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71.
Axial and radial water flow in the trunks of oak trees: a quantitative and qualitative analysis 总被引:1,自引:0,他引:1
Granier A Anfodillo T Sabatti M Cochard H Dreyer E Tomasi M Valentini R Bréda N 《Tree physiology》1994,14(12):1383-1396
Axial water flow in the trunks of mature oak trees (Quercus petraea (Matt.) Liebl. and Q. robur L.) was studied by four independent techniques: water absorption from a cut trunk, sap flowmeters, heat pulse velocity (HPV) and thermoimaging. Estimation of the total water flow with sap flowmeters, HPV and water absorption yielded comparable results. We concluded from dye colorations, thermograms and axial profiles of sap flow and heat pulse velocity that, in intact trunks, most of the flow occurred in the current-year ring, where early-wood vessels in the outermost ring were still functional. Nevertheless, there was significant flow in the older rings of the xylem. Total water flow through the trunk was only slightly reduced when air embolisms were artificially induced in early-wood vessels, probably because there was little change in hydraulic conductance in the root-leaf sap pathway. Embolization of the current-year vessels reactivated transport in the older rings. 相似文献
72.
73.
Cherry leaf spot (Blumeriella jaapii (Rehm) Arx.) is a very serious disease of wild cherry (Prunus avium L.), which produces premature leaf defoliation and vigor decrease. In two clonal seed orchards of P. avium naturally infected by B. jaapii, spatial heterogeneity and autocorrelation of neighbor damage caused by cherry leaf spot impeded proper analysis of the fungus incidence. The iterative spatial analysis (ISA), based on variography and kriging, was successfully used to eliminate the effect of this spatial heterogeneity in analysis of genetic variation in susceptibility to B. jaapii. Significant differences among P. avium clones were found, with moderate to high broad-sense heritability estimates. Genetic by environment interactions, although significant, were not quantitatively important. A strong relationship between leaf spot susceptibility and bud burst was found. However, other factors must be affecting the genetic variation in leaf spot susceptibility, as differences among clones remained highly significant when considering the bud burst as a covariate in the genetic model. 相似文献
74.
Harald Dinkelmeyer Johannes Lehmann Andreas Renck Lucerina Trujillo Jose Pereira da Silva Jr Gerhard Gebauer Klaus Kaiser 《Agroforestry Systems》2003,57(3):213-224
Mixed tree cropping systems have been proposed for sustainable nutrient management in the humid tropics. Yet, the nutrient interactions between intercropped trees have not been addressed sufficiently. In the present study we compare the temporal and spatial patterns of the uptake of applied 15N by four different tree crops in a mixed tree cropping system on a Xanthic Ferralsol in central Amazônia, Brazil, during one year. Most of the N uptake occurred during the first two weeks. Very little N was recovered by peach palm (Bactris gasipaes), more by cupuassu (Theobroma grandiflorum) and annatto (Bixa orellana) and most by Brazil nut (Bertholletia excelsa). Due to tree pruning the total accumulation of applied 15N in the above-ground biomass of annatto decreased throughout the year. It remained constant in cupuassu and peach palm and increased in Brazil nut. Brazil nut showed an extensive root activity and took up more fertilizer N applied to neighboring trees than from the one applied under its own canopy in contrast to the other three tree crops. Therefore, trees with wide-spread root systems may not need to receive N fertilizer directly but can take up N applied to other trees in the mixed cropping system. This means that such trees may effectively decrease N leaching when intercropped with trees that have dormant periods or places with low N uptake, but also exert considerable resource competition.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
75.
Jorge Miguel Silva Faria Inês Sena Bruno Ribeiro Ana Margarida Rodrigues Carla Maria Nobre Maleita Isabel Abrantes Richard Bennett Manuel Mota Ana Cristina da Silva Figueiredo 《Journal of pest science》2016,89(1):207-217
The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quarantine pest since 1998. This nematode causes severe damage in economically important crops such as potato and tomato, making agricultural products unacceptable for the fresh market and food processing. Commonly used nematicidal synthetic chemicals are often environmentally unsafe. Essential oils (EOs) may constitute safer alternatives against RKN. EOs, isolated from 56 plant samples, were tested against CRKN hatching, in direct contact bioassays. Some of the most successful EOs were fractionated and the hydrocarbon molecules (HM) and oxygen-containing molecules (OCM) fractions tested separately. 24 EOs displayed very strong hatching inhibitions (≥90 %) at 2 µL mL?1 and were further tested at lower concentrations. Dysphaniaambrosioides, Filipendula ulmaria, Ruta graveolens, Satureja montana and Thymbra capitata EOs revealed the lowest EC50 values (<0.15 µL mL?1). The main compounds of these EOs, namely 2-undecanone, ascaridol, carvacrol, isoascaridol, methyl salicylate, p-cymene and/or γ-terpinene, were putatively considered responsible for CRKN hatching inhibition. S. montana and T. capitata OCM fractions showed hatching inhibitions higher than HM fractions. The comparison of EO and corresponding fractions EC50 values suggests interactions between OCM and HM fractions against CRKN hatching. These species EOs showed to be potential environmentally friendly CRKN hatching inhibitors; nonetheless, bioactivity should be considered globally, since its HM and OCM fractions may contribute, diversely, to the full anti-hatching activity. 相似文献
76.
