| Abstuct:Chenopodium Ambrosioides L. which natives to tropical America is a herbaceous and an invasive plant. Today, it widely occurs in China including Beijing, Shanghai and Chongqing Cities, and shangdong, shanxi, zhejiang, Jiangxi, Fujian, Taiwan, Guangdong, Hainan, Hunan, Hubei, Sichuan, Guizhou, Yunnan Provinces. It threatens the natural systems by displacing native plant communities and establishing monocultures in new habitats. The study was allelopathy of tissue cultured C. ambrosioides root exudates on root border cells and root tip cells of soybean.The study was effects of hormone and carbon source on the induction callus and adventitious root by using stem and leaf of seedlings. The results showed that Optimum mediums for stem callus and for leaf callus were MS+GA30.5mg·L-1+KT5mg·L-1+NAA2.5mg·L-1+6-BA2.5mg·L-1sucrose30g·L-1+agar7g·L-1, pH=5.8and MS+GA30.5mg·L-1+KT5mg·L-1+NAA5mg·L-1+6-BA2.5mg·L-1sucrose30g·L-1+agar7g·L-1, pH=5.8, Optimum mediums for induction of adventitious root was MS+6-BA0.5mg·L-1+IBA0.5mg·L-1+KT0.5mg·L-1sucrose30g·L-1+agar7g·L-1, pH=5.8. The major compounds in tissue cultured C. ambrosioides root exudates were Cyclopropaneoctanal2-octyl(27.75%),(R)-(-)-14-Methyl-8-hexadecyn-1-ol(19.71%) and7-Hexadecenal(11.06%).The root border cells of soybean development biological characteristic and responsing to tissue cultured C. ambrosioides root exudates were studied by using aeroponic culture and light microscope techniques. The root border cells of early stages were round and oval, which of later stages were clavate. The first root border cells occurred after germination16h (the root length was12.2mm), then PME activity was synchronously153.7%higher than primary root tip emergence. After germination21h to26h, releasing rate achieved2253root border cells per hour. PME (Pectin methylesterase) activity reached the maximum at26h and the number of the root border cell reached its maximum (about18149) at31h. With concentration of tissue cultured C. ambrosioides root exudates increasing and treatment time extending, the number and viability of root border cells decreased consecutively but PME activity increased. Some granular substance gathered around free root border cells, this phenomenon might be explained that root border cells exudates chelated the tissue cultured root exudates. The results suggested that tissue cultured C. ambrosioides root exudates had a certain effect of stress on root border cells of soybean, and root border cells could alleviate this stress through programmed cell death and chelating exudates.By using the biochemical analysis, the study was tissue cultured C. ambrosioides root exudates on root tip cells of soybean oxidative damage. The results showed that tissue cultured C. Ambrosioides root exudates could stimulate oxygen production and accumulate quickly malonaldehyde in high concentration100and1000μg·mL-1), they were significant difference. With the increase of treatment time, SOD and POD activities increased continuously in lower concentration1and10μg·mL-1), but it increased at first and then decreased in higher concentration100and1000μg·mL-1). CAT activity kept increasing trend, and it could reanch the maximum at24h. According to the analysis of DNA agarose gel electrophoresis, DNA of root tip cell of soybean didn’t destroy by tissue cultured C. Ambrosioides root exudates.In summary, the tissue cultured C. Ambrosioides root exudates had an effect on root tips cells of soybean. Although root border cells could alleviate poison from root exudates through programmed cell death and chelating exudates, tissue cultured C. Ambrosioides root exudates could interfere with ROS metabolishm, stimulating the production of O2-and making plasmalemma overoxidation. But tissue cultured C. Ambrosioides root exudates didn’t damage DNA of soybean root tip cells. |
