低溫逆境下絲瓜的生長及其韌皮部蛋白質類型的的變化

Effects of Low Temperature on Plant Growth and Their Protein Patterns in Phloem Exudates of Luffa Cylindrica

一週大的絲瓜（Luffa cylindrica）幼苗置於人工氣候室內，分別在30, 25, 20及15°C下處理四週後，以鮮重量及大小為生長指標，同時以單向電泳活性檢定法及雙維電泳分析法，調查植株體上抗性同功酵素與韌皮部蛋白質的類型變化。低溫處理不但抑制植物的生長，同時也增高根／莖比值。在30, 25°C下植株的葉片生長曲線都呈S形，然而15°C下則為非S形。植物長在15°C下其抗性同功酵素呈出：綠色的葉片及子葉的第二群同功超氧歧化酶有增強的現象；下胚軸及子葉上的第二群同功過氧化酶有增強現象；葉子上的第三群同功酸性磷酸酶被誘導生成。以上同功酵素圖譜也顯示其類型具組織和發生時期的特異性。此外，植株長在15°C下也誘導一新合成的韌皮部蛋白質，其分子量為36.5 kDa而等電點為pH 4.9。

One-week-old seedlings of luffa cylindrica were grown in phytotron at 15, 20, 25 and 30°C for four weeks. Growth curves of the plant organs were compared with their fresh weight and size during the cultured period. Isozymes of defensive enzymes and phloem proteins were measured on eletrophorogram of native gel and 2-dimensional gel, respectively. Low temperature not only retards plant growth, but also increases the ratio of root/shoot. Leaf blades of plants grown at 25 and 30°C have typical sigmoid growth curve but with different slope factors. Plants grown at 15°C do not show the normal sigmoid curves in leaf growth. Isozyme patterns in plant grown at 15°C are changed as follows: two minor bands in group II isozyme of acid phosphatase were induced in green leaf blades and cotyledons; group II isozymes of peroxidase were enhanced in hypocotyls and cotyledons; group III isozyme of acid phosphatase was induced in leaf. All isozyme patterns show the specificity in tissues and developmental stages. One of phloem proteins with molecular weight of 31.5 kDa and pI at4.9 was induced in plants grown at 15°C.