ABA和GA刺激的ROS代谢调节水稻幼根伸长分析

本文探索水稻幼根生长过程中ABA和GA对ROS代谢的影响,结果显示:低于0.5μmol/L的ABA促进根伸长,超过此浓度的ABA抑制根伸长;H2O2与ABA相似,低浓度促进而高浓度抑制;在观察浓度范围内,GA促进根伸长.利用3,3'-二氨基联苯胺(diaminobenzidine,DAB)组织化学染色方法检测根尖部位H2O2代谢情况,结果显示,对照、ABA,GA和ABA+GA处理后,根尖分别呈现浅黄色、深棕色、黄色和深棕色,说明ABA比GA诱导较多H2O2产生.进一步研究发现,ABA和ABA+GA分别上调过氧化物酶(peroxidase,POD)活性13.4%和8.37%,GA下调POD活性19.0%;同时,ABA和ABA+GA处理分别下调过氧化氢酶(catalase,CAT)活性14.8%和16.3%,GA则上调CAT活性5.16%.以上结果表明,ABA可能通过上调POD和抑制CAT活性来提高ROS含量,而GA与之相反,严谨控制ROS浓度,促进水稻生长.

Analysis of ABA-and GA-stimulated Reactive Oxygen Species Mediating the Elongation of Rice Seeding Roots

The results show that less than 0.5 μmol/L ABA accelerates the rice seeding root elongation, but more than 0.5 μmol/L ABA turns to inhibit the process. Similar to ABA, H_2O_2 accelerating turns to inhibiting the rice seeding root elongation at 1mmol/L concentration. GA accelerating rice root elongation in the all concentration is used. By diaminobenzidine (DAB) stains to detect the H_2O_2 accumulation in rice seeding roots, the results show that H_2O_2 accumulation are intensified by ABA or ABA +GA treatment but not by GA. Moreover, ABA and ABA +GA up-regulated the activity of peroxidase (POD) in 13.4% and 8.37%, respectively, but GA down-regulated the activity of POD in 19.0%. Moreover, the activity of catalase (CAT) is strongly down-regulated by ABA and ABA + GA in 14.8% and 16.3%, respectively, but GA up-regulated the activity of CAT in 5.16%. In a word, ABA and GA control the activities of both POD and CAT and thus regulating the H_2O_2 accumulation in rice seeding roots, suggesting that ABA and GA may modulate plant growth and development by mediating the ROS metabolism.