The Effect of Mechanical Stimulation On the Collenchyma of Apium graveolens L.

Although the possibility that mechanical stimulation is a factor in the quantity of strengthening tissue in the stems of plants has been frequently suggested, few experiments have been designed to test this hypothesis. Although some work has been done on tensile strength of collenchyma (Ambronn 1881, Esau 1936, Curtis 1938), very little consideration has been directed to the study of the effect of mechanical stimulation on the structure and/or quantity of this tissue or any of the mechanical tissues of the plant. Venning (1949) reported that wind motion from an electric fan stimulated the development of collenchyma within the petioles of Apium graveolens L., but had no effect on the number of collenchyma bundles per petiole. He reported that stimulation by wind motion resulted in larger areas of collenchyma and in an increase in cell wall thickness of the collenchyma

The Use of the Terms Flint and Chert

Reference to almost any two text books in geology will show that there are different usages for the terms flint and chert. Perhaps much of the confusion is due to the fact that the origin of these substances is unknown, in which case exact definition at this time would be premature. Whatever the reason it seems advisable to bring out the variability of definition, if for no other purpose than to state a problem without attempting its solution. Blackwelder & Barrows- Elements of Geology, 1911, page 39. Flint is defined as a very compact, dark grey, siliceous rock. Farther on, chert is said to be an impure flint, usually of light color; both occur in limestones

An Analysis of Plantational Terms : An Addition

Author Institution: Ohio State Universit

Ascent of Mt. Namosi, Fiji

This mountain, a little over 3000 feet high, towers above the native village of Namosi in the interior of Viti Levu, Fiji. It has seldom been climbed due to the unusually precipitous sides. A brief account of the ascent together with some notes on the geology

A Modification of the Carbowax Embedding Technique for Plant Tissue

The highly hydrate condition of the wall material of the cells of collenchyma causes considerable difficulty in the preparation of permanent sections of the material which are suitable for quantitative studies. When standard procedures of dehydration and embedding are employed, excessive shrinkage of the wall material is common. In an attempt to avoid this shrinkage, polyethylene glycol (carbowax) was used as the killing, fixing, dehydrating and embedding medium. This method met with considerable success. The schedule outlined is a modification of that used by A. R. Spurr

Therapeutical use of the cannabinoids in psychiatry

OBJETIVO: Revisar os principais avanços no potencial uso terapêutico de alguns compostos canabinoides em psiquiatria. MÉTODO: Foi realizada busca nos bancos de dado PubMed, SciELO e Lilacs e identificados estudos e revisões da literatura sobre o uso terapêutico dos canabinoides em psiquiatria, em particular canabidiol, rimonabanto, Δ9-tetraidrocanabinol e seus análogos. RESULTADOS: O canabidiol demonstrou apresentar potencial terapêutico como antipsicótico, ansiolítico, antidepressivo e em diversas outras condições. O Δ9-tetraidrocanabinol e seus análogos demonstraram efeitos ansiolíticos, na dependência de cannabis, bem como adjuvantes no tratamento de esquizofrenia, apesar de ainda carecerem de mais estudos. O rimonabanto demonstrou eficácia no tratamento de sintomas subjetivos e fisiológicos da intoxicação pela cannabis e como adjuvante no tratamento do tabagismo. Os potenciais efeitos colaterais, de induzir depressão e ansiedade limitaram o uso clínico deste antagonista CB1. CONCLUSÃO: Os canabinoides têm demonstrado que podem ter amplo interesse terapêutico em psiquiatria, porém mais estudos controlados são necessários para confirmar estes achados e determinar a segurança destes compostos.OBJECTIVE: To review the main advances related to the potential therapeutic use of cannabinoid compounds in psychiatry. METHOD: A search was performed in the online databases PubMed, ScieELO, and Lilacs for studies and literature reviews concerning therapeutic applications of cannabinoids in psychiatry, especially cannabidiol, rimonabant, Δ9-tetrahydrocannabinol, and their analogues. RESULTS: Cannabidiol was found to have therapeutic potential with antipsychotic, anxiolytic, and antidepressant properties, in addition to being effective in other conditions. Δ9-tetrahydrocannabinol and its analogues were shown to have anxiolytic effects in the treatment of cannabis dependence and to function as an adjuvant in the treatment of schizophrenia, although additional studies are necessary to support this finding. Rimonabant was effective in the treatment of the subjective and physiological symptoms of cannabis intoxication and functioned as an adjuvant in the treatment of tobacco addiction. The potential to induce adverse reactions such as depression and anxiety restrained the clinical use of this CB1 antagonist. CONCLUSION: Cannabinoids may be of great therapeutic interest to psychiatry; however, further controlled trials are necessary to confirm the existing findings and to establish the safety of such compounds

Carbohydrate Breakdown in Cell Walls of Collenchyma of Celery

Celery plants (Apium graveolens L.) were placed in darkness for 18 days and the collenchyma cells of the petioles of these plants were subjected to acid hydrolysis and qualitative and quantitative analyses to determine the effect of prolonged dark treatment on the metabolism of the wall components. Chromatographic separation and spectrophotometric measurement of the amounts of sugars present after 18 days of treatment indicated a great reduction in amounts of galactose and arabinose, a smaller reduction of mannose and xylose, and no reduction of glucose. The changes reported are attributed to a possible metabolic turnover of wall materials brought about by the low carbohydrate level which existed under the experimental conditions. The role of the plant cell wall in the general metabolism of the cell is briefly discussed