Monochoria Korsakowii Research Articles

Genetic diversity and the population structure of Monochoria korsakowii in Japan revealed by nuclear simple sequence repeat (SSR) markers

Monochoria korsakowii is an endangered annual herbaceous plant that grows in and around Japanese paddy fields. In the present study, the genetic diversity and population structure were analyzed in 10 populations of M. korsakowii consisting of 200 individuals from Hokkaido, Honshu, and Kyushu, using 15 pairs of nuclear simple sequence repeat (SSR) markers. The results showed that M. korsakowii populations have low genetic diversity (P = 32.9, Ne = 1.0949, I = 0.0911, H = 0.0584, and PPL = 20.56 %), which could be attributed to the highly disturbed habitat, low gene flow, and repeated genetic bottlenecks. The M. korsakowii populations exhibited high genetic differentiation (ranging from 0.5674 to 0.933) owing to the limited gene flow between them. It was inferred that the gene flow between the M. korsakowii populations was hindered by factors such as geographical distance, mountains, straits, and human activities. Thus, comprehensive conservation strategies should be implemented to protect the existing gene pools and enhance population structure.

Occurrence and mechanism of target-site resistance to bensulfuron-methyl in Monochoria korsakowii from China

Monochoria korsakowii is an increasingly significant threat to rice production across China, particularly in Liaoning province. Few studies have reported herbicide resistance in M. korsakowii, and resistance status and mechanisms are poorly understood. Here, thirty field populations of M. korsakowii were collected from 11 rice-growing regions of Liaoning, and 97% of populations had evolved resistance to bensulfuron-methyl (BM), with majority (24 of 28) showing high resistance levels (RI > 10). The first in-depth analysis of molecular features of AHAS1 and AHAS2 in BM-resistant populations showed that four Pro197 mutations (Pro197 to His, Ala, Leu or Ser) in AHAS1 and one mutation (Pro197Ser) in AHAS2 were identified. Notably, novel double Pro197Ser mutations co-occurred in both AHAS1 and AHAS2 in the most resistant line LN-20. Furthermore, resistant mutants were used to investigate the effect of Pro197 mutations on AHAS functionality, binding modes, gene expression and cross-resistance in M. korsakowii. All the detected Pro197 mutations considerably reduced in vitro AHAS sensitivity to BM by weakening hydrogen bonds and hydrophobic interactions in the predicted BM-AHAS complexes, especially the double Pro197Ser mutations. This novel resistance mutation combination slightly impacted the extractable AHAS activity, and increased the affinity and catalytic rate of pyruvate. Also, the AHAS expression level was significantly up-regulated. Moreover, all mutations provided resistance only to other sulfonylureas herbicides but not triazolopyrimidine or pyrimidinyl-benzoates herbicides. In conclusion, bensulfuron-methyl resistance in M. korsakowii was grim in Liaoning, China, and amino acid mutations on AHAS isozymes were the primary resistance mechanism. Double Pro197Ser mutations in both AHAS1 and AHAS2 confer higher herbicide resistance than single mutations in AHAS1. Thus, this work deepens our understanding of resistance status and mechanisms of M. korsakowii.

Photosynthetic response, antioxidase activity, and cadmium uptake and translocation in Monochoria korsakowii with cadmium exposure.

To identify the tolerance mechanisms of wetland plants exposed to heavy metal, a hydroponic experiment was used to investigate variations in photosynthetically physiological parameters and antioxidant enzyme activities in leaves of Monochoria korsakowii exposed to 0.05, 0.15, 0.30, and 0.45 mM Cd2+ for 7 d. The Cd2+ concentrations in the plant roots, stems, and leaves were also investigated. Cd2+ exposure significantly decreased the total chlorophyll content, net photosynthetic rate, intercellular carbon dioxide concentration, and stomatal conductance, while stomatal limitation value had the opposite trend (P < 0.05). During Cd2+ stress, ascorbate peroxidase activity significantly increased (P < 0.05). The translocation factor for Cd2+ was significantly lower than that of the control, and both were less than 1 (P < 0.05). Cd2+ stress damaged the photosynthetic apparatus in the leaves. During Cd2+ stress, M. korsakowii alleviated oxidative stress by increasing the activities of antioxidant enzymes, such as APX. Under 0.45 mM Cd2+ stress, increased heat dissipation was responsible for alleviating the photooxidative damage to photosynthetic organs in the leaves. Meanwhile, the majority of Cd2+ was immobilized in the roots, thus alleviating excessive Cd2+ phytotoxicity in the aboveground parts. Generally, M. korsakowii has potential application in the phytoremediation of low-cadmium-polluted water.

