SPORE SURFACE MORPHOLOGY OF HAWAIIAN ACACIA RUST FUNGI
SPORE SURFACE MORPHOLOGY OF HAWAIIAN ACACIA RUST FUNGI
复制标题
夏威夷金合欢锈菌孢子表面形态
DOI:
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发表时间:
1985
期刊:
影响因子:
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通讯作者:
C. S. Hodges
中科院分区:
文献类型:
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作者:
D. Gardner;C. S. Hodges
Certain spore states of rust fungi on endemic Acacia spp. in Hawaii are typified by pedicellate spores with reticulate wall ornamentation and a series of equatorial germ pores. These spore states include aeciospores and urediniospores of the macrocyclic form of Uro? myces digitatus, aeciospores of U. koae, and teliospores of Endoraecium acaciae and E. hawaiiense. Reticulate spores of this type are apparently rare among the rusts. Spore orna? mentation of the Hawaiian rusts is similar to that found on other Acacia rusts in Australia, New Zealand, Taiwan, and Japan. The similarity of morphology and host may indicate a close phylogenetic relationship among these forms. There are four distinct rusts on endemic Acacia spp. in Hawaii: three en? demic? Uromyces koae Arth., Endoraecium acaciae Hodges & Gardner, and E. hawaiiense Hodges & Gardner?and one, Uromyces digitatus Wint. [=U. phyl? lodiorum (B. & Br.) McAlp.], believed to be indigenous (5). An endemic micro? cyclic variant of U. digitatus also occurs in Hawaii (5). We consider the endemic rust species to be closely related to one another (as are the endemic Acacia hosts themselves) and probably to have evolved from U. digitatus. There is evidence that divergent evolution among these fungi is still in progress (5). Cummins and Hiratsuka (2) placed U. digitatus, U. koae, and U bicinctus McAlp. in the recently revived genus Atelocauda (see 5). More recently, Ono (13) determined that U. hyalospora Sawada did not belong in Uromyces and placed this species in Atelocauda for the present. However, because of dissimilarities in life cycles and host genera of the species now included in Atelocauda, Ono sug? gested the need for more detailed study of this genus. We have chosen to retain the original binomials here to provide continuity with our previous studies (4, 5). The native Hawaiian Acacia rusts recognized thus far are unusual in that the aecial and the uredinial states (where the latter exist) of each species are charac? terized by spores with walls that are closely and strongly reticulate and have several prominent equatorial germ pores. The aecial state of each species is uredinoid. These common features suggest a close relationship between the Hawaiian species and U. hyalospora, U. bicinctus, and Uromycladium spp., which are in? digenous to Australia and Taiwan (5). Reticulate aeciospores or urediniospores ofthe type found among the Hawaiian Acacia rusts are apparently rare. Littlefield and Heath (10) classified aeciospore ornamentation into four types based on their verrucose or echinulate processes. Urediniospores, with few exceptions, were classified as echinulate. The exceptional