S U M M A R YLittle is known about non-mycorrhizal endophytic fungi in tropical orchids; still less is known about how endophytes vary within and between individual orchid plants, b'ungal endophytes were isolated from roots and leaves of epiphytic and lithophytic orchids in the genus Lepanthes; seven species, from rainforests in Puerto Rico, were sampled. The endophytes observed most frecjuently were Xylaria species and Rhizoctonia-\'\ke fungi, found in 29 % of roots and 19 % of leaves, and 45 "o of roots and 31 "" of leaves, respectively. Five deuteromycete genera were also isolated, occurring in 19 "" of roots and 43 ",, of leaves (combined). At least nine species oi Xvlaria were found, with several species sometimes occurring in a single plant. Differences between roots and leaves in frequency of Xylaria and Rhizoitoiiia isolates were not significant, although differences among orchid species in number and types of endophytes were. Heterogeneity of endophytes in single plants and plant organs was greater than diflerences between species. Many Lepanthes species are very restricted in distribution, and knowledge of their interactions with endophytes might be useful in species management.
Mycorrhizal symbiosis is important for growth of coffee (Coffea arabica), but differences among coffee cultivars in response to mycorrhizal interactions have not been studied. We compared arbuscular mycorrhizal (AM) extraradical hyphae in the soil and diversity of AM fungi among three coffee cultivars, Caturra, Pacas, and Borbón, at three farms in Puerto Rico. Caturra had significantly lower total extraradical AM hyphal length than Pacas and Borbón at all locations. P content did not differ among cultivars. Extraradical hyphal lengths differed significantly among locations. Although the same morphotypes of mycorrhizal fungal spores were present in the rhizosphere of the three cultivars and total spore density did not differ significantly, frequencies of spore morphotypes differed significantly among cultivars. Spore morphotypes were typical of Glomus and Sclerocystis. Levels of soil nutrients did not explain differences in AM colonzation among cultivars. The cultivar Caturra is a mutant of Borbón and has apparently lost Borbón's capacity to support and benefit from an extensive network of AM hyphae in the soil. Widespread planting of Caturra, which matures earlier and has higher yield if fertilized, may increase dependence on fertilizers.
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