Browsing by Author "Yang, Chih-Kai"

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    Molecular genetic and biochemical evidence for adaptive evolution of leaf abaxial epicuticular wax crystals in the genus Lithocarpus (Fagaceae)
    (2018-09-17) Yang, Chih-Kai; Huang, Bing-Hong; Ho, Shao-Wei; Huang, Meng-Yuan; Wang, Jenn-Che; Gao, Jian; Liao, Pei-Chun
    Abstract Background Leaf epicuticular wax is an important functional trait for physiological regulation and pathogen defense. This study tests how selective pressure may have forced the trait of leaf abaxial epicuticular wax crystals (LAEWC) and whether the presence/absence of LAEWC is associated with other ecophysiological traits. Scanning Electron Microscopy was conducted to check for LAEWC in different Lithocarpus species. Four wax biosynthesis related genes, including two wax backbone genes ECERIFERUM 1 (CER1) and CER3, one regulatory gene CER7 and one transport gene CER5, were cloned and sequenced. Ecophysiological measurements of secondary metabolites, photosynthesis, water usage efficiency, and nutrition indices were also determined. Evolutionary hypotheses of leaf wax character transition associated with the evolution of those ecophysiological traits as well as species evolution were tested by maximum likelihood. Results Eight of 14 studied Lithocarpus species have obvious LAEWC appearing with various types of trichomes. Measurements of ecophysiological traits show no direct correlations with the presence/absence of LAEWC. However, the content of phenolic acids is significantly associated with the gene evolution of the wax biosynthetic backbone gene CER1, which was detected to be positively selected when LAEWC was gained during the late-Miocene-to-Pliocene period. Conclusions Changes of landmass and vegetation type accelerated the diversification of tropical and subtropical forest trees and certain herbivores during the late Miocene. As phenolic acids were long thought to be associated with defense against herbivories, co-occurrence of LAEWC and phenolic acids may suggest that LAEWC might be an adaptive defensive mechanism in Lithocarpus.
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    Nuclear and chloroplast DNA phylogeography suggests an Early Miocene southward expansion of Lithocarpus (Fagaceae) on the Asian continent and islands
    (2018-11-08) Yang, Chih-Kai; Chiang, Yu-Chung; Huang, Bing-Hong; Ju, Li-Ping; Liao, Pei-Chun
    Abstract Background Most genera of Fagaceae are thought to have originated in the temperate regions except for the genus Lithocarpus, the stone oaks. Lithocarpus is distributed in subtropical and tropical Asia, and its ancestral population is hypothesized to be distributed in tropical regions in Borneo and Indochina. Borneo and the nearby islands (the Greater Sunda Islands) were connected to the Malay Peninsula and Indochina prior to the Pliocene epoch and formed the former Sundaland continent. The Southeast Asian Lithocarpus, is thought to have dispersed between continental Asia and the present Sundaland. The drastic climate changes during the Pliocene and Pleistocene epochs which caused periodic sea-level changes is often used to explain the cause of its diversity. The aim of this study was to establish phylogenetic relationships by analyzing nuclear (nrDNA) and chloroplast (cpDNA) DNA in order to describe and analyze the origin, causes of diversification and historical biogeography of Lithocarpus. Results Phylogeny reconstructed through the multiple-species coalescent method with nrDNA and cpDNA revealed that the continental-Asian taxa were clustered at the basal lineages. The derived lineages of tropical Lithocarpus, with the inference of a subtropical ancestral state, imply a southward migration in the Early Miocene period with subsequent in situ diversification in the Greater Sunda Islands. The gradual decrease in temperature since the Middle Miocene period is proposed as a cause of the increase in the net diversification rate. Conclusions The historical ancestral origin of Lithocarpus has been suggested to be mainland Asia. Southward migration in the Early Miocene period with subsequent in situ diversification could explain the current diversity of stone oaks in Southeast Asia. This study also considered the multiple origins of stone oaks currently indigenous to the subtropical islands offshore and near mainland China. Our results provide phylogenetic evidence for a subtropical origin of Asian stone oaks and reveal the process of diversification and how it fits into the timeline of major geologic and climatic events rather than local, episodic, rate-shifting events.
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    以顧客信任度為基礎之車用電腦研發策略
    (2018) 楊智凱; Yang, Chih-Kai
    近年來，隨著後個人電腦時代的來臨，電腦漸漸由個人用途轉變為專用機，廣泛運用於各種領域。工業電腦的應用需要更多的防護措施，注重在不同環境下的穩定，在惡劣的環境下要求穩定。例如：收銀機、提款機、公共資訊站、汽車生產線控制等，自動化時代已成為二十一世紀的必然趨勢。另一方面，網際網路的盛行，帶來新的應用及市場，因此工業電腦產業所面臨之市場潛力無窮。企業必須以滿足顧客信任的需求為其研發之最高指導原則，進而不斷的在其產品與服務上推陳出新，以維持其競爭優勢。然而，創新研發往往是個曠時費力的工作且具有高度的不確定性，如何及早確認研發方向並達到顧客信任，是為一項重要的研究議題。有鑑於此，本研究以顧客需求為基礎，以期在早期產品開發階段將顧客需求轉化為相關之產品規格，因此傳輸接口更改為U.2或M.2是提高客戶對產品信任度的最佳策略。使研發方向得以符合顧客之所需並提升客戶信任度。
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    臺灣殼斗科植物分類研究
    (2019) 楊智凱; Yang, Chih-Kai
    無中文摘要