Tuber melanoexcavatum sp. nov., an edible black truffle from China

A new black truffle species with a basal cavity, Tuber melanoexcavatum, is identified and described. The new species is morphologically similar to T. pseudobrumale, T. pseudoexcavatum, and T. mesentericum in having a basal cavity. However, T. melanoexcavatum differs from T. pseudobrumale and T. pseudoexcavatum in having black pyramidal warts and 5 to 8 spored asci, and differs from T. mesentericum by having spiny ascospores and 1 to 5 spored (rarely 6 spored) asci. Phylogenetic analysis indicates that T. melanoexcavatum is most closely related to T. pseudobrumale, but the two still clearly differentiate. Tuber melanoexcavatum grows as a mycorrhizal association with Cyclobalanopsis glaucoides. Tuber melanoexcavatum is considered an edible black truffle species and is indigenous to China.

Stable Isotope Analysis of Water Uptake Sources of Primary Forests in the Central Yunnan Karst Plateau

Ecosystems in the central of Yunnan karst plateau are very fragile due to thin soil layer and intensive infiltration capacity of rock fracture, which result in a very limited amount of water storage for plant uptake. Water retention in the soil zone and shallow fractured rock zone (subcutaneous) is a key factor for plant growth. Distinction of water sources taken by karst plants is a challenging task for botanists and hydrologists but is needed for ecosystem management. In this study, stable isotope analysis was used to investigate water sources for Cyclobalanopsis glaucoides primary forests at Shilin Geopark in Bajiang vally, central Yunnan of China. Proportions of water sources for plant uptake were determined by the δD and δ18O values of plant stem water, and water taken from soil layers and the subcutaneous zone. The analysis reveals that water was mainly taken from the soil layers and to less degree the subcutaneous zone as well. In dry seasons with scarce precipitation, plants in the primary forest were prone to take more water from subcutaneous zone and deeper layer of soil. Different species had different water use strategies, Cyclobalanopsis glaucoides took a larger proportional water from the deeper layer of soil, suggesting its deeper roots and wider range of shallower roots. However, Olea yunnanensis and Pistacia weinmannifolia extracted more percentage of water from the deeper soil water and subcutaneous water because of its deeper roots.