Developmental morphology of branching flowers in Nymphaea prolifera

Abstract

Nymphaea and Nuphar (Nymphaeaceae) share an extra-axillary mode of floral inception in the shoot apical meristem (SAM). Some leaf sites along the ontogenetic spiral are occupied by floral primordia lacking a subtending bract. This pattern of flower initiation in leaf sites is repeated inside branching flowers of Nymphaea prolifera (Central and South America). Instead of fertile flowers this species usually produces sterile tuberiferous flowers that act as vegetative propagules. N. prolifera changes the meristem identity from reproductive to vegetative or vice versa repeatedly. Each branching flower first produces some perianth-like leaves, then it switches back to the vegetative meristem identity of the SAM with the formation of foliage leaves and another set of branching flowers. This process is repeated up to three times giving rise to more than 100 vegetative propagules. The developmental morphology of the branching flowers of N. prolifera is described using both microtome sections and scanning electron microscopy.

Morphology of Hydatellaceae, an anomalous aquatic family recently recognized as an early‐divergent angiosperm lineage

“…The apparently perianthless simple flowers of Hydatellaceae differ considerably from flowers of Nymphaeales, which possess a perianth enclosing multiple organs. Furthermore, our observations indicate a cymose branching pattern in Hydatellaceae, which is unusual for Nymphaeales, though Nuphar and Nymphaea have a peculiar branching pattern with flowers replacing leaves in the ontogenetic spiral (Weidlich, 1976a, b;Schneider et al, 2003;Grob et al, 2006, and other references cited therein). One could speculate that the flowersubtending bract is merely suppressed in Nymphaea, on the basis of observations of bract-like organs at the base of pedicel in Nuphar (reviewed by Schneider et al, 2003), but occasional observations of more than one such bract in Nuphar makes such a hypothesis problematic.…”

A família Nymphaeaceae no estado do Ceará, Brasil

“…É caracterizada por apresentar uma pseudoviviparidade, onde ramos florais dão origem a novos indivíduos clonais (sensu Sculthorpe 1967). Grob et al (2006) relata para N. prolifera Wiersema algo semelhante, onde formase um pedicelo e uma estrutura floral apresentando peças florais, porém os tecidos meristemáticos que dariam origem ao androceu e gineceu cessam o desenvolvimento e originam folhas e posteriormente novos indivíduos. Sculthorpe (1967) referiu-se a este tipo de estrutura como pseudoestolho.…”

Shoot Architecture and Branching Pattern in Perennial Hydatellaceae (Nymphaeales)

“…Flowers of Nymphaea have long been described as occupying leaf sites in a phyllotaxic spiral (Raciborski 1894b). Some authors have described flowers as developing instead of leaves and thus lacking subtending bracts (Cutter 1957a(Cutter , 1957b(Cutter , 1961Weidlich 1976aWeidlich , 1976bSchneider et al 2003;Grob et al 2006). Others have concluded that the apparent position of flowers in the same spiral as leaves is due to reduction of the subtendingleaf component of a primordium that would potentially give rise to both a subtending leaf and an axillary bud (Chassat 1962;Endress and Doyle 2009).…”