多效唑浸种对渗透胁迫下玉米根边缘细胞发生的影响

以‘农大108’玉米种子为材料,采用不同浓度(50、100、150、200、250、300、350 mg·L-1)的多效唑溶液进行浸种处理,研究其对渗透胁迫(20％ PEG-6000)下玉米种子萌发、根系生长和根系边缘细胞数目、活性及黏胶层厚度的影响.结果表明:与对照相比,渗透处理抑制了玉米种子露白与根系生长,增加了边缘细胞数目与黏胶层厚度.预先用多效唑浸种后再进行渗透胁迫处理进一步降低了主根的长度,但增加侧根的生长而使根系鲜重增加,进一步增加了根边缘细胞黏胶层厚度,在一定程度上减少了由于渗透胁迫造成的边缘细胞数目的增加程度.无论是渗透处理还是预先用多效唑浸种处理对边缘细胞活性的影响均不大.可见,多效唑浸种能够增加玉米根系的抗旱能力与边缘细胞黏胶层厚度的增加有关,而与边缘细胞数目、活性的关系不大；多效唑浸种溶液的适宜浓度范围为200～250 mg·L-1.

Effects of Seed-Soaking with Paclobutrazol Solution on Generation of Maize Root Border Cells under Osmotic Stress

The experiment was carried out with ’Nongda 108’ to investigate the effects of paclobutrazol(50,100,150,200,250,300,350 mg·L-1) on corn seed germination,root growth,the number,viability and mucus layer thickness of root border cells in corn seedlings under osmotic stress(20% PEG-6000).Compared with the control,seeds germination and root growth of corn seedlings under osmotic stress were obviously inhibited,while border cell number and mucus layer thicken were greatly improved.In the maize roots treated by seed soaking in paclobutrazol solution,decreasing length of the taproot,increasing number of the lateral roots and increasing weight of the root system were found.Thickness of the border cell mucus layer increased,while the increasing degree of the border cell number by osmotic stress reduced in treatment of seed soaking in paclobutrazol.Both the osmotic and the paclobutrazol did not show significant effects on the viability of root border cells.It is indicated that PP333 could enhance maize ability to mitigate the osmotic stress dangers through improving mucus layer thickness of border cells,having little relations with the number and viability of root border cells.The most suitable consistency of PP333 is 200~250 mg·L-1.