‘Dust seeds’ with undifferentiated embryos and their germination in mycoheterotrophic Monotropoideae (Ericaceae)

2020 ◽  
pp. 1-19
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seed Germination ◽  
Direct Contact ◽  
Symbiotic Germination ◽  
Dust Seeds ◽  
Broad Overview

Abstract ‘Dust seeds’ with an undifferentiated (organless) embryo are known to be produced by mycoheterotrophic species (MH) in nine families of angiosperms. However, aside from the numerous studies on seed germination of orchids, relatively little is known about germination in MH families. In the Ericaceae, some degree of mycoheterotrophy (full, partial or initial) and dust seeds with an undifferentiated embryo occur in all species in the three tribes of Monotropoideae, the only subfamily of Ericaceae with this combination of characters. In most species, the seed is <0.90 mm in the greatest dimension, the endosperm is absent (Pityopus) or consists of few to many (30–40) cells, and the embryo is minute, consisting of as few as two cells in Monotropa. Germination in Monotropoideae is monopolar, with only the radicular pole of the embryo participating in germination. Thus, germination polarity differs from that of the dust seeds of orchids in which only the plumular pole of the embryo (protocorm) participates in germination. The dust seeds in Monotropoideae require the presence of fungi, either direct contact with a fungus or the presence of a diffusible substance therefrom, to germinate (symbiotic germination). Recently, representatives of the four genera of tribe Pyroleae have been successfully germinated asymbiotically in vitro. We present a broad overview of dust-size seeds in angiosperms and conclude that they should be subdivided into at least two major categories.

scholarly journals Low-specific Symbiotic Germination of Dendrobium Huoshanense in Vitro, an Endangered Epiphytic Orchid Endemic From South China

2021 ◽  
Author(s):  
Yan-Jing Tang ◽  
Jun Dai ◽  
Yang Li ◽  
Dong-Yu Zhou ◽  
Yong-Mei Xing ◽  
...  
Keyword(s):  
Seed Germination ◽  
Mycorrhizal Fungi ◽  
Blue Staining ◽  
Fungal Strains ◽  
Epiphytic Orchid ◽  
Symbiotic Germination ◽  
Orchid Seed ◽  
Dendrobium Huoshanense ◽  
Initial Seed

Abstract Background: Dendrobium huoshanense is an endangered epiphytic orchid and is endemic to Anhui province of China with a narrow distribution. In nature, orchid seed germination depends on specific mycorrhizal fungi and it is generally assumed that there is a high specific symbiotic germination in narrow distribution orchid. To evaluate the mycorrhizal compatibility and germination-promoting activity of mycorrhizal fungi of D. huoshanense in vitro, we isolated and identified cultured mycorrhizal fungi from the roots of D. huoshanense and D. officinale. A total of 20 mycorrhizal fungal strains (D. huoshanense (n = 6), D. officinale (n = 12), D. nobile (n = 1), D. moniliforme (n = 1)) were used to test the germination-promoting activity of D. huoshanense. Results: In symbiotic germination tests, the mycorrhizal fungi displayed different efficiency in stimulating D. huoshanense seed germination, nine strains stimulated seed development to an advanced seedling stage, while the rest promoted only initial seed germination to stage 2 or stage 3, and the most effective in promoting rapid seed germination was strain 12825(seb) isolated from D. moniliforme, besides, the second most effective fungus was strain WX-7(seb) isolated from D. officinale, both of them belong to Sebacina isolated from non-D. huoshanense. In this study, all twenty fungal strains formed pelotons inside seeds of D. huoshanense based on the trypan blue staining results. Conclusions: Despite its narrow specific habitat preference, D. huoshanense was found to be a mycorrhizal generalist during symbiotic seed germination in vitro. The study is the first to demonstrate the different abilities of orchid mycorrhizal fungi to promote seed germination, protocorm formation and seedling development of D. huoshanense in vitro, providing important microbiological resources for its conservation and reintroduction in nature.

scholarly journals An expanded role for in vitro symbiotic seed germination as a conservation tool: two case studies in North America (Platanthera leucophaea and Epidendrum nocturnum)

