Further evidence that in African acacia,white is a warning colour to herbivores: the white pseudo-galls of Vachellia seyal     

Jeremy Midgley  Huyam Altayeb  Patrick Mbosso 《African Journal of Range and Forage Science》2016,33(2):127-129

Pseudo-galls of three East African acacia (Vachellia) species were compared to determine the correlates of gall colour and their potential defensive functions. Although all three species produce white thorns, the pseudo-galls of V. gerrardii and V. drepanolobium are dark coloured. In contrast, pseudo-galls of V. seyal var. fistula are white. Associated with this, they are thin-walled and poorly used by aggressive mutualistic ants. We suggest that this weak functionality is compensated for by the highly visible white colour. This aposematism may also involve mimicry as only the fistula variety of V. seyal has galls and only this variety co-occurs with other Vachellia species that have functional galls. Vachellia seyal seyal does not have pseudo-galls and this variety does not occur with other Vachellia species that have pseudo-galls.  相似文献   

Ecosystem services from coffee agroforestry in Central America: estimation using the CAF2021 model     

van Oijen  Marcel  Haggar  Jeremy  Barrios  Mirna  Büchi  Lucie  Cerda  Rolando  Cerretelli  Stefania  López  Erick  de Melo Virginio Filho  Elias  Ospina  Alejandra 《Agroforestry Systems》2022,96(7):969-981

The goal of sustainable coffee production requires multiple functions from agroforestry systems. Many are difficult to quantify and data are lacking, hampering the choice of shade tree species and agronomic management. Process-based modelling may help quantify ecosystem services and disservices. We introduce and apply coffee agroforestry model CAF2021 (https://doi.org/10.5281/zenodo.5862195). The model allows for complex systems with up to three shade tree species. It simulates coffee yield, timber and fruit production by shade trees, soil loss in erosion, C-sequestration, N-fixation, -emission and -leaching. To calibrate the model, we used multivariate data from 32 different treatments applied in two long-term coffee agroforestry experiments in Costa Rica and Nicaragua. Without any further calibration, the model was then applied to agroforestry systems on 89 farms in Costa Rica and 79 in Guatemala where yields had been reported previously in farmer interviews. Despite wide variation in environmental and agronomic conditions, the model explained 36% of yield variation in Costa Rica but only 15% in Guatemala. Model analysis quantified trade-offs between yield and other ecosystem services as a function of fertilisation and shading.

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Champagne wine polyphenols protect primary cortical neurons against peroxynitrite-induced injury   总被引：1，自引：0，他引：1  

Vauzour D  Vafeiadou K  Corona G  Pollard SE  Tzounis X  Spencer JP 《Journal of agricultural and food chemistry》2007,55(8):2854-2860

White wines are generally low in polyphenol content as compared to red wines. However, Champagne wines have been shown to contain relatively high amounts of phenolic acids that may exert protective cellular actions in vivo. In this study, we have investigated the potential neuroprotective effects of Champagne wine extracts, and individual phenolics present in these extracts, against peroxynitrite-induced injury. Organic and aqueous Champagne wine extracts exhibited potent neuroprotective activity against peroxynitrite-induced injury at low concentrations (0.1 microg/mL). This protection appeared to be in part due to the cellular actions of individual components found in the organic extracts, notably tyrosol, caffeic acid, and gallic acid. These phenolics were observed to exert potent neuroprotection at concentrations between 0.1 and 10 microM. Together, these data suggest that polyphenols present in Champagne wine may induce a neuroprotective effect against oxidative neuronal injury.  相似文献   

Challenges for Multilevel Stakeholder Engagement in Public Trust Resource Governance     

Emily F. Pomeranz  Daniel J. Decker  William F. Siemer  Arthur Kirsch  Jeremy Hurst  James Farquhar 《Human Dimensions of Wildlife》2014,19(5):448-457

