ABSTRACT
The conversion of natural systems to cultivated systems contributes to changes in the activities of microbial communities and biochemical processes in the soil. A total of 80 surface soil samples (0-15 cm) from 6 rainfed land use systems viz. agriculture, horticulture, agri-horticulture, forest, agroforestry and eroded lands were analyzed for biochemical properties and to derive soil quality index. The soils are slightly acid to neutral in reaction (pH-6.4-6.9) with 0.09-0.23 dS m?1 electrical conductivity (EC), loamy sand to sandy loam in texture, 1.4-6.1 g kg?1 soil organic carbon (SOC), 86-406 kg ha?1 available nitrogen, 29.3-32.6 kg ha?1 available phosphorus,65-226 kg ha?1 available potassium,10.3-21.3 mg kg?1 DTPA-Mn, 12.1-34.2 mg kg?1 DTPA-Fe, 0.34-1.01 mg kg?1 DTPA-Cu and 0.76-1.15 mg kg?1 DTPA-Zn, respectively under different land use systems. Among soil biochemical properties, the enzymic activity among land use systemsis varied from 7.4 to 12.8 µg TPF g?1 h?1 for dehydrogenase activity, 22.3 to 34.5 µg pNP g?1 h?1 for acid phosphatase, 43.4 to 60.1 µg pNP g?1 h?1 for alkaline phosphatase, 3.31 to 4.77 µg NH4-N g?1 soil min?1 for urease activity-, basal soil respiration ?0.13 to 0.30 µg CO2 g?1 soil h?1 for basal respiration , 46.5 to 242.6 µg g?1 soil for soil microbial biomass carbon (MBC) and 8.68 to 30.6 g kg?1 for total easily extractable glomalin (TEGP), respectively. The principle component analysis showed that SOC, EC, TEGP, MBC and DTPA-Zn are robust soil quality indicators under different land use systems in submontane Punjab. The forestry system has higher values for physicochemical, biochemical properties and soil quality index as against agri-horticulture, horticulture, agroforestry, agriculture and eroded system. In subsystems, eucalyptus-based forestry and mango based agri-horticulture systems are served as a better system for soil quality assessment in submontane Punjab, India.
ABSTRACT
Objective:To clarify the effect of the arbuscular mycorrhizal （AM） fungi on the rhizosphere soil nutrient content，AM fungi infection rate and total rhizome saponins content of Paris polyphylla var. yunnanensis under symbiosis culture. Method:The changes in the root AM fungi infection rate，rhizosphere soil nutrient content，total rhizome saponins content of P. polyphylla var. yunnanensis and the relationship of the rhizosphere soil factors，the infection rate and the total rhizome saponins content after AM fungi inoculation were analyzed by the method of combining room temperature pot inoculation and data analysis. Result:As compared with the CK group，the root AM fungi infection rate of the AM inoculation group was significantly enhanced （P<0.05），the content of easily extractable glomalin，total glomalin，and total nitrogen increased significantly，while available potassium content and pH significantly decreased. After inoculation with AM fungi，the contents of total phosphorus，available phosphorus，available nitrogen，ammonium nitrogen，nitrate nitrogen，available potassium，and organic matter in the rhizosphere soil of P. polyphylla var. yunnanensis showed significant differences as compared with the CK group. The soil nutrient status was improved，and the total saponin content in the rhizome of P. polyphylla var. yunnanensis was increased. Conclusion:Inoculation with AM fungi can improve the rhizosphere soil nutrient status of P. polyphylla var. yunnanensis，promote the nutrient transformation in the rhizosphere soil，promote the growth of P. polyphylla var. yunnanensis，and improve the quality of medicinal herbs.
ABSTRACT
Objective:To investigate the infection rate of Paris polyphylla var. yunnanensis at different periods，the changes of mineral nutrients in rhizosphere soil and the correlation among the factors under different arbuscular mycorrhizal （AM） fungi conditions. Method:28 kinds of AM fungi were inoculated into the seedlings of P. polyphylla var. yunnanensis by single factor pot experiment. The samples were collected in August （fruit ripening period） and November （senescence period） to analyze the infection rate and the physical and chemical properties of rhizosphere soil. Result:The mycorrhizal infection rate of each treatment group was 75%-100% in the fruit ripening period and senescence period. The contents of easily extracted glomalin and total glomalin in rhizosphere soil increased to different degrees in these two periods as compared with CK group， the pH of rhizosphere soil in the two treatment groups showed an increasing trend， the content of organic matter in rhizosphere soil decreased significantly in the fruit ripening period in all the treatment groups，and the organic matter in rhizosphere soil in the senescence period showed no significant differences. The total N and K contents in rhizosphere soil decreased in both periods， and the other physical and chemical properties of rhizosphere soil increased or decreased without significant change regularity. Correlation analysis showed that the infection rate was correlated with the physical and chemical properties of rhizosphere soil to a certain degree. Conclusion:Inoculation of AM fungi can affect the physical and chemical properties of rhizosphere soil of P. polyphylla var. yunnanensis to some extent，and provide reference value for the application of AM fungi in the cultivation of traditional Chinese medicine.
