• 한국환경과학회지
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• 제18권12호
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• pp.1361-1368
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• 2009

The effects of $Cd^{2+}$ ions on the Chl a fluorescence of 5 hydrophytes (e.g. Lemna, Salvinia, Ricciocarp, Nymph, Typha plants) were investigated in order to select $Cd^{2+}$-sensitive plant species and to get informations on physiological responses of plants to $Cd^{2+}$ stress. Lemna plants were most sensitive to cadmium stress, while Nymph plants were tolerant. However, in all $Cd^{2+}$-treated plants, Fv/Fm, the maximum photochemical efficiency of PS II, decreased in proportion to the increase of $Cd^{2+}$ concentration and treatment time. The Chl a fluorescence transient O-J-I-P was also considerably affected by $Cd^{2+}$ ions; the fluorescence yield decreased consid- erably in steps J, I and P in $Cd^{2+}$ treated plants, although it followed a typical polyphasic rise in non-treated plants. In Lemna plants, the functional parameters, ABS/CS, TRo/CS와 ETo/CS and RC/CS, decreased in proportion to the increase of $Cd^{2+}$ concentration, while N, Mo and Kn increased. The structural parameters, ${\Phi}po$, ${\Phi}po$/($1-{\Phi}po$), Plabs, SFlabs, Kp and RC/ABS, also decreased according to the increase of $Cd^{2+}$ concentration. Consequently, Lemna plants will be useful as a experimental model system to investigate responses of plants. And several functional or structural parameters could be applied to determine quantitatively the physiological states of plants under stresses.

• Journal of Plant Biology
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• 제12권3호
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• pp.1-7
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• 1969

The lethal actions in Arabidopsis thaliana and Lemna polyrhiza brought about by certain inorganic form of Mn, Ba, Hg, Cu salts, and organic form of Na salts, were studied with aseptic artificial media. These metal ions at certain concentrations caused lethality of either Arabidopsis or Lemna when the media were without Ca ion. On the contrary, addition of Ca to the media protected the organisms from such lethality. It was postulated for the present from the proceeding evidence that Ca adsorbed and distributed along the sites between the plasma and cell membrane acts for suppressing permeation of toxic level of metal ions causing the lethality of these plants.

• 한국응용곤충학회지
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• 제46권1호
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• pp.13-18
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• 2007

포충나방과의 물명나방아과에 속하는 얼룩애기물명나방(Elophila turbata (Butler, 1881))에 대한 성충, 종령유충, 번데기의 형태적 특징과 암수생식기를 도해하여 재기재하였으며, 또한 이 종의 생태적 특징을 관찰하고, 기주식물로 개구리밥, 좀개구리밥(Lemna perpusilla), 생이가래(Salvinia natans)를 확인하였다.

• Journal of Plant Biology
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• 제20권2호
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• pp.77-82
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• 1977

The inhibiotory effect of ethphon on the flowering in Lemna perpusilla 6746 was shown to be related to sucrose concentrations and dilution factors of Hutner's medium. When grown in 1/10-strength Hutner's medium under 10(14) cycles, the plants have been completely inhibited in the floral induction by ethephon (>5ppm) in the presence of sucrose (>20 mM) in the meduim. However, in a less diluted Hutner's medium (1/2-strength), the inhibition of flowering by ethephon was observed to be partially diminished by sucrose at a high concentration (30mM), while a low concentration of sucrose enhanced the inhibitory effect of ethephon in flowering. As inductive dark periodswere extended, the effects of both compounds were partially nullified. Since no significant amount of ethylene possibly released in ethephon decomposition in the medium was detected, the inhibitory effect of ethephon in flowering was postulated to be exerted only through ethylene production within the plants. Plants were incubated in 10 ppm ethephon-containing medium during either dark or light periods, singly or periodically. The most effective single treatment with ethephon was observed during the 4th dark period, when formation of floral stimulus was assumed to be completed beyond a critical level. This postulation can be partially supported by a fact that the plants should be exposed to at least more than four consecutive 10(14) cycles for flowering.

• 환경위생공학
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• 제17권2호
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• pp.40-47
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• 2002

In this study, water hyacinth plants(Eichhornia crassipes), water parsley(Oenanthe javanica) and Lemna paucicostate were used to treat contaminants such as COD, T-N and T-P in far m·fishing village wastewater. The results were as follows : In the batch system experiment, water hyacinth was showed at the high removal efficiency in the 173∼412kgCOD/ha·day concentration that is rather than 260mg/1 of the high concentration. The next is Oenanthe javanica, Lemna. Oenanthe javanica was showed the high removal efficiency in the 96∼173kgCOD/ha·day concentration that is less than 260mg/1 of the low concentration.

