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植物依靠向光性爭取最多的光線,以進行光合作用,製造食物供給所有生物。雖然在十九世紀時植物的向光性就已經被發現,並且參與植物向光性的主要荷爾蒙為植物生長素也已經熟知,但是主要是植物的哪一個組織接受光訊息以誘導向光性,以及細胞內的哪些分子參與訊息傳遞,則都不清楚。因此這個研究,以可以發射特殊波長的發光二極體為光源照射綠豆小苗以研究向光性,結果顯示藍光和綠光而不是紅和黃光可以誘導向光性。就向光性訊息傳導的組織層面的研究而言,將豆苗的葉、葉柄、生長點、子葉分別除去後,再側面照光,發現向光性要產生必須要有生長點或葉柄,並且發現莖可以誘導向光性,而葉子不能誘導向光性,因此莖是主要接受光訊息以誘導向光性的組織。就向光性訊息傳導的分子層面的研究而言,植物以鈣離子的螯合劑和鈣離子通道阻斷劑處理後發現,細胞質內鈣離子濃度的增加是藍光和綠光誘導的向光性所需要的過程,有趣的是藍光誘導向光性的訊息傳導過程中,除了經由細胞內的鈣離子濃度的增加外,還有其它鈣離子不參與的訊息傳導途徑。此外,以蛋白質磷酸?抑制劑和蛋白質去磷酸?抑制劑處理植物後發現,藍光和綠光所誘導的向光性訊息傳導,都包含蛋白質去磷酸?第1 和2a 型在細胞內的作用。因此植物的向光性需要有生長素才會表現,生長素由生長點製造後由生長點和葉柄儲存,在光刺激之下會誘導莖產生傳遞訊息,此訊息會傳遞到含有生長素的生長點和葉柄,使得生長素流向照光組織細胞,並且使得細胞內鈣離子濃度增加,活化蛋白質去磷酸?第1 和2a 型,進而造成植物的向光性。Phototropism allows plants to receive the most amount of light to perform photosynthesis, which produces food and energy for all organisms. The phenomenon of phototropism has been known since the 19th century, and auxin has been identified to be the main hormone involving in phototropism. However, the major plant tissue responsible for receiving light signal is not fully understood, and the signal transduction pathway within cells after light activation is not clear. Therefore, the phototropism of mungbean seedlings is examined by Light Emitting Diodes (LED) which produce the specific wavelength of light in this study. Results point out that blue and green lights rather than red and yellow lights induce phototropism of moonbeam. The phototropism of mungbean seedlings is further studied by plants whose leaves, petioles, apical meristem, or cotyledons were removed, showing that the presence of either apical meristem or petioles is needed for inducing phototropism. Also, stem ,not leaves, is the major tissue that receives light activation, and induces phototropism. The signal transduction of phototropism was further analyzed in the presence of calcium ion chelator and channel blockers. The signal transduction of phototropism induced by blue or green light contains the increasing concentration of calcium ion within cytosol. Interestingly, there is a calcium-independent tansduction pathway for blue light only to induce phototropism. Additionally, staurosporine (STA), a protein kinase inhibitor and okadaic acid (OKA), a protein phosphatase inhibitor, were used to study the signal transduction pathway of phototropism, and results indicated that protein phosphatase 1 and 2a is needed for both blue and green lights to induce phototropism. Conclusively, the phototropism is triggered by the reception of light by stem, and the light signal is transferred to apical meristem and petioles that reserve auxin produced from apical meristem. Auxin is then transferred to the cells that is illuminated, increases the concentration of calcium ion and activates protein phosphatase 1 and 2a in cells, and finally phototropism occurs.
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本研究將在來米粉、糯米粉、蓬萊米粉和糙米粉等米穀粉加入麵粉中做米饅頭,探討直接法與中種法所做各種不同比例米穀粉饅頭的差異,找出品質最佳的米饅頭。 研究發現:直接法米饅頭在糯米粉20%〜50%時,會Q軟有嚼勁,口感佳。蓬萊米粉米饅頭在鬆軟度和彈性方面品質最佳,可以加到40%。糙米粉米饅頭在鬆軟度和彈性方面次於添加蓬萊米粉,可以加到40%。在來米粉米饅頭,鬆軟度和彈性最差,不可添加超過40%,添加超過40%時,饅頭會變得乾、硬,易龜裂。 中種法米饅頭中,糯米粉米饅頭在鬆軟度和彈性方面品質最佳。由於中種法的麵糰膨脹力較強,饅頭組織變得柔軟細緻,口感好。因此,除了在來米粉50%的口感硬,不適合以外,其餘米穀粉皆可製作添加20%~50%的米饅頭。
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去年,升上了三年級,開始練習寫毛筆字「書法」是我們的國粹,同學們學得十分認真,但是一不小心,就弄得頭黑手黑連衣服褲子都黑了,上學期老師准許我們用原子筆寫作業,手和衣服也時常被原子筆沾得藍一塊、紅一塊,洗都洗不乾淨,真使媽媽和我們頭痛極了,於是請教老師,怎麼洗去墨汁和原子筆汁?老師說這是一個好問題,就讓我們一起來做研究吧!