ABSTRACT
Arbuscular mycorrhizal fungi (AMF) are well-known for their ability to improve plant growth and help plants withstand abiotic stress conditions. Unlike other fungi and bacteria, AMF cannot be stored, as they are obligate biotrophs. Long-term preservation of AMF spores is challenging and may lead to the loss of viability and efficiency. This study aimed to understand the effect of prolonged subculture of AMF species on the growth and glomalin-related soil protein (GRSP) from red pepper (Capsicum annuum L.). AMF spores were mass-produced using different techniques and subcultured in pots with sorghum sudangrass as the host plant for 3 years. Experimental soil samples were collected from natural grassland. Five different AMF inocula were used in triplicate as treatments. After 70 days of growth, red pepper plants were harvested and plant dry weight, plant nutrient content, mycorrhizal colonization, AMF spore count, and soil glomalin content were determined. AMF-treated plants displayed higher dry weight than controls, with only fruit dry weight being significantly different. Similarly, significant differences in phosphorous and potassium contents of the above-ground plant parts were observed between mycorrhizal and control treatments. In addition, soil GRSP content was significantly higher in plants inoculated with Rhizophagus sp. and Gigaspora margarita. The increased plant growth and GRSP content suggest that AMF can be maintained for 3 years without losing their efficiency if subcultured regularly with different symbiotic host plants.
Subject(s)
Bacteria , Capsicum , Colon , Colony Count, Microbial , Fruit , Fungi , Grassland , Plants , Potassium , Soil , Sorghum , SporesABSTRACT
The availability of soil nutrients (especially phosphorus) and soil water strongly influence mycorrhizal symbiosis in forest ecosystems. The aim of this study was to evaluate the impact of litter removal and increased soil moisture availability on the spore density and mycorrhizal colonization of apogeotropic and non-apogeotropic roots of a secondary forest stand in eastern Amazonia. We determined the percentage of mycorrhizal colonization of apogeotropic and non-apogeotropic (0-10 cm soil depth) fine roots (diameter 2 mm), spore density, glomalin concentration, and soil phosphorus availability. Litter removal did not reduce soil phosphorus availability. The spore density was not affected by litter removal. In general, the variables varied on a seasonal basis, except the mycorrizal colonization of non-apogetropic roots and glomalin concentration, but were not affected by irrigation. Mechanical damage to the apogeotropic root system, inherent to the fortnightly litter removal, may have contributed to decrease mycorrhizal colonization of both apogeotropic and non-apogeotropic roots and, consequently, soil glomalin. Our results suggest that the reduction of soil cover may have negative impact over the fungus-plant symbiosis.
A disponibilidade de nutrientes, especialmente fósforo, e de água no solo influenciam fortemente a simbiose micorrízica em ecossistemas florestais. O objetivo do estudo foi avaliar o impacto da remoção de serapilheira e do aumento da disponibilidade de água no solo sobre a densidade de esporos e a colonização micorrízica em raízes apogeotrópicas e não-apogeotrópicas em floresta secundária na Amazônia oriental. Foram analisadas a porcentagem de colonização micorrízica de raízes finas (diâmetro ≤ 2 mm) apogeotrópicas e não-apogeotrópicas (presentes na camada de 0-10 cm do solo), a densidade de esporos, o teor de glomalina e a disponibilidade de fósforo no solo. A remoção de serapilheira não reduziu a disponibilidade de fósforo no solo. A densidade de esporos também não foi afetada pela remoção de serapilheira. De forma geral, as variáveis estudadas variaram sazonalmente, com exceção da colonização micorrízica em raízes não-apogeotrópicas e do teor de glomalina, mas não foram afetadas pela alteração na disponibilidade de água no solo decorrente da irrigação. Danos mecânicos ao sistema radicular apogeotrópico, inerentes à remoção quinzenal da serapilheira, devem ter contribuído para reduzir a colonização micorrízica em raízes apogeotrópicas e não-apogeotrópicas e, consequentemente, o teor de glomalina no solo. Os resultados deste estudo sugerem que a redução da cobertura do solo pode impactar negativamente a simbiose fungo-planta.
Subject(s)
Spores , Forests , Phosphorus/analysis , Mycorrhizae , Soil MoistureABSTRACT
In this study, eight soil samples were collected from organic and conventional farms in a central area of South Korea. Spore communities of arbuscular mycorrhizal fungi (AMF) and glomalin, a glycoprotein produced by AMF, were analyzed. Spores of Glomus clarum, G. etunicatum, G. mosseae, G. sp., Acaulospora longula, A. spinosa, Gigaspora margarita, and Paraglomus occultum were identified at the study sites, based on morphological and molecular characteristics. While Acaulospora longula was the most dominant species in soils at organic farms, Paraglomus occultum was the most dominant species in soils at conventional farms. Species diversity and species number in AMF communities found in soils from organic farms were significantly higher than in soils from conventional farms. Glomalin was also extracted from soil samples collected at organic and conventional farms and was analyzed using both Bradford and enzyme-linked immunosorbent assays. The glomalin content in soils from organic farms was significantly higher than in soils from conventional farms. These results indicate that agricultural practices significantly affect AMF abundance and community structure.