Plastid phylogenomics and biogeography of the genus Monochoria (Pontederiaceae)

Abstract Monochoria C. Presl is a genus of Pontederiaceae and confined to the Old World, with species mainly distributed in tropical and subtropical Africa, Asia, and Australia. However, phylogenetic relationships and biogeography within Monochoria are yet to be fully resolved. Here, we sequenced 14 Monochoria plastomes, representing around eight of the ~10 species of Monochoria, and two plastomes from related genera. We undertook comparative analyses and phylogenetic reconstructions of Monochoria using these and other available sequences. We found the plastomes of Pontederiaceae to be highly conserved in structure, and identified six regions as mutational hotspots among species of Monochoria. Our data strongly support the monophyly of Monochoria and two main clades within the genus. We confirm that Monochoria australasica Ridl. is sister to the rest of the genus and that Monochoria korsakowii (Regel &amp; Maack) defines the second split within Monochoria. In addition, we inferred the African endemic species Monochoria africana (Solms) N. E. Br. to be closely related to Monochoria plantaginea (Roxb.) Kunth and an undetermined specimen from Australia (Monochoria sp. AU63). Estimation of divergence times and biogeography implied that the African species M. africana originated in Asia, and the most recent common ancestor of Monochoria was distributed in Australasia/Asia at approximately 15 Ma, followed by diversification in Asia during the late Miocene and Pliocene. Long‐distance dispersal, likely mediated by migratory birds, to Africa and Australia during the Pliocene and Pleistocene, might have contributed to the extant transoceanic distribution of the genus. Additionally, based on our phylogenetic results, we revised the description of Monochoria valida G. X. Wang &amp; Nagam here.

Effect of Soil Transplantation to Abandoned Paddy Field on the Conservation of Threatened Hydrophyte Species

Threatened or near threatened hydrophytes, Ottelia alismoides, Monochoria korsakowii, Najas graminea, Najas minor and Chara braunii, appeared in an inundated paddy field after the 2011 Tohoku-oki Tsunami in Japan. Due to the reconstruction of roads and agricultural restoration efforts implemented following the disaster, the top soil of the paddy field was transplanted to another abandoned paddy field in 2014 to avoid extirpation of the aforementioned species. We then conducted vegetation surveys in July and September from 2014 to 2016. Monochoria korsakowii appeared at the transplantation site from 2014 to 2016, forming a large community in 2016. The volume of this species was significantly higher than that in July 2014 and 2015. Although Ottelia alismoides and Chara braunii appeared in 2014, they were not observed in 2015. Najas graminea and Najas minor were not observed during the vegetation survey, and Salvinia natans and Alisma plantago-aquatica newly appeared at the transplantation site. Our findings suggest that transplantation of surface soil and the seed bank therein to an abandoned paddy field is well suited for the conservation of hygrophytes such as Monochoria korsakowii, Ottelia alismoides and Chara braunii. Preventing disturbances that suppress the growth of herbaceous perennial plants is considered necessary for maintaining the habitats of threatened plant species.

Divergent responses of leaf N:P:K stoichiometry to nitrogen fertilization in rice and weeds

AbstractNitrogen (N) inputs have been found to exert strong influence on leaf stoichiometry in natural ecosystems, but there are few studies investigating the effects of N in agroecosystems. Using a 5-yr fertilization experiment in rice fields, we examined the effects of N inputs on leaf stoichiometry of one crop, rice (Oryza sativa L.), and its four common weeds, barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.], Monochoria korsakowii Regel and Mack, alligatorweed [Alternanthera philoxeroides (Mart.) Griseb.], and Japanese mazus [Mazus pumilus (Burm. f.) Steenis], and further evaluated whether and how straw return mediates these effects. We found that rice and weed leaf nitrogen:phosphorus:potassium (N:P:K) stoichiometry exhibited divergent responses to N fertilizer. Weed leaf N:P:K stoichiometry was not sensitive to low (120 kg N ha−1) and regular (240 kg N ha−1) N inputs, but rice plants were, with significantly increased leaf N concentration and N:P and N:K ratios. The opposite trend was found for high N inputs (360 kg N ha−1). Rice leaf N concentration [N] did not increase further, and N:P ratios even decreased, whereas E. crus-galli and M. korsakowii had significantly increased [N] and N-related stoichiometry. We also found that the positive effects of regular N inputs on rice leaf N:P and N:K ratios were significantly dampened by straw return, but the positive effects on N:P ratios in M. pumilus leaves were enhanced by straw return. Compared with weeds, rice leaves contained low elemental concentrations across fertilization levels at grain-filling stages. These results indicate that rice has a lower N requirement than weeds at grain-filling stages, and the N supply should be managed at a relative low level to reduce the nutrient acquisition and competitive abilities of weeds. From a stoichiometric perspective, this study highlights the importance of N management in combination with straw return in controlling weeds and increasing the nutrient-use efficiency of crops.

