The B-class of MADS box genes has been studied in a wide range of plant species, but has remained largely uncharacterized in legumes. Here we investigate the evolutionary fate of the duplicated AP3-like genes of a legume species. To obtain insight into the extent to which B-class MADS box gene functions are conserved or have diversified in legumes, we isolated and characterized the two members ...

BACKGROUND AND AIMS Eriocaulaceae (Poales) is currently divided in two subfamilies: Eriocauloideae, which comprises two genera and Paepalanthoideae, with nine genera. The floral anatomy of Actinocephalus polyanthus, Leiothrix fluitans, Paepalanthus chlorocephalus, P. flaccidus and Rondonanthus roraimae was studied here. The flowers of these species of Paepalanthoideae are unisexual, and form ca...

This paper describes an open-flower mutant, designated opf, that we discovered in a genetic screen of fast neutron bombardment mutants in an attempt at floral-dip transformation of Melilotus alba (Fabaceae; white sweetclover), an alternative papilionoid legume host for Sinorhizobium meliloti. The opf mutant developed flowers with reflexed sepals and petals, thereby exposing the stamens and carp...

Nectar robbers are thought rarely to pollinate flowers, especially those with sexual organs hidden within corollas. In this study, we examined whether robbers pollinate flowers of distylous Primula secundiflora. Distylous plants have two floral morphs. Pin flowers have long styles and short stamens, and thrum flowers have short styles and long stamens. Flowers of P. secundiflora were commonly r...

Polyamines (PAs) like putrescine, spermidine, and spermine are ubiquitous polycationic molecules that occur in all living cells and have a role in a wide variety of biological processes. High amounts of spermidine conjugated to hydroxycinnamic acids are detected in the tryphine of Arabidopsis thaliana pollen grains. Tapetum localized spermidine hydroxycinnamic acid transferase (SHT) is essentia...

Stamens are the plant male reproductive organs essential for plant fertility. Proper development of stamens is modulated by environmental cues and endogenous hormone signals. Deficiencies in biosynthesis or perception of the phytohormone jasmonate (JA) attenuate stamen development, disrupt male fertility, and abolish seed production in Arabidopsis thaliana. This study revealed that JA-mediated ...

Cells in developing organisms do not only differentiate, they differentiate in defined patterns. A striking example is the differentiation of flowers, which in most plant families consist of four types of organs: sepals, petals, stamens and carpels, each composed of characteristic cell types. In the families of flowering plants in which these organs occur, they are patterned with the sepals in ...

MADS -box genes play an important role in plant ontogeny, particularly, in the regulation of floral organ induction and development. Eight full-length cDNAs of HAM genes ( Helianthus annuus MADS ) have been isolated from sunflower. They encode MADS-box transcription factors expressed in inflorescence tissues. In the frames of the ABCDE model, the HAM proteins were classified according to their ...

To identify genes involved in Arabidopsis thaliana petal and stamen organogenesis, we used a gene trap approach to examine the patterns of reporter expression at each stage of flower development of 1765 gene trap lines. In 80 lines, the reporter gene showed petal- and/or stamen-specific expression or lack of expression, or expression in distinct patterns within the petals and/or the stamens, in...

PREMISE OF THE STUDY The mint family (Lamiaceae) is the sixth largest family of flowering plants, with the tribe Mentheae containing about a third of the species. We present a detailed perspective on the evolution of the tribe Mentheae based on a phylogenetic analysis of cpDNA and nrDNA that is the most comprehensive to date, a biogeographic set of analyses using a fossil-calibrated chronogram,...