scholarly journals Symbiotic and Asymbiotic Germination of Dendrobium officinale (Orchidaceae) Respond Differently to Exogenous Gibberellins

2020 ◽  
Vol 21 (17) ◽  
pp. 6104 ◽  
Author(s):  
Juan Chen ◽  
Bo Yan ◽  
Yanjing Tang ◽  
Yongmei Xing ◽  
Yang Li ◽  
...  
Keyword(s):  
Seed Germination ◽  
Mycorrhizal Fungi ◽  
Calcium Binding ◽  
Germination Rate ◽  
Dendrobium Officinale ◽  
Fungal Colonization ◽  
Fungal Mycelium ◽  
High Concentration ◽  
Symbiotic Germination ◽  
Asymbiotic Germination

Seeds of almost all orchids depend on mycorrhizal fungi to induce their germination in the wild. The regulation of this symbiotic germination of orchid seeds involves complex crosstalk interactions between mycorrhizal establishment and the germination process. The aim of this study was to investigate the effect of gibberellins (GAs) on the symbiotic germination of Dendrobium officinale seeds and its functioning in the mutualistic interaction between orchid species and their mycobionts. To do this, we used liquid chromatograph-mass spectrometer to quantify endogenous hormones across different development stages between symbiotic and asymbiotic germination of D. officinale, as well as real-time quantitative PCR to investigate gene expression levels during seed germination under the different treatment concentrations of exogenous gibberellic acids (GA3). Our results showed that the level of endogenous GA3 was not significantly different between the asymbiotic and symbiotic germination groups, but the ratio of GA3 and abscisic acids (ABA) was significantly higher during symbiotic germination than asymbiotic germination. Exogenous GA3 treatment showed that a high concentration of GA3 could inhibit fungal colonization in the embryo cell and decrease the seed germination rate, but did not significantly affect asymbiotic germination or the growth of the free-living fungal mycelium. The expression of genes involved in the common symbiotic pathway (e.g., calcium-binding protein and calcium-dependent protein kinase) responded to the changed concentrations of exogenous GA3. Taken together, our results demonstrate that GA3 is probably a key signal molecule for crosstalk between the seed germination pathway and mycorrhiza symbiosis during the orchid seed symbiotic germination.

Ultrastructure of symbiotic germination of the orchid Dendrobium officinale with its mycobiont, Sebacina sp.

2014 ◽  
Vol 62 (3) ◽  
pp. 229 ◽  
Author(s):  
J. Chen ◽  
H. Wang ◽  
S. S. Liu ◽  
Y. Y. Li ◽  
S. X. Guo
Keyword(s):  
Seed Germination ◽  
Mycorrhizal Fungi ◽  
Morphological Changes ◽  
Cortical Cell ◽  
Embryo Cell ◽  
Dendrobium Officinale ◽  
Transmission Electron ◽  
Symbiotic Germination ◽  
Fungal Hyphae ◽  
Stage 1

Dendrobium officinale is an endangered epiphytic orchidaceous medicinal plant. Similar to other orchid plants, the seed germination of D. officinale under natural conditions depends nutritionally upon mycorrhizal fungi. The compatible fungi have been isolated from D. officinale protocorms using in situ seed baiting technique in our previous studies. However, the interaction between seed germination of D. officinale and its mycobiont is still unclear. In the present study, we investigated the morphological changes of seed and fungus during the symbiotic germination using a light microscope and transmission electron microscope. Seeds of D. officinale have no conspicuous suspensor cells. The fungus enters into the embryo cell through the posterior end of the embryo and colonises the cortical cell in the first stage of germination (Stage 1). Then, the hyphae form pelotons with the protocorm development (Stages 1–3). After protocorm formation, the reinvaded fungal hyphae conspicuously decrease. Invaded hyphae lose bioactivity, form clumps and start degeneration at Stage 4 or 5 (seedling development). When penetrating the neighbouring cortical cell, the fungal hyphae constrict to collar shape at the contacted site and follow by swelling in the apex. Our study suggested that fungi trigger protocorm development and concomitant reserve utilisation during the symbiotic germination.

Allelopathic potential of Artemisia campestris ssp. caudata on Lake Huron sand dunes

1997 ◽  
Vol 75 (11) ◽  
pp. 1903-1912 ◽  
Author(s):  
Kyeong W. Yun ◽  
M. A. Maun
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Mycorrhizal Fungi ◽  
Sand Dune ◽  
Sand Dunes ◽  
Dry Weight ◽  
Fungal Colonization ◽  
Test Species ◽  
Allelopathic Potential ◽  
Artemisia Campestris

Greenhouse studies were conducted to test allelopathic effects of Artemisia campestris ssp. caudata on seed germination and seedling growth of several sand-dune species and colonization by mycorrhizal fungi. The aqueous extracts of A. campestris showed no inhibitory effect on seed germination, seedling elongation, or dry-weight growth of plants at lower concentrations (10 and 50%), but 100% concentration of the extracts caused varying degrees of inhibition depending on the test species. The mixing of dry leaves of seedlings of A. campestris to the sand showed severe inhibition of Elymus canadensis seedlings. The percent germination of test species in soil from the rhizosphere of A. campestris was significantly lower than that of the control. The leaf area and dry weight were also lower but the differences were not significant. The aqueous extract inhibited mycorrhizal fungal colonization in roots of three sand-dune grasses. Key words: allelopathy, Artemisia campestris ssp. caudata, seed germination, seedling growth, mycorrhizal fungi.

scholarly journals The Effects of Temperature, Light and Moisture on the Seed Germination of Siphonostegia chinensis Benth.

