Seed reserves and early symbiotic protocorm development of Platanthera hyperborea (Orchidaceae)

1992 ◽  
Vol 70 (2) ◽  
pp. 291-300 ◽  
Author(s):  
K. A. Richardson ◽  
R. L. Peterson ◽  
R. S. Currah
Keyword(s):  
Fungal Symbiont ◽  
Terrestrial Orchid ◽  
Parenchyma Cells ◽  
Fungal Hyphae ◽  
Orchid Seed ◽  
Seed Reserves ◽  
Polyphosphate Bodies ◽  
Suspensor Cells ◽  
Rhizoctonia Cerealis ◽  
Storage Reserves

Seeds of the terrestrial orchid Platanthera hyperborea consist of a thin testa and a simple embryo without a cotyledon. Epidermal and parenchyma cells of the embryo contained lipid and protein as storage reserves. Many of the protein bodies had globoid crystals identified by their P, Ca2+, Mg2+, and K+ content. Germination occurred with either Rhizoctonia cerealis or Ceratorhiza goodyerae-repentis as the fungal symbiont on Warcup's medium. The fungus entered through dead suspensor cells and triggered protocorm development and concomitant utilization of lipid and protein reserves. Fungal hyphae formed pelotons with protocorm cells initially, and these went through stages of vacuolation and collapse. Some hyphae stored small numbers of polyphosphate bodies. Clumps of degenerated hyphae were usually encased within material that stained positive with aniline blue, presumably callose. Key words: Platanthera, orchid, seed, protocorm, endophytic fungus.

Morphogenèse comparée de protocormes du Cypripedium acaule (Orchidaceae) cultivés in vitro avec ou sans sucre

1995 ◽  
Vol 73 (9) ◽  
pp. 1391-1406 ◽  
Author(s):  
Gilles Leroux ◽  
Denis Barabé ◽  
Joachim Vieth
Keyword(s):  
Posterior Pole ◽  
Secretory Cells ◽  
In Vitro Germination ◽  
Anterior Pole ◽  
Fungal Symbiont ◽  
Terrestrial Orchid ◽  
Starch Grains ◽  
Meristematic Region ◽  
Storage Reserves

Seeds of the terrestrial orchid Cypripedium acaule from temperate regions contain an undifferentiated embryo consisting of about one hundred cells. These cells contain lipid and protein storage reserves. The development of the seeds was studied in vitro on a germination medium with or without dextrose (glucose). On the medium containing dextrose, proembryos develop and form a protocorm. From the anterior pole of the protocorm appears a "promeristem", a structure that will form a scale and the apex of the seedling. The formation of the root never precedes that of the apex. In the protocorm, the amount and size of starch grains show an increasing antero-posterior gradient. Only the apex, the procambium, and the secretory cells do not accumulate starch grains. On the medium without dextrose, the proembryos develop slowly into a protocorm, and a semi-meristematic region can be recognized at the anterior pole. However, no other tissue differentiation occurs and the protocorm soon degenerates without having undergone organogenesis. The protocorm accumulates a few starch grains, more voluminous and more numerous at the posterior pole, that agglomerate around the nucleus; but during the development, these rapidly disappear from the cells. Generally, all cells are strongly vacuolated. These observations indicate that orchid seeds cannot reach the seedling stage without a sugar input, which is ensured by a fungal symbiont in nature. Key words: Orchidaceae, morphogenesis, protocorm, starch, sugar effect, in vitro germination.

scholarly journals Anatomía vegetativa de Ctenitis melanosticta (Dryopteridaceae, Pteridophyta)

2017 ◽  
pp. 7
Author(s):  
Victoria Hernández-Hernández ◽  
Teresa Terrazas ◽  
Klaus Mehltreter
Keyword(s):  
Diagnostic Value ◽  
Anatomical Studies ◽  
Anatomical Features ◽  
Adaxial Epidermis ◽  
Parenchyma Cells ◽  
Fungal Hyphae ◽  
Available Information

The root, rhizome, petiole and blade anatomy of Ctenitis melanosticta was studied and compared with the available information for closely related genera. Root is diarc with sclerenchyma and parenchyma cells in the cortex, with fungal hyphae exclusively in the latter. The occurrence of sclereid nests in the rhizome is shared with Dryopteris and Campyloneurum. A cortical band was present in petiole and lamina, as in Dryopteris and other genera of the most derived ferns. The lamina had unifacial mesophyll and under the adaxial epidermis there were several layers of the fiber, as described for Elaphoglossum and Thelypteris, but differed from Asplenium, Dryopteris, and Polybotrya with collenchyma. The anatomy of C. melanosticta was similar to that of most species studied of Dryopteridaceae, although with some differences. Additional anatomical studies in species of Dryopteridaceae will allow to confirm the diagnostic value of several anatomical features, such as the lack of cortical band in the rhizome, the sclereid nests, the unifacial mesophyll, and the cortical band in the lamina.

