Protective Effect Of Root Border Cells On Root Tip Cell By Treated With Volatile Oil From Chenopodium Ambrosioide L.

Chenopodium Ambrosioides L. is known as smelly grass, insecticidal mustard,which is classified in the family of Chenopokiaceae. It is an annuals herbs, whichincluded in the list of the second batch of invasive plants (Huan Fa [2010], No.4).Studies have reported that C. Ambrosioides have allelopathic effects on plant seedgermination, and have some genetic and cellular toxicity. The primary researches in ourlab showed that root border cells（RBCs）of recipitent plants have the effect ofameliorating on allelochemical stress caused by C. Ambrosioides to some extent, but themechanism of remains to clarified by the further researches. To investigate theprotective effects of RBCs by allelopathy of volatile oil from C. Ambrosioides and themechanism of the effects, using aeroponic culture and on the basis of analyzing the pea(Pisum sativum L.) RBCs biological characteristics, we further studied the protectiveeffects of RBCs on pea root tips with RBCs or without RBCs under the stress of volatileoil from C. Ambrosioides by the treatment of pea root tips with the dose of0μL,2μL,4μL,6μL,8μL and10μL. The results showed that:(1) When the pea root grows about12mm in length, the RBCs began to appear andthe shape at first mostly for nearly circular, after gradually become nearly elliptic,elongated, rod–shaped and kidney shape.When the root length was reached to25mm,the number of RCBs reached the maximum of about14000, the cells viability rate keptabout80%.(2) By the treatment of pea roots with different doses of volatile oil from C.Ambrosioides for6h,12h and24h respectively, Effects of volatile oil from C.Ambrosioides on the production of RCBs of pea. The results showed that, volatile oilfrom C. Ambrosioides could induce the death of pea RCBs, and with the increasing of the treatment time and treatment dosage, the degree of the toxic effect increases. Underthe effect of volatile oil, in the keeping group, the mortality induced by low dose ishigher, high dose treatment group was on the contrary. Compared with the control, withthe increase of treatment dose, the number of RCBs increased first and then decreased,however, PME activity continued rising. Compared with removing group, the number ofRCBs reduced less in the keeping group. Indicate the RCBs can alleviate volatile oilpoison effect. In the removing group, PME activity increases more, suggests thatallelopathy of C.Ambrosioides induced RCBs producing.(3) By the treatment of pea roots with different doses of volatile oil from C.Ambrosioides for24h,48h and72h respectively, Effects of volatile oil from C.Ambrosioides on cells antioxidant system and genetic toxicity of root tips. Furthermore,the ameliorating effects of RCBs under volatile allelopathy were also studied. Theresults show that the volatile oil of C. Ambrosioides had a genetic toxicity. Under thevolatile oil stress, mitotic processes of pea root tip cell was inhibited significantly. Indifferent group of lasting for different time, with the increasing of the dosage of volatileoil, mitotic index declined, the microkernel increased and then decreased. DNA Ladderanalysis showed that volatile oil did not induce the cell apoptosis of pea root tip cells.Compared with the group of keeping RCBs, the group of RCBs had removing moreapparent genetic toxicity. In the keeping RCBs group the treatment of high dose (10μL)and long time (72h) caused the number of RCBs about70%of the treatment of lowdose (2μL) for24h. However, in the removing RCBs group, under the same conditions,the number of RCBs by the treatment removing RCBs was about50%of the treatmentkeeping RCBs, indicating that the RCBs could alleviate genetic toxicity caused byvolatile oil. Volatile oil from C.Ambrosioides could restrain the growth of pea radical,the inhibition effect was more apparent under the condition of removing RCBs.Compared with the control, the MDA content and SOD activity of root tip increasedsignificantly, and the activities of POD and CAT decreased obviously. These resultswere positively correlated with volatile oil dose. Compared with keeping RCBs group,removing group had a higher MDA content, lower SOD activity, and the decline of theactivities of POD and CAT was even more. These results showed that, the RCBs hadprotective effects on root tip.In summary, volatile oil from C. Ambrosioides can induce the generation of RCBs,cause oxidative and genetic damage to root tip meristemaatic cells and inhibit the growth development of the root. The RCBs can ameliorate the damage caused byallelopathy from volatile oil from C. Ambrosioides stress.