The Studies Of Physiology And Biochemistry On Artificial Induced Tobacco Para-nodule

We set up the symbiotic nitrogen-fixation system with a mutant of fast-growing strain in R.sp.vigna. Which have nitrogen-fixation activity only in the symbiotic system and the tobacco K326 which is being extended to the whole country. The plant hormone 2,4-D was used to induce artificial tobacco para-nodule.We carried on the following 4 kinds of treatments to the regenerated tobacco K326 plantlets, which were produced from the leaves of the sterile seedling of tobacco.(CK:native Jensen non-nitrogen medium; D:Jensen with 0.3mg/L2,4-D alone; R: Jensen with 5×108/L rhizobium alone; D+R: Jensen with 0.3mg/L 2,4-D and 5 ×108/L rhizobium)In our experiment, effects on the activity of superoxide dismutase(SOD) and the contents of MDA,soluble protein chlorophyll and choromosome in tobacco's leaf,stem and root at different treatments and for different time were studied. The results show that 2,4-D inhibited accumulation of MDA in the tobacco stem and leaf cell, induced increase content of soluble protein and activity of SOD(from the first week to the third week); later ,2,4-D accelerated the decrease of the content of MDA and soluble protein and activity of SOD of each organization of tobacco.The effect of treatment content of MDA with rhizobium alone is always higher than that of CK at different growth stages in tobacco root ,stem and leaf cells, and rhizobium could induce activity of SOD and content of soluble protein to increase in the first and the second week.At later, the content of MDA descended and was lower than that of CK in the root cell, and rhizobium could promote descrease of soluble protein content and SOD activity of tobacco root, stem and leaf cells, and could still inhibit the tobacco chlorophyll synthesis at the prophase of treatment(from the first week to the second week), but the rhizobium also could decelerate the chlorophyll destroyed with the extension of time; as the tobacco dissimilarity develops, the variety of the content of MDA was treated with 2,4-D and rhizobium didn't achieve to the utmost as with the use of only either 2,4-D or rhizobium treated. At the prophase treatment, the common processing accelerated each organization of tobacco in the MDA accumulation, and stimulated soluble protein content and SOD activity of each organization to go up.However, at this time it inhibited the tobacco chlorophyll synthesis with the extension of the time. In each organization of tobacco of the common processing, although the content of MDA still presented the up-trend but lower than that of CK. At this time, the activity of SOD was all higher than that of CK in each organization. After different treatment, we found that it was the tobacco root cell that was victimized at the earliest, the stem cell was second to it and the leaf cell was victimized at the latest. The results still show that mitotic index of tobacco root cell was promoted to increase with the use of different treatments in the second week. The mitotic index of tobacco root cell was promoted most obviously with use of 2,4-D and rhizobium treatment. Along with the extension of time, the mitotic index of tobacco root cell was inhibited obviously in different treatments, and caused chromosome mutations in different degrees. Therefore, according to our experiment, when using plant hormone 2,4-D, the artificial induced tobacco para-nodule had certain stimulative function at the early period , then it is harmful to growth of tobacco with the extension of time.