• Asian-Australasian Journal of Animal Sciences
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• 제15권4호
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• pp.537-542
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• 2002

A study was conducted to evaluate the nutritive potential value of different aquatic plants: duckweed (Lemna trisulaca), duckweed (Lemna perpusila), azolla (Azolla pinnata) and water-hyacinth (Eichhornia crassipes) from Bangladesh. A wide variability in protein, mineral composition, gas production, microbial protein synthesis, rumen degradable nitrogen and in situ dry matter and crude protein degradability were recorded among species. Crude protein content ranged from 139 to 330 g/kg dry matter (DM). All species were relatively high in Ca, P, Na, content and very rich in K, Fe, Mg, Mn, Cu and Zn concentration. The rate of gas production was highest in azolla and lowest in water-hyacinth. A similar trend was observed with in situ DM degradability. Crude protein degradability was highest in duckweed. Microbial protein formation at 24 h incubation ranged from 38.6-47.2 mg and in vitro rumen degradable nitrogen between 31.5 and 48.4%. Based on the present findings it is concluded that aquatic species have potential as supplementary diet to livestock.

• Journal of Plant Biology
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• 제35권4호
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• pp.403-408
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• 1992

장일식물인 Lemna gibba G3의 개화유도과정에 있어서 polyamine의 관련성을 조사하였다. 이 식물의 개화는 연속광하에서 agmatine, putrescine, spermidine 및 spermine에 의해 촉진되었으며 이들의 체내 합성억제물질인 methylglyoxal-bis(guanylhydrazone)(MGBG)과 cyclohexylamine(CHA)에 의해서 억제되었다. Polyamine은 영양생장률을 거의 일정한 수준으로 유지하면서 개화를 촉진시켰으며, 억제물질에 의한 개화억제는 오히려 영양생장률의 증가를 수반하였다. 이러한 현상은 이 물질들의 개화촉진 또는 억제효과가 생장률의 일반적인 촉진 또는 억제효과에 의한 것이 아니라 선택적으로 개화과정에 작용한 결과일 것이라는 추측을 뒷받침해 준다. 배양액의 첨가된 spermidine 또는 spermine의 개화촉진 폭은 배양액에 이들의 억제물질의 함유여부와 관계없이 거의 일정한 수준으로 나타났다. 이렇듯, 외부에서 공급된 후 체내에 흡수된 spermidine과 spermine의 개화에 대한 기여도가 한정되어 있는 것으로 보아 L. gibba G3의 개화유도과정이 식물체내에서 합성되는 spermidine과 spermine에 크게 의존하고 있을 것으로 판단된다. 한편, 개화유도과정이 시작되어 점차적으로 증가한 체내의 spermidine 함량은 개화가 유도되지 않은 경우에 비하여 24시간만에 약 2배의 수준에 도달하였다. 이렇듯 체내의 spermidine량이 급격히 증가된 사실은 체내의 polyamine의 질적 및 양적 변화가 L. gibba G3의 개화유도초기과정에서 매우 중요한 역할을 하고 있을 것이라는 가정을 뒷받침하는 또 하나의 예비적 증거라 할 수 있다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2006년도 학술발표회 발표논문집
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• pp.421-422
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• 2006

• Journal of Plant Biology
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• 제19권1호
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• pp.14-18
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• 1976

Inhibition of flowering in Lemna perpusilla 6746 by 30 mM sucrose was reversed by the addition of acetylcholine (>$10^{-4}M) supplemented with 10^{-4}M$ ascorbic acid to 1/10-strength Hunter's growth medium. The reversible effect of acetylcholine was found to be greater at early stages of flowering than in the later period. Promotive effects of both acetylcholine ($10^{-3}M) and eserine(10^{-5}M$) on flowering in the short-day plant under various photoperiodic conditions were studied. It was indicated that the application decreased length of the critical dark period for the floral induction, and it was also shown that the endogenous status of acetylcholine was involved in the floral response which had a correlation with phytochrome. Interruption of inductive dark periods by red irradiation (1min) immediately followed by far-red light (1 min) completely inhibited flowering, while the addition of acetylcholine and eserine to the medium under the same condition slightly promoted flowering, indicating possible involvement of phytochrome system in acetylcholine activity for photoperiodic sensitivity of floral response in Lemna perpusilla 6746.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2003년도 춘계 학술발표회 논문집
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• pp.72-75
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• 2003

Plant species have shown the capability to absorb U into the biomass. Norman(l952) even suggested that uranyl ion acts as an accessory microelement in growth of Lemna and flax roots. The plants, termed metal hyperaccumulators, can extract and accumulate more than 1000-10,000mg heavy metal per kilogram of dry weight of plants (0.1-1%). The most vital main factors influencing the ability and efficiency of phytoremediation is the ability of the plant to uptake the metals from soil before the accumulation mechanism happens in the plant tissue. (omitted)