| Systemic acquired resistance is a common resistance reaction direct against many kinds of phytopathogen. Many research have test and verify it. But now this on, mechanisms of SAR and signal transduction channel are still unclear. This paper is on the base of interaction of tobacco and TMV to research what is signal molecule and where it is in total signal transduction channel. the results indicated that: A series of biochemical and physiological reactions in tobacco happened after the stress of TMV. The activity of SOD POD. CAT. LOX increased rapidly. Those enzymes all reached their peak in 24-48h, but the speed of increase and the number of the peak are both different in resistance plant and sensitive plant. The level of Oiin Xanthi-NN form two peaks, but only one in K346 and rapidly decreases to normal. The average level of H202 is obvious higher in Xanthi-NN than that in K346 and it insist on the level for a long time. Those mean that Oj and H2O2 act as signal molecule in signal transduction and the level of them must be stable in a relatively long time. 0.0 1% salicylic acid is sprayed to the middle leaves of Xanthi-NN and K346. After two days, inoculate TMV to research the affection of SA to the level of active oxygen species (AOS) and related protection enzymes. The result means: SA can induce notable resistance of Xanthi-NN and K346, but the affection to K346 is more notable than that to Xanthi-NN; The degree of symptom in K346 is 45% less than control after treated by SA. The level of H202 and SOD in Xanthi-NN both increases, but that of Of and CAT both reduces; In K346 the time and the number of Of reachs the peak later or less than that of control, but the level of H2O2 is induced. The result of electrophoresis of pathogenesis-related proteins means: because of the induced of SA, three kind of new proteins appear in leaves being treated at 1 20h and a kind of new protein has appeared in leaves not being treated since 96h. although new proteins doesn抰 appear in K346, density of protein become more than control. 69 Before use TMV inoculate two kind of tobacco with different resistance 0.1mM ~7~Iti!i and Mannite are sprayed to their middle leaves (usually the fourth leaf) to change the active oxygen species (AOS)level in plant .The change of AOS can affect the signal transduction channel. The result appears :(l)the affection to middle leaf for those matters sprayed to different tobacco is more notable than leaves not being treated ;(2)after ~ sprayed to Xanthi-NN, the level of AOS increases rapidly and is very high in a relative long time ; The average Level of 02 and H202 in treated leaf is higher than that of CK in 12 ?96 hours. After Xanthi-NN treated by Paraquat, activity of SOD~. CAT~ LOX all increase, but the level of SA increases a little .In K346 treated the average level of AOS increases, but not induces spacious HR;(3) too kind of tobacco treated by Mannite increasing of the level of AOS is inhibited, but the Xanthi-NN also present HR and mosaic symptom appearing in K346 is sooner than in Xanthi-NN, so is the degree of mosaic. |
