• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.236-243
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• 2009

The halophyte Leymus chinensis (Trin.) is a perennial rhizome grass (tribe Gramineae) that is widely distributed throughout China, Mongolia and Siberia. This study was conducted to investigate an optimal condition for plant regeneration from mature seeds, leaf base segments, and root segments in L. chinensis. Plant growth regulators affecting embryogenic callus induction and plant regeneration were investigated by four-factor-three-level [L9 (34)] orthogonal test in this study. The effects of explants types (mature seeds, leaf base segments and root segments), callus types, medium types were examined in this study. Wild type (WT) and Jisheng No. 1 plants (JS) were used for primary callus induction. A clear explants difference was seen during callus induction; mature seeds were considered as the preferred explants; and the highest frequency of callus induction was obtained in Medium 6 using mature seeds as explants in WT. Plant regeneration ability was evaluated by frequencies of green callus forming, shooting, rooting, and shooting with roots. Effect of α-naphthalene acetic acid (NAA) on shoot regeneration was remarkable with the highest frequency of 70.8% in WT after 2-month culture. The medium with 0.2- 0.5 mg/L NAA was found to have the highest shoot induction. All regenerated shoots were successfully rooted when transferred on half-strength Murashige and Skoog (MS) basal medium. The acclimatized plantlets were grown to mature with flowering and seeds setting in green house conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.872-879
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• 2007

A study was conducted to investigate the seasonal changes in nutrient composition of pasture, voluntary intake and digestibility of sheep grazing an introduced Leymus chinensis pasture located in western Jilin Province, China. The whole-plant of L. chinensis and the samples simulating ingestion by sheep (simulating sample) were collected in spring (May, 2004), summer (July, 2004), autumn (September, 2004) and the end of winter (April, 2005). The contents of gross energy (GE), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and alkanes were determined. Voluntary intake and apparent digestibility of the nutrients in each season were also examined using 6 mature Chinese Northeast Merino ewes (differed among the seasons) grazing on a paddock of 1 ha size. The apparent digestibilities of GE, dry matter (DM), OM, CP, NDF and ADF of L. chinensis were significantly greater (p<0.05) in spring and summer than in autumn and winter. Metabolizable energy (ME) content was 12.13, 11.62, 8.66 and 10.40 MJ/kg DM for L. chinensis in spring, summer, autumn and winter respectively, and the corresponding voluntary feed intakes were 91, 119, 59 and 58 g/d per kg metabolic weight ($LW^{0.75}$). The ME contents and DM intakes in autumn and winter were significantly lower than in spring and summer (p<0.05). The intake of L. chinensis pasture was sufficient to provide ME requirements for maintenance by the dry ewes in all the seasons, but inadequate for maintenance protein requirement in winter. (Supported by funds from National Basic Research Program of China, Grant No. 2007CB106800).

• Journal of Life Science
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• v.28 no.7
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• pp.772-777
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• 2018

To understand the adaptability of Leymus chinensis forage grass to environmental stresses, we analyzed the $H_2O_2$ scavenging activity based on several antioxidant enzymes and total phenolics content, including peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT), in shoots and roots subjected to salt and dehydration stresses during seedling growth. After NaCl or PEG treatment, plants showed reduced seedling growth under over 200 mM NaCl or 30% PEG treatment condition in shoots and roots compared with the control condition. In addition, plants showed high enzymatic activity of CAT in the shoots, whereas they exhibited high activity levels of APX and POD in the roots in both the NaCl and PEG treatment conditions. These results seem to indicate that Leymus chinensis seedlings responding to salt and dehydration stresses during initial growth is associated with enhanced activity of $H_2O_2$ scavenging antioxidant enzymes in the shoots or roots. The plants also showed high levels of total phenolics under NaCl treatment, with a high concentration in both the shoots and roots. Our results showed that the induced activity patterns of APX in the roots and CAT in the shoots indicate that low $H_2O_2$ levels were mainly maintained through tissue-specific redox homeostasis involving enzymes such as APX and CAT during salt and dehydration stresses. This study highlights the importance of antioxidant enzymes in the establishment of Leymus chinensis seedlings under high salinity conditions, such as typical desertification.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.51-55
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• 2005

Chinese leymus (Leymus chinensis Trin.) is a perennial grass that is widely distributed at high pH sodic and arid soil in the northeastern Asia. An efficient regeneration system was established through somatic embryogenesis of mature seeds to understand its high adaptability to harsh environmental conditions on the basis of molecular biology. The calli were efficiently induced (about $70\%$) from mature seeds on MS medium supplemented with $1.5\;\cal{mg/L}$ 2,4-D. Somatic embryos were formed from the surface of embryogenic callus on MS medium supplemented with $2.0\;\cal{mg/L}\;kinetin\;and\;0.5\;\cal{mg/L}$ NAA after 3 weeks of culture. Roots were induced from the shoot when transferred to MS medium without plant growth regulator for 1 week. Plant regeneration rate was $36\%$ and regenerated plantlets were grown to normal mature plants in pot. An efficient plant regeneration system in this study will be useful for molecular breeding of L. chinensis.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.818-824
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• 2014