Evidence for a fungal liaison between Corallorhiza trifida (Orchidaceae) and Pinus contorta (Pinaceae)

1995 ◽  
Vol 73 (6) ◽  
pp. 862-866 ◽  
Author(s):  
Carla D. Zelmer ◽  
R. S. Currah
Keyword(s):  
Key Words ◽  
Pinus Contorta ◽  
Woody Plant ◽  
Orchid Mycorrhiza ◽  
Terrestrial Orchid ◽  
Bright Yellow ◽  
Fungal Hyphae ◽  
Triple Symbiosis ◽  
Relative Inability ◽  
Slow Growing

Corallorhiza trifida Châtelain, or pale coral root orchid, is a heterotrophic, leafless, rootless, terrestrial orchid with a circumboreal distribution. Because of its relative inability to photosynthesize, the orchid obtains energy through the digestion of fungal hyphae that grow within the cells of its contorted, yellowish, coralloid rhizomes. Recently, we isolated and cultured strains of a slow-growing basidiomycete with bright yellow, clamped hyphae that are typical of the fungal cells present in C. trifida endomycorrhizas from different treed habitats at widely distributed locations in the northern hemisphere. By inoculating the roots of Pinus contorta Douglas ex Loudon seedlings with this fungus we were able to demonstrate its ability to form distinctive ectomycorrhizas with an ectotrophic, woody plant. The formation of endomycorrhizas with C. trifida and ectomycorrhizas with P. contorta indicates that in nature a triple symbiosis, with a circumboreal distribution, exists among certain trees, the coral root orchid, and this yellow basidiomycete that links the two and functions as a mycorrhizal symbiont in both. Key words: Corallorhiza trifida, orchid mycorrhiza, triple symbiosis, ectomycorrhiza, Pinus contorta.

Survival of transplanted terrestrial orchid seedlings in urban bushland habitats with high or low weed cover

2006 ◽  
Vol 54 (4) ◽  
pp. 383 ◽  
Author(s):  
A. Scade ◽  
M. C. Brundrett ◽  
A. L. Batty ◽  
K. W. Dixon ◽  
K. Sivasithamparam
Keyword(s):  
Seedling Survival ◽  
Canopy Cover ◽  
Growing Season ◽  
Wire Mesh ◽  
Terrestrial Orchid ◽  
Natural Habitats ◽  
Orchid Species ◽  
Weed Cover ◽  
Orchid Seed ◽  
Adjacent Field

The conservation of wild orchid populations may depend on the establishment of propagated orchids to field sites to help sustain depleted populations if natural recruitment is not successful. However, very little is known about biotic factors which influence the establishment of terrestrial orchid seedlings in natural habitats. An experiment was established to measure the survival of six orchid species during their first growing season following transplantation to a West Australian urban bushland with a Banksia and Eucalyptus canopy and understorey dominated either by weeds or native vegetation. Symbiotically germinated orchid seedlings raised in the laboratory for 5 months before planting were established in adjacent field sites with high or low weed cover. There was a gradual mortality of seedlings at field sites throughout the growing season, primarily owing to insect grazing, and this was not affected by the enclosure of seedlings by wire mesh or shade cloth. Overall rates of survival varied from 49% for Microtis media R.Br., a species capable of growing in disturbed habitats, to 21% for Caladenia arenicola Hopper & A.P.Brown, the most common native orchid at these sites. However, not all surviving seedlings produced a tuber, so their expected rate of survival after the next dry season was reduced further. The factors having the greatest impact on seedling survival were site aspect (slope and canopy cover), weed cover and orchid species respectively. Orchid seedling survival was not well correlated with the presence of existing orchids of the same species at the same sites or the presence of compatible fungi in soil at these sites (simultaneously measured by orchid seed baiting).

Interactions between a fungal endophyte and gametophyte cells in Psilotum nudum

1981 ◽  
Vol 59 (5) ◽  
pp. 711-720 ◽  
Author(s):  
R. L. Peterson ◽  
Melanie J. Howarth ◽  
Dean P. Whittier
Keyword(s):  
Energy Source ◽  
Endophytic Fungus ◽  
Cell Walls ◽  
Fungal Endophyte ◽  
Hyphal Cell ◽  
Cell Organelles ◽  
Host Cytoplasm ◽  
Psilotum Nudum ◽  
Parenchyma Cells ◽  
Fungal Hyphae

Mature Psilotum gametophytes found in greenhouse pots containing plants of Hoya, Philodendron, Aspidistra, or Diffenbachia were processed for microscopy. An endophytic fungus was abundant in the rhizoids and in most cortical parenchyma cells except at the growing apices. Although the fungus has not been identified, it is an aseptate fungus with coarse hyphae which occasionally form vesicles. Endophytic fungal hyphae store quantities of lipid which appear to be released into the host cytoplasm upon fungal degeneration. This lipid and the remnants of hyphal cell walls may be used as an energy source by the achlorophyllous gametophyte. Gametophyte cell organelles, including the nucleus, appear to degenerate after fungal breakdown, and the cells presumably die. Although reinfection of cells containing degenerated hyphae was found, it was not particularly common.

