Seed dispersal and site characteristics influence germination and seedling survival of the invasive liana Euonymus fortunei (wintercreeper) in a rural woodland

2018 ◽  
Vol 48 (11) ◽  
pp. 1343-1350 ◽  
Author(s):  
Todd J. Rounsaville ◽  
Carol C. Baskin ◽  
Eric Roemmele ◽  
Mary A. Arthur

The invasive liana Euonymus fortunei (Turcz.) Hand.-Maz. (wintercreeper) is an emerging invader that through monodominance of woodlands can drastically reduce native species diversity and alter nutrient cycling. We studied how the vegetation and soils of invaded (INV), “native” (NAT), and wintercreeper removal (REM) site treatments influenced seed germination and seedling survival of this invader. The effect of aril (with vs. without) was also tested for wintercreeper seeds under field and in vitro conditions as a proxy for gravity vs. animal dispersal of seed, respectively. Germination was significantly delayed for seeds sown with an aril (vs. without), as well as those sown in INV soils (vs. NAT or REM), but neither site nor aril affected total germination. The proportion of germinated seedlings that survived after the first winter was significantly different based on site (p = 0.054) and aril (p = 0.071) treatments, with lower survival resulting from seeds sown without arils, and for seeds sown in INV sites. Magnesium (Mg) concentrations were significantly higher among INV soils (vs. NAT) and provide further support that wintercreeper is a driver of soil nutrient change. Our findings that aril-enclosed (gravity-dispersed) seeds yielded greater survival, despite being locally dispersed within invaded sites (where survival was lowest), support the historically slow rate of spread for this species.

Author(s):  
Aleksandra Yurievna Nabieva

Abstract Background Terrestrial orchids belonging to the Orchis genus are difficult to propagate and are under great pressure in their natural habitats. Studies regarding the influence of photoperiod and temperature regimes on Orchis militaris germination and morphological changes during immature seed development in vitro are scarce. Our aim was to identify photoperiod, temperature, and different nutrient media requirements for optimization of O. militaris seed germination and vigorous seedling production. Results Post-germination morphological changes were recorded with O. militaris seeds collected from 32-day-old fruits, where the percentage of O. militaris seeds without embryo was 38.4%. The highest rate of O. militaris seed germination (82.6%) was obtained on Malmgren modified terrestrial orchid medium (mM), enriched by 5% coconut water, 5% birch sap, and 0.1% AC. Nine percent of seedlings were able to reach the advanced seedling stage (stage 6) after 12 months of maintenance on this medium. In all 3 modified media (Harvais, Knudson С and Malmgren), regeneration was via the production of protocorms and seedlings without callus formation. It was proved that more abundantly vigorous protocorms were formed on the modified Harvais 2 under continuous darkness, while the subculture in Knudson C medium with AC addition could be necessary to stimulate their further development. The regeneration success of the species for in vitro conditions was increased by following its natural seasonal cycle. Conclusion This study demonstrated an efficient micropropagation system for O. militaris using immature seeds and thus widely opened the perspectives for its conservation in nature. The favorable conditions of seed germination periods for in vitro culture, identified as the definite shift of temperatures and photoperiod regimes intrinsic to the species in nature, could improve seedling survival of this medicinally important orchid.


2016 ◽  
Vol 5 (11) ◽  
pp. 5016 ◽  
Author(s):  
K. B. Khare* ◽  
Loeto D. ◽  
Wale K. ◽  
Salani M.

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.


2021 ◽  
Vol 9 (8) ◽  
pp. 1647
Author(s):  
Gui-E Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu ◽  
Shi-Bo Ma

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.


age ◽  
2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Charles Hunt Walne ◽  
Annabeth Gaudin ◽  
W. Brien Henry ◽  
Kambham Raja Reddy

2015 ◽  
Vol 25 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Kee Hwa Bae ◽  
Eui Soo Yoon

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)


1986 ◽  
Vol 64 (10) ◽  
pp. 2368-2371 ◽  
Author(s):  
Keith N. Egger ◽  
J. W. Paden

Forty isolates of postfire ascomycetes (Pezizales) were tested for in vitro pathogenicity on seeds and germinants of lodgepole pine, Pinus contorta Dougl. Two known pathogens, Caloscypha fulgens (Pers.) Boud. and Botrytis cinerea Pers., were included as a check of the method. Caloscypha fulgens was the only fungus that caused serious declines in seed germination, although several species of postfire Pezizales were capable of preemergence seed infection. Rhizina undulata Fr. and Pyropyxis rubra (Peck) Egger were strongly pathogenic on germinants. Pyropyxis rubra was not previously known to be pathogenic. Many isolates were weakly pathogenic on germinants under the conditions tested.


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