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.

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.

The effect of mineral nutrition on apogamy in Pteridium

1969 ◽  
Vol 47 (5) ◽  
pp. 773-777
Author(s):  
L. L. Treanor ◽  
D. P. Whittier
Keyword(s):  
Mineral Nutrition ◽  
Nutrient Medium ◽  
Mineral Elements ◽  
High Concentrations ◽  
Mineral Levels ◽  
Induced Apogamy

The effect of mineral nutrition on apogamy was studied because earlier investigators proposed that low mineral levels induced apogamy. The weight of the gametophytic tissue and the number of apogamous plants per culture and per gram of gametophytic tissue were determined in relation to variations in the levels of mineral elements. The apogamous response was promoted only by high concentrations of phosphorus, and an increase in the gametophytic weight was produced by high levels of potassium. The omission of any of the elements from the nutrient medium inhibited apogamy and, except calcium, reduced the gametophytic weight.

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.

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.

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 effect of sodium on the mineral balance of plants, using the example of root celery and stalk celery. Part I. The role of sodium and potassium in the process of accumulation and utilization of mineral elements

2013 ◽  
Vol 41 (2) ◽  
pp. 295-314
Author(s):  
Urszula Kruszelnicka
Keyword(s):  
Nutrient Medium ◽  
Mineral Elements ◽  
Antagonistic Effect ◽  
Apium Graveolens ◽  
Mineral Balance ◽  
High K ◽  
Mineral Components ◽  
Low K ◽  
Sodium And Potassium

In the years 1977 - 1980, studies were conducted on the effect of sodium used to supplement low (K = 800 mg/5 kg) and high (K = 1400 mg/5 kg) potassium doses on the content of mineral components, their accumulation in the yield and the percentage of their utilization. The study was carried out on root celery - <i>Apium graveolens</i> L. var. <i>rapaceum</i> (Mill.) and stalk celery - <i>Apium graveolens</i> L. var. <i>dulce</i> (Mill.). The results obtained in these experiments point to the following conclusions: it was found that potassium and sodium mutually limit each other's uptake. Sodium was more antagonistic towards the uptake of calcium than was potassium. However, no clearly antagonistic effect of these elements on the uptake of magnesium was determined. The accumulation of potassium and sodium by the experimental plants rose while the percentage of utilization of these elements decreased as their level in the nutrient medium increased. Sodium exerted a more distinct effect on the accumulation and utilization of other mineral elements than did potassium.

Axenic culture of the downy mildew fungus Plasmopara halstedii in Agrobacterium rhizogenes-induced roots of sunflower (Helianthus annuus)

1991 ◽  
Vol 69 (12) ◽  
pp. 2709-2715 ◽  
Author(s):  
G. A. Zahka ◽  
F. Virányi
Keyword(s):  
Comparative Study ◽  
Helianthus Annuus ◽  
Downy Mildew ◽  
Agrobacterium Rhizogenes ◽  
Nutrient Medium ◽  
Axenic Culture ◽  
Root Culture ◽  
Good Source ◽  
Plasmopara Halstedii ◽  
Intact Plants

The downy mildew fungus, Plasmopara halstedii (Farlow) Berlese & de Toni, was cultured axenically in association with sunflower roots derived from petioles inoculated with Agrobacterium rhizogenes. An axenic zoosporangial suspension, obtained from sporulating cotyledons, was added to A. rhizogenes-induced root pieces on agar or in liquid nutrient medium. Roots showed profuse P. halstedii sporulation after 1 week. A comparative study in infection morphology with excised sunflower roots (not induced by A. rhizogenes) of the same cultivar showed no difference, both of which resembled P. halstedii infection in roots from intact plants. The dual-member cultures with A. rhizogenes induced roots were a good source of axenic P. halstedii inoculum, and zoosporangia remained viable for up to 2 monhts in dual-member cultures maintained at 18–20 °C. Noteworthy features were the balanced state of host and parasite and the prolific production of P. halstedii oospores. Key words: downy mildew, sunflower, Plasmopara halstedii, Helianthus annuus, root culture, Agrobacterium rhizogenes.

Special Issue on “New Media and Social Psychology”

2006 ◽  
Vol 37 (2) ◽  
pp. 57-57
Author(s):  
Bernad Batinic ◽  
Anja Goeritz
Keyword(s):  
Social Psychology ◽  
New Media ◽  
Special Issue

Review of The New Media and Education: Their Impact on Society.

1967 ◽  
Vol 12 (10) ◽  
pp. 525-525
Author(s):  
MORTON DEUTSCH
Keyword(s):  
New Media
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