• Horticultural Science & Technology
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• v.29 no.5
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• pp.494-499
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• 2011

Cold pretreatment, washing medium and composition of nutrient media may have marked effects on microspore embryogenesis. When microspores isolated from radish (Raphanus sativus L. cv. Gwanhun) flower buds were washed with Nitsch & Nitsch (NLN) medium liquid medium containing $130g{\cdot}L^{-1}$ sucrose (NLN-13), yields of microspore-derived embryos were greater than when using B5 liquid medium containing $130g{\cdot}L^{-1}$ sucrose. Microspore viability is known to decrease rapidly with storage; however, in this experiment, microspore viability was maintained for 24 h at $4^{\circ}C$ without media. Among the various medium concentrations used ($0.25{\times}$, $0.5{\times}$, $1.0{\times}$, $2.0{\times}$, and $4.0{\times}$ NLN liquid medium), $0.5{\times}$ NLN liquid medium induced the most efficient formation of microspore-derived embryos. In addition, microspore-derived embryos yields were greater when microspores were cultured in $0.5{\times}$ NLN liquid medium supplemented with $0.25{\times}$, $0.5{\times}$, and $1.0{\times}$ NLN microelements, compared to medium not supplemented with microelements. In this study, the highest yield of microspore-derived embryos was observed when the microspores derived from flower buds were washed using NLN-13 liquid medium and then cultured on $0.5{\times}$ NLN liquid medium supplemented with $0.25{\times}$ NLN microelements, followed by incubation at $25^{\circ}C$ for 30 days.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.263-271
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• 2001

Inoculated anthers of Capsicum annuum L. were subjected to 4 and 32$^{\circ}C$ pretreatment and their influence on the microspore viability, early cytological changes and the induction frequency of microspore embryo was investigated. Viability of freshly isolated microspores was between 62 and 64%. During temperature pretreatment, microspore viability showed a rapid decrease and this tendency enhanced with the 32$^{\circ}C$ pretreatment. Irrespective of temperature pretreatment, microspore viability declined to nearly zero after nine days. Before temperature pretreatment, most of the microspores in anthers were at late uninucleate stage. Several types of multinuclear microspores appeared from the 2 day after culture onwards, together with many degenerated and non-induced microspores. The 32$^{\circ}C$ pretreatment gave higher proportions of embryogenic microspore than other treatment. However, the temperature pretreatment had no clear effect on the frequencies of symmetrical binucleate rnicrospore. The multinucleate grains might originate either by symmetrical or asymmetrical division. After 2 days of pretreatment at 25 and 32$^{\circ}C$ , degenerated microspore increased above 50%. In contrast, during 4$^{\circ}C$ treatment, nucleus of most microspores remained intact for 14 days. The 32$^{\circ}C$ pretreatment produced more embryos than 4$^{\circ}C$ treatment. The most effective period of 32$^{\circ}C$ pretreatment was 4 days. In contrast, effective period of 4$^{\circ}C$ pretreatment was 2 days and longer time had deleterious effect on induction of microspore embryo.

• Journal of Plant Biology
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• v.36 no.2
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• pp.183-192
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• 1993

Efficient plant regeneration system was established through the culture of rice (Oryza sativa L.) microspores. Microspores released by anther shedding culture developed into proembryos and calluses in B5 medium within two weeks of culture. The optimal hormone and carbon sources were dependent on the genotypes used. Microspore's viability decreased rapidly in culture time, therefore less than 3% of the total microspores were viable at the 9th day when the first microspore division was observed. Of two types of microspores (pollen dimorphism) observed in culture, only the P-grain, larger microspores than normal one was able to divide. Using 4',6-diamidino-2-phenylindole (DAPI) fluorescence staining, it was confirmed that the symmetrical division of uninucleate microspore was the first step leading to continuous microspore development. Microspore-derived proembryos and calluses were regenerated to plants in N6 medium containing 1 mg/L NAA and 5 mg/L kinetin, and 78.3% of the regenerated plants were haploids.

• Journal of Plant Biotechnology
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• v.34 no.4
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• pp.363-373
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• 2007

To establish an efficient and reliable microspore culture system for pepper (Capsicum annuum L.), the effect of light intensity used for donor plant's growth, microspore isolation methods, the composition of culture medium, and culture period in light on the production of embryos were investigated. The viability of microspores taken from the plants grown under the light intensity of 10,000 lux was almost same as that from the lower (5,500 lux) light intensity, and the embryo induction and development were a bit higher when donor plants were grown under the lower light intensity. This result implies that lower light intensity does not interfere with the embryo induction and development. However, it was very difficult to prepare microspores for culture since only a small number of flower buds could be harvested from plants grown under the light intensity of 5,500 lux. Microspore isolation methods greatly affected microspores viability; that is, when microspores were isolated by blending rather than maceration, the greater number of viable microspores were easily generated (about 13 times). Among media used for microspores culture in this study, MN medium was most efficient for embryo induction and development. Total number of embryos and the number of cotyledonary embryos were highest when microspores were cultured in dark for 4 weeks, and then in light for one week. These results will be provide valuable information to set up efficient microspore culture system of hot pepper with a high frequency of embryo production, which are applicable to gene transformation and mutagenesis.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.13-17
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• 1995

In order to induce haploid plant through pollen culture, pollens of Paeonia albiflora were cultured on MS liquid medium The development of micospore through pollen culture was examined The effect of low temperature (5$^{\circ}C$, 10 days) pretreatment on callus induction and embryogenesis in pollen culture was not evident Calli derived from pollen gave rise to globular embryos when transferred onto solid medium containing 0.5 mg/, 2,4-L. The effect of low temperature pretreatment and medium. combination to pollen viability was unrecognized. Pollen viability was reduced as the culture proceeded.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.573-578
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• 2012

A total of eleven Chinese cabbage accessions were used for microspore culture and were grown to take basal data. Based on the collected data, breeding materials were chosen to develop new improved Chinese cabbage cultivars. The range of microspore-derived embryoid taken from flower buds was 1.6 to 35.4 embryoids. The embryoids from IT26110 and IT26153 among the Chinese cabbages were more than 34 per flower bud. The viability rate after cold treatment was low from 0.2 to 11.7%. The range of fertility rate was 7.7 to 58.8% in general but the IT26118, IT26122, IT26128, IT26130, and IT26164 were more than 50%. The result of their seed production ability by selfing was 11.9 seeds per siliqua in IT26128 while the others were less than 10 seeds. In the microspore culture using parents of different hereditary, the number of embryoids, the number of plants, the rate of fertility and their pure seed production ability appeared to be very different in doubled haploid lines obtained from fertile plants of Chinese cabbage.

• Korean Journal of Medicinal Crop Science
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• v.5 no.3
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• pp.196-201
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• 1997

To characterize active cells during microspore culture of Angelica gigas, flow cytometric and epifluorescent techniques were applied. The knowledge obtained from these types of studies will give us insight into early stage in plant development and may lead to the application of microspore-derived from haploid plants for breeding in recalcitrant species. Viability of cultured microspore differed depending on the developmental stages. Frequencies of active cells from tetrad, uni-nucleate, bi-nucleate and matured pollen were 12.8, 49.3, 42.3 and 31.7%, respectively. Alive microspores have luminescent the green fluorescence stained with FDA and blue fluorescence stained with DAPI.