Perianth organs in Nymphaeaceae: comparative study with emphasis on epidermal and structural characters.

FERRUCCI, M. S.; GALATI, B. G.; ZINI, L. M.

JOURNAL OF PLANT RESEARCH

SPRINGER TOKYO

Año: 2017 p. 1 - 16

0918-9440

The perianth organs of six species of Nymphaeaceae,representing Euryale, Nymphaea and Victoria, werestudied on the basis of macroscopical, micromorphological,and anatomical characters. The aims were to determinewhether perianth is differentiated among tepal whorls consideringthe presence of sepaloid and petaloid characters,and to evaluate the occurrence of both features in individualtepals. Selected perianth series were examined macroscopically,with light microscopy, and scanning electronmicroscopy. Osmophores were detected using neutral redand Sudan. In all tepals examined, stomata and hydropoteswere present on the abaxial and adaxial surfaces. These areanomocytic or stephanocytic; hydropotes of irregular typeare also present. The outer series of tepals display morphoanatomicalcharacters in most part related with photosyntheticand protective functions. Osmophore activity is veryscarce and petaloid epidermal morphology is present onlyin N. lotus, thus allowing interpretation of this whorl as primarilysepaloid. The second series exhibits both petal-likeand sepal-like characters; in N. amazonum and N. gardnerianasepaloid and petaloid group of cells are present on theabaxial surface of individual tepals. Therefore, this whorl is transitional between the outer and the innermost ones. Boththe morpho-anatomy and presence of osmophore activityindicate that the innermost series is entirely petaloid. Innertepals of E. ferox, N. alba, and V. cruziana share the presenceof epidermal cells with predominantly smooth cuticle,whereas those of N. amazonum, N. gardneriana, and N.lotus share a cuticular ornamentation consisting of numerouspapillae on each cell. Morphological characters of theperianth epidermis are in some respects congruent with themolecular phylogeny of Nymphaeaceae. Our results supportthe co-expression of sepaloidy and petaloidy withinindividual tepals and the mosaic model of perianth evolutionproposed for the angiosperms.