Lankesteriana ◽  
2015 ◽  
Vol 7 (1-2) ◽  
Author(s):  
Emily Massey ◽  
Lawrence Zettler
Keyword(s):  
North America ◽  
Seed Germination ◽  
Case Studies ◽  
Mycorrhizal Fungi ◽  
Orchid Species ◽  
Symbiotic Germination ◽  
Symbiotic Seed Germination ◽  
Platanthera Leucophaea

Interest in using mycorrhizal fungi to cultivate orchids from seed in vitro (=symbiotic seed germina- tion) has intensified in recent years and this approach is now an important conservation tool worldwide. In North America, symbiotic germination has been attempted for a growing number of orchid species in peril as a means to acquire seedlings suitable for reintroduction.

scholarly journals Influence of Culture Conditions on In Vitro Asymbiotic Germination of Anacamptis longicornu and Ophrys panormitana (Orchidaceae)

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2543
Author(s):  
Myriam Arcidiacono ◽  
Caterina Catalano ◽  
Antonio Motisi ◽  
Maurizio Sajeva ◽  
Francesco Carimi ◽  
...  
Keyword(s):  
Seed Germination ◽  
Nitrogen Source ◽  
Culture Conditions ◽  
Ms Medium ◽  
Symbiotic Germination ◽  
Terrestrial Orchids ◽  
In The Wild ◽  
Asymbiotic Germination ◽  
Very High

This study is the first approach to in vitro asymbiotic germination of two species of Sicilian threatened terrestrial orchids, Anacamptis longicornu and Ophrys panormitana. Seeds were collected in the wild and cultured in two different media—Orchimax medium (OM) and Murashige and Skoog (MS)—and exposed to different photoperiods and temperatures to evaluate the best conditions for the specific stages of development. The germination of A. longicornu was very high on OM (95.5%) and lower on MS medium (21.4%), whereas O. panormitana germinated only on OM medium, with significantly lower percentages (12.0%), compared with A. longicornu. This difference is caused by variation in quality and quantity of nutrients used, primarily by nitrogen source. The results show that temperature and photoperiod widely affect seed germination and development. Although further investigations on asymbiotic and symbiotic germination are needed for the improvement of conservation of Mediterranean terrestrial orchids, our results contribute to the conservation of this group of plants.

Seed-borne fungi of cowpea [Vigna unguiculata (L.) Walp] and their possible control in vitro using locally available fungicides in Botswana.

2016 ◽  
Vol 5 (11) ◽  
pp. 5016 ◽  
Author(s):  
K. B. Khare* ◽  
Loeto D. ◽  
Wale K. ◽  
Salani M.
Keyword(s):  
Seed Germination ◽  
Continuous Light ◽  
Sodium Hypochlorite Solution ◽  
Distilled Water ◽  
Percentage Germination ◽  
Department Of Agriculture ◽  
Hypochlorite Solution ◽  
Cowpea Cultivars ◽  
Petri Plate

Seeds of three cowpea cultivars namely Black eye, ER 7 and Tswana obtained from the Department of Agriculture Research, Gaborone were tested for the presence of seed-borne fungi, and their possible control in vitro using locally available fungicides. Four hundred fifty seeds of each cultivar of cowpea were disinfected with 2% sodium hypochlorite solution for 10 min and washed three times with sterile distilled water before placing them in PDA plates (5 seeds/9 cm Petri plate), incubated at 22±2o C for 12 hour each under continuous light and dark. A total of eight fungi were detected from seeds of cowpea. These were Aspergillus flavus, A. niger, Cylindrocarpon sp., Fusarium equisiti, F. oxyaporum, Penicillium chyrosogenum, Rhizopus oligosporus and R. stolonifer. Rhizopus spp. were dominant fungi recovered from seeds, followed by Penicillium, Aspergillus, Fusarium and Cylindrocarpon. The fungi detected resulted in decay and rotting of seeds, and thereby reducing percentage germination of seeds (22%, 37% and 63 % seed germination in Black eye, ER7 and Tswana varieties of cowpea respectively). Out of four fungicides tested, benlate, captan, dithane M 45 and chlorothalanil. Dithane M45 effectively controlled seed-borne fungi, and enhanced seed germination to an average of 86% (93% germination with no fungi detected in Tswana variety) as compared to chlorothalonile (79%), benlate and captan (77%) and un-treated seeds (45%). The fungal incidence was reduced to 2.3%, 4.3%, 5.3% and 5.3% when seeds were treated with dithane M-45, chlorothalonil, benlate and captan respectively as compared to 62% in non-treated seeds.

scholarly journals Phytase-Producing Rahnella aquatilis JZ-GX1 Promotes Seed Germination and Growth in Corn (Zea mays L.)

