• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.325-330
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• 1989

This study was undertaken to assess the effects of seed treatment and soil moisture content on mesocotyl elongation in rice seedlings. The effect of the high temperature pre-treatment on the mesocotyl elongation was 7 times as great as the control (non treatment). The mesocotyl lengths were of maximum value at the 8％ soil moisture, but of minimum value at the 16％ soil moisture plot, showing decreasing trend of mesocotyl length as soil moisture increases. The mesocotyl elongations were much greater at the ABA treated plot than at the GA$^3$, IAA and Kinetin plots. The relationship between the mesocotyl and excised root elongations was not evident, but the weight of excised roots became heavier with longer mesocotyl length.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.50-54
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• 2000

The elongation of mesocotyl and coleoptile plays important roles in the seedling emergence and stand establishment of dry direct-seeded rice. Experiments were carried out to elucidate the effects of seed-presoaking treatments of GA$_3$ and some inorganic salts on the mesocotyl, and coleoptile elongation of rice. Seed-soaked GA$_3$ promoted the elongation of mesocotyl, but little effect on the coleoptile elongation. The stimulation effects of GA$_3$ were found to be enhanced by addition of CaCl$_2$ However, the sole treatment of CaCl$_2$ showed no stimulating effect on the mesocotyl and coleoptile elongation. Mesocotyl elongation was most prominent in the combined treatments of 50ppm GA$_3$ with 100 mM CaCl$_2$. The synergistic effects of GA$_3$ and CaCl$_2$ on mesocotyl elongation varied with varietal groups. The stimulating effects of GA$_3$ were enhanced significantly by the addition of CaCl$_2$ in japonica varieties, Dongjinbyeo, Ilpumbyeo and Milyang 95, and tall indica variety, Labelle, but not in semidwarf Tongil type varieties, Tongilbyeo, Milyang 23, and Nampungbyeo, and semi-dwarf indica, Short Labelle. The promoting effects of GA$_3$ on the mesocotyl elongation were decreased in proportion to the lowered osmotic potential by PEG 6000 on the contrary to CaCl$_2$ This implies that the synergistic effects of CaCl$_2$ with GA$_3$ on mesocotyl elongation was not caused by osmotic potential lowered by CaCl$_2$ addition but by the salt itself. Salts such as Ca(NO$_3$)$_2$, MgCl$_2$ BaCl$_2$, NaCl, KCl and KNO$_3$ showed the synergistic effects with GA$_3$ on mesocotyl elongation as well. The degree of synergistic effects showed no differences among salts tested, implying that there is no specificity of ions constituting the salts.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.26-26
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• 2017

Seed germination stimulated by light is said to be photoblastism. Photoblastism has not been reported in cereal crops, especially in the rice, but Korean weedy rice was reported to have photoblastism and longer mesocotyl than cultivar. Photoblastic weedy rice (PBR) was used to identify QTLs for photoblastism and mesocotyl length. In previous works, QTLs for photoblastism, pbr1 and pbr12 were identified on chromosomes 1 and 12 using 124 F4 lines from a cross between Ilpum and PBR using bulked segregant analysis. Two QTLs for mesocotyl elongation, qMel-1 and qMel-3 were mapped on chromosomes 1 and 3 120 F8 lines from the same cross. Of interest, the RM8260-RM246 region of pbr1 overlapped with a region of qMel-1. To know whether these two QTLs are functionally related, 110 F3 lines were developed from a cross between Ilpum and CR7124. CR7124 having photoblastism and long mesocotyl was selected from 120 F8 lines. 95 F3 lines were measured for germination rate in a light and dark condition and mesocotyl length. Mesocotyl length and germination rate in the dark condition in F3 lines showed significant correlation (r = 0.7, P < 0.0001). 95 $F_3$ lines were genotyped with RM7419 on chromosome 1. ANOVA showed that RM7419 was tightly linked to QTLs for photoblastism as well as mesocotyl length on chromosome 1 (P < 0.0001) indicating the tight linkage of two QTLs. Fine mapping of the two QTL is underway to analyze their functional relationship.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.296-302
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• 1989

