Instrumental monitoring of the birth and development of truffles in a Tuber melanosporum orchard

• Published in: Mycorrhiza 2014-04, Vol.24 (Suppl 1), p.65-72
• Main Authors: Pacioni, G., Leonardi, M., Di Carlo, P., Ranalli, D., Zinni, A., De Laurentiis, G.
• Format: Article
• Language: English
• Subjects: Agriculture; Agriculture - methods; Agronomy. Soil science and plant productions; Ascomycota - growth & development; Biological and medical sciences; Biomedical and Life Sciences; Carbon dioxide; Carbon Dioxide - analysis; Climate; Ecology; Edible fungi production; Environmental conditions; Forestry; Fruiting Bodies, Fungal - growth & development; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Host plants; Larvae; Life Sciences; Microbiology; Mycorrhizae - growth & development; Orchards; Original Paper; Parasitism and symbiosis; Plant physiology and development; Plant Sciences; Soil - chemistry; Soil Microbiology; Summer; Symbiosis; Temperature; Tuber melanosporum; Water stress
• ISSN: 0940-6360; 1432-1890
• DOI: 10.1007/s00572-014-0561-z

Mycorrhizal symbiotic plants, soil suitability, temperature, and humidity are, by general consensus, considered decisive factors in truffle production. However, experimental approaches to define the environmental conditions that stimulate formation of truffle primordia and promote their growth to maturity have been lacking. By analysis of data of many atmospheric and soil parameters collected since 2009 within a Tuber melanosporum orchard, the trends of metabolic activity, detected as CO 2 production in the soil, have been identified as the most reliable parameter to indicate the ‘birth’ of the truffle primordia. They seem to be produced when mycelial activity is intense and undergoes water stress, after which it resumes. About 6–18 days after recovery of metabolic activity, we could collect primordia of T. melanosporum. Many die or develop too early and consequently rot or are eaten by insect larvae. These events occur several times during summer and autumn, those that ‘sprout’ in late summer or later grow steadily and reach maturity. Using a particular ground-penetrating radar (GPR) setup to discriminate truffles, we could identify individual truffles in the soil after they have enlarged to at least 6 mm in diameter and follow their growth in volume and diameter over time. These two instrumental methods (CO 2 sensor and GPR), although yet to be improved, open new important perspectives to better understand truffle biology and manage truffle orchards to support the newly acquired demonstration of the fundamental role of host plants for the nutrient transfer to the ectomycorrhiza-mycelium-fruiting body complex of T. melanosporum .