The nutrient composition of pasture, voluntary intake and digestibility of diet ingested by goats grazing on an introduced Leymus chinensis pasture were measured across spring (May), summer (July), autumn (October) and winter (March). In each season, 12 Inner Mongolian Cashmere goats (6 wethers and 6 does with an average live weight of $22.2{\pm}1.3$ kg and $19.5{\pm}0.8$ kg, respectively) were used to graze on a 2 hectares size paddock. Diet selection was observed and the plant parts selected by grazing goats and whole plant L. chinensis were sampled simultaneously. The alkane pair $C_{32}:C_{33}$ and $C_{36}$ were used to estimate intake and digestibility, respectively. The results showed that the plant parts selected by goats had higher crude protein (CP) and lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) than the whole plant, especially in the autumn and winter. The voluntary intake of dry matter (DM), CP, ADF, NDF, and metabolizable energy (ME) by goats was highest in summer (p<0.05). The goats ingested more CP, ME, and less ADF in spring than in autumn (p<0.05). The intakes of DM, CP, and ME were lowest in winter (p<0.05). There were significant differences in nutrient intake between wethers and does in each season, except for the ADF and ME intake per metabolic weight ($LW^{0.75}$). The nutrient digestibilities were higher in spring and summer, and decreased significantly during the autumn and winter (p<0.05). Goats, especially wethers, had a relative constant NDF digestibility across seasons, however, the apparent digestibility of CP in both wethers and does, decreased to negative values in winter. The grazing goats experienced relatively sufficient nutrients supply in spring and summer, and a severe deficiency of CP and ME in winter.

• Korean Journal of Plant Resources
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• v.23 no.6
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• pp.526-534
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• 2010

Genomes of clusters of related eukaryotes are now being sequenced at an increasing rate. In this paper, we developed an accurate, low-cost method for annotation of gene prediction and exon-intron structure. The gene prediction was adapted for delta 1-pyrroline-5-carboxylate-synthetase (p5cs) gene from China wild-type of the halophytic Leymus chinensis (Trin.), naturally adapted to highly-alkali soils. Due to complex adaptive mechanisms in halophytes, more attentions are being paid on the regulatory elements of stress adaptation in halophytes. P5CS encodes delta 1-pyrroline-5-carboxylate-synthetase, a key regulatory enzyme involved in the biosynthesis of proline, that has direct correlation with proline accumulation in vivo and positive relationship with stress tolerance. Using analysis of reverse transcription-polymerase chain reaction (RT-PCR) and PCR, and direct sequencing, 1076 base pairs (bp) of cDNA in length and 2396 bp of genomic DNA in length were obtained from direct sequencing results. Through gene prediction and exon-intron structure verification, the full-length of cDNA sequence was divided into eight parts, with seven parts of intron insertion. The average lengths of determinated coding regions and non-coding regions were 154.17 bp and 188.57 bp, respectively. Nearly all splice sites displayed GT as the donor sites at the 5' end of intron region, and 71.43% displayed AG as the acceptor sites at the 3' end of intron region. We conclude that this method is a cost-effective way for obtaining an experimentally verified genome annotation.

• Journal of Plant Biotechnology
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• v.37 no.2
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• pp.228-235
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• 2010

The establishment of cell suspension culture and plant regeneration of the halophytic Leymus chinensis (Trin.) are described in this study for the first time. Callus induction solid medium containing Murashige and Shoog (MS) basic salt, $2.0\;mg\;l^{-1}$ 2,4-dichlorophenoxyacetic acid (2,4-D), and $5.0\;mg\;l^{-1}$ L-glutamic acid with $30.0\;g\;l^{-1}$ sucrose and $4.0\;g\;l^{-1}$ gelrite for solidification induced the highest rate of cell division in Type 1 callus among calli of various types. Liquid medium with the same hormone distribution was therefore, used for cell suspension culture from Type 1 callus. Over a 30 d suspension culture at 100 rpm, great amounts of biomass were accumulated, with 71.07% average daily increment and 22.32-fold total fresh weight increment. Comparison of before and after suspension culture, the distribution of different size callus pieces and the maintenance of callus type were basically unaltered, but a slight increase in relative water contents was observed. To induce the potential of plant regeneration, the directly transferring on plant regeneration solid medium containing MS basic salt, $0.2\;mg\;l^{-1}$ $\alpha$-naphthalene acetic acid (NAA), $2.0\;mg\;l^{-1}$ kinetin (Kn), and $2.0\;g\;l^{-1}$ casamino acid and indirectly transferring were simultaneously performed. Even now growth rates of suspension-derived callus on solid medium were approximately half of those of Type 1 callus, but faster somatic embryogenesis was observed. Rooting of all regenerated shoots was successfully performed on half-strength MS medium. All plants appeared phenotypically normal.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.529-538
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• 2010

Proline accumulates in plants under environmental stresses including saline stress and alkaline stress. Here, we investigated the responses to two different stresses, saline stress (200 mM NaCl) and alkaline stress (100 mM $Na_2CO_3$) in two Leymus chinensis (Trin.) genotypes, LcWT07 and LcJS0107, and effects of exogenous proline on the activities of antioxidant enzymes. Both saline stress and alkaline stress significantly induced the accumulation of proline in leaves of the two genotypes after 96 h, and alkaline stress caused a transient and significant increase in LcJS0107 plants at 6 h. A reduction in the activities of catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11), but not in the activity of superoxide dismutase (SOD, EC 1.15.1.1), was detected in plants exposed to saline and alkaline stresses. Remarkable decrease in relative water contents (RWC) was found in 144 h stressed plants. However, lipid peroxidation estimated by malonyldialdehyde (MDA) content in leaves remained relatively stable. With the addition of exogenous proline, it did not cause changes of proline levels in two genotypes, but combined with saline or alkaline stress, the exogenous application of proline significantly induced proline accumulation after even short treatment periods. Combined with salt stress, the exogenous application also increased the activities of CAT and APX. These results indicated that exogenous proline not only increases proline levels in vivo as a osmotic adjustment under stress, but mitigates the detrimental effects of saline and alkaline stresses by increasing the activities of antioxidant enzymes.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.122-122
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• 2003

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.04a
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• pp.146-146
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• 2005