鎘逆境對水稻幼苗脯胺酸累積和水分傳輸之影響

Effect of Proline Accumulation and Water Transport in Rice Seedlings Exposed to Cadmium Stress

黃脩惠(Hsiou-Huei Haung) ； 邱志郁(Chih-Yu Chiu) ； 陳財輝(Tsai-Huei Chen) ； 陳建德(Chien-Teh Chen)

《臺灣農業化學與食品科學》 43卷3期 (2005/06) Pp. 193-199

https://doi.org/10.6578/TJACFS.2005.026

摘要

本試驗以生長十二天之台中在來一號水稻(Oryza sative cv. Taichung Native 1)為材料，進行鎘逆境影響水稻幼苗生長、蒸散速率、脂質過氧化產物(MDA)，鉀離子濃度及脯胺酸濃度等的研究，並探討鎘在水稻幼根滯留的機制。水稻幼苗經氯化鎘(0-500μM)處理24小時後，根部鎘濃度隨鎘處理濃度提高呈線性增加。但地上部鎘濃度在10μM 鎘處理下，鎘的累積即有顯著差異。然而，當鎘濃度提高至100μM時發現並未增加地上部鎘的累積。據以推測低度鎘逆境下，植物有延滯鎘向地上部輸送而累積於根部的趨勢。測定蒸散速率，發現水稻幼苗之蒸散速率於10μM鎘處理後即顯著下降。測定低度鎘逆境下水稻幼苗根部的生理變化，發現根部MDA濃度於鎘處理濃度達500μM時才有顯著下降。水稻幼苗根部鉀的濃度於鎘處理濃度達100μM時顯著降低，地上部則於500μM鎘處理時才見降低。水稻幼苗根部脯胺酸濃度於10μM鎘處理濃度時即有顯著增加，且隨根部鎘累積濃度的增加而增加，地上部則於500μM鎘處理時才見增加。綜論之，低度鎘逆境下水稻幼苗地上部鎘濃度，並未隨根部鎘濃度的增加而增加，其滯留於根部的可能原因與水稻根部脯胺酸濃度的增高有關。進一步進行低濃度鎘 (50μM)逆境的時間序列試驗，結果也證實隨著鎘處理時間的增加，水稻根部脯胺酸累積量相對增加，水稻蒸散速率雖下降，但未逐漸加劇。

關鍵字

鎘逆境 ； 水稻幼苗 ； 脯胺酸 ； 蒸散速率

並列摘要

Cadmium (Cd) exposure affects the growth, transpiration rate and proline content of rice seedlings, by which the transport of C d may be retained. Twelve-day-old rice (Oryza sative cv. Taichung Native 1) seedlings were subjected to excess C d treatments, and the dry weight transpiration rate, malondialdehyde (MDA, product of lipid peroxidation), potassium content and proline content were assess. Excess cadmium chloride (0-500μM) was imposed on the culturemedium for 24 horns. The presence of excess C d increased C d content in the roots. Though the C d content in the shoot was increase under 10μM C d treatment, the continue increase of C d amount in medium did not increase the C d content in the shoot, suggesting a mechanism of holding C d in the roots has initiated. The impose of C d decreased the rate of transpiration at the concentration of 10μM C d. Cadmium treatment decreased the MDA content of root as the concentration of C d reached 500μM. Potassium content w as decrease in the shoot and root by the application of 500 and 100μM C d respectively. The proline content was increase in the shoot and root by the application of 500 and 10μM C d respectively In conclusion, the retaining of C d in the rice root might relate to the increase of proline content. The results of the time course of C d treatment also revealed the trend of the increase of proline content, and the temporal decrease of transpiration rate.

並列關鍵字

Cadmium ； Rice ； Proline ； Transpiration rate