken to investigate the effects of the copper fungicide Kocide 101 and its residues in soil on the growth, nodulation and nitrogen fixation of beans (Phaseolus vulgaris L.). The soil used was a sandy clay loam classified as Typic Rhodustalf. The bean variety SUA 90 was used as test crop. The bean rhizobia strains CIAT 899, PV, and a local isolate were used. Kocide 101 applied at the recommended rate (equivalent to 1.7 mg kg^‐1 soil) had no significant negative effects on the growth, nodulation or nitrogen fixation of bean plants. Higher levels of Kocide 101 significantly (P < 0.05) reduced plant growth, nodulation and nitrogen fixation. The bean plants inoculated with the “local isolate”; rhizobia had the highest dry matter weights, nodule numbers and nodule dry weights, and also had more N fixation. They were followed by those inoculated with the PV, strain and, lastly, those inoculated with CIAT 899. The growth and nodulation of bean plants were still curtailed by the Kocide 101 residues four months after the fungicide was first applied to the soil. Therefore, occurrence of high levels of Kocide 101 in soils can have long‐term effects on the performance of the bean‐rhizobia symbiosis.  相似文献   

Weismanns potentiell unsterbliche Einzeller sind sterbliche Selbstklonlinge     

F. Preuss 《Anatomia, histologia, embryologia》2000,29(6):385-384

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Antibody-mediated response of pigeons to Argas polonicus larval feeding and characterization of larval antigen     

F Dusbábek  S Lukes  V Matha  L Grubhoffer 《Folia parasitologica》1989,36(1):83-92

Circulating antibodies to larval Argas polonicus antigen detected in the blood of pigeons by means of ELISA reach their highest level 3-6 days post-tick attachment. During 6-8 days post infestation when most larvae detach from their host, there is an abrupt drop of the antibody level in blood followed by second peak at day 10-15. During the secondary and subsequent infestations the dynamics of the antibody production is analogous, but the maximum absorbance values found are higher with each following infestation. This is in direct correlation with the growth of immune resistance of hosts. The transfer of immunoglobulins of resistant pigeons produces in naive hosts a partial resistance in a statistically significant (P less than 0.01) reduction of the number of engorged larvae, in the shortening of larval feeding period and in the decrease of their mean weight after feeding. However this resistance was significantly (P less than 0.01) less expressed than in naturally resistant pigeons during secondary infestation. The protracted effect on the duration of premoulting period and the percentage of moulted larvae manifested in larvae after secondary infestation was not apparent in molecular weight of approximately 19, 21, 23, 27, 45 and 165 kilodaltons, were recognized by serum of resistant pigeons.  相似文献   

Effects of temperature,relative humidity and age of conidia on the incidence of spotting on gerbera flowers caused by Botrytis cinerea     

J. Salinas  D. C. M. Glandorf  F. D. Picavet  K. Verhoeff 《European journal of plant pathology / European Foundation for Plant Pathology》1989,95(1):51-64

In recent years, spotting of ray florets of gerbera flowers has become an important problem. This type of small necrotic lesions may occur before, but especially shortly after harvesting the flowers.Botrytis cinerea was easily isolated from such lesions. Inoculation withB. cinerea only gave typical necrotic lesions, when dry conidia were dusted on the flowers with a short period of high rh after inoculation. At 18–25 °C a high rh for at least 5 hours was necessary. Rotting of ray florets and receptacles byB. cinerea occurred when inoculated flowers were kept wet for a few days. Spots consist of one to several necrotic, usually epidermal cells. A single conidium could give rise to a necrotic lesion after germination. Germination of conidia and lesion formation occurred between 4 and 25 °C; at 30 °C, germination and lesion formation did not occur. Between 18 and 25 °C, many lesions became visible within 1 day after inoculation; at 4 °C it took 2 to 3 days before lesions could be seen. If kept dry, conidia ofB. cinerea remained ungerminated on ray florets of gerbera flowers and could be removed from the ray florets. Within 1 day at high rh, germination occurred and lesions were produced. Conidia ofB. cinerea, stored dry, were able to survive much longer than the lifetime of a gerbera flower. Even after storage at room temperature for up to 14 months, some conidia were able to germinate in vitro and on ray florets and induce the formation of lesions. Addition of gerbera pollen diffusate stimulated germination and lesion formation.  相似文献   

The physical stability of suspension concentrates with particular reference to pharmaceutical and pesticide formulations     

Paul F. Luckham 《Pest management science》1989,25(1):25-34

The word stability is ubiquitous in colloid science but means different things to different people. In a suspension concentrate it is possible to identify three different physical processes which may lead to instability in a particulate system, namely a change in particle size due to Ostwald ripening, particle aggregation and particle sedimentation. Although these processes may occur simultaneously they are here treated separately in order to promote understanding of the physical forces involved.  相似文献   

The pyrethrins and related compounds. Part XXXV. Esters of aryl-substituted cyclopentane alcohols and analogues     

Andrew W. Farnham  Norman F. Janes  Bhupinder P. S. Khambay 《Pest management science》1989,25(2):205-218

Synthesis of a range of 1-, 2-and 3-phenyl, benzyl and phenethyl substituted cyclopentanols and cyclopentylmethyl alcohols and related unsaturated compounds is reported. Results of bioassays of their esters with known pyrethroidal acids against two species of insect lead to recognition of some structure-activity relationships in this series. The distance and relative orientation between the alcoholic and aryl functions appears crucial, but in other respects the nature of the spacer group between them is less important. The most effective alcoholic components are based on cyclopentenes.  相似文献