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1.
Tanavat Kaensaksiri Puangpaka Soontornchainaksaeng Noppamas Soonthornchareonnon Sompop Prathanturarug 《Plant Cell, Tissue and Organ Culture》2011,107(2):187-194
Mutational breeding was conducted using in vitro-grown shoot-tips of Centella asiatica (L.) Urban treated with colchicine (0.025–0.400% for 12–36 h) to induce polyploidy. Treated shoot-tips were grown on Murashige
and Skoog (MS) medium supplemented with 4.54 μM thidiazuron (TDZ), and regenerated plantlets were acclimatized and transferred
to soil. Two months following transfer to ex vitro conditions, ploidy levels of regenerated plants were determined by flow
cytometry and by determining chromosome counts. Treating shoot-tips with colchicine concentrations ranging from 0.050–0.200%
for 12–24 h promoted induction of tetraploids. Morphological and growth characteristics and the triterpenoid contents of the
polyploids were also measured. Tetraploid plants demonstrated significantly longer stomata and a higher stomatal index compared
to those of the diploid control plants. Furthermore, a positive trend in both biomass and triterpenoid production was obtained
with the tetraploid and mixoploid plants of C. asiatica. 相似文献
2.
A protocol for in vitro induction of crape myrtle tetraploids using nodes from in vitro-grown shoots (2n = 48) was established. Nodal buds were excised from in vitro-grown shoots, maintained on proliferation medium containing
Murashige and Skoog medium supplemented with 4.44 μM 6-benzyladenine , 0.54 μM α-naphthaleneacetic acid, and treated with
a range of concentrations of colchicine under three different conditions. Nodal bud explants treated in liquid proliferation
medium supplemented with either 15 or 20 mM colchicine for 24 h turned necrotic and died; whereas, those cultured on solid
proliferation medium supplemented with either 125 or 250 μM colchicine for 30 days survived, but no tetraploid plants were
obtained. However, when explants were cultured in liquid proliferation medium containing 250, 500 or 750 μM colchicine for
10 days, tetraploid plants (2n = 96) were obtained. Incubation of explants in medium containing 750 μM colchicine promoted the highest frequency of survival
(40%) of explants and of recovered tetraploids (60%). Morphological and anatomical characteristics of leaves, including leaf
index, stomata size and number, stomata index (length/width), and number of chloroplasts in guard cells correlated with ploidy
of crape myrtle plants. The number of chloroplasts in guard cells of stomata was a stable and reliable marker in discriminating
plants of different ploidy levels. Chromosome counts and flow cytometry confirmed these findings. 相似文献
3.
Polyploids have great breeding value as they could have higher vegetative yields, higher qualities and greater tolerances against biotic and abiotic stresses. This research is focusing on in vitro colchicine-induced tetraploids in cassava. The survival rate of explants decreased with the increase of colchicine concentrations. Based on the survival rate, the treatment with 0.05 g l?1 colchicine for 2 days was the best protocol for tetraploid induction in the cassava variety ‘Xinxuan 048’. The determination of ploidy levels showed that 28 autotetraploidy and 12 mixoploidy plantlets were obtained from 44 plantlets. Thus, 90.9% of the plants were variants. Significant differences in morphology and anatomy were found between the diploid and tetraploid plants. Tetraploid plants showed better photosynthetic capacities than the original diploid plants. The tetraploid cassava regenerated herein will enrich the germplasm spectrum and open a new arena for breeding novel triploids with elite cultivars by interploid crossing in the future. 相似文献
4.
Revision of ploidy status of Dioscorea alata L. (Dioscoreaceae) by cytogenetic and microsatellite segregation analysis 总被引:1,自引:0,他引:1
Gemma Arnau A. Nemorin E. Maledon K. Abraham 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(7):1239-1249
Dioscorea alata is a polyploid species with several ploidy levels and its basic chromosome number has been considered by most authors to
be x = 10. Standard chromosome counting and flow cytometry analysis were used to determine the chromosome number of 110 D. alata accessions of the CIRAD germplasm collection. The results revealed that 76% of accessions have 2n = 40 chromosomes, 7% have 2n = 60 chromosomes and 17% have 2n = 80 chromosomes. Progenies were produced from 2n = 40 types of D. alata and the segregation patterns of six microsatellite markers in four different progenies were analysed. The Bayesian method
was used to test for diploid versus tetraploid (allo- and autotetraploid) modes of inheritance. The results provided the genetic
evidence to establish the diploidy of plants with 2n = 40 chromosomes and to support the hypothesis that plants with 2n = 40, 60 and 80 chromosomes are diploids, triploids and tetraploids, respectively, and that the basic chromosome number of
D. alata is x = 20. The findings obtained in the present study are significant for effective breeding programs, genetic diversity analysis
and elucidation of the phylogeny and the species origin of D. alata. 相似文献
5.