The mesocotyl elongation, having much effect on emergence and stand establishment in the direct sowing culture of rice, was investingated and summarized as follows: As to origin of cultivars, the average lengths of mesocotyl were 9.6 mm in the Indica-Japonica hybrid cultivars, 4.4 mm in the native cultivars and 3.2mm in the Japonica type, respectively. The mesocotyl lengths were tjereh, aman, aus, boro and bulu in order, with the mesocotyl lengths of 29.3mm and 5.4 mm in tjereh and bulu, respectively. The mesocotyl lengths were great in Baekkyungjo, Dadajo & Hejo among the native cultivars, in Sangpungbyeo, Paltal & Gokyangdo of the Japonica type and in Weonpungbyeo, Gayabyeo, Milyang 30 & Sujeongbyeo in Indica- Japonica hybrid cultivars, respectively. The mesocotyl length was the greatest at the seeds sampled I week after flowering (39. 3mm in length), and became decreased with the longer grain-filling. The mesocotyl elongated worse with the longer duration of seed storage regardless of seed maturity, and became longer at the 5$^{\circ}C$ storage plot than at the 15 and 25$^{\circ}C$ plots.

• The Korean Journal of Mycology
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• v.12 no.2
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• pp.65-73
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• 1984

Strain IV caused highest reduction of germination and caused abnormal elongation of all part of the plant which finally died. Milyang 23 and Nampungbyeo formed mesocotyl. Samnambyeo and Jinjubyeo did not formed mesocotyl on the soil surface in nursery boxes when they were planted on soil infested with each strain of F. moniliforme. Infected seedlings with mesocotyl recovered after transplanting in the the field. The most frequency of Strain IV was isolated from infected rices and this strain was isolated from all part of rice. When rice seedling infected with Strain IV were transplanted in paddy field, most of rice showed Bakanae symptom. Ear emergence of rice was more delayed when seedlings infected with Strain IV were transplanted than that of healthy plant. Number of panicle per hill and grain yield from rice when infected rice seedling by Strain IV were transplanted were more decreased than that of the healthy plant in paddy field.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.151-151
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• 2017

In Asia, rice production has some difficulties with reduction of farm household population and increase of elderly population. As a result, it has resulted in inefficiency and we needs to reduce labor force and improve labor productivity. Direct-seeding in rice could reduce labor and production costs, the area of direct seeding is increasing in japonica rice production in Asia. In direct seedling cultivation competition against weeds is one of most important concern. So, low temperature germinability and mesocotyl elongation should be considered. In this study, we evaluated the mesocotyl length and low temperature germination conducted association analysis using 137 korea core collections. An average length of mesocotyl among 137 core collections was skewed range from 0mm to 43mm. we searched candidate gene around target SNP. Such related traits, genome-wide association study (GWAS) analysis was carried out using GAPIT. Also, average mesocotyl length of 394 korea landrace cultivars was measured ranging from minimum 0 mm to maximum 34mm. 30 out of 394 Korea landrace cultivar conducted re-sequencing, and haplotype analysis of candidate gene. we searched these related resources, which including germination of low temperature and mesocotyl elongation. This could be used for the development of direct-seeding cultivars. The valiated accession of core collection and landrace cultivars will be used development of direct-seedling cultivar in the future.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.19-29
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• 1995

The effect of seeding depth on the growth, mesocotyl elongation and herbicidal response of rice(Oryza sativa L., Japonica type, cv. "Tongjin") and barnyardgrass(Echinochloa crus-galli Beauv. var orizicola Ohwi.) were studied in greenhouse experiments. Barnyardgrass growth as affected by different water depths was briefly tested. Rice and barnyardgrass were broadcast in soil into Oem, 1cm, 2cm and 3cm in seeding depth under dry direct-seeded condition. Butachlor(N-(buthoxymethyl)-2-chloro-N-(2,6-diethylphenyl) acetamide) at dose rate of 1800g ai/ha and thiobencarb(S-[(4-chlorophenyl)methyl] diethyl carbamothioate) at dose rate of 2100g and 4200g ai/ha were soil applied to them at 5 days after seeding. At 10 days after seeding, plants harvested to examine their growth as affected by seeding depth. Root length and shoot fresh weight of rice untreated was greatest in 1cm- and 3cm-seeding depth, respectively, however, mesocotyl did not elongate. While plant height of barnyardgrass grew regardless of seeding depth and water depth, but root length was greatest in 1cm-seeding depth of dry condition and reduced with increased water depth. And mesocotyl was elongated in only dry condition and its length increased with increased seeding depth. At 10 days after application thiobencarb applied pre-emergence inhibited plant height, and shoot fresh weight of rice in only 0cm-seeding depth under dry condition whereas was unaffected in above 1cm-seeding depth, similar to untreated control, and ever increased root length and root fresh weight of rice. On the other hand, shoot, root and leaf growth of barnyardgrass was, severely inhibited regardless of application rates and seeding depths. Reduction of shoot growth by treatment of herbicide was significantly greater than that of root growth. Consequently, reduction of barnyardgrass growth by treatment of thiobencarb did not be associated with seeding depth and mesocotyl elongation as affected by different seeding depth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.502-511
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• 1994

