Osmotic adjustment,proline accumulation and cell membrane stability in leaves of Cocos nucifera submitted to drought stress     

Fabio P. Gomes  Marco A. Oliva  Marcelo S. Mielke  Alex-Alan F. Almeida  Leonardo A. Aquino 《Scientia Horticulturae》2010

The role of drought-induced proline accumulation in coconut leaves is still unclear. With the objective of evaluating the impact of water shortage on leaf osmotic potential, proline accumulation and cell membrane stability in young plants of two Brazilian Green Dwarf coconut ecotypes from contrasting areas (Brazilian Green Dwarf from Una, Bahia, UGD, and from Jiqui, Rio Grande do Norte, JGD), a pot experiment was conducted under greenhouse conditions. Three drought cycles consisting of suspension of irrigation until the net photosynthetic rate (A) approached zero and rewatering until recovery of A to 85% of the irrigated control plants. Pre-dawn leaf water potential (Ψ_PD) reached −1.2 MPa at the point of maximum stress (PMS). Dry matter production and leaf area were severely reduced by drought treatment in the two ecotypes. Corrected values of osmotic potential were significantly reduced in stressed plants of the two ecotypes. Green dwarf coconut palm showed low osmotic adjustment (from 0.05 to 0.24 MPa) and significant accumulation of proline (from 1.5 to 2.1 times in relation to control) in leaflets in response to water deficit. Considering the growth reduction observed in both ecotypes, proline was not associated to osmoregulation. On the other hand, the absence of membrane damage, as indicated by electrolyte leakage method, suggests that the protective role of proline in this specie can be more important. The two ecotypes of Green dwarf coconut palm behaved similarly in the present experiment for most traits evaluated. Slight differences among the ecotypes were observed with respect to the response to treatments, such as higher proline accumulation in JGD.  相似文献   

Object-orientated image analysis for the semi-automatic detection of dead trees following a spruce bark beetle (<Emphasis Type="Italic">Ips typographus</Emphasis>) outbreak     

Marco Heurich  Tobias Ochs  Thorsten Andresen  Thomas Schneider 《European Journal of Forest Research》2010,129(3):313-324

The survey and continuing inventory in the Bavarian Forest National Park of deadwood areas resulting from a spruce bark beetle calamity are being performed by means of visual evaluation of colour infrared aerial photographs. With the aid of the object-oriented image analysis software eCognition, it was possible to develop a partially automated method for this purpose. In order to verify the classification results, a test area was classified, and the results compared with those obtained by the previously used method. In addition, the classification results from two consecutive years were compared, and accuracy assessment methods were used to scrutinize the results. Classification in the deadwood areas yielded a total classification accuracy of 91.5%. In regard to objectivity and degree of detail, the newly developed method is significantly superior to the former method, which is based on visual interpretation with a stereo workstation. One problem, however, was the insufficient spatial accuracy of the respective orthophotos. Because of this, it was not possible to detect changes over the course of specified time intervals. Therefore, a practical application of this method would require that the orthophotos from various dates or times be precisely spatially assigned. This requirement can be achieved with the production of new orthophotos.  相似文献   

Using CERES-Wheat to simulate durum wheat production and phenology in Southern Sardinia,Italy   总被引：3，自引：0，他引：3  

Marco Dettori  Carla Cesaraccio  Andrea Motroni  Donatella Spano  Pierpaolo Duce 《Field Crops Research》2011

Durum wheat is a crop of great economic relevance for Mediterranean regions, especially in developing countries. A decreasing trend in durum production is expected in the near future because of several factors, in particular environmental constraints due to climate change and variability. The aim of this work was to test the predictive performance of CERES-Wheat model, implemented in DSSAT software systems, under Mediterranean climate condition and soil types of Southern Sardinia, Italy. CERES-Wheat model was calibrated for three durum wheat Italian varieties (Creso, Duilio, and Simeto) using a 30-year data set (1974–2004) and a trial and error iterative procedure. Then, the model was validated and evaluated using several statistics. The model showed a quite good performance in predicting grain yield and anthesis date, with errors comparable with those reported by other studies conducted on bread and durum wheat. Predictions of grain weight and grain number did not match very well observations, confirming the difficulties of CERES-Wheat in estimating grain yield components. The results of this study suggest the need of specific field experiments and further model evaluations and improvements to better understand model simulation results of grain yield components of durum wheat.  相似文献   