長沼町に発生する水田雑草「ミズアオイ」に対する数種除草剤の効果

長沼町に発生する水田雑草「ミズアオイ」に対する数種除草剤の効果

Occurrence Cause, Mechanism and Control of Herbicide-Resistant Weeds in Rice Field of Korea

Sulfonylurea (SU)-resistant weeds of eight annual weeds, Monochoria vaginalis, Scirpus juncoides and Cyperus difformis, etc., and four perennial weeds, Scirpus planiculmis, Sagittaria pigmaea, Eleocharis acicularis and Sagittaria trifolia as of 2013 since identification Monochoria korsakowii in the reclaimed rice field in 1998. And the resistant Echinochloa oryzoides to ACCase and ALS inhibitors has been confirmed in rice fields of the southern province, Korea in 2009. In the beginning, the M. vaginalis, S. juncoides and C. difformis of these SU-resistant weeds were rapidly and individually spreaded in different fields, however, these resistant weeds have been occurring simultaneously in the same filed recently. The resistant biotype by weed species demonstrated about 10- to 1,000-fold resistance, based on GR50 values of the SU herbicides tested. And the resistant biotype of E. oryzoides to cyhalofop-butyl, pyriminobac-methyl, and penoxsulam was about 14, 8, and 11 times more resistant than the susceptible biotype base on GR50 values. The products and applied area of SU-included herbicides have been increased rapidly, and have accounted for about 69% and 96% in Korea, respectively. In Korea, the main cause of SU-resistant weed is extensive use of these herbicides. The top ten herbicides by applied area were composed of all SU-included herbicides by 2003. The concentrated and successive treatment of ACCase and ALS inhibitors for control of barnyardgrass in rice led up to the resistance of E. oryzoides. Also, SU-herbicides like pyrazosulfuron-ethyl and imazosulfuron which effective to barnyardgrass can be bound up with the resistance of E. oryzoides. The ALS activity isolated from the resistant biotype of M. korsakowii to SU-herbicides tested was less sensitive than that of susceptible biotype. The concentration of herbicide required for 50% inhibition of ALS activity (I50) of the SU-resistant M. korsakowii was 14- to 76-fold higher as compared to the susceptible biotype. No differences were observed in the rates of ( 14 C)bensulfuron uptake and translocation. Acetolactate synthase (ALS) genes from M. vaginalis resistant and susceptible biotypes against SU-herbicides revealed a single amino acid substitution of proline (CCT), at 197th position based on the M. korsakowii ALS sequence numbering, to serin (TCT) in conserved domain A of the gene. Carfentrazone-ethyl and pyrazolate were used mainly to control SU-resistant M. vaginalis by 2006 in Korea. However, the alternative herbicides such as benzobicyclone, to be possible to control simultaneously the several resistant weeds, have been developing and using broadly, because the several resistant weeds have been occurring simultaneously in the same fieled. The top ten herbicides by applied area in Korea have been occupied by products of 3-way mixture type including herbicides with alternative mode of action for the herbicide resistant weeds. Mefenacet, fentrazamide and cafenstrole had excellent controlling effects on the ACCase and ALS inhibitors resistant when they were applied within 2nd leaf stage.

