Cycad plant

Cycads pollination by insects may be one of the earliest forms of insect-pollination. Like conifers, cycads bear their reproductive cells in cones rather than flowers. Individual cycad plants are either male or female, male plants having pollen cones and female plants, seed cones. Fertilization requires transfer of pollen grains from pollen cones to seed cones. The role of insects in this process has received attention in a cycad commonly known as the cardboard palm (Zamia furfuracea). This is a handsome horticultural plant with... 

Spontaneous intestinal neoplasms in animals, particularly the common laboratory rodents, are rare[47]. The serendipitous discovery by Laquer and colleagues in 1963 that cycad meal extracted from the seeds and roots of cycad plants, produced intestinal (and other) tumors when fed to rats[48] heralded the onset of an explosion of interest in chemically-induced bowel tumors. It was suggested that the active carcinogen in the cycad meal was cycasin or its aglycone... 

Ferns and allies b) Seed plants Gymnosperms Conifers, cycads, ginkgos, gnetae 700... 

The specificity of each orchid s scent for only a few kinds of bees is at first surprising. The entire group of orchids makes use of about sixty different fragrance chemicals, each orchid typically using about seven to ten components for its particular scent. Most of these compounds are among the widely distributed plant chemicals we have previously met in cycads and in other flowering... 

Some plants regularly eaten by humans contain neurotoxins that pose serious health problems. On Guam, for example, the seeds of Cycas circinalis used to be an important source of carbohydrates. Seeds of Cycas rumphii were ground into flour for tortillas. However, the seeds contain jS-N-methylamino-i-alanine, a suspected excitotoxin that overstimulates and destroys nerve cells. This compound causes a parkinsonism-like disease in macaques (Spencer et al, 1987). Other toxins have been proposed to be responsible for the disease, among them cycasin, another cycad toxin (Stone, 1993). 

Cycadophyta Cycads 100 Vascular plants with unprotected seeds and no flowers (gymnosperms)... 

Chemical-induced liver injury is encountered in a variety of circumstances. Some natural toxins such as the peptides of Amanita phalloides, the pyrrolizidine alkaloids, the toxin of the cycad nut, and other plant toxins are hazards posed by the environment. Some mycotoxins are ingested unknowingly because of feed contamination due to climatic conditions favorable to fungal growth. Other circumstances of exposure to hepatotoxins include contamination of water supply with cyanobacterial toxins, which led to the tragic death of 60 patients in a hemodialysis clinic in Brazil in 1996 (Jochimsen et al, 1998). 

Although BMAA has been an instructive agent, it is unclear whether it is the principal toxin in cy-cad plants (Kisby et al., 1992). Studies using cycad extracts found no correlation between BMAA content and toxicity in cultured neurons. However, the cycad samples had a high content of Zn +, and Zn + produced a dose-dependent damage of neurons that parallelled the Zn + content of the cycad extracts (Duncan et al., 1992). It is possible that a complex mechanism involving Zn +, BMAA and perhaps other cycad toxins contributes to the ALS-parkinsonism-dementia complex of Guam. 

Plant Almond, coffee beans, alfalfa, corn, cycads, soybean, sesame, apricot, apple... 

The flora that has been preserved in the Beacon Supergroup of the Transantarctic Mountains and in Australia, South Africa, India, and South America contain leaves of Glossopteris, Gangamopteris, and Dicroidium, as well as gymnospermous trees (Meyer-Berthaud and Taylor 1989), cycads, ferns, and palyno-morphs (pollen, spores, and acritarchs). The fossilized remains of these plants occur primarily in the Buckley, Fremouw, and Falla formations. 

Smith PJ (1972) The resource potential of Antarctica. Comments Earth Sci (geophysics) 3(l) 23-28 Smoot EL, Taylor TN (1986) Evidence of simple polyembryony in Permian seeds from Antarctica. Amer J Botany 73 1079-1081 Smoot EL, Taylor TN, Delevoryas T (1985) Structurally preserved plants from Antarctica. I. Antarticycas gen. nov., a Triassic cycad stem from the Beardmore Glacier area. Amer J Botany 72 1410-1423... 

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