Pimarane diterpene from Viguiera arenaria (Asteraceae) inhibit rat carotid contraction     

Ambrosio SR  Tirapelli CR  Bonaventura D  De Oliveira AM  Da Costa FB 《Fitoterapia》2002,73(6):484-489

ent-Pimara-8(14),15-dien-19-oic acid (PA) isolated from Viguiera arenaria (Asteraceae; Heliantheae) inhibited rat carotid rings contraction induced by phenylephrine (10(-8) mol/l) or potassium chloride (45 mmol/l) at concentration ranging from 5 to 20 microg/ml. This inhibitory effect was not reversible after the removal of this compound from the medium bath.  相似文献   

Afforestation trials with Prosopis chilensis (Mol.) Stuntz and Prosopis flexuosa D.C. in the Dry Chaco, Argentina     

Leonor Cataln  Carlos Carranza  Laura Gonzlez  Ulf Karlin  Marcela Ledesma 《Forest Ecology and Management》1994,70(1-3):113-119

In implantation trials carried out with Prosopis chilensis and Prosopis flexuosa, the following variables were considered: implantation time (December and March), implantation technique (direct seeding and seedling transplantation) and age of the seedlings at the time of transplantation (60, 105 and 150 days). Survival was evaluated for more than 9 months after implantation and trials were repeated in 3 consecutive years.

Results from both species were similar and they show that survival after transplantation was higher (60–80%) than from direct seeding (35–45%). Survival from transplantation was independent of the size and age of the seedlings and it was less affected by climatic conditions than direct field sowing. Survival from direct seeding was higher in March than in December. The best time for either implantation alternative would be the end of the summer or beginning of fall, when climatic conditions increase the probability of seedling survival.  相似文献   

The dehesa: an agrosilvopastoral system of the Mediterranean region with special reference to the Sierra Morena area of Spain     

Richard Joffre  Jean Vacher  Carlos de los Llanos  Gilbert Long 《Agroforestry Systems》1988,6(1):71-96

A multidisciplinary team undertook a six-year investigation on the agro-ecological and socio-economic aspects of the dehesa system in the Sierra Norte area, a part of the Sierra Morena of the Sevilla Province, Western Andalusia, Spain. This paper summarizes its findings on the various agro-ecological features of the system and evaluates the system's functional aspects vis-a-vis the trends and developments in land use in the region over the past few centuries. The synergistic effects of tree cover on understorey grassland vegetation is discussed in terms of soil fertility build-up and favourable micro-climatic and hydrological features, and the potential use of this information in future research and development programmes to improve the dehesa system in the Mediterranean region is outlined.  相似文献   

温度对大叶桃花心木(Swietenia macrophylla King)幼苗叶片的光合影响   总被引：2，自引：0，他引：2  

张成军  祖元刚  郭佳秋 《林业研究》2003,14(2):130-134

本文研究了大叶桃花心木（Swietenia macrophylla King）一年生幼苗在经过夜温处理后的光响应曲线和在饱和光强下的CO2反应曲线.结果表明:在大气CO2浓度下,叶片的最佳光合作用温度在25-31℃之间,而在饱和CO2浓度下为31-35℃.在25℃以下光合速率开始降低,主要是由于羧化效率的降低,而当温度超过31℃时,光合速率下降,是因为羧化效率的降低和呼吸速率的增加.CO2浓度对光合的促进作用在低温下受到抑制,这意味着未来在CO2浓度增高的情况下,高浓度的CO2对热带常绿植物光合的促进在冬天低温情况下表现不十分明显.图4参23.  相似文献   

Intermediate reactive oxygen and nitrogen from macrophages induced by Brazilian lichens     

Santos LC  Honda NK  Carlos IZ  Vilegas W 《Fitoterapia》2004,75(5):473-479

The activity of ten compounds isolated from Brazilian lichen over the release of hydrogen peroxide and nitric oxide was evaluated in the culture of peritoneal macrophage cells from mice. Salazinic, secalonic A and fumarprotocetraric acids were the compounds that induced the greatest release of H2O2, whereas 12R-usnic and diffractaic acids induced the release of NO. These results indicate that lichen products have potential immunological modulating activities.  相似文献   

Inhibitory action of kaurenoic acid from Viguiera robusta (Asteraceae) on phenylephrine-induced rat carotid contraction     

Tirapelli CR  Ambrosio SR  Da Costa FB  De Oliveira AM 《Fitoterapia》2002,73(1):56-62

ent-kaurenoic acid (KA) isolated from Viguiera robusta was tested for activity on vascular smooth muscle contactility. Cumulative concentration-response curves were obtained for a stepwise increase (10(-10)-10(-05) mol/l) in the concentration of phenylephrine (Phe), a selective alpha(1)-adrenergic agonist. The effects in the presence of KA (0.2, 2.0 and 20.0 microg/ml), and 90 min after the removal of KA from the medium bath were compared to controls. At 20.0 microg/ml, KA inhibited the in vitro contractility of rat carotid artery elicited by Phe, but had no effect at lower concentrations (0.2 and 2.0 microg/ml). The effect elicited by KA was reversible after 90 minutes.  相似文献   

A new Delta7,22 sterol from the bulbs of Autonoë madeirensis     

Paulo A  Dias C  Jimeno ML  Borges C  Nascimento J 《Fitoterapia》2005,76(7-8):765-767

The spectral data of a new Δ^7,22 sterol, 24S-ethyl-5α-cholesta-7,22E-dien-3α-ol β-galactopyranoside, isolated from the bulbs of Autonoë madeirensis, are reported.  相似文献   

Tracking leaf area index and coefficient of light extinction over the harvesting cycle of black wattle     

Alexandre Behling  Carlos Roberto Sanquetta  Ana Paula Dalla Corte  Sylvio Péllico Netto  Aurélio Lourenço Rodrigues  Bráulio Otomar Caron  Augusto Arlindo Simon 《林业研究》2016,27(6):1211-1217

The amount of photosynthetic radiation intercepted by a crop is a function of the incident solar radiation on the plants, the leaf area index (L _AI), and the light extinction coefficient (k). We quantified L _AI and k in stands of black wattle (Acacia mearnsii De Wild.) over a 7-year growth cycle at two locations in the state of Rio Grande do Sul, Brazil. Our study was conducted in commercial stands in agroecological regions with high densities of black wattle plantations. L _AI was calculated as the ratio between the leaf area of a tree and its planting space, and k was derived from Beer’s law. L _AI depends on the planting site and stand age. Between the two sites, the L _AI was similar over time, the amount of variation differed. Values of k depended only on stand age, with the highest average observed for stands up to 5 years old. The trend of k during the plantation cycle was inversely proportional to L _AI and was correlated with L _AI, leaf area, leaf dry mass, canopy volume, height, branches dry mass, total dry mass, and crown diameter.  相似文献   

Agroforestry systems as a profitable alternative to slash and burn practices in small-scale agriculture of the Brazilian Amazon     

Stéphane Tremblay  Marc Lucotte  Jean-Pierre Revéret  Robert Davidson  Frédéric Mertens  Carlos José Sousas Passos  Christina A. Romaña 《Agroforestry Systems》2015,89(2):193-204

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Empirical models to predict LAI and aboveground biomass of Coffea arabica under full sun and shaded plantation: a case study of South of Minas Gerais,Brazil     

Priscila Pereira Coltri  Jurandir Zullo Junior  Vincent Dubreuil  Glaucia Miranda Ramirez  Hilton Silveira Pinto  Gustavo Coral  Camila Giorgi Lazarim 《Agroforestry Systems》2015,89(4):621-636

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