• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.977-986
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• 1996

The uncertainty of rains at the onset of wet season (WS) and the drought risk involved hinder growing more than one rainfed lwoland rice crop per year. Establishing transplanted rice well into the WS leaves insufficient moisture in the soil for subsequent crop. Rice establishment early in the season gives the farmer better opportunities to grow a crop after rice. An experiment was conducted startign in 1993 to evaluate dry seeding of rice through slit soil seeding. It is done utilizing the vertical metering slit seeder for conserving soil moisture coming from the first rains in the early WS to sustain germination and establishment of the seeding at least until the succeeding rains under therainfed lowland (RL) environment. The treatment consisted of slit-seeding the PSBRc 14 into the tilled and nontilled plots at 100kg/ha and at depths of <10 mm (shallow seeding) and 60-70m (deep seeding). The control treatment was broadcast seeded on tilled soil and harrow to cover the seeds The superior crop establishment observed in 1995 WS experiment on nontilled, slit-seeded plots confirmed the results observed in 1993 WS and 1994 WS experiments. Emergence in deep seeding was not significantly different from shallow seeding in nontilled plots giving an average yield of 2.1 t/ha in all slit-seeded plots. This offers an advantage of reduced energy in put in nontilled shallow seeding. However, heavy weed infestation has to be addressed at the early stage of rice in nontilled soil to get the full advantage from slit seeding. The consistently better crop establishment observed in slit seeding over that of broadcast seeding in the WS of 1993, 1994 and 1995 also demonstrates that the slit seeding technology can be adopted with confidence in the rainfed lowland field condition to reduce the risks involved in broadcast seeding.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.247-253
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• 1995

The herbicide butachlor [N-(butoxymethyl)-2-chloro-N-(2,6-di-methylphenyl) acetamide] is widely used by farmers as a tool for weed management of transplanted rice(Oryza sativa L.) in Taiwan. The herbicide did not stop germination of rice and weed seeds, but strongly inhibited the subsequent growth of young shoots and roots. The inhibition was also strong on established seedlings. However, they could recover to normal growth after the herbicide effect disappeared. Butachlor greatly decreased the endogenous indole-3-acetic acid (IAA) but increased the endogenous abscisic acid (ABA) contents of rice seedlings. Addition of lAA into growth medium (Hoagland's solution) partly relieved growth inhibition. Pretreatment of both gibberellic acid ($GA_3$) and IAA 24 hours before butachlor treatment almost completely alleviated the butachlor-interfere with GA and/or IAA metabolism or their action resulting in the growth inhibition of rice. Butachlor was readily absorbed by rice roots. During 24 hours of uptake experiment, 32% of the applied herbicide was absorbed. Pretreatment of the herbicide for 2 days did ncx affect the absorption. Of the absorbed herbicide, 80% remained in roots, only 20% transported into shoots, and more than 50% was metabolized to water soluble substances. Thin-layer chromatographic (TLC) analysis indicated that the Rf value of the most abundant metabolite was butachlor-glutathione conjugate. Rice, barnyardgrass (Echinochloa crus-galli (L.) Beauv.), and monochoria (Monochoria vaginalis Presl) seedlings contained relatively high level of non-protein thiols, while the glutathione S-transferase (GST) activity was found highest in rice, barnyardgrass the next, monochoria the lowest. The difference in GST activity among these species might be related to their sensitivity to butachlor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.303-307
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• 2008

Cotyledon Black Decay (CBD) on soybean sprout mimics the black spot due to microbial infection. CBD, not visible or predictable at seedlot state, for some reason, shows up exclusively on cotyledon of soybean sprout during sprouting process. Such an incidence rate fluctuated from 0.8 to 19.5% over three years from 2004. We suspected some pod-infecting anthracnose fungi and/or pod-blight pathogen, or pod-sucking bean bug, one of the major pests of soybean, might have involved, of which we ruled out fungal pathogen because it was preventable through heat treatment, a proven method for seedlot disinfestation. The healthy seeds artificially fed by bean bug for one to seven days were sprouted, and 6 to 41% of the soybean sprout revealed the CBD mimic to those occurred in soybean sprout from previous commercial seedlot screening experiments. This finding is the first report to confirm that bean bug damage to pod at $R_8$ stage is directly responsible for the CBD, which did not concur with any other deleterious effects on sprouting such as reduction in hypocotyls elongation and rooting except unsightly sprout quality. However, earlier feeding either at green pod or greenish yellow pod stage ($R_6$ -early $R_7$ stage) resulted in rather severe damages, which strikingly reduced hypocotyls growth to about one forth to about two third, as well as the reduction in rates of seed germination.