한국 논에서 제초제 저항성잡초의 발생 현황, 메카니즘 및 방제

Sulfonylurea (SU)-resistant weeds of eight annual weeds, Monochoria vaginalis, Scirpus juncoides and Cyperus difformis, etc., and four perennial weeds, Scirpus planiculmis, Sagittaria pigmaea, Eleocharis acicularis and Sagittaria trifolia as of 2013 since identification Monochoria korsakowii in the reclaimed rice field in 1998. And the resistant Echinochloa oryzoides to ACCase and ALS inhibitors has been confirmed in rice fields of the southern province, Korea in 2009. In the beginning, the M. vaginalis, S. juncoides and C. difformis of these SU-resistant weeds were rapidly and individually spreaded in different fields, however, these resistant weeds have been occurring simultaneously in the same filed recently. The resistant biotype by weed species demonstrated about 10-to 1,000-fold resistance, based on <TEX>$GR_{50}$</TEX> values of the SU herbicides tested. And the resistant biotype of E. oryzoides to cyhalofop-butyl, pyriminobac-methyl, and penoxsulam was about 14, 8, and 11 times more resistant than the susceptible biotype base on <TEX>$GR_{50}$</TEX> values. The products and applied area of SU-included herbicides have been increased rapidly, and have accounted for about 69% and 96% in Korea, respectively. In Korea, the main cause of SU-resistant weed is extensive use of these herbicides. The top ten herbicides by applied area were composed of all SU-included herbicides by 2003. The concentrated and successive treatment of ACCase and ALS inhibitors for control of barnyardgrass in rice led up to the resistance of E. oryzoides. Also, SU-herbicides like pyrazosulfuron-ethyl and imazosulfuron which effective to barnyardgrass can be bound up with the resistance of E. oryzoides. The ALS activity isolated from the resistant biotype of M. korsakowii to SU-herbicides tested was less sensitive than that of susceptible biotype. The concentration of herbicide required for 50% inhibition of ALS activity (<TEX>$I_{50}$</TEX>) of the SU-resistant M. korsakowii was 14-to 76-fold higher as compared to the susceptible biotype. No differences were observed in the rates of [<TEX>$^{14}C$</TEX>]bensulfuron uptake and translocation. Acetolactate synthase (ALS) genes from M. vaginalis resistant and susceptible biotypes against SU-herbicides revealed a single amino acid substitution of proline (CCT), at 197th position based on the M. korsakowii ALS sequence numbering, to serin (TCT) in conserved domain A of the gene. Carfentrazone-ethyl and pyrazolate were used mainly to control SU-resistant M. vaginalis by 2006 in Korea. However, the alternative herbicides such as benzobicyclone, to be possible to control simultaneously the several resistant weeds, have been developing and using broadly, because the several resistant weeds have been occurring simultaneously in the same fieled. The top ten herbicides by applied area in Korea have been occupied by products of 3-way mixture type including herbicides with alternative mode of action for the herbicide resistant weeds. Mefenacet, fentrazamide and cafenstrole had excellent controlling effects on the ACCase and ALS inhibitors resistant when they were applied within 2nd leaf stage.

공검지(경북 상주) 습지보호지역의 식물상

생태계내 생물종 분포는 환경조건에 의해 결정되므로 종의 분포를 확인하는 것은 중요하다. 본 연구는 경상북도 상주에 있는 공검지를 대상으로 2012년 4월에서 10월까지 식물상을 조사하였다. 조사결과 관속식물은 69과 176속 204종 2아종 29변종 5품종으로 총 240분류군이었다. 이중 특산식물은 3분류군, 식물구계학적 특정식물종은 질경이택사, 물옥잠, 노랑어리연꽃 등 11분류군, 귀화식물은 26분류군으로 귀화율은 10.8%로 나타났다. 수생식물은 31분류군으로 한국 수생식물의 17.8%에 해당된다. 따라서, 습지보존을 위하여 불필요한 인간의 간섭을 최소화하고, 생태계의 변화에 대한 지속적인 모니터링을 통하여 효율적인 관리대책을 마련하는 방안이 요구된다. Knowing how many species live in a ecosystem is a major work because of the distributions of species are determined by the environmental condition. This study was carried out to investigate the distribution of vascular plants of Gonggeom-ji, located in Sangju-si, Gyeongsangbuk-do, from April to October on 2012. The vascular plants were summarized as 240 taxa including 69 families, 176 genus, 204 species, 2 subspecies, 29 varieties, and 5 forma. Among the investigated taxa, 3 taxa of Korean endemic plants were included. Based on the list of specially designated plants by Ministry of Environment, 11 taxa including Alisma orientale, Monochoria korsakowii and Nymphoides peltata were recorded. The naturalized plants were identified as 26 taxa and the ratio of naturalized index (NI) was 10.8% of vascular plants recorded. 31 taxa of hydrophytes showed 17.8% of Korea. To conservation of wetlands, we suggest that it is required to minimize for unnecessary disturbance of human and to make a strategy for effective management by continuous monitoring for ecosystem alteration.

