Growth Regulation by Ethylene in Fern Gametophytes. III. Inhibition of Spore Germination

Edwards, Maurice E.; Miller, John H.

doi:10.2307/2441526

Cited by 47 publications

(24 citation statements)

References 14 publications

(24 reference statements)

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“…In the density experiment, only the central gametophytes were harvested. Gametophytes were fixed in a mixture of acetocarmine and chloralhydrate (Edwards & Miller 1972), heated in a water bath at 50 ° C for 2 h, and rinsed with distilled water. To observe both gametophyte surfaces under the light microscope, they were mounted between two coverglasses.…”

Section: E X P E R I M E N T a L T R E A T M E N T Smentioning

confidence: 99%

Environmental sex determination in ferns: effects of nutrient availability and individual density in Woodwardia radicans

DeSoto

Quintanilla

Méndez³

2008

Journal of Ecology

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Summary 1.In environmental sex determination (ESD) gender is decided after conception, depending on the environment, rather than being genetically fixed. ESD in plants has been mainly studied in angiosperms, where the dominant form of ESD is sexual lability. Surprisingly, ESD has rarely been studied in homosporous ferns, the only plants in which ESD is the rule, rather than the exception. 2. Here, we address the mechanism underlying ESD for the fern Woodwardia radicans by experimentally manipulating nutrient availability and gametophyte density. 3. Stress (limited nutrient supply, crowding) affected sexual expression in W. radicans gametophytes in a way compatible with ESD. Under good growth conditions (low density or high nutrient), gametophytes matured sexually at a relatively large size and turned into females and subsequently into bisexuals. Under harsh growth conditions, gametophytes matured sexually at a smaller size and turned into males. 4. Interestingly, gametophyte sexual expression was consistent with the size-advantage model, because the number of archegonia increased with gametophyte size, but not the number of antheridia. 5. The sex switch threshold size was variable and decreased with increasing stress, as predicted by age and size to maturity models. 6. Synthesis. Sexual expression in fern gametophytes can be fruitfully studied within the ESD theoretical framework. Stress induced male expression in gametophytes in a way compatible with ESD. In addition, size-related patterns of sexual expression were consistent with the size-advantage model, because female function benefited more from a larger size than did male function. Finally, the sex switch threshold size was variable and decreased with increasing stress, a result predicted by age and size to maturity models but seldom empirically tested before.

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Section: E X P E R I M E N T a L T R E A T M E N T Smentioning

confidence: 99%

Environmental sex determination in ferns: effects of nutrient availability and individual density in Woodwardia radicans

DeSoto

Quintanilla

Méndez³

2008

Journal of Ecology

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“…Fern spores can be divided into two groups, green and non-green, based on tbe presence or absence of significant amounts of cblorophyll in tbe quiescent spore. In tbe green spore species, germination can be assayed two days after ligbt induction by using tbe acetocarminecbloral bydrate metbod of Edwards and Miller (1972). In the non-green species, germination is usually determined by assaying swelling of tbe cell, splitting of the spore coat (perine and exine) and tbe presence of significant amounts of cbloropbyll (greening) using brigbtfield microscopy (Mobr 1956).…”

mentioning

confidence: 99%

Early quantitative method for measuring germination in non‐green spores of Dryopteris paleacea using an epifluorescence‐microscope technique

Scheuerlein¹,

Wayne²,

Roux³

1988

Physiologia Plantarum

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A method is described to determine germination by blue-light excited red fluorescence in the positively photoblastic spores of Dryopteris paleacea Sw. This fluorescence is due to chlorophyll as evidenced from 1) a fluorescence-emission spectrum in vivo, where a bright fluorescence around 675 nm is obtained only in red light (R)-irradiated spores and 2) in vitro measurements with acetone extracts prepared from homogenized spores. Significant amounts of chlorophyll can be found only in R-treated spores; this chlorophyll exhibits an emission band around 668 nm, when irradiated with 430 nm light at 21 degrees C. Compared to other criteria for germination, such as swelling of the cell, coat splitting, greening, and rhizoid formation, which require longer periods after induction for their expression, chlorophyll fluorescence can be used to quantify germination after two days. This result is confirmed by fluence-response curves for R-induced spore germination; the same relationship between applied R and germination is obtained by the evaluation with the epifluorescence method 2 days after the light treatment as compared with the evaluation with bright-field microscopy 5 days after the inducing R. Using this technique we show for the first time that Ca2+ contributes to the signal-transduction chain in phytochrome-mediated chlorophyll synthesis in spores of Dryopteris paleacea.

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“…Plants were grown for 4 or 5 days under these conditions. Measurement of orientation-To determine the relative orientation of protonema and rhizoid, spores which were germinated on liquid media were mounted on a microscope slide in a drop of an acetocarmine-chloral hydrate mixture (Edwards and Miller, 1972). The preparation was covered with a cover glass and ringed with heavy mineral oil to preserve the slide for several days.…”

mentioning

confidence: 99%

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

Miller

Greany

1974

American J of Botany

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When spores of the fern, Onoclea sensibilis L., are allowed to germinate in darkness, the rhizoid and the protonema are positioned at close to a right angle. If the spores are exposed initially to light and allowed to germinate, the rhizoid and protonema are positioned nearly axially, at opposite ends of the spore. The greater the duration and intensity of the initial illumination, the greater the tendency towards axial arrangement. All colors of light are active to some degree, and the effects are intensity‐dependent. The response occurs in a uniform light field and is not dependent on a directional stimulus; the phenomenon reflects the relative arrangement of one part of the gametophyte to another part but not the orientation of growth with respect to an external stimulus. Direct tests show that neither the relative rhizoid orientation nor initial polarity of germination are affected by unilateral white light or polarized red light; the subsequent growth of the protonema, however, is oriented perpendicular to the plane of light polarization. The effects of light in determining the positional relationship between rhizoid and protonema are interpreted in terms of a hypothesis proposing light‐induced changes in the structure and mechanical properties of the spore wall.

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Growth Regulation by Ethylene in Fern Gametophytes. III. Inhibition of Spore Germination

Cited by 47 publications

References 14 publications

Environmental sex determination in ferns: effects of nutrient availability and individual density in Woodwardia radicans

Environmental sex determination in ferns: effects of nutrient availability and individual density in Woodwardia radicans

Early quantitative method for measuring germination in non‐green spores of Dryopteris paleacea using an epifluorescence‐microscope technique

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

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