Constraints to symbiotic germination of terrestrial orchid seed in a mediterranean bushland

2001 ◽  
Vol 152 (3) ◽  
pp. 511-520 ◽  
Author(s):  
A. L. Batty ◽  
K. W. Dixon ◽  
M. Brundrett ◽  
K. Sivasithamparam
Keyword(s):  
Terrestrial Orchid ◽  
Symbiotic Germination ◽  
Orchid Seed

Banking site soil for the germination of terrestrial orchid seed collections

2009 ◽  
Vol 37 (1) ◽  
pp. 222-228 ◽  
Author(s):  
K.D. Sommerville ◽  
M.M. Heslewood ◽  
J.P. Siemon ◽  
C.A. Offord
Keyword(s):  
Terrestrial Orchid ◽  
Orchid Seed ◽  
Seed Collections

scholarly journals Asymbiotic seed germination and multiplication of an endangered orchid – Paphiopedilum venustum (Wall. ex Sims.)

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Saranjeet Kaur ◽  
Kamlesh Kumar Bhutani
Keyword(s):  
Seed Germination ◽  
Shoot Multiplication ◽  
Ex Situ ◽  
Terrestrial Orchid ◽  
Asymbiotic Seed Germination ◽  
Orchid Seed ◽  
Early Seedling ◽  
Potato Powder ◽  
Survival Frequency

The present study was intended to facilitate ex situ conservation of <em>Paphiopedilum venustum</em>, a highly floriferous endangered terrestrial orchid species. A protocol was established for in vitro propagation and shoot multiplication. The cultures were initiated through asymbiotic seed germination technique, using undehisced and dehisced capsules. Four defined asymbiotic orchid seed germination media (terrestrial orchid medium, modified terrestrial orchid medium, Malmgren modified terrestrial orchid medium, Knudson C medium) were evaluated for their effectiveness in achieving maximum seed germination and early seedling development. The effect of darkness and 12-h photoperiod was also tested. Optimum seed germination, i.e., 82.7% was achieved on modified terrestrial orchid medium under a 12-h photoperiod using seeds from undehisced capsules. Shoot multiplication was accomplished using organic [peptone (1.0, 2.0 g L<sup>−1</sup>)] and inorganic [banana homogenate (10, 20, 30 g L<sup>−1</sup>) and potato powder (5.0, 10 g L<sup>−1</sup>)] growth supplements. Peptone at 1.0 g L<sup>−1</sup> was the most effective in multiplying the shoots. Plantlets were acclimatized in the greenhouse with 80% survival frequency.

scholarly journals Crosstalk during the Carbon–Nitrogen Cycle That Interlinks the Biosynthesis, Mobilization and Accumulation of Seed Storage Reserves

2021 ◽  
Vol 22 (21) ◽  
pp. 12032
Author(s):  
Manpreet Kaur ◽  
Yamini Tak ◽  
Surekha Bhatia ◽  
Bavita Asthir ◽  
José M. Lorenzo ◽  
...  
Keyword(s):  
Seed Quality ◽  
Seed Storage ◽  
Mobile Form ◽  
Carbon And Nitrogen ◽  
Storage Reserve ◽  
Seed Reserves ◽  
Storage Products ◽  
Source Sink ◽  
Seed Storage Reserves ◽  
Storage Reserves

Carbohydrates are the major storage reserves in seeds, and they are produced and accumulated in specific tissues during the growth and development of a plant. The storage products are hydrolyzed into a mobile form, and they are then translocated to the developing tissue following seed germination, thereby ensuring new plant formation and seedling vigor. The utilization of seed reserves is an important characteristic of seed quality. This review focuses on the seed storage reserve composition, source–sink relations and partitioning of the major transported carbohydrate form, i.e., sucrose, into different reserves through sucrolytic processes, biosynthetic pathways, interchanging levels during mobilization and crosstalk based on vital biochemical pathways that interlink the carbon and nitrogen cycles. Seed storage reserves are important due to their nutritional value; therefore, novel approaches to augmenting the targeted storage reserve are also discussed.

scholarly journals Subcellular Organization of the Developing Cotyledons of Pisum Sativum L.

1966 ◽  
Vol 19 (1) ◽  
pp. 49 ◽  
Author(s):  
Joan M Bain ◽  
FV Mercer
Keyword(s):  
Pisum Sativum ◽  
Fat Metabolism ◽  
Cell Formation ◽  
Physiological Changes ◽  
Pisum Sativum L ◽  
Parenchyma Cells ◽  
Subcellular Organization ◽  
Cell Organization ◽  
Developmental Phases ◽  
Storage Reserves

Morphological, anatomical, submicroscopical, and physiological changes in whole seeds and embryos of Pisum sativum L. cv. Victory Freezer were followed during 54 days of development of the seed. Four developmental phases-cell formation, cell expansion, synthesis of storage reserves, and maturation and dormancy-were recognized in the development of the embryo. Each phase was characterized by a distinctive physiology and a distinctive subcellular organization of the parenchyma cells. The subcellular organization associated with carbohydrate, protein, and fat metabolism and the significance of membranes in cell organization is described.

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