Search results for "Twig"
showing 6 items of 6 documents
Paleohistology of the Cretaceous resin‐producing conifer Geinitzia reichenbachii using X‐ray synchrotron microtomography
2021
International audience; PremiseThe conifer Geinitzia reichenbachii was a common member of the Cretaceous Laurasian floras. However, the histology of G. reichenbachii leafy axes was never described in detail, and our knowledge of its paleoecology remains very limited. Using new and exquisitely preserved silicified material from the Upper Cretaceous of western France, we describe G. reichenbachii from the gross morphology to the cellular scale, then discuss paleoecological and taphonomical implications.MethodsWe examined specimens from two localities in western France (Claix and Moragne) using propagation phase-contrast X-ray synchrotron microtomography.ResultsThe cuticle and the inner tissue…
Twig and Shoot Dieback of Citrus, a New Disease Caused by Colletotrichum Species
2021
(1) Background: This study was aimed at identifying the Colletotrichum species associated with twig and shoot dieback of citrus, a new syndrome occurring in the Mediterranean region and also reported as emerging in California. (2) Methods: Overall, 119 Colletotrichum isolates were characterized. They were recovered from symptomatic trees of sweet orange, mandarin and mandarin-like fruits during a survey of citrus groves in Albania and Sicily (southern Italy). (3) Results: The isolates were grouped into two distinct morphotypes. The grouping of isolates was supported by phylogenetic sequence analysis of two genetic markers, the internal transcribed spacer regions of rDNA (ITS) and β-tubulin …
Technical Note: Comparison of Techniques for Evaluating the Relative Preference by Sheep Among Saltbush Clones
2004
This research compared 4 field methods of evaluating the relative preference by sheep of 28 clones of saltbush (Atriplex halimus L.). The methods were as follows. 1) Leaf dots (LD): 8 leaves per shrub were marked on the lower surface with a small dot using a water-resistant, nontoxic ink. 2) Twig marks (TM): 2 current-year twigs per shrub were marked with 3 lines using the same ink approximately in the middle of the basal, median, and apical thirds. 3) Branch length (BL): 2 branches per shrub were marked with ink at the base of the current year's growth. The twigs were measured from the marked point to the top, before and after sheep browsing. 4) Ocular estimation (OE): the percentage of th…
Joint brood guarding in parent bugs — an experiment on defence against predation
1995
Females of Elasmucha grisea defend their eggs and small nymphs against invertebrate predators. Females sometimes guard their clutches side by side on the same birch leaf. We studied benefits of this joint guarding both in the field and in the laboratory. We found that adjacent females had significantly larger clutches than solitary females. In the laboratory, we studied the effectiveness of joint versus single defence against ant (Formica uralensis) predators. We established female pairs from initially singly guarding females by cutting off pieces of leaves with egg clutches and pasting them beside another female guarding her clutch. In the control group the females with their clutches were…
Volatile constituents of flowering twig oil
2004
Summary The chemical constituents of the volatile oil of mature flowering twigs of wild Hyptis swaveolens growing widely in northern India were analyzed by gas chromatography–mass spectrometry. Forty one compounds consisting of 77.75% of the oil were identified. The major constituents of the oil were sabinene (14.18%), β-caryophyllene (12.52%), caryophyllene oxide (10.50%), abietatriene (6.42%), terpinen-4-ol (4.88%), limonene (4.42%), cis -sabinene hydrate (3.52%), spathulenol (3.14%), α-terpinolene (2.75%), β-pinene (2.42%), p -cymen-8-ol (1.76%), trans -sabinene hydrate (1.33%) and abietadiene (1.01%).
Arthrinium phaeospermum , Phoma cladoniicola and Ulocladium consortiale , New Olive Pathogens in Italy
2013
In recent years, leaf necrosis and twig dieback in the olive crop have been detected in Sicily (Italy). In this article, we identify the predominant fungal species associated with symptomatic leaves and twigs, using morphological features and DNA sequencing of the internal transcribed spacer (ITS) region, as Alternaria alternata, Arthrinium phaeospermum, Phoma cladoniicola and Ulocladium consortiale. The pathogenicity of these four species was tested on olive plants cv. Biancolilla. All species were pathogenic on leaves, but only U. consortiale produced cortical lesions on twigs, thus suggesting its main role in the Olea europaea twig dieback. To our knowledge, this is the first report of A…