Localized hemibiotrophy in Colletotrichum: cytological and molecular taxonomic similarities among C. destructivum, C. linicola and C. truncatum   总被引：1，自引：1，他引：1  

A. O. Latunde-Dada  J. A. Lucas 《Plant pathology》2007,56(3):437-447

The infection process of hemibiotrophic isolates of Colletotrichum linicola (from flax, Linum usitatissimum ) and C . truncatum (from broad bean, Vicia faba and lentil, Lens culinaris ) was studied by light microscopy. Host surfaces were penetrated directly leading to a symptomless, biotrophic phase characterized by the elaboration of large multilobed, multiseptate, vesicular primary hyphae that were restricted to the initially infected epidermal cells. Biotrophy lasted for the first 48 h of the host-pathogen interaction and was rapidly succeeded by a necrotrophic phase during which narrow, secondary hyphae invaded the surrounding leaf tissues and water-soaked spreading lesions with sporulating, monosetate acervuli were produced on infected host surfaces. Molecular taxonomic analysis of the nucleotide sequences of the amplified D2 and ITS-2 regions of rDNA revealed very close similarities (97–99%) between these isolates and those of C . destructivum obtained from cowpea ( Vigna unguiculata ) and lucerne ( Medicago sativa ), and also of C . truncatum obtained from pea ( Pisum sativum ). This association was consistent with results from a comparative assessment of some in-planta and in-vitro morphological and growth characteristics of these hemibiotrophic fungi. It was concluded that localized hemibiotrophy is an infection strategy utilized predominantly by a closely-related group of pathogens comprising C . destructivum , C . linicola and C. truncatum , and the formation of multilobed primary hyphae restricted to the first penetrated cell might therefore be a key taxonomic character which correlates consistently with ITS sequence data.  相似文献   

Mammary mass aspirate from a Yorkshire terrier     

Fernandes PJ  Guyer C  Modiano JF 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1998,27(3):79-92

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An attempt to protect calves against experimental bovine leukosis using allografts   总被引：1，自引：0，他引：1  

D H Roberts  M H Lucas  G Wibberley  C Swallow 《Veterinary microbiology》1985,10(3):231-239

Six calves sensitised by implanting skin from a calf were later inoculated with lymphocytes from the same calf after the calf had been infected with bovine leukosis virus (BLV). Two out of 6 calves challenged did not develop BLV antibodies and BLV was not isolated from these animals, whereas all of the 5 control calves became infected with BLV.  相似文献   

Use of quantitative real-time PCR to determine the local inflammatory response in the intestinal mucosa and muscularis of horses undergoing small intestinal resection     

Zofia M. Lisowski  Lucas Lefevre  Tim S. Mair  Emily L. Clark  Neil P. H. Hudson  David A. Hume  R. Scott Pirie 《Equine veterinary journal》2022,54(1):52-62

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Untersuchungen zur Ermittlung toxischer Wirkungen von Derivaten der 2,4-Dichlor- und 2,4,5-Trichlorphenoxyessigsäure (2,4-D und 2,4,5-T) auf Bruteier von Fasanen,Wachteln und Hühnern     

V. Hilbig  K. Lucas  V. Sebek 《Journal of pest science》1976,49(2):21-25

Studies on the susceptibility of eggs of gallinaceous birds to 2,4,5-T and 2,4-D. First report Studies were performed on a total of 3,693 eggs from Japanese quails, 1,080 eggs from pheasants and 500 hen's eggs to investigate the possible effect of 2,4-D or a mixture of 2,4-D and 2,4,5-T on the hatching rate, body weight and malformations of offsprings.Non-incubated and preincubated (3 days) eggs were sprayed with up to 10 times the amount of herbicides normaley used. The eggs serving as controls were treated with tap water.As compared with the controls, the herbicides did not affect hatching rate, body weight or the number of malformations.  相似文献   

Process studies in aPinus radiata-pasture agroforestry system in a subhumid temperature environment. I. Water use and light interception in the third year     

I. A. M. Yunusa  D. J. Mead  K. M. Pollock  R. J. Lucas 《Agroforestry Systems》1995,32(2):163-183

In this study we determined soil moisture storage, evapotranspiration (ET) and light interception in an agroforestry trial consisting of pine trees grown over (1) control (bare ground), (2) ryegrass/clovers (Lolium perene/Trifolium spp.), (3) lucerne (Medicago sativa), and (4) ryegrass only during the third growing season between 1992 and 1993. The results show that:

