Full Text Cite Share

Abstract : Lilies as cut flowers are one of the most popular ornamental plants in South Korea. It is necessary to develop lily cultivars with high qualities. Therefore, highly efficient propagation systems are needed following release of elite cultivars. In this study, we used taurine treatment to improve the growth conditions including shoot and bulb formation, fresh weight gain, and reduction of rooting and browning.We experimentally evaluated the effect of taurine as a growth stimulator, at concentrations of 0, 2.5, 5, 10, 15 and 20 mg/l. The results showed that 20 mg of taurine enhanced shoot formation by 85% and increased fresh weight 5.5-fold, which was higher than the approximately four-fold increase in the control. In addition, multiple bulb formation rate was increased by 80% and rooting by 82% following exposure to 20 mg/l of taurine. The efficiency of taurine treatment was higher than that of control with 50% multiple bulb formation rate and 60% rooting rate. The browning was 10.6% at 2.5 mg/l of taurine when compared with 0.8% at 20 mg/l. Taurine showed a positive effect on the overall growth of lily plants in terms of increased fresh weight, shoot formation rate, rooting, and formation of multiple bulbs, indicating that taurine can be used as an alternative to amino acids or as an antioxidant such as citrate and vitamin C in plant tissue culture.

Full Text Cite Share

Abstract : The expression profiles of low-temperature-related genes were examined in in vitro potatoes exposed to a cold condition for 1-3 days. The expression levels of PPI1 and CI21B genes were lineraly elevated from day 1 to day 3, while the opposite trend was observed for CBF4 and CI21A. In addition, the expression of the genes CI21A and CI21B varied, along with specific tissues (leaf, stem, and tuber) and the treatment periods. Therefore, potato shoot tips were cryopreserved with LS and PVS2 containing different oncentrations of AFP. It can thus be inferred that the presence of AFP in LS and PVS2 was likely to elevate expression pattern of the genes. Furthermore, the concentration of AFP (1,500 ng/ml for LS and 500 ng/mg for PVS2) was the best for the cryopreservation of potatoes.

Full Text Cite Share

Abstract : Barnyardgrass (Echinochloa crus-galli) is one of the worst weeds in rice (Oryza sativa), but there are few reports about the genetic diversity and herbicide resistance of barnyardgrass in Vietnam. In this study, we used random amplified polymorphic DNA (RAPD) analysis and greenhouse testing to study the genetic diversity and quinclorac resistance levels of 15 Echinochloa crus-galli populations in the Mekong Delta, Vietnam, and the state of Arkansas, U.S. The quinclorac resistance of Echinochloa crus-galli populations in Vietnam was confirmed; 9 populations were resistant to quinclorac with R/S ratios ranging from 1.9 to 6.3. Six oligonucleotide primers produced a total of 55 repeatable bands of which 46 were polymorphic (83.3% average) among the 15 populations. Genetic distance was calculated, and cluster analysis separated the 15 populations into 2 main clusters with the genetic distances within the clusters ranging from 0.09 to 0.39. The two main clusters were divided into 7 subclusters, and the quinclorac resistant and susceptible populations were located randomly within each subcluster. Six out of 13 weed populations from Vietnam belonged to one cluster and a single Echinochloa species. The remaining 7 populations were identified as potentially different species in the Echinochloa genus. Nine Echinochloa populations from Vietnam were tested and identified as quinclorac resistant. The connection between quinclorac resistance levels and weed groups defined by RAPD analysis in the study is unclear; the quinclorac resistance of each resistant population could have evolved individually, regardless of differences in genetic diversity and location of the sampled populations.

