MEM 57 C04-Studies of Cycad Reproduction at Fairchild Tropical Garden.

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08/09/2020 02:07:58

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NORSTOG, K. (Fairchild Tropical Garden, 11935 Old Cutler Road, Miami, Florida 33156, U.S.A.). Studies of cycad reproduction at Fairchild Tropical Garden. Memoirs of The New York Botanical Garden 57: 63–81. 1990. Fairchild Tropical Garden is located in a region of subtropical climate where occasional frosts inhibit growth of some tender tropical plants. However, all genera and species of cycads can be grown out-of-doors the year around.
A major problem in propagation of cycads at FTG is production of fertile seeds of a majority of exotic cycads. It is thought that this is due to absence of specific insect pollen vectors. With appropriate methods of artificial pollination, all species can be sexually propagated and certain hybrids can be produced. One such hybridization, Zamia furfuracea × Z. spartea, is described.
Studies on the role of wind and insects in pollination of cycads have been done at FTG and suggest a dual function for wind and insects—wind conveys pollen to metastrobili and insects further transport the pollen to the ovules. These studies suggest that cycad metastrobili are the functional equivalents of angiosperm carpels and further suggest an ancient origin for plant-insect coevolution. 
Cycads produce multiflagcllatcd male gametes. These differ from those of ferns, lycopods, and mosses mainly in redundancy of organelles and imply certain phylogenetic lines of evolution.

Keywords: cycads, reproduction, pollination, fertilization, hybridization, spermatogenesis, spermatozoids