Investigated were the relationships between plumule elongation characteristics and seedling emergence of 98 varieties including native, improved and red rice varieties of Korea, and varieties from U.S.A., Italy, Japan, etc. under proper and excess soil moisture regimes. Under excess soil moisture condition the seedling emergence and establishment rates were much lower in most of the varieties and the seedling emergence rates were delayed substantially in all varieties employed. The seedling emergence rates were lowest in dwarf and some semi-dwarf varieties showing poor plumule elongation under proper soil moisture condition. The seedling emergence and establishment rates were significantly correlated with the length of mesocotyl, coleoptile and incomplete leaf under both soil moisture regimes, and with the lower first and second internode length under excess soil moisture condition. Average emergence duration showed significant negative correlation with the length of mesocotyl, coleoptile and incomplete leaf under both soil moisture regimes and significant positive correlations with the first and third lower internode length. Based on the standardized partial regression analysis only the variations of mesocotyl and coleoptile length contributed significantly to the varietal difference in seedling establishment rate, and so did the variations of mesocotyl and incomplete leaf length to the varietal differences in emergence speed. In conclusion varieties with greater elongation characteristics of mesocotyl, coleoptile and incomplete leaf are desirable for higher and speedy seedling establishment in dry-direct seeding.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.169-174
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• 1985

Antidoting effect of 1,8-naphthalic anhydride (NA) on butachlor [2-chloro-2', 6'-diethyl-N-(butoxyethyl) acetanilide] phytotoxicity in rice was determined at different seeding depths and application rates of butachlor. The most sensitive response to NA was found in mesocotyl of rice (Oryza saliva L.). The mesocotyl length decreased with use of NA when seeded 2 to 4 cm deep, whereas no effect was obtained in plant height, root length and coleoptile length. Phytotoxic effect of butachlor to rice sown in vermiculite saturated with butachlor solutions decreased with use of NA at all seeding depths employed. However, depth protection was not observed when planted 3 to 4 cm deep without use of NA. Use of NA resulted in reduction in the phytotoxicity at concentrations of butachlor lower than 40 ppmw. The results indicated that the antidoting effect of NA was not due to reduction of mesocotyl elongation which would result in decrease in butachlor uptake through the mesocotyl.

• Korean Journal of Weed Science
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• v.5 no.1
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• pp.56-62
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• 1985

Effects of butachlor [N-(butoxymethyl)-2-chloro-2', 6'-diethyl acetanilide] and 1,8-naphthalic anhydride (NA) on post-germination growth, mesocotyl and root anatomy and root-cell membrane permeability of rice (Orvza saliva L.) were investigated. Lengths of mesocotyl and radicle were markedly decreased as the application rates of butachlor increased from 0.1 to 100 ppmW and NA from 1 to 100 ppmW, but there was no effect on coleoptile elongation. Application of butachlor-NA resulted in increase in coleoptile elongation, but decrease in mesocotyl elongation. Partial breakdown of cortical cells in root and mesocotyl was caused by either trutachlor or NA treatments, resulting in increase in intercellular air space. Further increase in the intercellular air space of root and mesocotyl was obtained when butachlor was applied in combination with NA. Increase in root-cell membrane permeability occurred when either butachlor or NA was applied. However, butachlor-NA treatments resulted in reduction in the permeability.