• Journal of Plant Biology
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• v.38 no.1
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• pp.95-105
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• 1995

Complete microsporogenesis of Hibiscus syriacus L. were carried out employing LM, TEM, and SEM to investigate the pollen ontogeny that undergoes considerable structural differentiation. The process first began with several cell diYisions in the anther primordium that produces 3 different tissues of epidennal, archesporial, and connective tissues. Only archesporial tissue involved further differentiation into the tapetum and formation of reproductive cells, pollen mother cells (PMC). The tapetum and PMC were closely associated with each other structurally and metabolically by exhibiting numerous plasmodesmata, mitochondria, and many small vacuoles in their dense cytoplasm. A callosic wall began to surround the PMC while meiosis took place in the PMC to produce 4 microspores. When thick callose encircled each microspore as a frame, the sporodenn development initiated from the plasma membrane of a pollen grain in a tetrad. The first fonned sporoderm layer was bacules and tectum of sexine that originated from the plasma membrane. After the dissolution of a callose, further development Qf sporoderm continued in the order of nexine 1, nexine 2, and intine layer. The nexine layer was thicker (ca. $2-3.5\;\mu\textrm{m}$) than the intine layer whose thickness was about $0.9-1.5\;\mu\textrm{m}$. Upon completion of the sporoderm development, that is after intine formation, spines and apertures of pollen surface ornamentation initiated from the tectum. Spines were dimorphic, about $4-9\;\mu\textrm{m}\;an;15-20\;\mu\textrm{m}$ in length, and no basal cushion was detected. The mature pollen grains ranged $100-200\;\mu\textrm{m}$ in diameter, but their average was about $170\;\mu\textrm{m}$. About 120 spines were observed over the spheroidal pollen surface. Apertures were simple punctures of $2-3\;\mu\textrm{m}$ in diameter and about 50 apertures were arranged somewhat helically over the surface. Comparing such features of form and size of the pollen, sporodenn sculpture and structure, and aperture and spine conditions with known evolutionary trends in the genus Hibiscus, Hibiscus syriacus seemed to possess many advanced features in the sporodenn differentiation.iation.

• Journal of Plant Biology
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• v.36 no.4
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• pp.399-406
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• 1993

유채(Brassica napus L. cv. Topas) 소포자 배양에 의한 기내 배발생 과정을 관찰하고 발생과정에 따른 총단백질의 변화 양상을 이차원 전기영동을 통하여 분석하였다. 배양에 적합한 소포자의 발달 단계는 4,6-diamidino-2-phenylindole (DAPI) 형광염색으로 핵상관찰을 통하여 결정하였다. 최초의 소포자 생존율은 63.9%였으며 이러한 생존율의 차이로 배양초기에 소포자의 이형성이 나타났다. 배 발달 경로에 따른 최초의 세포분열은 화분벽 안에서 균등분열로 시작되어 배병의 발달이 선행된 후 배 발생이 일어났으며, 구형, 심장형, 어뢰형으로의 배 발달은 여러 조직의 분화와 더불어 빠르게 진행되었다. 소포자배 발달과정을 치상단계의 소포자, 배양 3일째의 초기 분열세포, 구형 및 심장형배, 어뢰형배, 성숙한 자엽단계의 배 등의 5단계로 나누어 각각 2차원 전기영동을 수행한 결과, 최초 소포자 단계에서 나타났던 23개의 단백질들은 배 달달 경로로 진행됨에 따라 사라지고, 배양 3일째에는 8개의 단백질이 특이적 또는 지속적으로 발현되었다. 배의 발달과 더불어 20∼50 kD 사이에서 총 42개의 단백질이 급격히 나타나거나 또는 후기 배로 진행하면서 점차적으로 발현되었다.