0000000000364852
AUTHOR
Somayeh Naghiloo
Nectar protection in arid-adapted flowers of Zygophyllaceae-Zygophylloideae
Abstract The survival of plants in arid areas depends on efficient adaptation to extreme environments. The protection against nectar loss is an important challenge for flowers in arid environments. Flowers of arid-adapted Zygophyllaceae subfamily Zygophylloideae are characterized by a peculiar structure called staminal scales (SS). The special arrangement of SS around the perigynous disc nectary (DN) suggests their adaptive function for protection against nectar loss. We aim to test the protective function of SS and to understand the synorganised evolution of SS and DN in relation to nectar protection. We, first, manipulate flowers by removal of SS in two representatives of Zygophylloideae.…
A combination of dichogamy and herkogamy mediates reproductive success in the desert shrub Zygophyllum fabago
Abstract Zygophyllum fabago is a species within the arid-adapted family Zygophyllaceae. The species is characterized by the co-occurrence of dichogamy and herkogamy. In order to understand the effect of these two complementary anti-selfing mechanisms in reproductive success, we conducted a detailed study of floral biology in Z. fabago. Our results indicated an incomplete separation of the female and male phases which is referred to as partial dichogamy. We found two floral morphs with distinct stigma position: the Central-morph (C-morph) and the Lateral-morph (L-morph). The stigma-stamen distance in the L-morph was significantly larger than in the C-morph in early, mid, and late male stages…
Developmental analysis of merosity and sexual morphs in Rubiaceae: A case study in Rubia and Cruciata
The Rubiaceae is characterized by considerable diversity in floral features. To shed light on the variation of floral developmental patterns in Rubiaceae, a comparative study was carried out on pentamerous flowers of Rubia tinctorum L. and tetramerous flowers of Cruciata (Cruciata laevipes Opiz.; Cruciata glabra (L.) Ehrend.), two herbaceous genera of the tribe Rubieae. We aim to study the mechanism responsible for meristic variation and to discuss the expression of andromonoecy in C. laevipes. Developmental peculiarities include the time overlap in the initiation of petal and stamen whorls in Cruciata, the lack of calyx, and a very weak sympetaly in all species examined. Our results show t…
Pollination biology in Roepera (Zygophyllaceae): How flower structure and shape influence foraging activity
The foraging behavior of bees is a complex phenomenon that depends on numerous physical features of flowers. Of particular importance are accessibility of floral rewards, floral proportions, symmetry and orientation. The flowers of Roepera are characterized by the presence of staminal scales (SS), which play an important role in nectar protection. We studied two species of Roepera with different symmetry and flower orientation, which are mainly visited by honeybees (Apis mellifera). We aimed to show how the foraging behavior of honey bees is affected by the function of SS, floral symmetry and orientation. The foraging behavior was documented by video photography. Handling time, access to ne…
Flower ontogeny inCapparis spinosa(Capparaceae) with special emphasis on symmetry expression
The flower ontogeny of Capparis spinosa L. was studied using scanning electron microscopy (SEM) in order to shed light on the early expression of symmetry in a representative member of Capparaceae. Sepals start decussately with the abaxial and adaxial sepals, followed by the lateral ones. Petal appearance proceeds uni-directionally from the abaxial to the adaxial side. Stamens develop centrifugally on an androecial ring. Five to seven carpel lobes arise on a gynoecial ring. Monosymmetry is established in early development by the uni-directional petal appearance and is further enhanced by the acquisition of an abaxial nectary appendage and differential development of perianth organs at anthe…
The plasticity of breeding system in arid-adapted Zygophylloideae
Abstract The assurance of reproductive success is an important challenge for arid-adapted plants. Self-compatibility is suggested as a mechanism to compensate for the inadequate breeding opportunities in extreme environments. Zygophylloideae is an arid-adapted subfamily which has successfully radiated in different ranges of arid habitats. In order to study the significance of selfing for the reproductive success of the Zygophylloideae, we calculated pollen ovule ratios (P/O) and conducted bagging experiments for autogamy and xenogamy in eleven representative members of Zygophylloideae and three species of the sister subfamilies Tribuloideae and Larreoideae. Our results revealed an extremely…