Flower production

Crombie L (1995) Chemistry of pyrethrins. In Pyrethrum flowers, production, chemistry toxicology, and uses, ed by Casida JE, Quistad GB. Oxford University press, New York, Oxford, pp 124... 

Elliott M (1995) Pyrethrum flowers production, chemistry, toxicology, and uses. In Casida JE, Quistad GB (eds) Chemicals in insect control. Oxford University Press, New York... 

Work with duckweed and poinsettias indicates that as long as these plants are growing in the presence of low ozone levels, growth rates, etc. are reduced. As soon as the plants are removed to clean, ozone-free air, growth resumes at a normal rate, and the plant rapidly reaches its normal size and habit. Thus duckweed exposed to 10 ppm of ozone for 14 days and then removed to fresh air exhibits a spurt in frond and flower production which quickly brings the population up to the normal level (44) (Table II). 

It is not unusual in the composition of a perfume to use not only an individual floral material such as phenylethyl alcohol as part of the main structure of the formula but to back this up by a more complex rose base as well a little of the natural flower product. This principle of simplicity within the main structure of the perfume, and increasing complexity within the lesser components, is one to which we will return in later chapters. 

More recently the great advance that has been made in chemical analysis and the synthesis of complex organic molecules has made possible a much closer approximation to the actual composition and odor of natural flower products. Even so, few of these reconstructed naturals, invaluable though they are, can provide a full replacement for the genuine product. They may best be thought of as specialized bases resulting from a collaboration between the chemist and creative perfumer. 

Figure 8. Changes in alkaloid content (mg g wet weight, left axis) and flower production per plant (number, one year obsv. right axis) in Lupinus argenteus with elevation. Data from Carey and Wink, 1994 re-plotted by author.

Those plants which elaborate alkaloids in the roots do so mostly in the actively growing parts thereof. Flower production, which inhibits root growth, can be circumvented by the culture of isolated rooted leaves. The absolute amount of alkaloid in such leaves can be as much as a hundred times that in the leaves on the plant and twenty times as much fractionally when based on dry weight (286). 

Crombie, L. Chemistry of pyrethrins Chapter 8 in Pyrethrum flowers Production, chemistry, toxicology and uses, edited by J.E. Casida and G.B. Quistad, Oxford University Press (1995). 

As early as 1965, a treatment of cytokinin applied directly to flowers or young fertilized ovaries was demonstrated to promote fruit set of seedless grapes [21]. Since that observation, a similar response has been documented for many other plant species, including pea [11], mung bean [4], and soybean (Table 1) [5, 16]. Analyzing the effect of a cytokinin treatment on yield parameters, it was reported that a 2 mM solution of BA applied to main stem nodes of soybeans had no effect on flower production, but greatly reduced floral abortion (Table 2) [3]. Despite a higher subsequent rate of pod abortion on treated plants, the net effect was more pods per raceme at maturity. 

Very probably in those instances where application of auxins has been correlated with increased pistillate flower production the effect is indirect. Burg and Burg (1966), for example, report that auxins stimulate ethylene production. Perhaps once again this is the factor most directly involved in morphogenesis... 

Cytokinins probably play a role in sex expression. It may be that in certain monecious species cytokinins are below a critical level for differentiation of perfect flowers. Topical applications of cytokinin to a known staminate flowered grapevine 3 weeks before anthesis induced the plant to produce perfect flowers (Negi and Olmo 1966). An additional example is to be found in the production of male flowers by Mercurialis annua following treatment with cytokinins (Durand 1969). Furthermore, soaking of Luff a acutangula seed in a N-benzyladenine solution promoted early pistillate flower production (Bose and Nitsch 1970). In this connection it may be important to note that cytokinins have been reported to induce ethylene formation in plant tissues (Fuchs and Lieberman 1968). 

Mature flower Flower production Flower number... 

Specific areas discussed include advantages and uses of the stamen-hair system, review of floral and stamen-hair morphology, cultivation of stock plants, screening of untreated plants for abnormally high aberration rates, preparation and handling of cuttings for experimental use, and consideration of flower production and of statistically acceptable numbers of cuttings and stamens rec[uired for a typical experiment. 

K. M. Marimuthu, L. A. Schairer, and A. H. Sparrow, The effects of space flight factors and gamma radiation on flower production and microspore division and development in Tradescantia, Radiation Botany 10, 249-259 (1970). 

Righter, F.I. 1939. Early flower production among the pines. J. For. 37 935-938. 

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