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Sieve‐Element Characters of the Proteaceae and Elaeagnaceae: Nuclear Crystals, Phloem Proteins and Sieve‐Element Plastids
Author(s) -
Behnke H.D.
Publication year - 1995
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1995.tb00529.x
Subject(s) - proteaceae , biology , botany , subfamily , sieve (category theory) , sieve tube element , phloem , biochemistry , mathematics , combinatorics , gene
The sieve‐element characters of 34 species from the Proteaceae and Elaeagnaceae have been studied by transmission electron microscopy. While nondispersive protein bodies and dispersive P‐protein are typical components of both families, specific forms and/or their distinctive origin accentuate some taxa. Within the Grevilloideae, subfamily of Proteaceae, a number of Australian species and genera contain protein crystals of nuclear origin arranged into rosette‐like bodies, while in the other members studied from the same subfamily no nondispersive protein bodies were found. Several Australian and South African genera of the Proteoideae contain compound‐spherical nondispersive protein bodies that reside in the cytoplasm from their very beginning. In the Elaeagnaceae three different P‐protein bodies are present of which one is tubular and dispersing, another is nondispersive and of irregular‐stellate form, and a third is globular (resembling a P‐protein from Cucurbita ). The great majority of the species studied from the Proteaceae contains form‐Ss sieve‐element plastids, Lomatia ilicifolia and Macadamia ternifolia are distinct in having form‐Pcs plastids. The average diameter of stem sieve‐element plastids in the family is 1.38 μm. The Elaeagnaceae (three species investigated) is a pure form‐So family (average diameter: 0.8 μm). There are no specific sieve‐element characters that would support any relationship between the Proteaceae and Elaeagnaceae. While affinities of the former to pre‐Gondwanan parts of the Rosanae/Myrtanae are discussed, a reconsideration of the Elaeagnaceae as a possible member of the Violanae (identical features with Cucurbitaceae) is proposed.