丛枝菌根真菌-植物对石油污染土壤修复实验研究

石油开采一方面促进我国国民经济发展,另一方面石油污染土壤现象日益严重,给区域人们身体健康带来危害,因此采取有效措施解决石油污染土壤问题迫在眉睫。丛植菌根真菌,能帮助植物更好的吸收矿质元素,在提高植物的抗逆性、抗病性,改善植物根际微环境、缓解重金属危害植物上有着十分重要的意义。该文就此在分析丛枝菌根修复技术基础上,重点研究了丛枝菌根真菌—植物对石油污染土壤修复的实验,效果显著,值得进一步推广。

Arbuscular mycorrhizal fungal diversity in some commonly occurring medicinal plants of Western Ghats,Goa region

Thirty-six medicinal plant species belonging to 25 families were surveyed to study Arbuscular mycorrhizal （AM） fungal diversity from different localities of North and South Goa of Western Ghats, Goa region, India. A total of 30 medicinal plant species were found to be mycorrhizal and six plant species showed absence of AM fungal colonization. Forty two AM fungal species belonging to five genera viz., Glomus, Acaulospora, Scutellospora, Gigaspora and Ambispora were recovered from the rhizosphere soil. Glomus was found to be the most dominant genera in the study sites, and Glomus fasciculatum the most dominant AM fungal species. Negative significant correlation was observed between percent colonization and spore density. Simpson＇s and Shannon Weiner diversity index studies carried out in North and South Goa exhibited less variation in both the sites, indicating a stable and a diverse plant community.

Effect of arbuscular mycorrhizal fungi on growth of Gmelina arborea in arsenic-contaminated soil

Arsenic （As） in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has dso a potential to be planted in arsenic contaminated areas. This study tssessed the role of arbuscular mycorrhizal （AM） fungi on the growth of 7. arborea in arsenic amended soils at nursery stage. Before sowing ;eeds, soils were treated with four different concentrations （10 mg.kg^-1, 25 mg.kg^-1, 50 mg.kg^-1, and 100 mg.kg^-1） of Arsenic. Growth parameters length of shoot and root, collar diameter, fresh and dry weight of shoot and root） of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal eedlings. Myeorrhizal seedlings planted in soil with 10-mg.kg^-1 arsenic howed best performance in terms of growth, biomass and mycorrhizal ：olonization, compared to other treatments with higher concentration of Lrsenie. With increasing arsenic concentration, growth of seedlings, nycorrhizal infection rate and spore population, all decreased ignificantly （p〈0.05）. The mycorrhizal seedlings had as much as 40% higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.

Growth, Cadmium Accumulation and Physiology of Marigold (Tagetes erecta L.) as Affected by Arbuscular Mycorrhizal Fungi

A pot experiment was carried out to study the effects of three arbuscular mycorrhizal fungi （AMF）, including Glomus intraradices, Glomus constrictum and Glomus mosseae, on the growth, root colonization and Cd accumulation of marigold （Tagetes erecta L.） at Cd addition levels of 0, 5 and 50 mg kg-1 in soil. The physiological characteristics, such as chlorophyll content, soluble sugar content, soluble protein content and antioxidant enzyme activity, of Tagetes erecta L. were also investigated. The symbiotic relationship between the marigold plant and arbuscular mycorrhizal fungi was well established under Cd stress. The symbiotic relationship was reflected by the better physiobiochemical parameters of the marigold plants inoculated with the three AMF isolates where the colonization rates in the roots were between 34.3% and 88.8%. Compared with the non-inoculated marigold plants, the shoot and root biomass of the inoculated marigold plants increased by 15.2%- 47.5% and 47.8%-130.1%, respectively, and the Cd concentration and accumulation decreased. The chlorophyll and soluble sugar contents in the mycorrhizal marigold plants increased with Cd addition, indicating that AMF inoculation helped the marigold plants to grow by resisting Cd stress. The antioxidant enzymes reacted differently with the three AMF under Cd stress. For plants inoculated with G. constrictum and G. mosseae, the activities of superoxide dismutase （SOD） and catalase （CAT） increased with increasing Cd addition, but peroxidase （POD） activity decreased with increasing Cd addition. For plants inoculated with G. intraradices, three of the antioxidant enzyme activities were significantly decreased at high levels of Cd addition. Overall, the activities of the three antioxidant enzymes in the plants inoculated with AMF were higher than those of the plants without AMF inoculation under Cd stress. Our results support the view that antioxidant enzymes have a great influence on the biomass of plants, and AMF can improve the capability of reactive oxygen species （ROS） scavenging and reduce Cd concentration in plants to alleviate Tagetes erecta L. from Cd stress.

Diverse plant mixtures sustain a greater arbuscular mycorrhizal fungi spore viability than monocultures after 12 years

Aims Intensive land management practices can compromise soil biodiversity,thus jeopardizing long-term soil productivity.Arbuscular mycorrhizal fungi(AMF)play a pivotal role in promoting soil productivity through obligate symbiotic associations with plants.However,it is not clear how properties of plant communities,especially species richness and composition influence the viability of AMF populations in soils.Methods Here we test whether monocultures of eight plant species from different plant functional groups,or a diverse mixture of plant species,maintain more viable AMF propagules.To address this question,we extracted AMF spores from 12-year old plant monocultures and mixtures and paired single AMF spores with single plants in a factorial design crossing AMF spore origin with plant species identity.Important Findings AMF spores from diverse plant mixtures were more successful at colonizing multiple plant species and plant individuals than AMF spores from plant monocultures.Furthermore,we found evidence that AMF spores originating from diverse mixtures more strongly increased biomass than AMF from monocultures in the legume Trifolium repens L.AMF viability and ability to interact with many plant species were greater when AMF spores originated from 12-year old mixtures than monocultures.Our results show for the first time that diverse plant communities can sustain AMF viability in soils and demonstrate the potential of diverse plant communities to maintain viable AMF propagules that are a key component to soil health and productivity.