流式細胞儀已經廣泛的應用在偵測多種生物體細胞核DNA含量及多倍體倍數。但是植物的細胞核懸浮液中常含有草酸鈣結晶，樣品中過大的雜質顆粒常會堵塞流式細胞儀吸取樣品的管子。首先，我們設計一種內裝化妝棉的過濾管，配合內含PVP-40的緩衝液移除樣品中的細胞雜質，使樣品更適合流式細胞儀分析。這簡單有效的方式可以移除樣品中的多醣類，草酸鈣結晶和代謝廢物等，使完整的細胞核被分離出來。利用此新方法分離蘭花成熟葉片的細胞核，並比較和先前分離方式分析的結果，證實我們發展方法比先前過濾方式能更有效的移除雜質，並發現蝴蝶蘭發育時具有內多倍體化現象。
在植物中廣泛存在內多倍體現象，其為細胞進行DNA複製後沒有進行細胞分裂，造成染色體重複加倍的過程。我們分析蘭花花朵發育時內多倍體現象產生的過程，並提出數學模型解釋內多倍體和細胞生長的關連。此模型包含邏輯生長模型和內多倍體模型。我們發現由低倍多倍體轉到高倍多倍體的轉換速率是費米函數的形式。用此函數描述倍體數間的轉換速率可明顯增進模型模擬的準確性。在花朵生長過程中，可以由計算得到植物生長速率、內多倍體間的轉換速率、以及每個倍體數所含有的總細胞數。模擬結果指出較高倍體數的細胞有較低的倍體數間轉換速率，而且其轉換到更高倍體數的能力會下降。當內多倍體現象停止時，細胞的鮮重也會停止增加。此外，平均細胞重和平均細胞倍體數呈現正相關，此結果說明內多倍體現象在細胞生長過程有重要功用。
溫度會影響植物生長及內多倍體進行。我們將利用第二章提出的數學模型及系統分析技巧，定量描述在蘭花花朵發育時，溫度變化對內多倍體的影響。較低的溫度降低植物生長速率和倍體數間轉換速率，但是因為低溫時生長期間較長，所以在細胞數目、花朵結構及多倍體細胞分佈上都沒有太大變化。結果顯示內多倍體細胞的分佈情形是分化過程中已經決定的，環境的變化並不會明顯影響倍體數細胞分佈形式。平均細胞重和平均細胞倍體數呈現正相關，而且此正相關會受到溫度影響，顯示細胞大小和其倍體數之間有正相關，而且正相關形式會受到溫度影響。此結果說明因為環境影響，會使得細胞有相同DNA含量卻有不同細胞大小。內多倍體現象可能可以藉由決定細胞核大小，進而控制植物細胞和器官的大小。

Flow cytometry is widely applied in determination of nuclear DNA content and ploidy level in many organisms. However, flow cytometers suffer from their intrinsic inability to tolerate large particles that associate with the isolated nuclei. A plant nuclei suspension can often contain a high level of crystalline calcium oxalate that blocks the fluidics system of the flow cytometer. First, we designed a cotton column, and added PVP-40 to the buffer to remove phenolic impurities and cytoplasmic compounds from plant nuclei, making the suspension suitable for flow cytometry. This simple and highly efficient protocol enables isolation of intact nuclei from plant tissues containing high levels of polysaccharides, calcium oxalate crystals, and other metabolites. Our protocol resulted in the isolation of intact nuclei from mature orchid leaves and flowers. This method can be used on recalcitrant tissues and is particularly effective on plants containing calcium oxalate crystals. It was also found that endoreduplication occurred during orchid leaf and flower development.
Endoreduplication, a process to amplify nuclear DNA without cell division, is widespread in plants. We analyzed the ploidy levels during orchid flower development and proposed an improved model to describe the relationship between endoreduplication and cell growth. Our model combined a logistic growth model with an endoreduplication model. We found that using the Fermi function to describe the transition rates from one C value to next higher C value significantly improved simulation of changes in growth and endoreduplication. The growth rate, endoreduplication transition rates, and total cell number of each C level at different developmental stages were computed. Our results indicated that cells with higher C values had lower transition rates and less potential for further endoreduplication, and the time that endoreduplication stopped occurred at the same time flower fresh weight stopped increasing. In addition, average cell fresh weight was positively correlated to average C value, suggesting that endoreduplication is a contributing factor to cell growth.
Temperature is the primary climatic factor affecting flower growth rate. A work used a new approach to quantify revealing environmental effect using an endoreduplication dynamic model and system identification techniques. Our study is much different from the previous studies for analyzing endoreduplication process determining the temperature effects on endoreduplication and cell division during flower development. The growth rates and endoreduplication transition rates decreased at lower temperature, but were compensated for by a longer period of growth. Therefore, the total cell number, floral structure and polyploidy pattern were not significantly affected. Our results indicated that systemic endoreduplication is intrinsically controlled by a differentiation program, and affected by environmental influences such as temperature changes. The relationship between the average C value and the average fresh weight is positive correlation and that can be effected by growth temperature, indicating that the final size of a cell is linked to its DNA content and the ploidy levels are regulated by environmental signals. This is clearly illustrated by the observation that the same cell with the same DNA content can reach different sizes depending on the environment. Endoreduplication cycle may determine nuclear size and be an important factor controlling cell size and organ size in plant.

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