HPLC Screening and GC-MS Confirmation of Triazine Herbicides Residues in Drinking Water from Sugar Cane Area in Brazil     

Lanchote  Vera Lucia  Bonato  Pierina Sueli  Cerdeira  Antonio Luiz  Santos  Neife Aparecida Guinain  de Carvalho  Dermeval  Gomes  Marco Antonio 《Water, air, and soil pollution》2000,118(3-4):329-338

The extensive use of chlorotriazines as selectiveherbicides in agriculture and their relatively highpersistence imply that these compounds are now presentin the environment, contaminating surface and groundwater. In European countries, United States andCanada, the drinking water ordinance demands a limitedconcentration of 0.5 μg L^-1 for the sum of allpesticides and 0.1 μg L^-1 with respect to eachcompound, implying on the necessity of sensitive andselective analytical methods. In the present study wedescribe two methods for the analysis of atrazine,simazine and ametryn residues in surface and groundwater collected from the Espraiado Stream watershed,Ribeirão Preto region, SP, Brazil. The HPLC methodused for sample screening was based on herbicideextraction with dichloromethane:isopropanol (9:1, v/v)followed by reversed-phase chromatography (RP-8) withdetection at 220 nm. The presence of herbicides wasconfirmed by GC-MS after ethyl acetate extraction. Atotal of 250 samples collected at different sites fromOctober 1995 to July 1996 were analyzed. Ametrynresidues were detected in 17 samples but almost alwaysat concentrations below those maximum levels recommended by international agencies of environmental control.  相似文献   

A micromorphological index of soil development for the Quaternary geology research     

Donatello Magaldi  Marco Tallini 《CATENA》2000,41(4)

Profile development indices of Harden [Harden, J.W., 1982. A quantitative index of soil development from field: examples from a chronosequence in Central California. Geoderma 285, 1–98] and Ferrari and Magaldi [Ferrari, G., Magaldi, D., 1983. Significato ed applicazioni della paleopedologia nella stratigrafia del Quaternario. Boll. Mus. Civ. St. Nat. Verona 10, 315–340] have shown their utility for comparative dating of some paleosols during geomorphological and geological surveys. In Italy and other countries, pedostratigraphic methods have been commonly applied to soil profiles formed in continental formations. Unfortunately, buried and relict paleosols are very scarce or badly preserved in some areas of Italy due to past and recent tectonic activity and to strong human impact dating back to prehistoric times.In order to use relict paleosols for correct chronostratigraphic interpretation of relict paleosols and in order to correlate them with old landscape forms for the reconstruction of Quaternary sequences, a new micromorphological index (MISODI) for assessing soil development and degree of weathering was devised. The index was tested in the extensional tectonic basin of L'Aquila-Scoppito (Abruzzi, Central Italy) where some chronostratigraphic information is available.Results demonstrate that there is a good relationship between presumed relative age of paleosols and degree of weathering and pedogenesis in B and B/C horizons as assessed by this index. The index has the potential to be adapted for application to other paleosol types in other countries.  相似文献   

Comparison of different culture media on the mycelial growth, sporangia and oospore production ofPhytophthora infestans     

Marco V. Medina  H. W. Platt 《American Journal of Potato Research》1999,76(3):121-125

