• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.285-296
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• 1995

Anatomical studies of sink tissues are required for better understanding the biological plant growth system and energy metabolism. Kinematics of root growth zones of two genotypes of tall fescue (Festuca arundinacea Schreb.) receiving 50 or 200 ppm N were determined. Longitudinal anatomy and cell dynamics of root growth zones were studied and calculated. The root growth zone is organized similarly to the leaf growth zone which has cell division, elongation, and maturation zones, but the root growth zone is only about 3.0 mm long compared to 25 to 30 mm for the leaf growth zone. The root cap extends about 0.4 to 0.5 mm from the apical initial, while the cell elongation zone for both cortical and metaxylem cells extends about 3.3 mm from the apical initial for both genotypes and N levels. Root cap cells elongate from an initial length of about 5$\mu{m}$ long to a final length of about 40$\mu{m}$ before being sloughed. Initial lengths of cortical and metaxylem cells were about 8.5 $\mu{m}$ and 13.0 $\mu{m}$, respectively. Elongation of cortex and metaxylem cell showed sigmoidal curves with final lengths of about 120 $\mu{m}$ for cortex cells and 650 $\mu{m}$ for metaxylem cells. Initial size and final size for both types were not affected by N level, but cell fluxes and cell elongation rates of cortical and metaxylem cells were about double in low N. Cell production rates were about 5 to 6 times higher in cortical cells than in metaxylem cells. Differences in N caused a larger change in cell production rate, duration of cell elongation, and relative cell elongation rate than did the genotypes. These data indicate that N application affects root growth longitudinally by changing cell production rate and elongation rate.

• Journal of Life Science
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• v.31 no.3
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• pp.280-286
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• 2021

Oryzalin is a herbicide that disrupts the arrangement of microtubules by binding to tubulin, thereby blocking the anisotropic growth of plant cells. Microtubules and microfilaments are cytoskeleton components that have been implicated in plant growth through their influence on the formation of cell walls. Microtubules also play roles in the sedimentation of amyloplasts in the root tip columella cells; this sedimentation is related to gravity sensing and results in downward root growth in the soil for absorption of water and minerals. However, the orientation of microtubules changes depending on the level of ethylene in plant cells. A recent study reported that oryzalin stimulated ethylene production via 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase and caused a concentration-dependent inhibition of root growth and gravitropic responses. The aim of the present study was to investigate the possibility that oryzalin-induced inhibition might be recovered by the application of inhibitors of ethylene production, such as 10-4 M cobalt ions and 10-8 M aminoethoxyvinylglycine (AVG). The inhibition of root growth and gravitropic response was overcome by 10-20% by an 8 hr treatment with cobalt ions or AVG. These results suggest that ethylene levels could regulate root growth and gravitropic responses in Arabidopsis.

• Journal of Life Science
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• v.21 no.7
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• pp.969-975
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• 2011

We focused on relationship between phytohormones and AtEXPA3 gene in gravitropic response of A. thaliana. RT-PCR analysis shows that AtEXPA3 was highly expressed in actively developing tissues such as leaf, rosette, root and flower tissues. AtEXPA3 gene expression was enhanced by gravistimulation, BR and IAA. Furthermore, decreased gravitropism was observed when treatment of AVG, an ethylene biosynthetic inhibitor, suggesting that ethylene has a gravistimulating effect itself as well as BRs and IAA. Inhibition of gravitropism in AtEXPA3 RNAi mutant suggests that BR, auxin and ethylene are playing roles as regulators of AtEXPA3. In addition, altered gravitropism in BRs signaling mutant (decreased in bri1-301, bak1, and increased BRI-GFP) indicated that BRs signaling mediated the gravitropism. In conclusion, gravitropic responses of Arabidopsis root resulting from root growth were mediated by increased expression of AtEXPA3 gene, which is stimulated by phytohormones.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.145-149
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• 2005

This experiment was conducted to identify the effect of several plant growth retardants on changes of endogenous free sugar and protein content in seedlings of Sedirea japonica cultured in vitro. The content of free sugar in the leaf was decreased as the treated growth retardant concentration was increased. Glucose content was higher than fructose and sucrose content in the leaf. Free sugar content of the root was increased as concentrations of growth retardants were increased. Sucrose content was higher compared with the content of fructose and glucose. The content of protein in the leaf was decreased as the growth retardants concentration was increased, but the tendency of protein content in the root was contrary to that in the leaf.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.594-599
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• 1995

Generally, excessive soil water stress in vegetative growth stage inhibits the growth of soybeans. Leaf area expansion of the plant during excessive soil water stress was only half and the respiration of roots was much diminished compared with the plant none water stress. When excessive soil water stress to the soybeans was continued for 7 days, outer epidermis and vascular system of tap root were severely cracked, more than thirty-five percent of nodule was died and the bacteroid layers of alive nodule were disintegrated.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.1
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• pp.31-34
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• 2001

