首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
A sandy culture experiment was conducted to investigate the effects of exogenous CaCl2 on the indole alkaloid accumulation in Catharanthus roseus under salt stress. One-month seedlings of C. roseus were treated with the different concentrations of NaCl (0, 50, and 100 mmol l? 1) and 7.5 mmol l? 1 CaCl2. The plant samples were analyzed after 7 days of the treatments. The NaCl-stressed plants showed decrease of fresh and dry weight and increase of malondialdehyde (MDA) content compared to control. Tryptophan decarboxylase (TDC) activity increased significantly under 50 mmol l? 1 NaCl without CaCl2 addition, 50 mmol l? 1 NaCl with 7.5 mmol l? 1 CaCl2, and CaCl2 treatment without NaCl addition. There was a significant increase in peroxidase activity under NaCl stress compared to control. The vindoline, catharanthine, vincristine, and vinblastine contents increased under salt stress (especially with 50 mmol l? 1 NaCl treatment with or without CaCl2). Addition of CaCl2 to NaCl-stressed plants increased biomass, TDC activity, vindoline, and catharanthine contents and lowered MDA and vincirstine contents compared to the plants without CaCl2. The plants treated with CaCl2 alone showed higher TDC activity, vindoline, catharanthine, and vinblastine content when compared to control. The results showed that exogenous CaCl2 could promote the indole alkaloid metabolism under salt stress.  相似文献   

2.
Nomenclatural notes on the aggregate Polycarpon tetraphyllum (Caryophyllaceae) are discussed. The names Hagaea alsinifolia, H. polycarpoides, Poycarpon colomense, P. diphyllum, and P. floribundum are typified, respectively, on an iconography by Boccone (lectotype), and specimens preserved in PAL (neotype), JE (lectotype), MA (Herbarium Cavanilles, lectotype), and COI (Herbarium Willkomm, lectotype). For the nomenclatural purposes, the names P. bivonae (nom. nov. pro P. polycarpoides), P. herniarioides (holotype in K), P. peploides (nom. superfl.etnom. illeg. according to the Arts. 52.1 and 52.2 of the ICN), P. polycarpoides subsp. catalaunicum (holotype in BC), and P. rotundifolium (holotype in LY-Herbarium Rouy) are also discussed. P. floribundum is a heterotipic synonym of P. tetraphyllum s.s. A new synonym (P. tetraphyllum = P. rotundifolium) and three new combinations (P. tetraphyllum subsp. colomense, P. tetraphyllum subsp. herniarioides and P. tetraphyllum subsp. catalunicum) are proposed according to the current concept in Polycarpon.  相似文献   

3.
Riassunto Dopo la discussione del metodo per la fissazione in toto del ventricolo sinistro a differenti pressioni passive di riempimento vengono riportati i dati biometrici ultrastrutturali della componente contrattile, dei mitocondri e del sistema trasversale del reticolo delle cellule miocardiche.L'aumento della pressione intraventricolare determina un rapido allungamento del sarcomero che raggiunge il valore di 2,2 a 10 mm Hg mentre il suo incremento è proporzionalmente minore ad elevate pressioni passive.Le miocellule degli strati sottoendocardici allo stesso livello pressorio sono inoltre maggiormente distese rispetto a quelle degli altri strati. Dall'analisi dei grafici relativi alle curve tensione/lunghezza e tensione/volume, risulta, inoltre, che l'allungamento dei sarcomeri è solo parzialmente responsabile dell'aumento della capacità ventricolare, per cui si può supporre che avvenga un nuovo ordinamento spaziale dei vari fasci nel contesto della parete.La distensibilitá passiva del sarcomero, qualora sia rapportata a precisi dati anatomo funzionali della cavità ventricolare, può essere ritenuta un valido modello per lo studio della contrattilità miocardica in condizioni normali e patologiche.
Ultrastructural bases of myocardial contractility: the passive distensibility of the sarcomere, as an index of ventricular function
Summary Having described a method of total fixation of the left ventricle at different levels of passive pressure, the Authors refer about biometrical and ultrastructural data of the contractile component, the mitochondria and the transversal reticular system of the heart muscle cells.The raise of pressure in the ventricle determines a rapid increase of the sarcomere length, which can reach the value of 2,2 at a pressure of 10 mmHg. However, with higher passive pressures, a proportional minor increase of the sarcomere is found.With the same pressure, the myocells situated directly under the endocardium, became more distended than the myocells situated further in the myocard.From the analysis of the diagrams tension/length and tension/volume follows that the increase of the sarcomere is only partially responsible for the augmentation of the ventricular capacity. It is therefore possible that at the same time a new spatial arrangement of the fibres occurs.The passive distensibility, studied under any functional and anatomical condition of the ventricle, may be considered a valuable in vitro model for the study of the myocardial contractility under physiological as well as pathological conditions.