The purpose of this study was to evaluate various culture media, with or without β-sitosterol, on mycelial growth, sporangia and oospore production by isolates ofPhytophthora infestans. Nine media were compared to rye agar (RA) which is frequently used to cultureP. infestans. Poor fungal growth across most isolates was observed on soybean agar, carrot agar and carrot agar with sterols relative to RA. Only clarified V8 juice containing β-sitosterol (CLV8S) resulted in significantly more sporangia production compared to RA. All other media performed similar to the RA. No significant differences were found in the sizes (length and width) of sporangia produced among the isolates tested on various media. Oospore production was greatest whenP. infestans was cultured on carrot agar with β-sitosterol (CAS) or CLV8S when compared to RA. Responses of isolate matings varied somewhat with an A2 isolate from Nova Scotia consistently producing fewer oospores in matings with A1 isolates compared to the other A1/A2 mating combinations. Rye agar and oat meal agar with or without β-sitosterol as well as clarified V8 juice agar with β-sitosterol are useful forin vitro growth of mycelium.  相似文献   

Automatic recognition and measurement of single trees based on data from airborne laser scanning over the richly structured natural forests of the Bavarian Forest National Park     

Marco Heurich 《Forest Ecology and Management》2008

The purpose of this study was to test a method for delineating individual tree crowns based on a fully automated recognition methodology. The study material included small-footprint time-of-flight laser scanner data acquired in the spring and summer of 2002. The data were collected with a Toposys II airborne laser system flown over the Norway spruce (Picea abies) and European beech (Fagus sylvatica) dominated forests of the Bavarian Forest National Park, Germany. The applied algorithm, which earlier had been validated for Swedish forest conditions, is a watershed algorithm that is based on the use of laser scanning data. 2584 trees in a total of 28 representative reference stands, each 0.1–0.25 ha in area, were included in the investigation. With the algorithm, 76.9% of the trees in the upper layer could be recognised. This corresponds to 85.2% of the timber volume determined by ground measurements. The results for conifers were more accurate in this respect than for deciduous trees. A negative aspect was the number of falsely identified trees, the percentage of which was 5.4%.  相似文献   

Forest structure and woody plant species composition along a fire chronosequence in mixed pine–oak forest in the Sierra Madre Oriental, Northeast Mexico     

Marco Aurelio Gonzlez-Tagle  Luitgard Schwendenmann  Javier Jimnez Prez  Rainer Schulz 《Forest Ecology and Management》2008,256(1-2):161-167

Although wildfires are occurring frequently in the pine–oak forests in the Sierra Madre Oriental (northeastern Mexico), data on post-fire succession and forest structure are still rare. Our objectives were to (1) assess the changes in woody plant species composition after fire and to (2) to relate successional patterns to environmental variability. Based on their fire history 23 plots were selected in the Parque Ecológico Chipinque (PECH). Changes in forest structure across the chronosequence of burned stands were deduced from density, height and diameter measurements of trees and shrubs (>5 cm in diameter) in all plots of 1000 m². Differences in woody plant species composition among the plots were evaluated using Shannon evenness measure and the Whittaker's measure and by Hierarchical cluster analysis and Detrended Correspondence Analysis. Hierarchical cluster analysis showed a high similarity among all recently burned plots, independed of the aspect. Multivariate analysis showed that local environmental factors, including time since fire, continue to structure species composition. Oak species (mainly Quercus rysophylla) resprouted successfully after fire and dominated young post-fire stands. Pine species (Pinus pseudotrobus and Pinus teocote) only appeared 18 years after fire and were the dominating species in mature stands (62 years after fire). In contrast, woody plant species composition in older stands tended also to be influenced by factors such as aspect and by the potential solar radiation (PSR) during the growing season. The results demonstrate that in the PECH, natural regeneration is sufficient and woody plant species composition will be similar to pre-fire conditions after 60 years of succession. We conclude that the park managers should consider incorporating natural disturbance regimes into their management practices.  相似文献   

Chemical characterization of wood samples colored with iron inks: insights into the ancient techniques of wood coloring     

Claudio Canevari  Marica Delorenzi  Claudia Invernizzi  Maurizio Licchelli  Marco Malagodi  Tommaso Rovetta  Maduka Weththimuni 《Wood Science and Technology》2016,50(5):1057-1070

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Responses of regeneration and species coexistence to single-tree selective logging for a temperate mixed forest in eastern Eurasia     

Lin Qi  Jian Yang  Dapao Yu  Limin Dai  Marco Contrereas 《Annals of Forest Science》2016,73(2):449-460

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