• Journal of Life Science
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• v.14 no.4
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• pp.644-649
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• 2004

During plant development, active gibberellins (GAs) control many aspects of plant growth and development including seed germination, stem elongation, flower induction, anther development and seed growth. To understand the biosynthesis and functional role of active GAs in high plants, this study investigated GA 3$\beta$-hydroxylase gene en-coding $GA_1$ and$GA_4$ catalizing last step in GA biosynthetic pathway. The antisense GA 3$\beta$-hydroxylase gene was inserted into expression vector, pIG121-Hm. Calli derived from mature seeds of rice (Oryza satiiva L. cv. Donjinbyeo) were co-cultivated with Agrohacterium tumefaciens EHA101 earring a pIG121-Hm containing hygromycin resistance ($Hyg^r$) and antisense GA 3$\beta$-hydroxylase gene. Seventeen transgenic plants obtained inhibiting GA 3$\beta$-hydroxylase. Transgenic plants had shorter plant height more than that of the Dongjinbyeo. Stable integration of antisense GA 3$\beta$-hydroxylase gene was confirmed by polymerase chain reaction of genomic DNA isolated from the leaf organs of the $T_o$ generation.

• Applied Biological Chemistry
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• v.3
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• pp.1-7
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• 1962

In order to study the rate control step in the protein metabolic course of the chlorophyll formation, the transaminase activities which are obtained freely in the extracts of cotyledons of germinating peas at the light and the dark places, are measured in Beckman mopel D.U, spectrophoto meter at 490 mu. In this case, of two enzymatic reaction products; oxalacetic acid and pyruvic acid, the former is converted to pyruvic acid by aniline citrate and after each pyruvate phenyl hydrazones are extracted by toluenes: when this is treated with strong alcoholic alkali, a colored hydrazone is formed and it is measured by above apparatus. The estimated G.O.T. and G.P.T. in the germinated cotyledons at dark and light places considerably differ in their activities; G.O.T. and G.P.T. activities which are formed at the light are more increased than at the dark and also they differ in their rates through germination, though G.O.T. activity increment is smoothly but that of G.P.T. is more sharply, and they are considered to be directly affected to the chlorophyll formation and indirectly to the growth. G.O.T. and G.P.T. in each fractions of cell in the cotyledons should be formed by dissociation of zymogens in the microsomal fractions and it seems to promoted by light. In the formation of the chlorophyll, the protein metabolism occurred mainly in the microsomal fractions and the rate determining step is found at the point where the zymogene that is able to produce G.P.T. is activated, and this activation is promoted by light as noted above.

• Journal of Plant Biology
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• v.35 no.3
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• pp.265-271
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• 1992

Vie investigated the effect of indole acetic acid (IAA) on diamine oxidase (DAO; EC 1.4.3.6) in the seedling of soybean (Glycine max L. forma Paldalkong). DAO activity was not detected in the resting soybean seeds. During germination it appeared in the elongating zone on day 3, increased up to day 4 and decreased thereafter. Endogenous IAA content has been shown the same pattern as DAO activity. However, cadaverine content was reduced on day 4. To investigate the effect of IAA on DAO activity, the segments of hypocotyl on day 3 were soaked in various concentration of IAA. The activity increased at low concentrations ($10^{-7}-10^{-6}M$) of 1M as compared to that of control but not at high concentrations ($10^{-5}-10^{-4}M$) of IAA. Differing from DAO activity, cadaverine content increased as concentrations of IAA increased. On the other hand, ethylene was induced by IAA at high concentrations. To study the effect of ethylene on DAO activity, we cotreated IAA and 2,S-Norbonadiene (NDE). In this case, DAO activity was not affected.fected.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.1 no.1
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• pp.22-30
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• 2020

