2004-01-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/664614摘要：由於全球溫室效應，造成地區性雨量分配不均，全球有越來越多的地區面臨無足夠淡水以供作物灌溉之困境。而台灣為一海島，因長期抽取地下水而引起海水入侵，造成嚴重之“鹽土“問題。再加上在作物栽培過程中，肥料之施加及長期灌溉的結果，造成土壤鹽化情形日趨嚴重。土壤鹽化亦是全球性的重要危機，其造成作物生產之嚴重問題，全球有20%的可耕地具有鹽害問題，如果以灌溉土壤而言，則50%具有鹽害 (Flower and Yeo, 1995)。高鹽逆境 (salt stress)會造成植物細胞缺水及離子不平衡等現象，進而影響植物的生長與發育。在農業生產系統中，鹽逆境則嚴重的影響作物之產量。因而了解植物在鹽逆境下之生理代謝反應及自我防禦機制，並進而應用於改進作物對鹽逆境之適應性及耐受性則為重要的課題。 鹽害對植物生理、代謝的影響層次極廣，如欲更有效率的改良水稻或其他作物對鹽逆境之耐受度，則需全面性地了解作物對高鹽環境之感應、訊息傳導及各種反應之作用機制。在改良作物以提高其抵抗鹽害能力之策略上，除了考慮提高產量之問題，亦應考慮逆境對其產物品質之影響。為解決這問題，本計畫全程規劃為三年 (93 – 95 年度)，預計將<br> Abstract: Salinity is one of the serious abiotic stresses for plant growth, and it reduces the crop productivity. Based on the estimation of the United Nations Environment Program, 20% of global agricultural land and 50% of irrigated cropland were under salt stress (Flower and Yeo, 1995). In order to produce the enough food for the continuously increasing population on the limited land, one of the most important things is to improvement the salt tolerance of crops. Soil salinity caused water deficient and ion imbalance stress in cells. Some reports indicated that kinds of the defense mechanisms could be induced in plant cells to against salt stress. First, salt stress activates plasma membrane/ vacuole ion transporter to keep the low concentration of Na+ in cytosol; second, synthesis of compatible solutes could be induced in plant cells to balance the cell osmotic potential, and accumulation of LEA and HSP protein was also increased for cell protection. In addition, some enzymes for scavenging the reduced oxygen species (ROS) will be accumulated when cells were salt-stressed. Although several genes involved to response the salt stress were identified, the molecular mechanisms of salt tolerance in plants are still unclear. Most of the previous studies related to the salt tolerance were focused on the model plants - Arabidopsis, and the knowledge about it in crops is limited. Effects of salt stress on crop production are board. Since it is expected to improvement the quantity and quality of products at the same time in salt-stressed crops in the future, an effort will be made in our project to identify genes that are responsive to the salt stress in rice (Oryza sativa). To achieve this, we will screen the salt-sensitive and salt-tolerant plants from the T-DNA gene trapping and activation tagging rice (TNG67) mutant library established by Dr. Su-May Yu (Institute of Molecular Biology, Academia Sinica). Then, the function and regulatory mechanisms of salt stress responsive genes and promoter fragments would be analyzed. The salt-responsive gene and promoter will be applied to increase the salt tolerance of rice plants. These data are not only provide the genes to improve the salt tolerance of rice, it also could be compared with the results from other sub-projects to understand the cross talk between salt stress and other abiotic stress (e.g. drought and temperature-shock stress). Finally, all the stress-responsive and developmental regulated genes that we get from all of our sub-projects will be collected and made to be a gene chip, and it could be used to study the other biotic and abiotic stress-defense mechanisms.水稻T-DNA 突變系鹽逆境Oryza sativarice salt stressT-DNA mutant