玉米切離葉片老化時的代謝有關物質分解的幾件事

Abstract

照光生長約8天的玉米(Zeamays)幼苗，剪下其第一片葉子前段，於黑暗28℃下，漂置在水或1×10-5MBA溶液中。漂置於水中者，葉綠素及蛋白質含量在兩天以後明顯地減少，但BA可以延緩這些徵狀的出現（劉．1984）。假如剛剪下的葉片，先在光線下，在35S－甲硫胺酸震盪5小時，再做如上述之處理，則黑暗中BA能使葉片保有較多的放射性於蛋白質部分及細胞中。由此可知，BA壓制了老化時蛋白質分解活性的加快及結構的瓦解。 當細胞分解代謝強烈發生時，其呼吸速率增加，但是BA也壓制這個現象的發生。細胞壁上半木纖維質I，半木纖維質II與纖維素的含量在老化時並沒有顯著的減少。酸性磷酸分解?的活性大大的增加。

If the first leaves of 8-day-old, light growing corn (Zea mays) seedlings were cut and placed in the water or 1×10-5 M BA solution under 28℃ and in the dark, the leaf segments in the water would lose chlorophyll and proteins significantly after 2 days, and the BA treatment would delay the appearance of these symptoms. (Liou, 1984). If the leaf segments were incubated with 35S-methionine for about 5 hours to label some proteins under the light and then transfered to the treatments described above, it was found that BA treatment could make the leaf hold more radioactivities in the protein fraction and inside the cell. So, I conclude that BA can suppress the increase of protrolytic activity and deterioration of cellular structure. When the degradation metabolism occurs extensively, respiration rate of leaf segments increases. BA can also suppress this increases, The hemucelluloseI, hemicellulose II and cellulose of the cell wall did not decrease significantly. But the acid phosphatase acttivities increases strongly.