The effect of light and other factors on spore germination in Botrychium dissectum

1973 ◽  
Vol 51 (10) ◽  
pp. 1791-1794 ◽  
Author(s):  
Dean P. Whittier
Keyword(s):  
Spore Germination ◽  
Nutrient Medium ◽  
Axenic Culture ◽  
Effect Of Light

Light-inhibited spore germination in Botrychium dissectum forma obliquum occurred in axenic culture on a nutrient medium containing 0.25% sucrose. The spores had to be cultured in darkness for 3–4 weeks before any germination would take place. Longer periods in the dark produced greater percentages of germination. Sucrose was unnecessary for germination, but it promoted gametophytic growth once germination had occurred.

scholarly journals The effect of light factor on the development of thallus and generative organs in Chara vulgaris L.

2014 ◽  
Vol 49 (4) ◽  
pp. 397-407 ◽  
Author(s):  
Janusz Maszewski
Keyword(s):  
Mitotic Activity ◽  
Axenic Culture ◽  
Light Period ◽  
Continuous Illumination ◽  
Chara Vulgaris ◽  
The Moment ◽  
Almost All ◽  
Effect Of Light ◽  
Generative Organs

During long-term axenic culture of Chara continuous illumination (L=24) increases mitotic activity of almost all types of cells. In such conditions only initiation of oogonia is inhibited, leading into a strong predomination of male generative organs. Prolonged darkness (L:D=1:23) exerts a mitodepressing effect. Oogonia and antheridia are especially susceptible to the reduction of the light period. Modifications of the elongating growth in various photoperiods are different in the polyploid regions of the vegetative thallus and in haploid cells of the antheridial filaments. Segments of both axial internodes and lateral pleuridia increase their dimensions at L:D=1:23, whereas at L=24 their growth is significantly inhibited. Different reaction is noted in the cells of antheridial filaments: at L=24 they are about 10% longer than in the control (L:D=14:10). The duration of the antheridium aevelopment, from the stage of unicellular filaments to the moment of antheridium opening, is 1.5 days shorter at L=24 as compared with the control. This shortening includes proportionally both the period of divisions within antheridial filaments and the period of spermatozoid differentiation.

The germination of Tmesipteris spores

1987 ◽  
Vol 65 (8) ◽  
pp. 1770-1772 ◽  
Author(s):  
Dean P. Whittier ◽  
David R. Given
Keyword(s):  
New Media ◽  
Nutrient Medium ◽  
Axenic Culture ◽  
Polar Axis ◽  
Mineral Elements

Spores of Tmesipteris elongata Dang, germinated in axenic culture on a nutrient medium containing mineral elements and 0.2% glucose after 8 months in the dark. No spores germinated in cultures kept in the light. Initiating germination, the monolete laesura (scar) split in the middle. As the laesura ruptured to its ends, the cell bulged out. The first division was perpendicular to the polar axis of the spore and formed distal and proximal cells. At one end of the proximal cell, brown materials accumulated in the wall. Transfer of the two-celled gametophyte to new media did not support further growth.

Gametophytes of Ophioglossum engelmannii

1983 ◽  
Vol 61 (9) ◽  
pp. 2369-2373 ◽  
Author(s):  
Dean P. Whittier
Keyword(s):  
Nutrient Medium ◽  
Apical Cell ◽  
Axenic Culture ◽  
Inorganic Nutrients ◽  
Cylindrical Structures

Gametophytes of Ophioglossum engelmannii Prantl grow in axenic culture on a nutrient medium containing inorganic nutrients and sucrose. The dark-grown prothalli are long, white, cylindrical structures without rhizoids. The gametophyte has a meristem with a single apical cell. Antheridia, which are partially sunken, and archegonia, which have short necks, are interspersed along the gametophyte. The prothalli are endophyte free. Since the gametophytes of O. engelmannii are undescribed from nature, no comparisons can be made between gametophytes from culture and those from nature. However, gametophytes grown in axenic culture have a morphology which is normal for the genus.

Germination of Psilotum spores in axenic culture

1973 ◽  
Vol 51 (10) ◽  
pp. 2000-2001 ◽  
Author(s):  
Dean P. Whittier
Keyword(s):  
Nutrient Medium ◽  
Axenic Culture ◽  
Mineral Elements ◽  
Psilotum Nudum

Spores of Psilotum nudum (L.) Griseb. germinated in axenic culture on a nutrient medium containing mineral elements and 0.25% sucrose after 6 months in the dark.

Spore germination in the Psilotaceae

1994 ◽  
Vol 72 (5) ◽  
pp. 688-692 ◽  
Author(s):  
Dean P. Whittier ◽  
John E. Braggins
Keyword(s):  
Key Words ◽  
Nitrogen Source ◽  
Spore Germination ◽  
Nutrient Medium

Spores of several species of Psilotum and Tmesipteris were sown on a nutrient medium containing minerals and 0.2% glucose. The nutrient medium contained ammonium as the nitrogen source and lacked nitrate. From 52 to 98% of the spores of P. nudum, P. complanatum, T. lanceolata, and T. sigmatifolia germinated after 6 months in the dark. Haploid spores of P. nudum began germinating in less than 2 months; however spores of the two Tmesipteris species reached 50% germination sooner than those of the Psilotum species. Spores of T. tannensis never germinated and those of T. elongata and P. × intermedium rarely germinated (<0.1%) and never formed mature gametophytes. Spores from only one species, T. lanceolata, occasionally germinated in the light, but gametophytic development never proceeded beyond the two-celled stage. Spores of T. lanceolata and T. sigmatifolia stored at −70 °C for 21 months germinated essentially as well as the fresh spores. The nutrient medium appears suitable for studies on gametophytes of the Psilotaceae because it promoted spore germination and gametophytic growth for most of the species tested. Key words: Psilotum, Tmesipteris, spore, germination.