K. K. Kidwell E. T. Bingham D. R. Woodfield T. C. Osborn 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(2-3):323-328
Isogenic diploid and tetraploid alfalfa (Medicago sativa L.) was studied with molecular markers to help understand why diploid performance and breeding behavior does not always predict that of tetraploids. In a previous study of partially heterozygous alfalfa genotypes, we detected a low correlation between yields of isogenic diploid (2x) and tetraploid (4x) single-cross progenies, and genetic distances were more highly correlated with yields of tetraploids than diploids. These differences may be related to the level of RFLP heterozygosity expected among progenies derived from heterozygous parents at the two ploidy levels. The objectives of this study were to determine the relationships among genetic distance, forage yield and heterozygosity in isogenic 2 x and 4 x alfalfa populations. Four diploid genotypes were chromosome doubled to produce corresponding isogenic autotetraploids, and these genotypes were mated in 4 × 4 diallels to produce 6 single-cross families at each ploidy level for field evaluation. Allele compositions of parents were determined at 33 RFLP loci by monitoring segregation of homologous restriction fragments among individuals within progenies, and these were used to estimate RFLP heterozygosity levels for all single-cross progenies at both ploidy levels. RFLP heterozygosity rankings were identical between progenies of isogenic diploid and tetraploid parents; but significant associations (P < 0.05) between estimated heterozygosity levels and forage yield were detected only at the tetraploid level. Since tetraploid families were nearly 25% more heterozygous than the corresponding diploid families, inconsistencies in the association between molecular marker diversity and forage yields of isogenic 2 x and 4 x single crosses may be due to recessive alleles that are expressed in diploids but masked in tetraploids. The gene action involved in heterosis may be the same at both ploidy levels; however, tetraploids benefit from greater complementary gene interactions than are possible for equivalent diploids.
Present address: AgResearch Grasslands, New Zealand Pastoral Agriculture Research Institute, Palmerston North, New Zealand 相似文献
6.
Tetraploid plants were produced from leaf explants of diploid Populus pseudo-simonii by treating the leaves with colchicine. Leaf explants were cultured on MS basal medium containing 1.78 μM BA and 1.08 μM
NAA for 0, 6 and 12 days, and then transferred to the same MS liquid medium with colchicine at concentrations of 25, 50 and
75 μM for 1, 2 and 3 days. The highest efficiency of tetraploid induction was 14.6% by treating leaf explants that were pre-cultured
for 6 days and then cultured in liquid MS with 50 μM colchicine for 3 days. Flow cytometric analysis was used to screen the
tetraploids out from the regenerated plants and chromosome number counting was employed to confirm the polyploidy level. Size
and frequency of leaf stomata between diploid and tetraploid plants were demonstrated to have significant differences. 相似文献
7.
Katrijn Van Laere Soraya C. França Hein Vansteenkiste Johan Van Huylenbroeck Kathy Steppe Marie-Christine Van Labeke 《Acta Physiologiae Plantarum》2011,33(4):1149-1156
In this study, we analysed morphological, anatomical and physiological effects of polyploidisation in Spathiphyllum
wallisii in order to evaluate possible interesting advantages of polyploids for ornamental breeding. Stomatal density was negatively
correlated with increased ploidy level. Stomatal size increased in polyploids. Tetraploid Spathiphyllum plants had more ovate and thicker leaves. The inflorescence of tetraploids had a more ovate and thicker spathum, a more cylindrical
spadix and a thicker but shorter flower stalk. Biomass production of the tetraploids was reduced, as expressed by lower total
dry weights, and tetraploids produced fewer shoots and leaves compared with their diploid progenitors. Furthermore, tetraploid
Spathiphyllum plants were more resistant to drought stress compared with diploid plants. After 15 days of drought stress, diploids showed
symptoms of wilting, while the tetraploids showed almost no symptoms. Further, measurements of stomatal resistance, leaf water
potential, relative water content and proline content indicated that the tetraploid genotypes were more resistant to drought
stress compared with the diploids. 相似文献
8.
