نتایج جستجو برای: calyx
تعداد نتایج: 1375 فیلتر نتایج به سال:
Protective floral structures may evolve in response to the negative effects of floral herbivores. For example, water calyces--liquid-filled, cup-like structures resulting from the fusion of sepals--may reduce floral herbivory by submerging buds during their development. Our observations of a water-calyx plant, Chrysothemis friedrichsthaliana (Gesneriaceae), revealed that buds were frequently at...
Depletion of a pool of readily releasable vesicles during repetitive presynaptic activity is a candidate mechanism for the induction of short-term synaptic depression. The large, calyx-type synaptic terminals in the brainstem auditory pathway, and especially the calyx of Held, offer unique possibilities for studying the cellular mechanisms leading to synaptic depression. Recent work at these sy...
Fenerivia species (Annonaceae) are characterized by a prominent flange immediately below the perianth, which has been interpreted as synapomorphic for the genus. The homology of this flange is controversial: previous studies of Fenerivia heteropetala (an aberrant species, with 12 perianth parts in three whorls) have suggested that the flange may represent a vestigial calyx resulting from a disr...
Abstract Evidence from the earliest-known crinoids (Tremadocian, Early Ordovician), called protocrinoids, is used to hypothesize initial steps by which elements of calyx evolved. Protocrinoid calyces are composed extraxial primary and surrounding secondary plates (both have epispires along their sutures) that unlike those more crownward fossil extant in equivalent calycinal plating strongly org...
Three new Brazilian species of the Brevantherum clade of Solanum (Solanaceae) are described, all closely related to the poorly known Solanum inornatum Witasek. Solanum bradei Giacomin & Stehmann, sp. nov., and Solanum kriegeri Giacomin & Stehmann, sp. nov., differ from S. inornatum in having very small deltate calyx lobes that are not accrescent in fruit. Solanum bradei is a shrub up to 1.8 m w...
A comprehensive procedure was established, which combined a high-performance liquid chromatography (HPLC) assay for the simultaneous quantification of 2″-O-β-L-galactopyranosylorientin (OGA) and veratric acid and a gravimetric analysis for the determination of the mass fraction of the floral parts (calyx, corolla, stalk, stamens and pistils and ovary) of Trollius chinensis, to investigate the d...
Results: Sixteen (76.16%) subjects were man and 5 (23.80%) were women, with the mean age of 35 ± 12 years. Mean stone size was 37.2 ± 16.6 mm. Percutaneous nephrolithotomy was performed because of the stone size (over 20 mm) in 18 (85.68%) and failed SWL in 3 (14.28%). Stone numbers were more than one in 18 (85.68%) subjects, and were in the pelvis and at least one calyx. The most common access...
Classically, the basic concept of chemical synaptic transmission was established at the frog neuromuscular junction, and direct intracellular recordings from presynaptic terminals at the squid giant presynaptic terminal have further clarified principles of neurotransmitter release. More recently, whole-cell patch-camp recordings from the calyx of Held in rodent brainstem slices have extended th...
The European mining bee species Andrena lathyri (Andrenidae) is a narrow specialist of flowers Lathyrus and Vicia (Fabaceae), from which both females males gain nectar by primary robbing. Both sexes are equipped with unique proboscis, much longer more strongly angled than in most other bees including the closely related species. comparison between shape proboscis interior host combined field ob...
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