Many areas of vegetation in the British uplands have reduced species diversity as a result of sheep overgrazing. It has been suggested that abandonment or re-wilding strategies might be used to reverse this. A likely first step would be the removal or reduction of grazing livestock from upland areas, with a presumption that this would lead to a recovery in species richness. However, we do not know if this would work, or the timescales involved. One of the important areas where more knowledge is needed is information on the size and composition of soil seedbanks as regeneration from zseed is a likely pathway of recovery. Here, we compared seedbanks in both grazed and ungrazed plots in five experiments at Moor House NNR in the northern Pennines; these sheep grazing exclusion experiments were started 52 and 63/64 years ago. Soil samples (n=10) were collected from both grazed and ungrazed plots in each experiment, and seed emergence counted in glasshouse trials. We detected only seeds of common species and very few dicotyledonous species. This suggests that the soil seedbank is unlikely to be a reliable source of the less common species for ecological restoration in these upland communities, suggesting an extinction debt. Therefore, seed addition and the creation of suitable safe-sites for germination may be needed in conjunction with grazing controls to allow the establishment of plants that will increase the species richness of the vegetation. However, this interventionist restoration approach remains to be tested.

• Applied Biological Chemistry
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• v.26 no.1
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• pp.28-34
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• 1983

The change of lactate dehydrogenase(LDH) activity and the possibility of the existence of LDH. isozyme were examined with different parts of soybean sprout. The enzyme activity was little changed in cotyledons throughout the early stagy of germination. However, hypocotyls and roots showed the continuous decline of the enzyme activity since the radicle emerged from seeds. It was found that LDH from hypocotyls. and roots was unstable as compared with LDH from cotyledons, even at low temperature. The enzyme from hypocotyls and roots was not purified with a good yield when the purification procedure developed for LDH from cotyledons. was employed. LDH from hypocotyls and roots has the Rm value of 0.29, and 0.25 from cotyledons. The apparent Km value for LDH from cotyledons was 0.45mM with sodium pyruvate, while crude homogenate of hypocotyls or roots showed biphasic phenomenon with two Km values 0.014 and 0.45mM. The results indicate the possibility that crude homogenate of hypocotyls or roots may contain a different LDH isozyme from the LDH of soybean reported previously.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.101-105
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• 1998

This study was carried out to find out the method of increasing seed germination rate of Dendropanax morbifera LEV. was drupaceous fruit. The length and width of ovarywas 7.8 to 10.7mm, 6.9 to 9.0mm, respectively, and the shape was elliptical. The ovary had 5 loculi with one speed per loculus , but one seed among 5 weeds was exalbuminous seed. The length and width of seed was 6.3 to 7.4mm, 2.0 to2.mm, respectively, and 1,000 seed weight was 14.3 to 18.0g. Seeding after stroring at $10^{\circ}C$ for 60 to 90 days was germinated to 87% . However, fall seeding directly after harvest was increased to 85% at hot-water treatement ($40^{\circ}C$) for 90 to 120 minute.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.390-393
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• 1997

Hormetic effects of low dose radiation were analyzed in terms of growth stimulation in radish and three cultivars of chinese cabbage. Seeds irradiated with ${\gamma}$ radiation were planted in the green house and in the experimental field. Though it varied with cultivars of tested plants, hormetic effect of low dose ${\gamma}$ radiation on an early stage of growth were shown especially in germination rates and elongation of seedlings. The height of seedlings increased in 0.2 Gy irradiated group of Seolim cultivar and radish, in 1 Gy irradiated group of Konaenggi cultivar and in 4 Gy irradiated group of Ducksung cultivar, respectively, In case of plants grown in the experimental field, prominent were the height increase of radish and Seolim cultivar in 1 Gy irradiated group and the fresh weight increase of both radish and cabbage in 4 Gy irradiated group.