Full Text Cite Share

Abstract : Thiamine pyrophosphate (TPP), the active form of thiamine is a cofactor for enzymes involved in central metabolism pathways. However, it is also known to have a role as a stress signaling molecule in response to environmental changes. Anabaena sp. and N. oculata are microorganisms which are abundantly found in Malaysia’s freshwater and marine ecosystem. However, not much studies have been done especially in regards to thiamine biosynthesis. This work aimed to amplify of gene transcripts coding for thiamine biosynthesis enzymes besides looking at the expression of thiamine biosynthesis genes upon stress application. Various stress inducers were applied to the cultures and RNA was extracted at different time points. The first two genes, ThiC and ThiG/Thi4 encoding enzymes of the pyrimidine and thiazole branch respectively in the thiamine biosynthesis pathway were identified and amplified. The expression of the genes were analysed via RT-PCR and the intensity of bands were analysed using ImageJ software. The results showed up to 4-fold increase in the expression of ThiC and ThiG gene transcript as compared to control sample in Anabaena sp. ThiC gene in N. oculata showed an expression of 6-fold higher as compared to control sample. In conclusion, stresses induced the expression of the gene coding for one of the most important enzymes in thiamine biosynthesis pathway. This is an agreement with the hypothesis that overexpression of thiamine is crucial in assisting plants to combat abiotic stresses.

Full Text Cite Share

Abstract : This study was conducted to investigate the optimal conditions for spore germination, prothallus propagation, sporophyte formation, and seedling growth in Polystichum braunii (Spenn.) Fée. The rate of spore germination and early prothalium development was high in Knop (41.2%), which had low mineral content. The optimal medium for prothallus propagation and sexual organ formation was 2MS medium (2% sucrose). Among the various mixtures of cultivation soil (bedding soil, peat moss, perlite, and decomposed granite), a mixture of bedding soil and decomposed granite at a ratio of 2:1 (v:v) had a positive effect on sporophyte formation (276.3 ea/7.5 m²). The most efficient conditions for promoting the growth of sporophytes were pots filled with only bedding soil.

Full Text Cite Share

Abstract : This study was carried out to find culture materials (explant parts) and medium components (medium type, sucrose and NaH₂PO₄ concentration) for in vitro propagation of Osmunda cinnamomea var. forkiensis sporophyte. The results of study: chopped segments of leaf blades, stipes, rhizomes and roots were cultured on a 1/2MS medium supplemented with 0.1% activated charcoal. Among these explant types, only the rhizome segments produced young sporophyte, regenerating vigorously on a 1/8MS medium. Adjusting the sucrose concentration to 2% and supplement to 50 mg･L^-1 NaH₂PO₄ in the 1/8MS medium proved to be more efficient for plant regeneration. Consequently, the addition of 0.1% activated charcoal to a modified 1/8MS medium (2% sucrose, 50 mg･L^-1 NaH₂PO₄, pH 5.8 and 0.8% agar) yielded the highest sporophyte regeneration.

Full Text Cite Share

Abstract : Flowering is one of the most important development traits related to the production of Brassica rapa crops. After planting, a sudden low temperature triggers premature flowering, which leads to a reduction in the yield and quality of harvested production. Therefore, understanding the mechanism of flowering control is important in the agricultural productivity for preventing Brassica rapa crops. Vernalization is generally known as the main factor of flowering in the Brassica plant. However, in the subspecies of Brassica rapa, some accession such as Yellow sarson and Komatsuna display the flowering phenotype without vernalization. Circadian genes, which diurnally regulate plant physiology, have a role for photoperiodic flowering but are related to the regulation of the vernalizarion mechanism. In this report, the 22 B. rapa accession were divided into two groups, vernalization and non-vernalization, and the sequenced circadian gene, BrPRR1s. Among them, the BrPRR1b gene was found to have deletion regions, which could classify the two groups. The PCR primer was designed to amplify a short band of 422bp in the vernalization type and a long band of 451bp in the non-vernalization type. This primer set was applied to distinguish the flowering types in the 43 B. rapa accession and 4 Brassica genus crop, Broccoli, cabbage, mustard, and rape. The PCR analysis results and flowering time information of each crop demonstrated that the primer set can be used as marker to discern the flowering type in Brassica crops. This marker system can be applied to the B. rapa breeding when selecting the flowering character of new progenies or introducing varieties at an early stage. In addition, these results displayed that the circadian clock genes can be a good strategy for the flowering control of B. rapa crops.