Ploidy manipulation in Citrus is a major issue of current breeding programs aiming to develop triploid seedless mandarins
to address consumer demands for seedless fruits. The most effective method to obtain triploid hybrids is to pollinate tetraploid
non apomictic cultivars with pollen of diploid varieties. Such non apomictic tetraploid lines are not found in the citrus
germplasm and need to be created. In this work we describe a new methodology based on in vitro shoot-tip grafting combined
with treatment of the micro-grafted shoot-tip with colchicine and oryzalin to achieve chromosome doubling and a dechimerization
procedure assisted by flow cytometry. Stable tetraploid plants of Clemenules, Fina and Marisol clementines and Moncada mandarin
have been obtained directly from shoot tip grafting combined with colchicine and oryzalin treatments or after dechimerization
of mixoploids plants (2x–4x). These stable tetraploid plants have been used in 4x × 2x hybridizations, to recover over 3,250 triploid hybrids in 3 years. 相似文献
9.
Endopolyploidy was observed in the protocorms of diploid Phalaenopsis aphrodite subsp. formosana with ploidy doubling achieved by in vitro regeneration of excised protocorms, or protocorm-like bodies (PLBs). Thirty-four
per cent of the PLBs regenerated from the first cycle of sectioned protocorms were found to be polyploids with ploidy doubled
once or twice as determined by flow-cytometry. The frequency of ploidy doubling increased as the sectioning cycles increased
and was highest in diploid followed by the triploid and tetraploid. Regeneration of the endopolyploid cells in the tissue
of the protocorms or PLBs is proposed as the source of the development of ploidy doubled plantlets. The frequency of ploidy
doubling was similar in seven other Phalaenopsis species, although the rate of increase within cycles was genotype specific. In two species, a comparison of five parameters
between 5-month-old diploid and tetraploid potted plants showed only the stomata density differed significantly. The flowers
of the tetraploid plant were larger and heavier than those of the diploids. This ploidy doubling method is a simple and effective
means to produce large number of polyploid Phalaenopsis species plants as well as their hybrids. The method will be beneficial to orchid breeding programs especially for the interspecific
hybridization between varieties having different chromosome sizes and ploidy levels. 相似文献
10.
In vitro induction of autotetraploids from diploid yellow passion fruit mediated by colchicine and oryzalin 总被引:2,自引:0,他引:2
M. M. Rêgo E. R. Rêgo C. H. Bruckner F. L. Finger W. C. Otoni 《Plant Cell, Tissue and Organ Culture》2011,107(3):451-459
In vitro chromosome doubling from hypocotyl segments of yellow passion fruit (Passiflora edulis Sims.) was carried out in the presence of either colchicine (0, 25, 250 and 1,250 μM) or oryzalin (0, 5, 15 and 30 μM). Murashige
and Skoog (in Physiol Plant 15:473–497, 1962)(MS)-based regeneration medium containing 250 or 1,250 μM colchicine markedly affected explant development leading to browning
and death of the hypocotyl segments. Oryzalin has similar effect to colchicine in inducing polyploidy. In vitro regenerated
autotetraploid plants induced by 25 μM colchicine or 15 μM oryzalin were further acclimatized and cultivated in hydroponics
system in greenhouse. Autotetraploids plants were more vigorous than the control diploids. The chromosome number of diploid
plants was 2n = 2x = 18, whereas that found on autotetraploid plants were 2n = 4x = 36. The stomata sizes of the autotetraploids were significantly larger than those on the diploid counterparts, while the
frequency of stomata was significantly reduced. Similarly, the chloroplast number of guard cells of autotetraploid plants
increased significantly. Two albino plants (4%) were generated in medium with 25 μM colchicine, indicating phytotoxic effects.
These plants are being grown to full maturity in order to test their potential to use in a breeding program. 相似文献
11.
Colchicine and oryzalin mediated chromosome doubling in different genotypes of Miscanthus sinensis 总被引:7,自引:0,他引:7
Koefoed Petersen Karen Hagberg Per Kristiansen Kell 《Plant Cell, Tissue and Organ Culture》2003,73(2):137-146
Different explant materials were treated with antimitotic agents to induce chromosome doubling in several Miscanthus sinensis clones. In vitro propagated plants established in soil, in vitro shoots, embryogenic callus, shoot apices and leaf explants were treated with different concentrations of colchicine or oryzalin. No tetraploids were obtained after antimitotic treatment of plants established in soil. The percentage of chromosome doubled plants after antimitotic treatment of single in vitro shoots was genotype dependent. Rooted in vitro plantlets were not a suitable target for antimitotic treatment, due to a high frequency of ploidy chimeras. Many tetraploid plants were regenerated after antimitotic treatment at the callus and explant level, but the efficiency was genotype dependent, primarily due to differences in the ability to form regenerable callus and to regenerate plants from embryogenic callus. Treatment of shoot apices with colchicine was the most efficient and reproducible system in the four genotypes tested. It was possible to repeatedly use the same colchicine-containing medium without any reduction in the induction of regenerable callus or in the percentage of tetraploids, thereby minimising the handling of this very toxic compound. 相似文献
12.