La ricerca è stata eseguita con i fondi del C.N. R.  相似文献   

4.
Abstract

A study on the type and distribution of trichomes, morphological traits of the calyx and content of antioxidant compounds was conducted on Teucrium arduini L. populations in Croatia and in Bosnia and Herzegovina. Non-glandular trichomes, peltate trichomes and small capitate trichomes with four secretory head cells were observed on leaves, stems and calyx, whereas long capitate trichomes with a unicellular head cell were observed exclusively on the calyx. Average calyx length was 5.23–6.51 mm, calyx tube length 2.92–3.68 mm, lower lip length 1.25–2.42 mm and upper lip length 1.89–2.99 mm. The concentration of antioxidant compounds in all populations was the highest in leaves: total polyphenols (TP): 8.43–13.55%; tannins (T): 1.79–7.33%; flavonoids (TF): 0.28–0.40%; phenolic acids (TPA): 2.90–5.07%. Inflorescences generally contained the smallest amount of TP (5.89–11.42%), T (0.87–6.50%) and TPA (1.66–2.27%), while the smallest content of TF was obtained for the majority of stem samples (0.06–0.12%). The researched populations did not differ with regard to the type and overall distribution of the trichomes, though the Bosnian populations have a shorter calyx tube and longer upper lip. Some variability was observed in the TP and T content between sampling sites, while quite high variability was noted in the TF and TPA content.  相似文献   

5.
Zusammenfassung In der Schilddrüse der normalen und reifen Meerschweinchen sind keine unabhängigen Zellen vorhanden, die besondere Merkmale im Ver gleich zu anderen parenchymalen Zellen vorstellen. Die bis jetzt geschilderten klaren und protoplasmareichen Zellen sind in der Tat follikuläre Zellen, die in ihrer innigen Struktur modifiziert sind und die in den Schnitten wegen besonderer Verhältnisse zu dem Bindegewebe und den Gefäßen abgesondert erscheinen. Ihre strukturalen Veränderungen stehen überwiegend in engem Zusammenhang mit der Funktion, die sie bei besonderen funktionellen Beschaffenheiten der Drüse erfüllen sollen.  相似文献   

6.
Abstract

New species for Flora of Sardinia. — The Author remarks the presence of new species for Sardinia with some observations on the distribution and habitat.  相似文献   

7.
Il famoso entomologo italiano, mio maestro F. Silvestri e' gia' scomparso trent'anni. Io ricordo con un profondo sentimento a porpetua memoria di questo grand'uomo dell' epoca in campo entomologico, boun amico del popolo cinese. Nei cinquantacinque anni precedenti, egli venne in Cina e amava la Cina, eglisperava affettuosamente che la Cina potrebbe diventare uno stato ricco e forte, ilpopolo cinese potrebbe vivere felicemente, e le scienze cinesi (include anche la ento-  相似文献   