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本研究主要是利用白膠與西卡紙製作成紙橋,乾燥後以一個人的體重對紙橋作初步測試,紙橋毫髮無傷。最後將三種不同斷面形式的紙橋模型,利用萬能試驗機測得紙橋的最大承載力。將試驗所得到的數值帶入所推導的力學公式中,求得紙橋三種不同斷面形式的關係。因為桁架的原理,讓紙橋能承受較大的載重,但在我們進一步的推導公式中發現,相同截面積所得到的壓應力應該相等,可是我們實驗所得到的結果並不相等;於是我們又進一步的探討,發現原來是我們所製作的模型並不是單純的桁架構件,所以會產生彎矩力以抵抗載重,此彎矩力相當於偏心載重所產生的彎矩,於是我們將所得數值加以比較,發現當偏心距愈大,所承受的最大承載力也就愈小。不同的斷面形式有不同之極慣性矩,極慣性矩愈大所能承載之彎矩愈大,最大承載力亦愈大。
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有一次看到太陽能電算機好神奇,照光就可運作,老師告訴我太陽能板照光可發電。拿出來把玩,發現它居然在太陽光改變角度下,其電流輸出有很大改變。一天當中太陽在天頂的位置都在改變,那是否可從中測出電流大小來知道太陽位置、時間及季節變化等?\r 當我著手去準備實驗時,發現太陽能板在室內黃色太陽燈管的反應,和室外太陽光不同,即太陽能板對高能輻射,能使光電流略增,且把多餘能量轉變成為熱能。那我是否可設計一個小實驗來證明上午 10 點到下午2點紫外線最強,及找出最危險的陽光入射角度呢?有一次在台北天文台拿到偏振光片,重疊時,角度的不同,可改變光的亮度,當角度成 90°時太陽變藍紫色,可見偏振光片可擋住低能量的光,而用來應證紫外線等高能輻射的工具。\r 媽媽的防曬乳液號稱可擋住紫外線,那是否可用太陽能板來作為偵測分析防曬乳液效能的工具呢?越想越興奮趕緊動手作實驗吧!
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在家裡的廚房、浴室之牆壁還有學校公廁以及排水溝附近,常發現有一種不知名,看起來有點像小蒼蠅又有點像是小飛蛾的昆蟲,經過判斷此種昆蟲為蛾蚋,是害蟲的一種,其佈滿細毛的身軀,可能藏有散布疾病的危機。本實驗即是以”蛾蚋”作為研究對象,首先先了解並記錄其生活史,再以其幼蟲為對象,試驗在不同清潔劑的處理下對幼蟲的影響。藉此推斷在自然狀況中,幼蟲是否能生存在會出現各種清潔劑的積水環境中,並期望能對蛾蚋有更深的認識,提供日後防治上的參考。實驗結果可以知道蛾蚋是屬於完全變態的昆蟲,整個生命週期約為一個月,但會隨溫度與食物量而有所增減。在感受性實驗中可以發現,測試試劑中的漂白水與潔廁劑對幼蟲的生存造成較大的影響,在低濃度處理下(0.125%)即可讓幼蟲死亡,但幼蟲對洗潔精的感受性較低,以50%的洗潔精處理皆至少能夠存活6個小時。一般而言,家庭或學校使用清潔劑時,濃度並不會太高,而實驗結果顯示當清潔劑在濃度不高且短時間內並不會對幼蟲造成太大的影響。水溝中除了有這些清潔劑外,豐富的有機質是牠們重要的食物來源,所以在能忍受清潔劑的威脅而又有食物來源之下,如不特別對環境做較徹底的清掃,難以杜絕此害蟲的存在。
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銅影響大豆及田菁根部生長、細胞死亡和訊息傳遞
隨著迅速的工業化,重金屬汙染已是嚴重的環境問題。在植物中,當植物體內累積過量的重金屬,對於植物根部、葉部等器官的生長與發育有嚴重的影響或傷害。銅離子為植物生長所必須之重金屬,但是過量銅離子會導致細胞死亡,生長受到抑制。本實驗以大豆( Glycine max )及田菁( Sesbania roxburghii )為植物材料,藉由Evans blue 染色法、螢光染色、西方墨點法、反轉錄聚合?鏈鎖反應等,觀察過量銅離子影響植物根部生長、細胞死亡和細胞訊息傳遞物質變化之情形,並探討過量銅離子影響大豆根部細胞死亡的訊息傳遞路徑。過量銅離子會限制植物根部的生長及造成根部細胞死亡。以螢光染色觀察根尖(ROS, reactive oxygen species)、Ca2+累積情形,根尖細胞Ca2+、ROS 累積隨處理銅濃度的增加而上升,可能影響細胞死亡程度。以Ca2+螯合劑EGTA 和W-7(CDPK(calcium-dependent protein kinase)、Calmodulin 抑制劑)前處理發現可以降低過量銅離子對大豆根部的細胞死亡程度,推測Ca2+、CDPK 參與銅引發大豆根部細胞死亡的途徑。為檢驗MAPK 參與根部細胞死亡的途徑,以西方墨點法偵測根部細胞MAPK 的TEY 或TDY 磷酸化,實驗結果發現,隨著過量銅離子濃度的升高,田菁、大豆根部42-kDa MAPK磷酸化情形有上升之趨勢。以RT-PCR 分析大豆MAPK1 及MAPK2 基因之表現量,發現在銅處理時大豆之MAPK1 和MAPK2 基因的轉錄情形增加。大豆( Glycine max )及田菁( Sesbania roxburghii )皆屬於豆科植物,可作為綠肥植物。探討銅影響大豆、田菁細胞死亡之訊息傳遞路徑,希望進而控制生物體所受的毒害情形及訊息傳遞途徑,加強生物體對重金屬的防禦機制,未來可以以基因轉殖等基因工程技術,轉入抗重金屬基因或增強植物體對抗重金屬的能力等,作為綠肥植物、抗重金屬植物吸 附重金屬來復育土地達綠色淨化等用途。 