1.	In the period when rainfall was frequent and exceeded the evaporative demand (Epot), ET and depletion of soil moisture were not affected by the ground cover treatments. During summer when rainfall was less frequent, but with moisture readily available in the soil profile, ET was associated with plant canopy, and was significantly higher for the pasture ground covers than for the control. Therefore, the more rapid growth by lucerne caused higher ET in this ground cover than in the ryegrass/clovers ground cover in which the pasture was slow growing. At the end of the study period, total ET was in the following order: lucerne (757 mm) > ryegrass/clovers (729 mm) > Control (618 mm).
2.	ET was dominated by pasture transpiration (Ep) during most of the growing season, but by tree transpiration (Et) in winter when large parts of the pasture canopy was shaded. Ep was always at least 16% higher for lucerne than for ryegrass/clovers species as a result of a greater radiation intercepted by the former.
3.	Fraction of incoming radiation intercepted by the tree crowns was in the following order: control > ryegrass > ryegrass/clovers > lucerne. At the end of the one-year period, fraction of intercepted radiation was 140% greater for control than for lucerne ground cover.
4.	The control produced the largest tree crowns, which were almost twice the tree crowns in the lucerne ground cover which produced the smallest trees. Accordingly, the trees in the control intercepted more radiation and rainfall, with the former being lost to evaporation, than the trees in the pasture.
5.	The fractions of radiation intercepted and ET accounted for by the trees and pastures were associated with the proportion of the plot area they occupied.

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The agroforestry systems database at ICRAF     

P. A. Oduol  P. Muraya  E. C. M. Fernandes  P. K. R. Nair  A. Oktingati  J. maghembe 《Agroforestry Systems》1988,6(1):253-270

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The Chagga homegardens: a multistoried agroforestry cropping system on Mt. Kilimanjaro (Northern Tanzania)     

E. C. M. Fernandes  A. Oktingati  J. Maghembe 《Agroforestry Systems》1985,2(2):73-86

The homegardens are characterised by an intensive integration of numerous multipurpose trees and shrubs with food crops and animals, simultaneously on the same unit of land.The Chagga are skilled farmers with an intimate knowledge of the crops and their ecological requirements. They have a good idea of functions/uses of the plant species on their farms. The large species diversity provides both subsistence and cash crops. It enables the farmer to keep his management options open and provides insurance against drought, pest and economic risks.  相似文献   

Forest villages: an agroforestry approach to rehabilitating forest land degraded by shifting cultivation in Thailand     

S. A. Boonkird  E. C. M. Fernandes  P. K. R. Nair 《Agroforestry Systems》1985,2(2):87-102

The Forest village scheme was introduced by the Forest Industries Organisation (FIO) of Thailand in 1967 as an attempt to stop further spread of the fast increasing shifting cultivation and deforestation in the country. The underlying princple of the scheme is to relate reforestation with social welfare of the people involved. It is essentially a modification of the traditional taungya method of plantation establishment.The salient aspect of the scheme is to induce the shifting cultivators to settle down in villages where each family is given tenure over a plot of land to construct a house and develop a homegarden around it. The farmers are required to help establish and maintain forest plantations, in which they are permitted to raise agricultural crops during the first three years of its establishment. The farmers are also given free medical and educational facilities, and technical advice on crop and livestock husbandry. They can also earn cash rewards for successful plantation establishment.Although the scheme has not achieved its full target in terms of area covered and number of families settled, it is proving to be a successful method of luring people away from destructive shifting cultivation. The approach is applicable to other countries and regions with similar land-use problems and socio-cultural background.The paper also examines the constraints to the effective working of the scheme, provides some simple suggestions for improving its functioning and identies some of the issues that can easily be tackled by research.  相似文献   

Environmental and physiological controls over oxygen and carbon isotope composition of Tasmanian blue gum, Eucalyptus globulus     

Cernusak LA  Farquhar GD  Pate JS 《Tree physiology》2005,25(2):129-146

We measured oxygen isotope ratios (delta18O) of xylem sap, phloem sap, leaves, wood and bark of Eucalyptus globulus Labill. growing in southwestern Australia. Carbon isotope ratios (delta13C) were measured in the dry matter of phloem sap, leaves and wood. Results were used to test several aspects of a mechanistic model of 18O enrichment and provided insights into post-photosynthetic variations in dry matter delta13C. Xylem water delta18O varied little within the tree crown, whereas variation at the landscape-level was more pronounced, with plantations near the coast being enriched by up to 3 per thousand compared with plantations less than 100 km inland. Phloem water was significantly enriched in 18O compared with xylem water in two of three sampling campaigns; mean enrichments were 0.5 and 0.8 per thousand. Phloem sap sugars exported from E. globulus leaves closely reflected observed leaf water enrichment when diurnal variation in photosynthesis was taken into account. Photosynthetic rates were higher in the morning than in the afternoon, whereas leaf water 18O enrichment increased to maximum values in the afternoon. A non-steady-state model of leaf water 18O enrichment accurately predicted observed values through a full diel cycle. Mean estimates of the proportion of organic oxygen effectively exchanging with xylem water during cellulose synthesis were close to 0.40 for both leaves and wood. Carbon isotope ratios of nascent xylem tissues did not differ from those of phloem sap sugars collected concurrently, whereas nascent leaf tissues were depleted in 13C by 2 per thousand compared with phloem sap sugars, suggesting that, in E. globulus, 13C enrichment of sink tissues compared with source leaves does not result from an enriching process within the sink tissue.  相似文献