The trend in wildlife management over the last two decades has been to develop locally based approaches for responsiveness to local conditions, but some state wildlife agencies are finding the amount of staff time required to service this approach prohibitive. Although local engagement strategies have been lauded as assuring that public trust obligations of state government to citizens are met, we can expect that states with a local focus as their operational level of stakeholder engagement may opt to change their approach to reflect their resource limitations. We argue for comprehensive regional level effort to understand stakeholders augmented with local engagement processes where needed to deal with special circumstances in smaller areas within a region. Such an approach can be anticipated to have implications for stakeholder engagement and human dimensions research needs, which we discuss in the context of public trust resource administration and good governance of wildlife resources.  相似文献   

Green roof vegetation type affects germination and initial survival of colonizing woody species     

Lori E. Miller  Amy E. Heim  Jeremy Lundholm 《Urban Forestry & Urban Greening》2014,13(4):892-899

Green roofs provide a number of valuable ecosystem services compared to conventional roofs, but may require yearly maintenance. Trees and other woody plants that persist on the roof may damage or overload shallow-substrate green roofs and their removal is a standard maintenance procedure. The germination potential of colonizing species may differ depending on the vegetation surrounding them. The aim of this study was to determine whether the germination of colonizing tree species (Picea glauca and Ulmus glabra) will vary depending on which plant species form the established vegetation seeds land in. To determine germination success, survival, and seed capture ability of the plant canopy, tree seeds were added either directly to the growing medium or atop the plant canopy, in replicated monocultures of 14 species native to Nova Scotia. When seeds were added directly to the soil, no significant difference was detected between the monocultures for germination success or survival for U. glabra or P. glauca. However, when the seeds were added atop the plant canopy, percent germination of U. glabra was significantly higher in Carex argyrantha green roof modules. Overall, sod forming graminoids showed higher germination of U. glabra. The number of seeds reaching the soil was typically lower in vegetation with a denser canopy. This study demonstrates that some vegetation repels colonizing tree species by reducing ground contact. Although these effects differed according to tree species, non-vegetated substrates enhanced seedling persistence. Additionally, the majority of tree seeds that germinated failed to survive a single growing-season on shallow-substrate green roofs.  相似文献   

Distribution and plant community associations of the understory bamboo <Emphasis Type="Italic">Fargesia qinlingensis</Emphasis> in the Foping National Nature Reserve,China     

Xi-Chun Du  Yi Ren  Gao-Di Dang  Jeremy Lundholm 《Annals of Forest Science》2011,68(7):1197-1206

• Introduction  

Fargesia qinlingensis is the primary food source for the endangered giant panda during the summer months in the Qinling Mountains, but little is known about its spatial distribution and plant community associations.  相似文献   

A cytokinin perception mutant colonized by Rhizobium in the absence of nodule organogenesis     

Murray JD  Karas BJ  Sato S  Tabata S  Amyot L  Szczyglowski K 《Science (New York, N.Y.)》2007,315(5808):101-104

In legumes, Nod-factor signaling by rhizobia initiates the development of the nitrogen-fixing nodule symbiosis, but the direct cell division stimulus that brings about nodule primordia inception in the root cortex remains obscure. We showed that Lotus japonicus plants homozygous for a mutation in the HYPERINFECTED 1 (HIT1) locus exhibit abundant infection-thread formation but fail to initiate timely cortical cell divisions in response to rhizobial signaling. We demonstrated that the corresponding gene encodes a cytokinin receptor that is required for the activation of the nodule inception regulator Nin and nodule organogenesis.  相似文献   

Glycan foraging in vivo by an intestine-adapted bacterial symbiont   总被引：1，自引：0，他引：1  

Sonnenburg JL  Xu J  Leip DD  Chen CH  Westover BP  Weatherford J  Buhler JD  Gordon JI 《Science (New York, N.Y.)》2005,307(5717):1955-1959

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Increased alkalinity in the Mississippi     

Jones JB  Stanley EH  Mulholland PJ 《Science (New York, N.Y.)》2003,302(5647):985-7; author reply 985-7

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The problems of bonus pay     

Berg JM 《Science (New York, N.Y.)》2004,304(5672):824

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