Many heavy metals are necessary for plants, but excessive quantities directly affect plant growth and survival of organisms, cause cell death, or even affect human life indirectly. Cu (copper ion) is a heavy metal, which is one of micronutrients essential for normal growth and development of plants. The purpose of this experiment is to study the effect of excessive copper on Glycine max and Sesbania roxburghii root tips. I conducted some experiments by means of Evans blue staining (analysis of cell death), western blot analyses, and fluorescence microscope in order to examine the way copper results in plant death. Measurement of root length and analysis of cell death showed that excessive copper could bring about the inhibition of plant growth as well as cell death. With fluorescence microscope, I found that excessive copper might increase the level of copper-caused reactive oxygen species (ROS) in both the root tips of Glycine max and Sesbania roxburghii. In addition, I used Oregon Green 488 BAPTA-1 so as to assess the accumulation of calcium ions in root tips and found that the exposure of root tips to excessive copper results in the accumulation of calcium ions. To investigate whether calcium ions and calcium-dependent protein kinase (CDPK) play a role in the cell death caused by excessive copper, I tested W-7, calmodulin and CDPK inhibitors, and EGTA, Ca2+ chelating agents, before copper treatment – immersing copper in CuCl2. In this way, plant cells would be effectively prevented from copper-caused death. Besides, to find out whether copper activates MAPKs in plant cells, I took advantage of western blot analysis with Phosphor-Map kinase Antibody and Map kinase Antibody. The results revealed that excessive copper might lead to TEY or TDY motif phosphorylation of approximate 42- and 64-kDa MAPKs in the cells of Glycine max root-tip and approximate 42-kDa MAPKs in the cells of Sesbania roxburghii root-tip. Furthermore, with RT-PCR, I found that the transcription of Glycine max MAPK1 and MAPK2 mRNA happens more frequently in root cells after copper treatment. In addition, this study suggested that the MAPK cascade CDPK pathway may function in the heavy-metal-signaling pathway in plant, and that calcium ions and ROS might get involved in the copper-caused death of plant cells. By studying signal transduction against heavy-metal toxicity in the plants, we can know how the organisms protect themselves. Sesbania roxburghiivv (or Glycine max), as green manure, could be used for metal-hyper-accumulator with the help of genetic engineering in the future.
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表面張力測量新方法-連通管原理的再應用
傳統表面張力的測量儀器多屬較為貴重、攜帶不便的精密儀器,不利於一般生活或教學上使用。我們發現開口不等高的連通管水面溢出低管口端時,高管口端水位比較高,於是試圖利用此液面高度差來測量表面張力。我們探討了連通管的高度、內徑大小及材質對於液面高度差的影響,並利用此原理測量已知表面張力的液體,將液面高度差所造成的壓力與標準值做比較。結果發現液面高度差確實可以用來測量表面張力,但是低管口端要用疏水性材質的細管,測量會較準確。如果使用內徑0.5mm 的鐵氟龍管,測量出來的液面高度差(h)×液體比重(ρ)的值,與標準表面張力(T)之間呈線性關係【T(dyne/cm)=10.6(h×ρ)+6.51】,相關係數高達0.9996 (p
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