Floral development in Phoenix dactylifera

Abstract

Inflorescence primordia in the date palm (Phoenix dactylifera L.) differentiate within axillary buds in November in the Coachella Valley, California. The rachillae are initiated as small mounds without subtending bracts on the flattened apex of the rachis and are enclosed by the prophyll. A single bract subtends each flower primordium. Flower primordia are initiated in an acropetal sequence along the rachillae. Although mature flowers are functionally unisexual, early development is similar in staminate and pistillate flowers. Six perianth parts are initiated within two alternating whorls: the sepals and the petals. Six stamens are initiated in two alternating whorls of three stamens each, the first opposite the sepals and the second opposite the petals. Lastly, three separate carpels are initiated. Pistillate and staminate flowers are identical and apparently bisexual at this stage. The two flower types diverge developmentally when the stamens become bilobed and elongate in the staminate but not the pistillate flowers. The pistillodes in the staminate flowers form rudimentary stigmatic surfaces at the tip of the carpels and meristematic lumps corresponding to the position of the ovule in normal carpels. The staminodes mature in the pistillate flowers as small triangular projections. Meiosis occurred in staminate and pistillate flowers (in March 1979) when the staminate flowers were about 5 mm long and the pistillate flowers were about 3 mm long.

Regulation of flower development in cultured ears of maize (Zea mays L.)

“…This differential development of initiated organs associated with male and female flowers is similar to the events that occur in a number of species noted by DeMason et al (1982); (b) observations on the external environmental factors that modify the expression of these developmental traits (Heslop-Harrison 1961;Moss and Heslop-Harrison 1968;Rood et al 1980); (c) extraction and assay for gibberellin-like and cytokinin-like substances from ears and tassels of different developmental stages (Sladky 1969(Sladky , 1986Rood etal. 1980); (d) exogenous application through sprays, drop-wise applications or hydroponic culture of putative regulators or their inhibitors (Nickerson 1959;Heslop-Harrison 1961;Hansen et al 1976;Krishnamoorthy and Talukdar 1979;Chailakhyan and Khryanin 1980).…”

Morphology and development of the female flowers in Geonoma interrupta (Arecaceae)

“…Observations on the short stigmatic tips with surface papillate already in flowers at stage I agree with [Vol. 89 AMERICAN JOURNAL OF BOTANY the early stigmatic development in Phoenix dactylifera (De Mason, Stolte, and Tisserat, 1982) and probably many other monocots, e.g., Ornithogalum caudatum (Tilton and Horner, 1980). Since the first report of a transmitting tissue in the styles of some Arecaceae (Venkata Rao, 1959b) and the description of a compitum in palms (Cocucci, 1964), this study on Geonoma interrupta represents a contribution towards a better understanding of the pollen tube transmitting tract in the family; nevertheless, additional studies on this matter are still greatly needed.…”

Evidence of Recombination Suppression Blocks on the Y Chromosome of Date Palm (Phoenix dactylifera)

“…Early insights into the anatomical features of date palm flowers suggested few morphological differences between male and female flowers during early stages of development (De Mason et al, 1982). More recent cytological studies revealed that date palm flowers are initially bisexual as indicated by the presence of carpel and stamen primordia in both male and female flowers, but during later stages of development, staminode and pistillode cells stop dividing and remain undifferentiated in female and male flowers respectively, leading to fully developed unisexual flowers (Daher et al, 2010).…”