8.
Zusammenfassung Durch Anwendung der Explantationsmethode vonMangold wird der Rumpfschwanzteil der Medullarplatte in vitro explantiert, um die Evolutionsfähigkeiten der isolierten Medullaranlage und die Entwicklungskorrelationen zwischen dem Chorda-Mesodermkomplex und der Morphohistogenese des Rückenmarks zu studieren.Es wird vor allem festgestellt, daß der Neuralstrang, der sich aus der explantierten Neuralplatte bildet, auch ohne Mitwirkung der Chorda oder irgendeines Stützorgans verlängerungsfähig ist.Von großer Bedeutung für die Morphohistogenese des Neuralstranges scheint die Chorda zu sein, und gewissermaßen auch das Mesoderm.Fehlt das Mesoderm, so schmelzen die Ganglien zu einer einzigen Masse zusammen, ventral zum Neuralstrang; die Struktur des Neuralstranges erleidet aber dadurch keine Veränderung.Fehlt die Chorda dagegen, so treten sehr wichtige Veränderungen im Neuralstrang ein, d. h. übermäßige große der Neuralröhre oder mehrfache Röhrenbildung, Zerstörung der Zellen- und Fasernanordnung, Neuroblastenabsonderung aus dem Rumpfteil des Neuralstranges.Wenn aber, auch bei fehlender Chorda, der Neuralstrang von Mesodermmassen begleitet wird, ist seine Struktur viel regelmäßiger.Es scheint also, daß das Mesoderm, außer die Wirkung auf die Zerteilung der Ganglienanlagen, auch gewissermaßen die ausgebliebene Wirkung der Chorda ersetzen kann.  相似文献   

9.
10.
Riassunto Sono stati effettuati tre anni (1984–86) di osservazioni epidemiologiche ed aerobiologiche per ricercare la relazione esistente tra concentrazione pollinica giornaliera delle Oleacee nell' atmosfera della città di Palermo e numero di casi di pollinosi dovute a tale polline. I dati aerobiologici sono stati ottenuti con un campionatore volumetrico VPPS 2000. Questi, elaborati con il metodo della media mobile su 7 giorni e correlati con i dati epidemiologici, hanno evidenziato che, nel nostro territorio, le famiglie di pollini che rivestono importanza clinica sono tre: Urticacee, prevalentemente Parietaria, Graminacee ed Oleacee, prevalentemente Olea europaéa. Le Oleacee occupano il terzo posto nel determinismo delle pollinosi (21,76% di tutte le pollinosi), mentre dal punto di vista aerobiologico sono al secondo posto. La mancanza di proporzionalità diretta è da mettere in relazione, verosimilmente, con il breve periodo sintomatologico e con un basso potere allergizzante di tale aeroallergene. E' stato registrato, negli ultimi dieci anni, anche in Sicilia, un aumento della frequenza di sensibilizzazione verso il polline delle Oleacee.   相似文献   

11.
Riassunto

L'A. illustra la morfologia e l'anatomia di Solenostemma Argel con particolare considerazione dei caratteri del legno secondario in rapporto all'abito sempreverde della pianta.  相似文献   

12.
Abstract

Floristic affinity of bentonic vegetational types of Cala di Mitigliano (Massa Lubrense Napoli). — We have studied the bentonic plants community in the Cala di Mitigliano. It appears that some species compositions repeat themselves with a certain regularity. This fact lets us recognize and consequently classify them. In Cala di Mitigliano we took an interest and considered only such species compositions. We calculated, in them and between them, the coefficient of affinity by SÖRENSEN (1948). The cluster analysis by average linkage and the use of an index of «individualisation» (Feoli, ined.) based on floristic comparison showed that the species compositions, although we chose such ones to describe the vegetation, equally change gradually from place to place.  相似文献   

