Floral organ

Grotewold, E., Drummond, B. J., Boen, B., and Peterson, T., 1994, The myh -homologous P gene controls phlobaphene pigmentation in maize floral organs by directly activating a flavonoid biosynthetic gene subset, Cell 76 543-553. 

Meric, C. and Dane, F., Calcium oxalate crystals in floral organs of Helianthus annuus L. and II. tuberosus L. (Asteraceae), Acta Biologica Szegediensis, 48, 19-23. 

Floral volatiles could play many roles instead of or in addition to pollinator attraction. For example, many terpenes, including P-myrcene, ( )-P-ocimene, linalool, and ( )-P-caryophyllene, react readily with ozone and other reactive oxygen species (27). Thus, floral volatiles could function to protect the reproductive organs from oxidative damage. A variety of monoterpenes and sesquiterpenes is reported to have antimicrobial activity (28). Hence, floral terpenes could help defend floral organs, like the moist stigma, from bacterial or fungal infection. 

Estiva tion (Aestivition).—The arrangements of the floral organs in the flower bud. 

Fruits may also be classified into a number of structural types. The individual seed-bearing structures of the flower called carpels constitute the gynoecium. The seed-containing cavity of a carpel is called the ovary, and its wall develops into the pericarp of the fruit. The edible fleshy part of a fruit most commonly develops from the ovary wall, but it may be also derived from the enlarged tip of stem from which floral organs arise, and sometimes leaf-like structures protecting the flowers may also become fleshy, e.g., in pineapple. 

Floral Organs A flower comprises four different organs called sepals, petals, stamens, and carpels, which are arranged in con-... 

A EXPERIMENTAL FIGURE 15-26 Mutations in floral organ-identity genes produce homeotic phenotypes. 

A EXPERIMENTAL FIGURE 15-27 Phenotypic analysis identified three classes of genes that control specification of floral organs in Arabidopsis. (a) Diagram of the arrangement of wild-type floral organs, which are found in concentric whorls. 

To test whether these patterns of expression are functionally important, scientists produced transgenic Arabidopsis plants in which floral organ-identity genes were expressed in inappropriate whorls. For instance, the introduction of a transgene carrying class B genes linked to an A-... 

Sequencing of floral organ-identity genes has revealed that many encode proteins belonging to the MADS family of transcription factors, which form homo- and heterodimers. Thus floral-organ identity may be specified by a combinatorial mechanism in which differences in the activities of different homo- and heterodimeric forms of various A, B, and C proteins regulate the expression of subordinate downstream genes necessary for the formation of the differ-... 

A EXPERIMENTAL FIGURE 15-28 Expression patterns of class A, B, and C genes support the ABC model of floral organ specification. Depicted here are the observed expression patterns of the floral organ-identity genes in wild-type, mutant, and transgenic Arabidopsis. Colored bars represent the A, B, and... 

C mRNAs in each whorl (W1, W2, W3, W4). The observed floral organ in each whorl is indicated as follows sepal = se petals = pe stamens = st and carpels = ca. See text for discussion. 

MACTAVISH, H.S., MENARY, R.C., Volatiles in different floral organs, and effect of floral characteristics on yield of extract from Boronia megastigma (Nees) Annal Bot., 1997, 80, 305-311. 

Wisman, E. andYanofsky, M. F. (2000). B and C floral organ identity functions require SEPALLATA MADS-box genes. Nature, 405, 200-203. 

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