Cytogeographical variability among 564 plants from 26 populations of Turnera sidoides subsp. pinnatifida in mountain ranges of central Argentina was analysed with meiotic chromosome counts and flow cytometry and is described at
regional and local scales. Populations were primarily tetraploids (2n = 4x = 28), although diploid (2n = 2x = 14), hexaploid (2n = 2x = 42), and mixed populations of diploids and triploids (2n = 3x = 21) were also found. Diploids, triploids, and hexaploids were fewer in number and restricted to narrow areas, while tetraploids
were the most common and geographically widespread cytotype. Diploids grew at higher altitudes and in colder and wet locations;
tetraploids had the broadest ecological spectrum, while hexaploids occurred at the lowest altitudes and in drier conditions.
The cytotypes were also spatially segregated at a microgeographical scale. Diploids grew in the piedmont, tetraploids were
in the adjacent valley, and in the contact zone of both cytotypes, patches of diploids and triploids were found. At a regional
scale, the distribution of the cytotypes may be governed by a combination of ecological and historical variables, while segregation
in the contact zone may be independent of the selective environment because the cytotypes are unable to coexist as a result
of reproductive exclusion. The role of triploids is also discussed. 相似文献
13.
Mohammad Abdoli Ahmad Moieni Hassanali Naghdi Badi 《Acta Physiologiae Plantarum》2013,35(7):2075-2083
Echinacea purpurea (L.) is one of the important medicinal plant species. To obtain the tetraploid plants of Echinacea purpurea with improved medicinal qualities, the root tips of two true leaves seedlings were imbibed in 0.25 % (w/v) colchicine solution for 24, 48, 72, 96 and 168 h. The ploidy level of plants was determined by chromosome counting of root tip cells, and confirmed by flow cytometric analysis. Tetraploid induction occurred in seedlings treated for 24, 48 and 72 h at colchicine solution. The morphological, physiological, cytological, and phytochemical characteristics of diploid and colchicine-induced tetraploid plants were compared. Results indicated that tetraploid plants had considerable larger stomata, pollen grain, seed and flower. Moreover, chloroplast number in guard cells, amount of chlorophyll (a, b, and a + b), carotenoids as well as width and thickness of leaves were increased in tetraploids. However, stomata frequency, leaf index, plant height, and quantum efficiency of photosystem II in tetraploid were lower than diploid plants. High-performance liquid chromatography analysis showed that leaves of the tetraploid plants had more cichoric acid (45 %) and chlorogenic acid (71 %) than diploid plants. It was concluded that morphological and physiological characteristics can be used as useful parameters for preliminary screening of putative tetraploids in this species. 相似文献
14.
R. C. Marinho C. Mendes‐Rodrigues A. M. Bonetti P. E. Oliveira 《Plant biology (Stuttgart, Germany)》2014,16(2):508-511
Approximately 70% of the angiosperm species are polyploid, an important phenomenon in the evolution of those plants. But ploidy estimates have often been hindered because of the small size and large number of chromosomes in many tropical groups. Since polyploidy affects cell size, morphometric analyses of pollen grains and stomata have been used to infer ploidy level. Polyploidy is present in many species of the Cerrado, the Neotropical savanna region in Central Brazil, and has been linked to apomixis in some taxa. Eriotheca gracilipes and Eriotheca pubescens are common tree species in this region, and present cytotypes that form reproductive mosaics. Hexaploid individuals (2n = 6x = 276) are polyembryonic and apomictic, while tetraploid and diploid individuals (2n = 2x = 92, 2n = 4x = 184) are sexual and monoembryonic. We tested whether morphometric analysis can be used to estimate ploidy levels in E. gracilipes and E. pubescens individuals. Pollen material from diploid and hexaploid individuals of E. gracilipes, and tetraploid and hexaploid individuals of E. pubescens, were fixed in 50% FAA, and expanded leaves were dried in silica gel. Pollen grains and stomata of at least five individuals from each population were measured. The results demonstrate that all measures were significantly different among cytotypes. Individuals with higher levels of ploidy (hexaploid) all presented measurements that were higher than those with lower levels (diploid and tetraploid). There was no overlap between ploidy levels in each species at 95% confidence interval. Thus, the size of the pollen grains and stomata are effective parameters for analysis of ploidy levels in E. gracilipes and E. pubescens. 相似文献
15.
