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  • Author or Editor: A. Spada x
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Cranberry (Vaccinium macrocarpon) plants colonized with ericoid mycorrhizal fungi are capable of utilizing organic nitrogen sources that are unavailable to non-mycorrhizal plants. Despite the importance of mycorrhizal colonization in the nitrogen nutrition of wild cranberry, almost all measurements of cranberry nitrogen uptake and assimilation have been carried out with non-mycorrhizal plants. We have found that cranberry can be inoculated directly in solution culture. We cultured the ericoid mycorrhizal fungus Hymenoscyphusericaein liquid culture, harvested and rinsed hyphae, and added ≈200 mg fresh weight hyphae per rooted cranberry cutting (cv. Stevens) growing in a modified Johnson's solution. After 6 weeks, newly developed roots were most heavily colonized. We examined the effects of NH4 + concentration (5, 10, 20, 50, 100, and 500 μm NH4 +) in solution on colonization rates. Colonization (% root length) increased with increasing ammonium concentration in solution, with maximum colonization at 50 and 100 μm NH4 +; colonization was much lower at 500 μm NH4 +. Cranberry inoculated with H. ericaein solution culture will be used for analysis of the effects of mycorrhizal colonization on uptake kinetics of NH4 +, NO3 -, and amino acids.

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The use of a sex-linked molecular marker for early sex diagnosis in the dioecious species Asparagus officinalis L. was evaluated. Screening of random genomic probes as a part of a restriction fragment length polymorphism mapping project resulted in the identification of a sex-linked (6.9 cM) marker. The usefulness of this molecular tool was compared to morphological markers for prediction of gender in several genotypes. The level of polymorphism detected by this probe was high, and the level of incorrect sex attribution, as determined by this method, was low (≈7%).

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