The measure mix matters: multiple-component plant protection is indispensable for coping with the enormous genome plasticity and mutation rates in pathogenic microorganisms     

Oliveira Garcia  Ely  von Tiedemann  Andreas  Deising  Holger B. 《植物病害和植物保护杂志》2021,128(1):3-6

Efficient plant protection is of fundamental importance in order to warrant food security. Here, we present arguments that a coordinate approach in plant protection is urgently required, taking advantage of a broad mix of measures, including modern synthetic chemistries, capable of protecting plants from adverse organisms.

  相似文献   

Crototropone, a new tropone derivative from Croton zehntneri     

Bracher F  Randau KP  Lerche H 《Fitoterapia》2008,79(3):236-237

Crototropone (3-hydroxy-5,6-dimethoxy-2-methylcyclohepta-2,4,6-trien-1-one) was isolated from roots of Croton zehntneri. The structure was established by spectroscopic methods.  相似文献   

Latitude and Date of Sowing Influences Phenology of Photoperiod‐Sensitive Sorghums     

A. L. Abdulai  M. Kouressy  M. Vaksmann  F. Asch  M. Giese  B. Holger 《Journal of Agronomy and Crop Science》2012,198(5):340-348

Matching phenology with prevalent abiotic and biotic conditions is a prerequisite for varietal adaptation to the environment. That is particularly important in the context of climate change because an increase in temperature is most likely to modify the precocity of the varieties. The forecast of flowering time in photoperiod‐sensitive sorghum is complex as flowering depends on temperature, day length and soil fertility. The objectives of this work were to quantify effects of latitude on the development of selected sorghum varieties and to verify the precision of our models to predict sorghum maturity. A field experiment at three locations along the latitudinal gradient in Mali with staggered sowing dates (SDs) was conducted. Seven sorghum cultivars covering a wide range of the diversity of cultivated sorghums in Mali were sown on the 10 of June, July and August in 2009 and 2010. Duration of the vegetative phase strongly decreased with latitude. Although the maximum day length difference between locations was < 8 min, for some varieties, we observed a reduction in crop duration of up to 3 weeks. Some varieties were photoperiod insensitive at one location but became photoperiod sensitive at another. The effect of latitude on the phenology is underestimated by the existing models. To determine the optimal areas for the varieties in West Africa and to forecast the effects of climate change, a correction of the simulation coefficients taking account of latitude is proposed. But, in the end, it will be necessary to develop a new model that will be able to predict the effects of both SD and latitude. More research is needed to understand physiological response mechanisms of the pronounced latitude effects on sorghum phenology.  相似文献   

Anatomical characteristics of thermally modified Eucalyptus nitens wood in an open and closed reactor system     

Maximilian Wentzel  Tim Koddenberg  Holger Militz 《Wood material science & engineering》2020,15(4):223-228

ABSTRACT

Eucalyptus nitens specimens were thermally modified under open and closed systems. The anatomical characteristics from selected modifications that presented similar mass losses were investigated by analyzing images taken from scanning electron microscopy, transmission light microscopy, and X-ray micro-computed tomography. Wood cell wall thickness, fiber, and lumen area were measured and compared to unmodified specimens, and the crack formation after modification was also analyzed. There was only a slight decrease in the measured characteristics when compared to unmodified specimens. The wood cell wall thickness was less affected than the fiber and lumen areas, and both modifications presented similar crack formations. Overall, there were no significant differences between open and closed system modifications in the anatomical structure.  相似文献   

Veränderung von Humusform, -vorrat und -verteilung im Zuge von Waldumbau-Maßnahmen im Nordostdeutschen Tiefland     

Holger Fischer  Oliver Bens  Reinhard Hüttl 《European Journal of Forest Research》2002,121(6):322-334

  相似文献   

Land Use and Precipitation Affect Organic and Microbial Carbon Stocks and the Specific Metabolic Quotient in Soils of Eleven Ecosystems of Mt. Kilimanjaro,Tanzania     

Holger Pabst  Friederike Gerschlauer  Ralf Kiese  Yakov Kuzyakov 《Land Degradation \u0026amp; Development》2016,27(3):592-602

Tropical ecosystems are under increasing pressure of land‐use changes, strongly affecting the carbon cycle. Conversion from natural to agri‐cultural ecosystems is often accompanied by a decrease in the stocks of organic and microbial carbon (C_org, C_mic) as well as changes in microbial activity and litter decomposition. Eleven ecosystems along an elevation gradient on the slopes of Mt. Kilimanjaro were used to investigate impacts of land‐use changes on C_org and C_mic stocks as well as the specific metabolic respiration quotient (q_sCO₂) in surface soils. Six natural, two semi‐natural and three intensively used agricultural ecosystems were investigated on an elevation gradient from 950 to 3,880 m asl. To estimate the effects of precipitation, rainfall regimes of 3·6 and 20·0 mm were simulated. C_org stocks were controlled by water availability, temperature and net primary production. Agricultural management resulted in decreases of C_org and C_mic stocks by 38% and 76%, respectively. In addition, agricultural systems were characterized by low C_mic:C_org ratios, indicating a decline in available substrate. Enhanced land‐use intensity leads to increased q_sCO₂ (agricultural > semi‐natural > natural). The traditional homegardens stood out as a sustainable land‐use form with high substrate availability and microbial efficiency. Soil CO₂ efflux and q_sCO2 generally increased with precipitation level. We conclude that soils of Mt. Kilimanjaro's ecosystems are highly sensitive to land‐use changes and are vulnerable to changes in precipitation, especially at low elevations. Even though q_sCO₂ was measured under different water contents, it can be used as an indicator of ecosystem disturbances caused by land‐use and management practices. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Nuclear gene indicates coat-color polymorphism in mammoths     