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Yongji Wang
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Germination Index ◽  
High Concentration ◽  
Complete Darkness ◽  
Germination Potential ◽  
Medium Level ◽  
Different Temperatures ◽  
High Level ◽  
Germination Experiment

To explore the optimum temperature, light intensityand water conditions for seed germination of Siphonostegia chinensis Benth.,seed germination experiment were carried out under different temperatures（5/15, 10/20, 15/25, 20/30℃）, different light intensity（14h light/10h darkness, complete darkness）and different concentrations（0％, 5％, 10％, 15％, 20％）of PEG-6000 solution. In terms of concentration, 5% PEG was regarded as the low level, 10% and 15% as the medium level, and 20% as the high level. The results showed that (1) Germination rate, germination potential, and germination index were increased with the rise of temperature. In addition, seed germination was significantly higher under the dark conditions than that with the 14h light/10h darkness. (2) No seed germination occurred when the temperature was below 10/20 ºC at 14h light/10h darkness. (3) Under 14h light/10h darkness, the germination rate, germination potential and germination index first increased and then decreased with the increase of PEG concentration. The low concentration was more beneficial to the seed germination. (4) Under the condition of complete darkness, the germination rate, germination potential and germination index decline with fluctuation with the increase of PEG concentration. Seed germination of Siphonostegia chinensis Benth. was inhibited in high concentration of PEG.

scholarly journals Effects of Exogenous Calcium on Datura Seed Germination under Drought Stress

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Yongji Wang
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
Germination Rate ◽  
Inhibitory Effect ◽  
Control Group ◽  
High Concentration ◽  
Moisture Condition ◽  
Moderate Drought ◽  
Exogenous Calcium ◽  
Effects Of Drought

With polyethylene glycol (PEG-6000), of 0% (CK), 5%, 10%, 15%, 25% used to simulate drought stress, and CaCl2 concentration 0 (CK), of 15, 20, 25 and 30mmol/L as ion gradient of exogenous calcium, the effects of drought, exogenous calcium and the interaction between the two on the Datura seed germination, so as to explore the optimal application amount of exogenous calcium to ease the suppression of drought stress on Datura seed germination. The results showed that the germination rate, germination potential and germination index of the Datura seeds were significantly lower than those of the control group. Under the normal moisture condition, exogenous calcium of moderate and low concentration had no significant effect on the Datura seed germination, while that of high concentration showed an inhibitory effect on the seed germination. Under drought stress, with the increasing concentration of exogenous calcium, the three indicators of Datura seeds showed a trend of increasing first and then decreasing. When the exogenous calcium had the concentration of 20 mmol/L, all the indicators of seed germination reached the maximum value, while showed a downward trend when exogenous calcium concentration was 25-30 mmol/L, and even increasingly sharp with drought intensifying. Therefore, in the production and utilization of Datura, 20 mmol/L of exogenous calcium can be used to soak seeds before sowing to improve the emergence rate under low and moderate drought conditions.

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 Organic Compounds: Contents and Their Role in Improving Seed Germination and Protocorm Development in Orchids

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Edy Setiti Wida Utami ◽  
Sucipto Hariyanto
Keyword(s):  
Seed Germination ◽  
Organic Compounds ◽  
Mycorrhizal Fungi ◽  
Scientific Literature ◽  
Culture Media ◽  
Germination Rate ◽  
Shoot Formation ◽  
Multiple Shoot ◽  
Seedling Development

In nature, orchid seed germination is obligatory following infection by mycorrhizal fungi, which supplies the developing embryo with water, carbohydrates, vitamins, and minerals, causing the seeds to germinate relatively slowly and at a low germination rate. The nonsymbiotic germination of orchid seeds found in 1922 is applicable to in vitro propagation. The success of seed germination in vitro is influenced by supplementation with organic compounds. Here, we review the scientific literature in terms of the contents and role of organic supplements in promoting seed germination, protocorm development, and seedling growth in orchids. We systematically collected information from scientific literature databases including Scopus, Google Scholar, and ProQuest, as well as published books and conference proceedings. Various organic compounds, i.e., coconut water (CW), peptone (P), banana homogenate (BH), potato homogenate (PH), chitosan (CHT), tomato juice (TJ), and yeast extract (YE), can promote seed germination and growth and development of various orchids. They also stimulate seedling development, formation of protocorm-like bodies (PLBs), plantlet growth, and multiple shoot formation. The addition of organic compounds to culture media, individually or in combination, accelerates seed germination and seedling development. Different types and concentrations of organic nutrients are needed for the success of in vitro cultures, depending on the species and genotype.

scholarly journals Effect of CuSO4 on the growth of Brassica juncea L.

2020 ◽  
Vol 10 (5) ◽  
pp. 245-247
Author(s):  
M.R. Pratik ◽  
B. Bavi ◽  
B. Bavi
Keyword(s):  
Seed Germination ◽  
Brassica Juncea ◽  
Copper Sulfate ◽  
Copper Sulphate ◽  
Germination Rate ◽  
High Concentration ◽  
Black Mustard ◽  
Germination And Growth

Seeds of Black Mustard (Brassica juncea) were sowed in a paper cup with copper sulfate at different concentration. This experiment aimed to determine the effect of the variation in concentration of copper sulphate on the germination and growth of seeds of Brassica juncea. We wanted to establish which is the highest concentration of copper that the seeds of Black Mustard can tolerate. Seedlings growth investigation and measurements were made after 5 days. The seed germination rate was low to no for the high concentration and for control that increased dramatically with the decrease in concentration. At high concentration, no growth was seen.

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.

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