Nitrogen Removal from Contaminated Water by Two Aquatic Plants

Two aquatic macrophytes (Monochoria korsakowii and Alisma plantago-aquatica) were grown in monoculture to test the relative growth rate(RGR) and abilities of removing total nitrogen(TN) by the manipulative indoor experiment. A nutrient treatment consisted of two levels of nitrogen[ low (14 mg L-1 N) and high (56 mg L-1 N) ]of nutrient solution. Result revealed that the RGR of the species was significantly different, however nutrients had no significant affect on the RGR. The results showed that TN in wastewater were significantly higher from unvegetated microcosms compared to vegetated. M. korsakowii was shown to be best removal effect with the removal rates of 94.9% and 77.0% at low and high concentrations of TN.

경상남도 양산시 주요지역의 관속식물상과 관리방안 - 천태산, 낙동강습지, 법기수원지, 양산천, 천성산을 중심으로 -

The purpose of this study is to offer the raw data for conserving the biodiversity of urban ecosystem by objective surveying and analysing the vascular plants distributed in major sites of Yangsan-si, Gyeongsangnam-do. The results are as follows. The numbers of vascular plants were summarized as 522 taxa including 110 families, 314 genera, 459 species, 4 subspecies, 46 varieties and 13 forms. The rare plants were 5 taxa including Aristolochia contorta, Drosera rotundifolia, Potentilla discolor, Viola albida and Hydrocharis dubia. The endemic plants were 13 taxa including Salix koriyanagi, Carpinus laxiflora, Stewartia pseudocamellia, Weigela subsessilis and so forth. The specific plants by floristic region were 30 taxa including Caltha palustris, Caryopteris incana, Ilex macropoda, Monochoria korsakowii and so forth. The naturalized plants were 44 taxa including Phytolacca americana, Lepidium virginicum, Solanum americanum, Aster subulatus var. sandwicensis, Panicum dichotomiflorum and so forth. The invasive alien plants were 5 taxa including Sicyos angulatus, Ambrosia artemisiifolia, Ambrosia trifida, Aster pilosus and Paspalum distichum.

한국 논에서 제초제 저항성잡초 발생 현황과 전망

ABSTRACT Sulfonylurea (SU)-resistant weeds include seven annual weeds such as Monochoria vaginalis, Scirpus juncoides and Cyperus difformis, etc., and three perennial weeds of Scirpus planiculmis, Sagittaria pigmaea and Eleocharis acicularis as of 2010 since identification Monochoria korsakowii in the reclaimed rice field in 1998. The Echinochloa oryzoides resistant to acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors has been confirmed in wet-direct seeding rice field of the southern province, Korea in 2009. In the beginning of occurrence of SU-resistant weeds the M. vaginalis, S. juncoides and C. difformis were rapidly and individually spreaded in different fields, however, theses resistant weeds have been occurring simultaneously in the same filed as time goes by. The resistant biotype by weed species demonstrated about 10- to 1,000-fold resistance, base on GR 50 (50% growth reduction) values of the SU herbicides tested. And the resistant biotype of E. oryzoides to cyhalofop-butyl, pyriminobac-methyl, and penoxsulam was about 14, 8, and 11 times more resistant than the susceptible biotype base on GR

Effects of ferrous iron (Fe) on the germination and root elongation of paddy rice and weeds

Laboratory experiments were conducted to analyze the iron (Fe) tolerance of paddy weeds and rice varieties (Oryza sativa) for germination and root elongation. Under a waterlogged soil condition, the Fe(II) content in a soil solution increased with an increase in the ratio of rice straw to the soil. In the presence of 0.9% (w/w) straw to soil, which corresponds approximately to 8 t of straw applied to an area of 1 ha × 10 cm depth in the field, ∼80 mg L−1 of Fe(II) was produced in the soil solution. Based on this result, the seeds of rice and the weeds were incubated in a solution with &lt;100 mg L−1 of Fe(II). The presence of 100 mg L−1 of Fe(II) suppressed the germination of Echinochloa crus‐galli var. crus‐galli, Cyperus serotinus, Cyperus difformis, and Monochoria korsakowii. However, it had no effect on the germination of Echinochloa oryzicola, Schoenoplectus juncoides (= Scirpus juncoides var. ohwianus), and Monochoria vaginalis. This level of Fe tolerance was the same as that of rice. These findings suggest that E. oryzicola, S. juncoides, and M. vaginalis can grow under more severe conditions than E. crus‐galli, C. serotinus, C. difformis, and M. korsakowii. In relation to seminal root elongation, the order of tolerance of Fe toxicity was O. sativa cv. Dunghan Shali &gt; O. sativa cv. Hoshinoyume &gt; E. oryzicola &gt; M. vaginalis &gt; S. juncoides. Thus, the results show that the tolerance of rice is greater than that of E. oryzicola, which had a comparatively strong tolerance among the weeds examined, and also that there are differences in tolerance among the rice varieties. These findings suggest that the difference in Fe tolerance is involved in weed control systems when organic materials are applied. If this difference is an important factor in the weed control system, Fe‐tolerant rice varieties, like cv. D. Shali, could facilitate weed control systems due to their higher Fe tolerance ability.

