Determination of Rhizoid Orientation by Light and Darkness in Germinating Spores of Onoclea sensibilis

Miller, John H.; Greany, Robin H.

doi:10.2307/2441609

Cited by 13 publications

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“…For measurement of the percentage of spore germination, solid Knop's medium (Miller and Greany 1974) was amended with AnalaR CdCIE.2H20 (Loba-Chemie Indoaustranal Co., India) to obtain Cd concentrations of 0.1, 1.0, 2.5, 5.0 and 10.0 ppm. Control experiments were performed simultaneously.…”

Section: Methodsmentioning

confidence: 99%

Chronic toxicity of cadmium in Pteris vittata, a roadside fern

Gupta

Devi

1994

Ecotoxicology

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: The effect of Cd at concentrations of 0.1, 1.0, 2.5, 5.0 and 10.0 ppm on Pteris vittata, a commonly occurring roadside fern was studied during the entire life cycle from spore germination to spore production. Light, fluorescence, scanning and transmission electron microscopy were used to study the structural changes due to Cd. With increasing Cd concentrations the following changes were observed: inhibition of first and second generation spores, abnormal development of protonema, disintegration of thylakoid organization, delayed formation of reproductive elements and abnormal sporangia. As the Cd content of the plants increased with increasing concentration in the medium, biomass-specific concentrations of chlorophyll and carotenoids decreased. The gametophytic phase was more sensitive than the sporophytic stage to Cd. The differences noticed during the three stages of development could be useful as markers for Cd contamination in the environment.

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Section: Methodsmentioning

confidence: 99%

Chronic toxicity of cadmium in Pteris vittata, a roadside fern

Gupta

Devi

1994

Ecotoxicology

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“…Spores can also have dierent types of responses to light. In Osmunda, the rhizoid makes a right angle with the protonema when germinated in the dark (Miller and Greany 1974). These ®ndings raise the question as to what extent the gravity eect on developmental polarity in Ceratopteris is in¯uenced by light, a question not addressed in the earlier report (Edwards and Roux 1994).…”

Section: Introductionmentioning

confidence: 77%

Influence of gravity and light on the developmental polarity of Ceratopteris richardii fern spores

Edwards

Roux

1998

Planta

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The polarity of germinating single-celled spores of the fern Ceratopteris richardii Brogn. is influenced by gravity during a time period prior to the first cellular division designated a "polarity-determination window". After this window closes, control of polarity is seen in the downward (with respect to gravity) migration of the nucleus along the proximal face of the spore and the subsequent downward growth of the primary rhizoid. When spores are germinated on a clinostat the direction of nuclear migration and subsequent primary rhizoid growth is random. However, in each case the direction of nuclear migration predicts the direction of rhizoid elongation. Although it is the most obvious movement, the downward migration is not the first movement of the nucleus. During the polarity-determination window, the nucleus moves randomly within a region centered behind the trilete marking. While the polarity of many fern spores has been reported to be controlled by light, spores of C. richardii are the first documented to have their polarity influenced by gravity. Directional white light also affects the polarity of these spores, but this influence is slight and is secondary to that of gravity.

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Orientation of the Plane of Cell Division in Fern Gametophytes: The Roles of Cell Shape and Stress

Miller

1980

American J of Botany

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Apical cells of Onoclea sensibilis L. protonemata were measured to determine areas of new walls which were formed during both transverse and longitudinal cell division. Actual wall areas were compared with calculated areas of hypothetical walls oriented in the opposite sense (i.e., an actual transverse wall compared with a hypothetical longitudinal wall, and the reverse). Among 87 out of 90 cells which were analyzed the actual walls had the least area. Thus, the minimal area hypothesis of cell partitioning accurately predicts wall orientation in this instance, although it appears, on other grounds, that the hypothesis does not furnish a plausible mechanism for wall orientation. The application of Lintilhac's concept of the orientation of cell walls in response to anisotropic stresses in the cell was explored. Photographs of apical cells during deplasmolysis indicated that unequal stresses might be generated in apical cells as a result of the osmotic distension of the elastic protoplast. It is concluded that the primary factor which determines the plane of cell division in the apical cell, and the transition from one‐ to two‐dimensional growth, is the local pattern of stress which exists at the position of the nucleus at the time of onset of cell division and wall formation. Calculations of some geometrical properties of idealized model cells are interpreted to mean that the accuracy of the minimal area hypothesis results from a coincidence of its predictions with predictions of Lintilhac's hypothesis, and no causal significance is attributed to wall areas.

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Determination of Rhizoid Orientation by Light and Darkness in Germinating Spores of Onoclea sensibilis

Cited by 13 publications

References 0 publications

Chronic toxicity of cadmium in Pteris vittata, a roadside fern

Chronic toxicity of cadmium in Pteris vittata, a roadside fern

Influence of gravity and light on the developmental polarity of Ceratopteris richardii fern spores

Orientation of the Plane of Cell Division in Fern Gametophytes: The Roles of Cell Shape and Stress

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