Römpler H  Rohland N  Lalueza-Fox C  Willerslev E  Kuznetsova T  Rabeder G  Bertranpetit J  Schöneberg T  Hofreiter M 《Science (New York, N.Y.)》2006,313(5783):62

By amplifying the melanocortin type 1 receptor from the woolly mammoth, we can report the complete nucleotide sequence of a nuclear-encoded gene from an extinct species. We found two alleles and show that one allele produces a functional protein whereas the other one encodes a protein with strongly reduced activity. This finding suggests that mammoths may have been polymorphic in coat color, with both dark- and light-haired individuals co-occurring.  相似文献   

Color and albedo heterogeneity of Vesta from Dawn     

Reddy V  Nathues A  Le Corre L  Sierks H  Li JY  Gaskell R  McCoy T  Beck AW  Schröder SE  Pieters CM  Becker KJ  Buratti BJ  Denevi B  Blewett DT  Christensen U  Gaffey MJ  Gutierrez-Marques P  Hicks M  Keller HU  Maue T  Mottola S  McFadden LA  McSween HY  Mittlefehldt D  O'Brien DP  Raymond C  Russell C 《Science (New York, N.Y.)》2012,336(6082):700-704

Multispectral images (0.44 to 0.98 μm) of asteroid (4) Vesta obtained by the Dawn Framing Cameras reveal global color variations that uncover and help understand the north-south hemispherical dichotomy. The signature of deep lithologies excavated during the formation of the Rheasilvia basin on the south pole has been preserved on the surface. Color variations (band depth, spectral slope, and eucrite-diogenite abundance) clearly correlate with distinct compositional units. Vesta displays the greatest variation of geometric albedo (0.10 to 0.67) of any asteroid yet observed. Four distinct color units are recognized that chronicle processes--including impact excavation, mass wasting, and space weathering--that shaped the asteroid's surface. Vesta's color and photometric diversity are indicative of its status as a preserved, differentiated protoplanet.  相似文献   

Ambient-temperature isolation of a compound with a boron-boron triple bond     

Braunschweig H  Dewhurst RD  Hammond K  Mies J  Radacki K  Vargas A 《Science (New York, N.Y.)》2012,336(6087):1420-1422

Homoatomic triple bonds between main-group elements have been restricted to alkynes, dinitrogen, and a handful of reactive compounds featuring trans-bent heavier elements of groups 13 and 14. Previous attempts to prepare a compound with a boron-boron triple bond that is stable at ambient temperature have been unsuccessful, despite numerous computational studies predicting their viability. We found that reduction of a bis(N-heterocyclic carbene)-stabilized tetrabromodiborane with either two or four equivalents of sodium naphthalenide, a one-electron reducing agent, yields isolable diborene and diboryne compounds. Crystallographic and spectroscopic characterization confirm that the latter is a halide-free linear system containing a boron-boron triple bond.  相似文献   

MRI features of CNS lymphoma in dogs and cats     

Palus V  Volk HA  Lamb CR  Targett MP  Cherubini GB 《Veterinary radiology & ultrasound》2012,53(1):44-49

The magnetic resonance (MR) imaging features of central nervous system lymphoma in eight dogs and four cats are described. Intracranial lesions affected the rostrotentorial structures in six dogs and caudotentorial structures in two cats. Lesions affected the spinal cord in two dogs and in two cats. One dog and one cat with intracranial lymphoma had signs of local extracranial extension and lymphadenopathy. Lesions were considered extraparenchymal in four dogs and three cats, intraparenchymal in two dogs and one cat, and appeared to have both intra- and extraparenchymal components in two dogs. All lesions were hyperintense in T2-weighted images when compared to white matter, most were hypointense in T1-weighted images (7/12), and most were hyperintense in fluid-attenuated inversion recovery (FLAIR) images (5/9). When compared to grey matter, these lesions appear either isointense (5/12) or hyperintense (7/12) on T2-weighted images, half of them were hypointense in T1-weighted images (6/12), and most were isointense in FLAIR images (7/9). Lesion margins were usually indistinct in T2-weighted images (10/12) and had perilesional hyperintensity in FLAIR images (7/9). The majority of lesions (10/12) had abnormal meninges around the lesion and half (6/12) had generalized contrast enhancement. Mass effect was evident in all lesions. Although not specific, when combined with the history and neurologic signs, MR features aid presumptive diagnosis that should be confirmed by cytology or histopathology.  相似文献