When root initiation ratio of cut Italian ryegrass (Lolium multiflorum Lam.) stems was examined in several medium conditions containing different IBA concentration, most higher root initiation ratio was confirmed at 1.0 mg/$\ell$ of IBA and the ratio was 37.5%. When cut Italian ryegrass stems were treated in cold chamber at 4$^{\circ}C$ for 40 days and incubated in growth chamber at 26$^{\circ}C$ for 1 month, the root iniation result was 0.0% at MS-0 medium, 8.3% at MS-0.5IBA medium, 37.5% at MS-1.0IBA medium, 16.7% at MS-1.5IBA medium and 12.5% at MS-2.0IBA medium.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.11b
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• pp.27-27
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• 2002

식용피(Echinochloa crus-galli var. formosensis Ohwi.) 유묘에 대한 생육저해 정도를 지표로 하여 경북 북부지방에 자생하는 10여종의 야생식물의 부위별 MeOH 추출물을 조사한 결과, 1,000 ppm에서 가죽나무(가지)및 할미꽃(경엽부)은 식용피 유묘의 뿌리의 생육을 약 60∼80% 억제시키는 것으로 나타났다. 식물생장억제활성이 나타난 상기 2종에 대해 각종 크로마토그래피법을 적용하여 활성의 본체를 분리ㆍ정제한 결과, 가죽나무 가지 및 할미꽂 경엽부로부터 500 ppm에서 식용피 유묘 뿌리의 생육을 각각 96%와 73% 억제하는 활성분획들이 획득되었으며, GC/MS 분석을 통해 이들 활성분획으로부터 수종의 식물생장억제활성물질들이 확인되었다.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.163-175
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• 2007

This study was initiated to investigate the effect of chitosan on Kentucky bluegrass growth. Chitosan was applied rates of 300, 500, and 800 times dilution at ten-day intervals after transplanting. We observed such growth characteristics asleaf length, root length, numbers of leaves, fresh weight and dry weight, and chlorophyll content. Treatment of 300 X diluted chitosan resulted in the longest leaf length of 26.2cm comparing with the 17.1cm average leaf length of control. Leaf numbers were 21.4 and 31.7 for the control and the 500 X dilution treatment. The root length in control was 16.8cm while the treatment of 500 X diluted chitosan increased root length to 27.4cm. Chlorophyll content resulted 19.9mg/$100cm^2$ for the control and 25.5mg/$100cm^2$ for the treatment of 300 X diluted chitosan. In general, we found that the treatment of 500 X diluted chitosan resulted higher leaf number, chlorophyll content, fresh and dry weight.

• Journal of Life Science
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• v.20 no.2
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• pp.298-303
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• 2010

In this work, the effects of $Cs^+$ on root growth of 2-day-old maize seedlings were scrutinized. CsCl (5 mM - 30 mM) decreased the fresh weight of the primary root and of the shoot above the coleoptilar node. The elongation growth of the primary root was also inhibited by CsCl. The CsCl-inhibited growth was partially restored by 60 mM KCl. Lineweaver-Burk plot of the reaction in the presence and absence of 60 mM KCl displayed competitive interaction of CsCl (at higher than 10 mM). However, the Reversal of the inhibition by 60 mM KCl did not follow the competitive relationship with 5 mM CsCl, indicating the presence of differential mechanisms of $K^+$ influence depending on the concentration of CsCl. The differential effects of CsCl dependent on the concentrations were also observed in the CsCl-evoked radial expansion of the subapical region of the root. In spite of the decrease in length of the root, shrinkage of the root apical meristem was not observed. CsCl above 10 mM induced the expression of ZmKUP1, indicating functional deficiency of $K^+$ due to competition with Cs. However, the expression of ZmKUP1 by 5 mM CsCl was unclear. Conclusively, exogenously applied $Cs^+$ decreased root elongation and fresh weight and caused radial expansion of the subapical region of the primary root in 2-day-old maize seedlings by complex mechanisms including competitive and noncompetitive interactions with $K^+$. Because the shrinkage of the root apical meristem was not observed, it is concluded that the effects of CsCl on maize root growth was mainly related to cell expansion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.1
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• pp.72-79
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• 2011

Here we report a simple screening system using hematoxylin staining (HS) of the root apex. It allowed rapid classification into different aluminum (Al) tolerance from 65 cultivars within one week. Using this system, we selected the most Al-tolerant (Jayae-2) and-sensitive (Pum-2) barley (Hordeum vulgare L.) The results show that the different responses in Al-induced growth inhibition, Al accumulation and expression of plasma membrane (PM) $H^+$-ATPase in root apices of selected two cultivars. It showed strongly Al-induced growth inhibition in a dosedependant manner only in Pum-2 but not in Jayae-2. Aluminum accumulation in root apices (10 mm) was significantly higher in Pum-2 only. The $H^+$-ATPase expression of PM vesicles by western blotting was decreased in Pum-2 but not in Jayae-2 treated with $20{\mu}M$ Al for 24 h. These finding indicate to screen from our system is rapid and reliable and to sustain the expression of PM $H^+$-ATPase at translational level is an important role in root growth as affected by Al.