13.
14.
Riassunto Furono istituiti confronti, in preparati col metodo Golgi-Cox, tra i caratteri dei neuroni piramidali grandi, medi e piccoli della corteccia cerebrale di Mammiferi di grandezza somatica molto differente, e piú precisamente: cavallo, bue, uomo, scrofa, pecora, capra, cane, gatto, coniglio, cavia, ratto, topo. Nell'uomo fu scelto il campo 4 di Brodmann; negli animali una regione della corteccia presumibilmente corrispondente.Nello stesso materiale fu determinata, in preparati col metodo Nissl, la densità dei neuroni, in modo da poter stabilire il numero dei neuroni per mm3 di corteccia.Furono riscontrate differenze modeste nella grandezza del pericario nei vari animali, incomparabilmente meno accentuate di quelle esistenti nello stesso materiale per i neuroni sprovvisti di dendriti (gangli sensitivi). Sono invece imponenti le differenze nell'estensione dell'arborizzazione dendritica. Tali differenze sono di più alto grado nelle grandi cellule piramidali che nelle medie e nelle piccole; però sono ben evidenti anche in queste ultime.Tra i valori ottenuti nella densità dei neuroni e quanto risulta nei preparati col metodo Golgi sull'estensione dell'arborizzazione dendritica negli animali di grandezza corporea differente, vi è coincidenza nel senso che, quanto più ampio è lo spazio occupato dall'arborizzazione dendritica dei neuroni della corteccia e quanto più numerosi sono i neuriti afferenti e le loro collaterali, tanto minore è la densità dei neuroni.I risultati delle presenti osservazioni si accordano con i recenti reperti col microscopic elettronico, secondo i quali i neuroni, la glia ed i vasi sanguiferi sono fittamente stipati, al punto che le fessure, le quali li separano, sono dell'ordine di grandezza submicroscopica; non esistono, nei centri nervosi, altri componenti al di fuori dei neuroni, della glia e dei vasi.Dedicato al Prof. Giuseppe Levi per il suo 88 compleanno. Ricerche compiute con un contributo del C.N.R.  相似文献   

15.
Coluzzi M 《Parassitologia》2002,44(3-4):207-212
The editorial note introduces the issue of Anopheles without malaria focused in 1902 by Celli and Gasperini. The historical problem is outlined until the puzzle was solved in the Fourties.  相似文献   

16.
Abstract

Puccinellia festucaeformis (Host) Parl.: germination and early growth on different salt substrates. Germination behaviour of Puccinellia festucaeformis seeds and early growth of seedlings at different experimental conditions was analysed. The following growth substrates were utilized: NaCl, KCl, KNO3, MgCl2, MgSO4, Na2SO4, NaNO3, CaCl2 at the decreasing concentrations of 0.50, 0.25, 0.12, 0.06M. Caryopses were allowed to imbibe and grow at alternating temperatures (10°-20°C or 20°-30°C) in the dark for 3 days. Seedling were grown for 15 days, at controlled light and temperature conditions, in the same nutrient substrates as those used for the germination experiments.

The germination experiments showed a high tolerance to salts up to 0.25M solution and for the whole range of MgSO4 concentrations. High growth temperatures increased the depressive effects of salt concentrations. Seedling growth was highly reduced when salt concentration was higher than 0.12M. High salt tolerance - maximum shoot and root growth - was showed by seedling allowed to grow on 0.50M MgSO4.

Germination and growth condition of Puccinellia festucaeformis is discussed in relation to the ecological features of this species and to its possible importance as bioindicator of MgSO4 rich natural substrates.  相似文献   

17.
Abstract

Autecology of Ulva rigida C. Ag.: 1. Influence of light intensity and temperature on oxygen production. The photosynthetic activity of Ulva rigida, growing in Bari's harbour (Adriatic Sea), has been assessed in the laboratory by measuring oxygen evolution as a function of white light intensities. Tests were performed at four temperatures. The data indicate the remarkable amount of O2 released in the environment.  相似文献   