2021 ◽  
Vol 9 (8) ◽  
pp. 1647
Author(s):  
Gui-E Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu ◽  
Shi-Bo Ma
Keyword(s):  
Seed Germination ◽  
Plant Growth ◽  
Biomass Accumulation ◽  
Root Surface ◽  
Phosphorus Concentration ◽  
Maize Seedlings ◽  
Total Phosphorus Concentration ◽  
Rahnella Aquatilis ◽  
Maize Seeds

Phytase plays an important role in crop seed germination and plant growth. In order to fully understand the plant growth-promoting mechanism by Rahnella aquatilis JZ-GX1，the effect of this strain on germination of maize seeds was determined in vitro, and the colonization of maize root by R. aquatilis JZ-GX1 was observed by scanning electron microscope. Different inoculum concentrations and Phytate-related soil properties were applied to investigate the effect of R. aquatilis JZ-GX1 on the growth of maize seedlings. The results showed that R. aquatilis JZ-GX1 could effectively secrete indole acetic acid and had significantly promoted seed germination and root length of maize. A large number of R. aquatilis JZ-GX1 cells colonized on the root surface, root hair and the root interior of maize. When the inoculation concentration was 107 cfu/mL and the insoluble organophosphorus compound phytate existed in the soil, the net photosynthetic rate, chlorophyll content, phytase activity secreted by roots, total phosphorus concentration and biomass accumulation of maize seedlings were the highest. In contrast, no significant effect of inoculation was found when the total P content was low or when inorganic P was sufficient in the soil. R. aquatilis JZ-GX1 promotes the growth of maize directly by secreting IAA and indirectly by secreting phytase. This work provides beneficial information for the development and application of R. aquatilis JZ-GX1 as a microbial fertilizer in the future.

scholarly journals In vitro seed germination response of corn hybrids to osmotic stress conditions

age ◽  
2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Charles Hunt Walne ◽  
Annabeth Gaudin ◽  
W. Brien Henry ◽  
Kambham Raja Reddy
Keyword(s):  
Seed Germination ◽  
Osmotic Stress ◽  
Stress Conditions ◽  
Corn Hybrids ◽  
Germination Response

scholarly journals Seed Germination and in vitro Plant Regeneration through Callus Culture of Two Lychnis Species

2015 ◽  
Vol 25 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Kee Hwa Bae ◽  
Eui Soo Yoon
Keyword(s):  
Plant Regeneration ◽  
Seed Germination ◽  
Callus Induction ◽  
In Vitro Propagation ◽  
Ornamental Plants ◽  
Leaf Explants ◽  
Adventitious Shoot ◽  
Temperature Treatment ◽  
In Vitro Plant Regeneration

Lychnis cognate Maxim and Lychnis fulgens Fish. Ex Spreng are two valued ornamental plants in Korea. Soaking of seeds in GA3 solution remarkably promoted germination up to 60%, but the control (0 mg/l) was not effective (> 5%). To select an adequate temperature for seed germination, seeds, previously soaked in a 1000 mg/l GA3 for 24 hrs, were incubated at 15, 20, 25, and 30°C. Seed germination of over 20% was obtained at 15, 20, and 25°C, but only 10% at 30°C. These results indicate that the seeds of L. cognate and L. fulgens are in a such dormant state that they hardly germinate even by dormancy breaker (GA3) and low (15 ? 25°C) temperature treatment. The highest callus induction was observed in the leaf explants of the seedlings on MS containing specific concentrations of 3.0 mg/l BA and 1.0 mg/l NAA. The adventitious shoot was formed < 90% of calli on 1/2 WPM medium. The height of in vitro propagated plantlet was no different media used for regeneration. This in vitro propagation protocol should be useful for conservation of endangered and ornamental plant.Plant Tissue Cult. & Biotech. 25(1): 1-12, 2015 (June)

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