Riccardo Aversano Francesco Di Dato Antonio Di Matteo Luigi Frusciante Domenico Carputo 《Plant biotechnology reports》2011,5(3):265-271
The cultivated potato as well as its tuber-bearing relatives are considered model plants for cell and tissue culture, and
therefore for exploiting the genetic variation induced by in vitro culture. The association between molecular stability and
tissue culture in different genetic backgrounds and ploidy levels has already been explored. However, it still remains to
be ascertained whether somaclonal variation differs between callus-derived chromosome-doubled and undoubled regenerants. Our
research aimed at investigating, through amplified fragment length polymorphism (AFLP) markers, the genetic changes in marker-banding
patterns of diploid and tetraploid regenerants obtained from one clone each of Solanum bulbocastanum Dunal and S. cardiophyllum Lindl (both 2n = 2x = 24) and tetraploids from cultivated S. tuberosum L. (2n = 4x = 48). Pairwise comparisons between the banding patterns of regenerants and parents allowed detecting considerable changes
associated to in vitro culture both at diploid and tetraploid level. The percentages of polymorphic bands between diploid
and tetraploid regenerants were, respectively, 57 and 69% in S. bulbocastanum and 58 and 63% in S. cardiophyllum. On average, the frequencies of lost parental fragments in regenerants were significantly higher than novel bands both in
S. bulbocastanum (48 vs. 22%) and S. tuberosum (36 vs. 18%) regenerants. By contrast, in S. cardiophyllum, a similar incidence of the two events was detected (32 vs. 29%). Our results revealed that structural changes after tissue
culture process strongly affected the genome of the species studied, but diploid and tetraploids regenerated plants responded
equally. 相似文献
16.
In vitro induction, regeneration and analysis of autotetraploids derived from protoplasts and callus treated with colchicine in Citrus 总被引:2,自引:0,他引:2
Shao-Hua Zeng Chuan-Wu Chen Liu Hong Ji-Hong Liu Xiu-Xin Deng 《Plant Cell, Tissue and Organ Culture》2006,87(1):85-93
In the present paper attempts were made to induce chromosome doubling of ‘Meiwa’ kumquat (Fortunella crassifolia) protoplasts and ‘Frost’ navel orange (Citrus sinensis Osbeck) embryogenic callus via colchicine treatment. Colchicine decreased protoplast viability, delayed protoplast division and inhibited callus growth, indicating presence of toxicity to cells. Cell lines established from ‘Meiwa’ protoplasts treated with 0.01 and 0.1% colchicine for 8, 16 and 24 h at each concentration showed different responses when they were cultured on embryoid-induction medium. Flow cytometry (FCM) demonstrated that tetraploids were detected in cell lines and embryoids from all of the treatments, with the highest frequency being 19.23%. As for ‘Frost’, tetraploid cells were only detected when the callus was treated with 0.1% colchicine for either 4 or 8 days, from which plantlets were regenerated. FCM and chromosome counting confirmed them as true tetraploids. The diploid cells were more active in mitotic division during a 12-day culture and smaller in size than their tetraploid counterpart. Potential applications of the novel tetraploid germplasms obtained through in vitro chromosome doubling to citrus cultivar improvement are discussed. 相似文献
17.
Tetraploid plants have been produced from nineZantedeschia cultivars usingin vitro colchicine treatment. Rapidly-multiplying shoot cultures were treated on a medium containing 0.05% colchicine for 1, 2 or
4 days to induce chromosome doubling. Following the treatment, most shoots were killed but the surviving shoots were multiplied
for several subcultures. These shoots were then rootedin vitro and transferred to a greenhouse. Plants were screened 2 months later by measuring stomatal length, and 110 out of 565 plants
were selected as putative tetraploids with a stomatal length significantly greater than in diploid control plants. Chromosome
counts were carried out on root tips from 44 plants and confirmed that 38 were tetraploids, 2 were chimeras (predominantly
tetraploid with a few octoploid cells), and 4 were diploids. Stomatal length has been rechecked in mature tetraploid plants
of the cultivar Black Magic, demonstrating that stomatal length is a good indicator of ploidy level inZantedeschia. This study has shown that multiplying colchicine-treated shootsin vitro for several subcultures prior to transfer to soil produced very few chimeras. The stomatal length measurements are non-destructive
and allow the rapid screening of a population for tetraploids. 相似文献
18.
