SUMMARYEndophytic bacteria and fungi were isolated from healthy maize plants collected in a field in Devon. The average bacterial counts in the stem core tissues showed that the plant parts closer to the soil were more heavily colonized by bacteria than those near the top of the plants, and that the lower and middle part of the stems hosted the most frequently isolated bacterial species. Of the fungal species isolated, 12 had a relative importance of more than 10°o m the core, 15 in the epidermis, and only 5 in the leaves. In general the distribution patterns were different among the three tissue types studied, with core and epidermis of the stems showing almost equal colonization frequencies and the leaves being most heavily colonized. More fungal species were recovered from the core and epidermis of the stem than from the leaves. The fungi most frequently isolated showed some patterns of tissue specificity, with Alternaria alternata almost exclusively associated with the leaves and Aureobasidium pulhilans var. melanigerum most often present in the epidermal tissues.Assays showed low fungal colonization of seeds taken from freshly matured cobs and of seeds dried for 8 wk before testing, in contrast to higher colonization frequencies observed for the seeds used for planting. The mean values for fungal isolations in the stem pieces mostly in contact with the soil flora or close to the ground were lower than those of the more centrally placed sections. These areas of low fungal infection yielded the highest bacteriai counts. The potential role of bacterial endophytes in biological control is briefly discussed.

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SUMMARYFungal endophytes have been isolated from inside the leaf blades, leaf sheaths, and roots of six-week-old plants as well as from seeds and ten-day-old seedlings of Orysa sativa (E.). The fungi isolated can be grouped in two categories; one containing organisms known mainly to be saprotrophic and the other comprising potential pathogens. Of the former Alternaria alternata (Fr,) Keissler and Epicoccum purpurascens Ehrenb. ex. Schlecht preferentially colonize the leaf blades of their host, whereas Cladosporium tenuissimum Cooke seems more generally distributed between leaf blades and leaf sheaths. Fusarium equiseti (Corda) Saec., F. oxysporum Schecht and Phoma sorghina (Sacc. Boerema) are latent in their hosts without causing disease symptoms. A. alternata, E. purpurascens, F. equiseti, and Nigrospora oryzae have also been frequenth-isolated from seeds and young seedlings and can be considered seed-borne. Prineipal components analysis has shown a marked tissue specificity among riee endophytes. Leaf sheaths of the rice varieties grown under dry conditions are colonized by endophyte communities different from those of the wet cultivars.

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