A new isoflavonol triglycoside, biochanin A 7-O-beta-D-apiofuranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->6 )-beta-D- glucopyranoside (1), was isolated from Andira inermis roots in addition to the known compounds genistein 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside and lanceolarin. 相似文献
77.
Summary The effects of heating cork in water vapour at 100°C and 300°C are studied and compared with those produced by heating in
air at the same temperatures. Dimensional and mass changes were measured and radial compression curves were obtained following
various treatments. The 300°C treatments originate a straightening of the originally corrugated cell walls, while the cell
wall material undergoes thermal degradation. Larger swellings and larger mass changes are observed in the treatments in water
vapour as compared to those in air. The 100°C treatments do not induce degradation and produce reversible changes in technological
properties which are simply due to differences in the water content. 相似文献
78.
Antonio D. Del Campo Rafael M. Navarro-Cerrillo Javier Hermoso Antonio J. Ibáñez 《Annals of Forest Science》2007,64(5):541-548
Commercial stocks of Aleppo pine in Spain vary in quality, but there is no accepted standard for evaluating quality. A RGP test was applied to six commercial seedling stocklots at two dates (November, February) and under two test conditions (growth-chamber, greenhouse). The RGP’s predictive ability was evaluated on two contrasting sites. There was a considerable variation in the RGP depending on application date, test conditions and stock factors. The RGP results for November were correlated with each other but they did not explain outplanting performance. The February results in the growth-chamber correlated well with survival at both sites. Regression models explained survival both in the lower (R 2 = 97%) and in the higher (R 2 = 92%) quality sites. RGP has a valid predictive ability for this species although it is sensitive to the test conditions. In this sense, a shorter and more intensive test performed right before planting may be more reliable. 相似文献
79.
Chi?De-fuEmail author Rafael?Ocete?Rubio Yan?Shan-chun Zhang?Dan-dan Wen?Zhen-hong 《林业研究》2002,13(4):255-259
Four-armed airflow olfactometer was used to determining the foraging behavior ofPteroptrix longgiclava (Girault) (Hymenoptera: Aphelinidae) andEncarsia gigas (Tshumakova) (Hymenoptera: Aphelinidae) to the essential oils which emitted from the healthy bark ofPopulus pseudo-simonii×P. nigra, the infested bark injured byQuadraspidiotus gigas (Thiem & Gerneck), the body and scale of fixed 1st-instar-nymph ofQ. gigas. The results from these experiments showed that the volatile oils produced from the injured bark and from the scale of fixed
1st-instar-nymph had a higher attractive ability to female adults of the two species of wasps. The essential oil produced
from the scale of the pest at dosages of 3–7 μL and the essential oil emitted by injured bark at dosages of 5–9 μL had a stronger
alluring effect on the host searching behavior ofPteroptrix longgiclava. The essential oil from the body of fixed 1st-instar-nymph ofQ. gigas also had certain effect on the host locating effort ofPteroptrix longgiclava andEncarsia gigas. Those two wasps did not shown any reaction to the essential oil produced by the healthy bark of poplar.
Foundation item: This paper was supported by National Natural Science Foundation of China (39970620) and the “TRAPOYT”
Biography: CHI De-fu (1962-), male, Ph.D., Professor in Northeast Forestry University, Harbin 150040, P.R. China
Responsible editor: Chai Ruihai 相似文献
80.
The Brazil nut tree(Bertholletia excelsa) is a frequent component of agroforestry systems in the Amazon because of its adaptation to nutrient-poor upland soils and multiple uses.We investigated the aboveground biomass production(kg dry weight),nutrient uptake and requirements(N,P,Ca,Mg,K) of Brazil nut trees of different sizes grown under agroforestry conditions and fertilized at different levels.Eight of 70 experimental trees with different size were harvested and stem,branches and leaves were separated.Nutrient contents were determined for three trees of varying size.Average tree growth was fast,but variability was high,suggesting considerable potential for the improvement of this economically important species.The trees responded to increased levels of fertilizer and lime with significantly increased foliar nutrient contents and growth,probably because of the improved availability of Mg and Ca for which the species seems to have a relatively high demand.In contrast to Brazil nut trees grown in forest or dense plantations,the agroforestry trees invested a substantial part of their biomass and nutrients in large branches and developed spreading crowns.To improve stem form,reduce competition with associated crops for light and recycle nutrients,regular pruning of lower branches or planting arrangements that favor self-pruning are recommended.These measures would also increase the recycling of Ca and Mg,large quantities of which are contained in the branches. 相似文献