Establishment of polyploid individuals within diploid populations is theoretically unlikely unless polyploids are reproductively isolated, pre-zygotically, through assortative pollination. Here, we quantify the contribution of pollinator diversity and foraging behaviour to assortative pollen deposition in three mixed-ploidy populations of Chamerion angustifolium (Onagraceae). Diploids and tetraploids were not differentiated with respect to composition of insect visitors. However, foraging patterns of the three most common insect visitors (all bees) reinforced assortative pollination. Bees visited tetraploids disproportionately often and exhibited higher constancy on tetraploids in all three populations. In total, 73% of all bee flights were between flowers of the same ploidy (2x–2x, 4x–4x); 58% of all flights to diploids and 83% to tetraploids originated from diploid and tetraploid plants, respectively. Patterns of pollen deposition on stigmas mirrored pollinator foraging behaviour; 73% of all pollen on stigmas (70 and 75% of pollen on diploid and tetraploid stigmas, respectively) came from within-ploidy pollinations. These results indicate that pollinators contribute to high rates of pre-zygotic reproductive isolation. If patterns of fertilization track pollen deposition, pollinator–plant interactions may help explain the persistence and spread of tetraploids in mixed-ploidy populations. 相似文献
19.
Clonal reproduction is associated with the incidence of polyploidy in flowering plants. This pattern may arise through selection for increased clonality in polyploids compared to diploids to reduce mixed‐ploidy mating. Here, we test whether clonal reproduction is greater in tetraploid than diploid populations of the mixed‐ploidy plant, Chamerion angustifolium, through an analysis of the size and spatial distribution of clones in natural populations using AFLP genotyping and a comparison of root bud production in a greenhouse study. Natural tetraploid populations (N = 5) had significantly more AFLP genotypes ( = 10.8) than diploid populations ( = 6.0). Tetraploid populations tended to have fewer ramets per genotype and fewer genotypes with >1 ramet. In a spatial autocorrelation analysis, ramets within genotypes were more spatially aggregated in diploid populations than in tetraploid populations. In the greenhouse, tetraploids allocated 90.4% more dry mass to root buds than diploids, but tetraploids produced no more root buds and 44% fewer root buds per unit root mass than diploids. Our results indicate that clonal reproduction is significant in most populations, but tetraploid populations are not more clonal than diploids, nor are their clones more spatially aggregated. As a result, tetraploids may be less sheltered from mixed‐ploidy mating and diploids more exposed to inbreeding, the balance of which could influence the establishment of tetraploids in diploid populations. 相似文献
20.
Kanoktip Pansuksan Ratchada Sangthong Ikuo Nakamura Masahiro Mii Kanyaratt Supaibulwatana 《Plant Cell, Tissue and Organ Culture》2014,117(3):381-391
Tetraploid plants were successfully induced for the first time in Mitracarpus hirtus L., by overnight immersion of shoot meristems in 0.1 % colchicine solution, followed by in vitro culture leading to plant regeneration. Examination of ploidy level by flow cytometric analysis and counting chromosome number at metaphase confirmed that original diploid plant (WT1) contained chromosome number as 2n = 2x = 28, whereas 2n = 4x = 56 was observed in the tetraploids induced with colchicine treatment (CC102 and CC110). Thicker root formation, larger stomata (1.3–2 times), and lower density of stomata (1.7–4 times) were observed in these tetraploid plants. After transplantation to the pot, tetraploid plant (CC110) showed higher fresh weights of aerial part and leaves (1.5 and 1.4 times respectively) than diploid. However, the methanolic extracts from leaves of tetraploid line CC102 showed inhibition against human pathogenic bacterium, S. aureus while WT1 and CC110 showed no activity. GC–MS revealed 40 unique compounds present in CC102, but absent in WT1 and CC110. Through hierarchical clustering analysis the 40 unique compounds in CC102 formed a cluster group found to correlate with anti-S. aurens activity. These results suggested that tetraploid M. hirtus CC102 created in this study provides a novel source of compounds useful in fighting infectious disease. 相似文献