Full Text Cite Share

Abstract : Mulberry (Morus sp.) of the family Moraceae is very economically important in Asian countries including Korea, because its leaf and fruit have been commercially used in sericulture and horticultural industries. Therefore it is necessary to develop the optimal production system for rapid and cost-effective propagation of mulberry. Our studies focused on establishing an acclimatization method for the successful plantlet production of new cultivar ‘Cheongsu’ which was transferred ex vitro after in vitro culture. In particular, effect of abscisic acid (ABA) addition into the last subculture medium on plantlet response to subsequent ex vitro transfer and its growth was investigated. During acclimatization, stomatal conductance and transpiration rate of ABA-pretreated plantlets were significantly lower than those of non-treated plantlets. Net photosynthetic rate of ABA-pretreated plantlets decreased after ex vitro transfer but increased after 14 days, and it was mostly higher than that of non-treated plantlets. Moreover, relative water content as well as chlorophyll contents and its ratio were also higher in ABA-pretreated plantlets. On the other hand, proline was considerably higher than in control plantlets. After 1 month of ex vitro transfer, survival rate of ABA-pretreated plantlets was 85.6%, which increased by 29.1% in comparison with control (56.5%). More vigorous growth was also observed in ABA-pretreated plantlets. From these results, it was found that application of ABA to the last subculture medium could improve acclimatization and promote survival of mulberry plantlets after ex vitro transfer, inducing water stress tolerance and alleviating abiotic stresses.

Full Text Cite Share

Abstract : The kenaf plant is used widely as food and in traditional folk medicine. This study evaluated the morphological characteristics, functional compounds, and genetic diversity of 32 kenaf cultivars from a worldwide collection. We found significant differences in the functional compounds of leaves from all cultivars, including differences in levels of chlorogenic acid isomer (CAI), chlorogenic acid (CA), kaempferol glucosyl rhamnoside isomer (KGRI), kaempferol rhamnosyl xyloside (KRX), kaemperitrin (KAPT) and total phenols (TPC). The highest TPC, KAPT, CA, and KRX contents were observed in the C22 cultivars. A significant correlation was observed between flowering time and DM yield, seed yield, and four phenolic compounds (KGRI, KRX, CAI, and TPC) (P < 0.01). To assess genetic diversity, we used 80 simple sequence repeats (SSR) primer sets and identified 225 polymorphic loci in the kenaf cultivars. The polymorphism information content and genetic diversity values ranged from 0.11 to 0.79 and 12 to 0.83, with average values of 0.39 and 0.43, respectively. The cluster analysis of the SSR markers showed that the kenaf genotypes could be clearly divided into three clusters based on flowering time. Correlations analysis was conducted for the 80 SSR markers; morphological, chemical and growth traits were found for 15 marker traits (corolla, vein, petal, leaf, stem color, leaf shape, and KGRI content) with significant marker-trait correlations. These results could be used for the selection of kenaf cultivars with improved yield and functional compounds.

Full Text Cite Share

Abstract : The vegetation period of trees might be prolonged by the delay of the leaf senescence in autumn. Thus, we focused on the generation of senescence-delayed transgenic trees to enhance biomass production. The PagMYC2, a gene containing the basic helix-loop-helix domain, was selected as a candidate for a senescence-delayed transgenic tree. The PagMYC2 gene was specifically induced after treatment with phytohormone jasmonic acid, and upregulated by abiotic stresses such as salinity, osmotic pressure and a low temperature. The constitutive overexpression of the PagMYC2 delayed the leaf senescence and inhibited chlorophyll degradation in the transgenic poplars. Leaf senescence analysis was performed in the leaf tissues of the PagMYC2-overexpression transgenic poplars. The transgenic poplars exhibited higher photochemical efficiency than did a wild type plant under a short-day condition (6 hours light/ 18 hours darkness) or a low temperature condition (15°C) that was similar to the weather conditions of autumn. These results suggest that the PagMYC2 is a useful genetic resource to improve biomass production, which is able to sustain growth with senescence- delayed leaves for a long time in autumn.