Influence Of Arbuscular Mycorrhizal Fungi On The Growth Of Tobacco And Tobacco Bacterial Wilt

A pol experiment was conducted to study the influence of AM fungi on growth of tobacco, tobacco bacterial wilt incidence and explored the mechanism of mycorrhizal fungi to improve the disease resistance of tobacco; Using PMMA compartment device to study the role of mycorrhizal hyphae bridge to transfer resistance signal; A field experiment was conducted to study the development of mycorrhizal symbionts under field conditions and its impact on tobacco yield and quality and disease resistance. Further reveal the mechanism of mycorrhizal fungi to enhance disease resistance in plants and provide theoretical basis for the arbuscular mycorrhizal biotechnology applications in tobacco production and control of tobacco bacterial wilt.(1) To investigate the influences of AM fungi on bacterial wilt of tobacco, a pot experiment was conducted to study the bacterial wilt of tobacco influence on disease incidence, POD activity and MDA concentration. The results showed that AM fungi inoculation can promote the growth of tobacco plants, compared with CK, the dry weight of tobacco shoot and root, P content and shoot N content of tobacco plants was increased significantly, and meanwhile, the disease incidence and disease index of bacterial wilt were reduced. Under the conditions of inoculation R.solan on tobacco, the peroxidase activity(POD) of the tobacco leaves, which under the treatments of Glomus intraradices and Glomus mosseae inoculation, increased by22.9%and26.9%compared with non-inoculation, respectively. At the same time, MDA content was decreased. These findings suggested that AM fungi can increased the resistance to bacterial wilt of tobacco plants.(2) In order to study double-arbuscular mycorrhizal fungi (When seedling inoculation and inoculated again when transplanting) on the growth and disease resistance of tobacco, a pot experiment was adopted, pre-double arbuscular mycorrhizal fungi on tobacco and after the formation of mycorrhizal symbiosis, vaccination R. solanacearum again. The results showed that double-arbuscular mycorrhizal fungi can enhance root colonization rate; Inoculated Pseudomonas solanacearum can inhibited the grown of tobacco, compared with the control without inoculation of Ralstonia solanacearum, tobacco plants dry shoot and root weight, phosphorus and potassium content, phosphorus and potassium uptake and shoot nitrogen content were significantly decreased. Under the conditions of inoculation Ralstonia solanacearum, inoculated with Glomus intraradices and Glomus mosseae can promote the growth of tobacco plants, dry of shoot and root weight, NPK content, NPK absorption were significantly improved. At the same time, after inoculated with Glomus intraradices and Glomus mosseae, a significant increase in POD, PPO and PAL activity in tobacco leaves, while significantly decreased MDA content. For example, after inoculation Glomus mosseae, three enzyme activity increased39.3%,43.4%,28.3%, respectively, and MDA decreased17.7%. Those showed that double-arbuscular mycorrhizal fungi can more efficient promote the growth of tobacco and tobacco plants can increase resistance to bacterial wilt of tobacco.(3) Using PMMA compartment device, adopt inoculating arbuscular mycorrhizal fungus (AMF, Glomus mosseae) to establish CMNs between donor and receiver tobacco plants and inoculation of Ralstonia solanacearum(R.solan) to the donor plants to studied whether the potential disease resistance signals can be transferred between the donor and receiver plants roots. The results showed that in the case of exclusion root exudates, volatile matter and mycorrhizal fungi itself involved in resistance information transfer, the receiver which connection with the donor(colonization by AMF and inoculation of R.solan) PAL, PPO, POD, shoot and root dry N, P content and shoot dry weight were significantly higher than the donor plants only inoculated with AMF. These findings suggested that the disease resistance signals produced by the pathogen induced donor plant could be transferred to the receiver plant roots through CMNs.(4) To study the influence of arbuscular mycorrhizal fungi on tobacco production quality and disease resistance under field conditions, inoculated with arbuscular mycorrhizal fungi when seeding and transplanting to the field as postemergence, sampling and analysis. The results showed that under field conditions, arbuscular mycorrhizal fungi and tobacco can effectively improve the nutritional status of tobacco plants after forming mycorrhizal symbiosis, accelerated tobacco plants photosynthesis (vigorous) and to promote the absorption of NPK. Compared with the control, the root length, plant height, stem girth, number of leaves were significantly higher than the control treatment, when inoculated with arbuscular mycorrhizal fungi and significantly improved the overall quality of the tobacco plants, from root elongation to vigorous growth stages; Besides, the enzyme activity were ignificantly higher than the control treatment, can significantly improve tobacco plants resistance against soil-borne diseases. Compared with the control treatment, arbuscular mycorrhizal fungi can make the sugar alkali ratio, the ratio of potassium to chlorine, the ratio of total nitrogen and nicotine ratio more in line with the required range of high quality tobacco, at the same time, inoculated with Glomus intraradices and Glomus mosseae can improves flue-cured tobacco yield approximately9.7%,10.6%. Those show that under field conditions arbuscular mycorrhizal fungi can improve tobacco yield, quality and disease resistance.