Induced apogamy in Tmesipteris (Psilotaceae)

2004 ◽  
Vol 82 (6) ◽  
pp. 721-725 ◽  
Author(s):  
Dean P Whittier
Keyword(s):  
Shoot Apical Meristem ◽  
Nutrient Medium ◽  
Apical Meristem ◽  
Vascular Tissue ◽  
Axenic Culture ◽  
Epidermal Cells ◽  
Direct Connection ◽  
Normal Anatomy ◽  
Induced Apogamy ◽  
Fern Gametophytes

Gametophytes of Tmesipteris lanceolata Dang., which are mycorrhizal in nature, were grown in axenic culture. If cultured in the light on a nutrient medium containing minerals and 0.5% glucose, they did not become photosynthetic; however, about 15% of them produced apogamous sporophytes with stems and microphylls. The gametophyte–sporophyte junction had a direct connection between the gametophyte and sporophyte tissues and lacked a foot, which is typical for apogamy. Gametangia were limited to the gametophyte portions of these gametophyte–sporophyte growths, and the vascular tissue was present only in the sporophyte regions. The apogamous aerial stems had the normal anatomy for a sporophyte, with vascular tissue, epidermal cells, stomata, and chlorenchyma. The origin of the apogamous sporophytes was different from the origin in fern gametophytes. The Tmesipteris sporophytes arose terminally from the gametophyte apices. It appears that the apical meristem of the gametophyte is converted to a shoot apical meristem to form the apogamous aerial shoot.Key words: Tmesipteris, Psilotaceae, apogamy, sporophyte, gametophyte.

scholarly journals The protease CspB is essential for initiation of cortex hydrolysis and dipicolinic acid (DPA) release during germination of spores of Clostridium perfringens type A food poisoning isolates

Microbiology ◽  
2009 ◽  
Vol 155 (10) ◽  
pp. 3464-3472 ◽  
Author(s):  
Daniel Paredes-Sabja ◽  
Peter Setlow ◽  
Mahfuzur R. Sarker
Keyword(s):  
Clostridium Perfringens ◽  
Spore Germination ◽  
Nutrient Medium ◽  
Deletion Mutant ◽  
Dipicolinic Acid ◽  
Food Poisoning ◽  
Wild Type ◽  
Cell Compartment ◽  
Gene Encoding

The genome of the Clostridium perfringens food poisoning isolate SM101 encodes a subtilisin-like protease, CspB, upstream of the sleC gene encoding the enzyme essential for degradation of the peptidoglycan cortex during spore germination. SleC is an inactive pro-SleC in dormant spores that is converted to active SleC during spore germination and Csp proteases convert pro-SleC to the active enzyme in vitro. In this work, the germination and viability of spores of a cspB deletion mutant of strain SM101, as well as cspB expression, were studied. The cspB gene was expressed only during sporulation, and only in the mother cell compartment. cspB spores were unable to germinate significantly with either a rich nutrient medium, KCl, or a 1 : 1 chelate of Ca2+ and dipicolinic acid (DPA); the viability of these spores was ∼104-fold lower than that of wild-type spores, although cspB and wild-type spores had similar viability on plates containing lysozyme, and cspB spores could not process inactive pro-SleC into active SleC during spore germination. Germination of cspB spores was blocked prior to DPA release and cortex hydrolysis, and germination and viability defects in these spores were complemented by an ectopic cspB. These results indicate that Csp proteases are essential to generate active SleC and allow cortex hydrolysis early in C. perfringens spore germination. However, Csp proteases likely play another role in spore germination, since cspB spores did not release DPA upon exposure to germinants, while sleC spores have been shown previously to release DPA, albeit slowly, upon exposure to germinants.

scholarly journals Response of spores and young gametophytes of Cyathea delgadii Sternb. (Cyatheaceae) and Blechnum brasiliense Desv. (Blechnaceae) to different light levels

2007 ◽  
Vol 21 (4) ◽  
pp. 909-915 ◽  
Author(s):  
Rosane Hiendlmeyer ◽  
Aurea Maria Randi
Keyword(s):  
Spore Germination ◽  
Culture Medium ◽  
Limiting Factor ◽  
Natural Light ◽  
Tree Fern ◽  
Natural Conditions ◽  
Germination Time ◽  
Light Levels ◽  
Mean Germination Time ◽  
Effect Of Light

Light is a limiting factor for fern stablishment because it controls germination of light sensitive spores. The aim of this work was to study the effect of light levels on spore germination in two ornamental ferns native to the Atlantic forest, under natural conditions. Cyathea delgadii is a tree fern and Blechnum brasiliense, a subarborescent fern. The effect of light levels was analyzed in April and July/2003, in Florianópolis, Santa Catarina state, Brazil. Sterilized spores were sown in Erlenmeyer flasks containing mineral culture medium with macronutrients, iron, and benomyl 0.01%. The Erlenmeyer flasks were kept in 50 cm³ boxes covered with black shade netting, which gave 5, 22, 42, and 62% natural light. Irradiance and temperature were scored daily at 14:00 h during the study period. Higher percentages of germination were observed at 5 and 22% light for both species. Germination of Cyathea delgadii spores at 22% light reached 76% and mean germination time was 19.7 days; at 5% light, germination reached 83.5% and mean germination time was 20.16 days. Germination of Blechnum brasiliense at 22% light reached 76% and mean germination time was 9.06 days; at 5% light, germination reached 84% and mean germination time was 13.18 days. The highest light levels inhibited spore germination and the gametophytes died during the test period.

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