| Histological and cytological interaction and products between wheat and wheat stem rust were studied using whole leaf clearing and staining technique, electronic microscopic observation and PAGE electrophoresis in the paper. The results was indicated as it follows:1. There were no histological differences shown between compatible and incompatible interaction of wheat stem rust and wheat till 96 hrs (primary infection hypha formed) after inoculation. Once the hautorial mother cells (HMC) and haustoria formed, the differences were shown below: .In the incompatible interaction, the mycelia, HMC and haustoria were inhibited. The hypersensitive response appeared, wheat cells became necrotic and the size of rust colony was smaller than that in the compatible interaction.In the compatible interaction, the mycelia grew around the wheat cells and developed haustoria in the wheat cells. 120 hrs after inoculation, there were a number of dead cells in the wheat leaves, which suggested that the recognition of single Sr. gene lines and races of wheat stem rust took place posterior to the formation of HMC or haustoria.2. Transmission electronic microscopic observations were done with incompatible and compatible interactions between wheat and stem rust. In the incompatible interaction, the result indicated that mycelia and haustoria were inhibited and distorted in shape. The wheat cells adjacent to the infection body became unclear or black. The inhibition on haustoria occurred in two different ways, i.e early inhibition and late inhibition. The wheat cells also produced some new structures responded to infection of wheat stem rust, which could affected the development of mycelia or haustoria, and showed hypersensitive responses, which is uniform as histological study. In the compatible interaction, mycelia and haustoria grew healthily in wheat leaves.3. Intercellular washing fluids: IWF, were extracted from wheat leaves Vacuum pump after infiltrated with double distilled water. The activity of elicitors was found in IWF from infected wheat leaves. The color of IWF was yellow andthe pH value was about 6. IWF from incompatible wheat /stem rust combination could induce HR in wheat leaves, however, the activity of IWF derived from compatible combination was weaker than that from incompatible combination. IWFs from health wheat leaves and water-injected leaves had no magnificent function to stimulate defensive enzymes. The IWF had no important influence on urediospore germination ability. Only those IWFs from infected leaves 5 days after inoculation had the inducing ability to stimulate. The limitation dilution was 100 X. The IWF from infected leaves could induce HR reaction, the resistance of wheat to stem rust fungi, specifically to specific race.4. Study on biochemical property of IWF showed that the active component of IWF was glycoprotein. The content of soluble sugar and protein in IWF from the incompatible group was higher than that from compatible ones. The later was higher than that from healthy leaves. The protein bands of IWF from infected leaves 7 days after inoculation had two ones more than those from healthy leaves. The activity of p-1,3 glucanase and chitinase of IWF from incompatible group was higher than that from compatible ones and healthy leaves; there was no cellulase activity in IWF and the activity of PG of compatible combination was the highest. Photo-spectrum analysis of IWF indicated that the concentration of IWF from compatible combination was the highest. The observation of plant cells after IWF extraction indicated that there was no considerable damage of plant cells after IWF extraction. All of these results suggested that the elicitors in IWF originated from wheat stem rust. Probably the elicitors came from mycelia or haustoria of Puccinia graminis f.sp. tritici in wheat leaves.5. The activity of defensive enzymes, including PAL, POD, PPO, CAT, SOD, P-1,3 glucanase, and the concentration of total soluble protein in wheat leaves increased after injection of IWF. But there were di...
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