18.
Zusammenfassung Die Wachstums- und Umbauvorgänge am Knochen des Hornfortsatzes vom männlichen und weiblichen Steinbock (Capra ibex) wurden histologisch untersucht.Der Hornfortsatz des Männchens erreicht eine weit erheblichere Größe als der des weiblichen Tieres. Bei dem Bock beginnt das Wachstum des Fortsatzes früher, ist quantitativ intensiver und dauert während des ganzen Lebens fort, während es beim Weibchen im vierten Lebensjahr aufhört.Die Zunahme an Dicke und Länge erfolgt durch die appositionelle Tätigkeit des Periostes. Das Dickenwachstum vollzieht sich ebenso wie bei der periostalen Ossifikation der Röhrenknochen. Jedoch ist die Knochensubstanz, die sich in den verschiedenen Altersstufen bildet, verschieden. Bei jungen Tieren lagern sich Bälkchen von geflechtartigem und parallelfaserigem Knochen ab, beim erwachsenen Steinbock kompakte Schichten von parallelfaserigem Knochen. Der primäre Periostalknochen wird später zu einer kompakten Schicht von sekundärem Osteonknochen umgebaut. Der Umbau schreitet von den tiefen, der Höhlung zugewandten Teilen zur Oberfläche hin fort. Der Ersatz beginnt in den proximalen Abschnitten des Hornfortsatzes und setzt sich distalwärts fort. Der Hornfortsatz nimmt schließlich die Struktur der Substantia compacta eines Röhrenknochens an, obgleich er, im Gegensatz zu den Röhrenknochen, keinerlei Muskeleinwirkung ausgesetzt ist. Das Längenwachstum beruht auf der fortschreitenden Ablagerung von neuem, primärem Bälkchenmaterial in der Spitzengegend. Dieses Gewebe erfährt später das gleiche Schicksal wie jenes, das sich früher in den proximalen Teilen gebildet hatte.Die Wachstums- und Umbauvorgänge der Knochensubstanz sind bei beiden Geschlechtern gleichartig. Die verschiedene Größe des Hornfortsatzes von Männchen und Weibchen beruht auf quantitativen, nicht auf qualitativen Unterschieden der Knochenbildung. Innere Umbauprozesse dagegen spielen sich bei beiden Geschlechtern während des ganzen Lebens lebhaft ab. Beim Weibchen erfolgt der Ersatz des primären Periostalknochens durch sekundären Osteonknochen im Zusammenhang mit dem begrenzten appositionellen Wachstum schneller und ausgedehnter.Vergleicht man gleichaltrige Tiere, so stellt man beim Weibchen einen stärkeren Umbau des Sekundärmaterials fest; auch ist dessen Struktur komplexer. Dies hängt mit der Tatsache zusammen, daß sich die Umbauvorgänge an einem Material abspielen, das längere Zeit in situ bleibt.Unter den Faktoren, die zu einem erhöhten Umbau der Knochensubstanz, einem gewissen Überwiegen von interstitiellen Abbauerscheinungen und einer größeren strukturellen Heterogenität im Hornfortsatze des Weibchens führen, werden außer der Begrenzung des appositionellen Wachstums auch die geringere funktionelle Aktivität und das Vorkommen von Trächtigkeits- und Säugeperioden in Betracht gezogen.Außerdem wird durch die vorliegenden Untersuchungen bestätigt, was schon für anderes Material angenommen wurde, daß nämlich die aktuellen mechanischen Momente in den Umbauprozessen der osteonischen Strukturen nicht die wichtigste Rolle spielen.

Parco Nazionale del Gran Paradiso: contributo scientifico N° 22.  相似文献   

19.
Abstract

Annual cycle of phytoplankton in the coastal waters of the « Parco Naturale della Maremma ». II. Flora and communities variations.—The hydrology of the marine coastal area of the Parco Naturale della Maremma and the annual cycle of phytoplankton standing crop have been examined in a preceding paper (Lenzi Grillini e Lazzara, 1978). In the present paper the species list and the main features of marine phytoplankton communities of the same area are reported as a result of an annual cycle of monthly collections effected in seven stations. The most conspicuous seasonal bloomings are due to Skeletonema costatum (Grev.) Cleve in February and to some species of the Chaetoceros gen. in November; the dinoflagellates play a minor role throughout the year, except for Gonyaulax minima Matz. with a light blooming episode in summer. The annual cycle of bottom living diatoms found in the samples appears to be very similar in its shape to the cycle of the pelagic species, as for the standing crop and for the species number. The community structure variations have been analyzed by means of diversity and dominance indexes and of species frequency diagrams. As it concerns the differences in species composition among the seven stations, the area in front of the rocky shore, with deeper and more saline waters, appears to be very homogeneous, whereas some differences have been observed in the shallow waters, in front of the sandy shore and under the influence of the Ombrone River mouth.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号