Plantation forestry with exotic trees in south China needs compatible symbionts to improve the growth of seedlings in nurseries and to enhance establishment and growth in the field. Scleroderma, a potentially suitable symbiont for inoculation, is not being used in containerized nurseries in the region due to poor knowledge of its host range. The ability of 15 collections of Scleroderma, nine from Australia and six from Asia, to colonize and promote growth of four important exotic plantation trees (Eucalyptus globulus Labill., Eucalyptus urophylla ST Blake, Pinus elliottii Engl., and Pinus radiata D. Don) was examined in a nursery potting mix. There was generally low host specificity of Scleroderma between tree genera. At 12 weeks after inoculation, 13 to 14 of the 15 spore collections formed ectomycorrhizas on seedlings of eucalypts or pines. The extent of colonization differed between spore treatments with two or four collections forming abundant mycorrhizas (>50% fine roots colonized) on E. globulus or E. urophylla, respectively, and three or five on P. radiata or P. elliottii, respectively. Three collections from Australia strongly colonized all hosts resulting in 26 to 100% of short roots being colonized. Chinese Scleroderma collections resulted in fewer mycorrhizas on eucalypts than on pines. Inoculation stimulated the growth (shoot height and dry weight) of eucalypt and pine seedlings by up to 105% where Scleroderma mycorrhizas developed. The results suggest that there is a need to source Scleroderma from outside China for inoculating eucalypts in Chinese nurseries whereas Chinese collections of Scleroderma could be used in pine nurseries. Further screening of Australian and Chinese Scleroderma should be performed in Chinese nurseries and in the field before final commercial decisions are made.

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Nutrient translocation from a host plant is vital to the growth and survival of its root parasitic plant, but few studies have investigated whether a parasitic plant is also able to transfer nutrients to its host. The role of N2-fixation in nitrogen (N) transfer between 7-month-old Dalbergia odorifera T. Chen nodulated with Bradyrhizobium elkanii DG and its hemiparasite Santalum album Linn. was examined by external (15)N labeling in a pot study. Four paired treatments were used, with (15)N given to either host or hemiparasite and the host either nodulated or grown on combined N. N2-fixation supplied 41-44% of total N in D. odorifera. Biomass, N and (15)N contents were significantly greater in both nodulated D. odorifera and S. album grown with paired nodulated D. odorifera. Significantly higher total plant (15)N recovery was in N donor D. odorifera (68-72%) than in N donor S. album (42-44%), regardless of the nodulation status in D. odorifera. Nitrogen transfer to S. album was significantly greater (27.8-67.8 mg plant(-1)) than to D. odorifera (2.0-8.9 mg plant(-1)) and 2.4-4.5 times greater in the nodulated pair than in the non-nodulated pair. Irrespective of the nodulation status, S. album was always the N-sink plant. The amount of two-way N transfer was increased by the presence of effective nodules, resulting in a greater net N transfer (22.6 mg plant(-1)) from host D. odorifera to hemiparasite S. album. Our results may provide N management strategies for D. odorifera/S. album mixed plantations in the field.