Variation in daily floral display and the potential for geitonogamous pollination in two monomorphic enantiostylous Monochoria species

Mirror-image flowers (enantiostyly) have long been considered a mechanism to promote cross-pollination between flowers of alternate stylar orientation. However, in monomorphic enantiostyly, the occurrence of both left- and right-styled flowers on the same individual plant might appear to promote geitonogamy rather than outcrossing relative to the condition of dimorphic enantiostyly. We investigated daily floral display during the flowering season in two experimental populations of monomorphic enantiostylous species, Monochoria korsakowii and Monochoria vaginalis (Pontederiaceae) to assess the potential effects of floral display on geitonogamous pollination. The left- and right-styled flowers exhibited a 1:1 ratio both within individuals and populations. In M. korsakowii and M. vaginalis, 86.0% and 71.3% daily floral displays involved fewer than three flowers thus reducing the likelihood of geitonogamy. Moreover, daily displays often involved one floral form and mixed-formed with unequal ratios of left- and right-styled flowers also reducing opportunities for geitonogamy. Therefore variation in daily floral display in these two Monochoria species suggests that the impact of monomorphic enantiostyly in promoting geitonogamy will be reduced by small display sizes, or through simulating dimorphic enantiostyly.

寝屋川市のミズアオイの生育地とその保全の取り組み

寝屋川市のミズアオイの生育地とその保全の取り組み

Seed germination responses of Monochoria korsakowii Regel et Maack, a threatened paddy weed, to temperature and soil moisture

AbstractTo better understand how to conserve Monochoria korsakowii Regel et Maack, a threatened plant species that was once a common annual paddy weed, the germination responses of M. korsakowii seeds to two ecological factors, temperature and soil moisture, were analyzed under laboratory conditions. Fully imbibed seeds that had been cold stratified were able to germinate over a wide temperature range with a required thermal temperature of 13–39°C. Germination was highly dependent on water table depth. Regeneration failure at the germination stage under the dry soil conditions of the fallow fields during the germination season of this species may be one of the reasons for the decline in M. korsakowii. Monochoria korsakowii had adapted to the traditional farming system, but does not persist under today’s farming systems, which include laying rice fields fallow and the use of herbicides. These are the main factors that have led to its decline over the years and to its status as a threatened plant.

Reproductive ecology of endangered plants Euryale ferox Salisb. and Monochoria korsakowii Regel et Maack and their management in a vegetation restoration site

Reproductive ecology of endangered plants Euryale ferox Salisb. and Monochoria korsakowii Regel et Maack and their management in a vegetation restoration site

Outcrossing rates as affected by pollinators and the heterozygote advantage of Monochoria korsakowii

Monochoria korsakowii shows somatic enantiostyly as each plant bears two kinds of flowers: left- and right-handed flowers, which differ in style deflection. Since the capsules of M. korsakowii and M. vaginalis contain hundreds of seeds, we detected heterozygotes with two isozyme markers, Adh-1 and Pgi-2 locus, and measured outcrossing rates for single fruits in each of the target genotypes. Outcrossing rates were measured on an experimental population of Adh-1 1/ Adh-1 1 homozygotes, in which target plants of the Adh-1 0/ Adh-1 0 homozygote were planted at three different positions. Outcrossing rates for M. korsakowii ranged from 37% to 80% with pollinators and were 0% without pollinators. The variation in the outcrossing rates was significantly affected by the species of pollinators but was not affected by the position of target in the experimental population. When the flowers were visited by both Apis cerana japonica and Xylocopa circumvolans, the mean outcrossing rate was 72.3%, and when visited by Apis cerana japonica only, the mean outcrossing rate was 49.2%. The heterozygous seeds, detected by Adh-1 locus in the present experiment, had greater weight, and produced larger seedlings than those from homozygous seeds. In a comparative experiment, the outcrossing rate for M. vaginalis, was zero because it had been self-pollinated before the flowers opened, or it was cleistogamous.

ミズアオイとコナギの分類と北海道における分布について

ミズアオイとコナギの分類と北海道における分布について