منابع مشابه
Evolution and biogeography of gymnosperms.
Living gymnosperms comprise only a little more than 1000 species, but represent four of the five main lineages of seed plants, including cycads, ginkgos, gnetophytes and conifers. This group has huge ecological and economic value, and has drawn great interest from the scientific community. Here we review recent advances in our understanding of gymnosperm evolution and biogeography, including ph...
متن کاملThrips pollination of Mesozoic gymnosperms.
Within modern gymnosperms, conifers and Ginkgo are exclusively wind pollinated whereas many gnetaleans and cycads are insect pollinated. For cycads, thrips are specialized pollinators. We report such a specialized pollination mode from Early Cretaceous amber of Spain, wherein four female thrips representing a genus and two species in the family Melanthripidae were covered by abundant Cycadopite...
متن کاملPhotocontrol of Chloroplast Lipids in Fern Gametophytes
In the gametophyte of the fern Anem ia phyllitidis synthesis of linolenic acid esterified in monogalactosyldiglyceride requires light. By induction-reversion experiments it could be demon strated that this light-dependent step is mediated by phytochrome. There is also evidence for phytochrome control of galactolipid and hexadecatrienoic acid synthesis. In continuous blue light the synthesis of...
متن کاملAn Expert System to identify Gymnosperms
The application of Artificial Intelligence (AI) techniques to the problem of botanical identification is not particularly widespread even less so on Internet. There are several interactive identification systems but they usually deal with raw knowledge so it appears that “research and development of web-based expert systems are still in their early stage” (Li et al., 2002). In this paper we pre...
متن کاملLong-Proboscid Flies as Pollinators of Cretaceous Gymnosperms
The great evolutionary success of angiosperms has traditionally been explained, in part, by the partnership of these plants with insect pollinators. The main approach to understanding the origins of this pervasive relationship has been study of the pollinators of living cycads, gnetaleans, and basal angiosperms. Among the most morphologically specialized living pollinators are diverse, long-pro...
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ژورنال
عنوان ژورنال: Botanical Gazette
سال: 1908
ISSN: 0006-8071
DOI: 10.1086/329524