The question of whether or not perennial plants senesce at the organism level remains unresolved. The aim of this study was to unravel whether or not plant age can influence the production and composition of seeds. Flower and seed production was examined in 3-, 8-, and 13-year-old Cistus albidus plants growing in experimental plots corresponding to the F2, F1, and F0 generations of the same pop...

Bamboos are typical examples of highly synchronized semelparous species. Their mass-flowering events occur at supra-annual intervals but they sometimes flower on a small scale in off-years. If some bamboo ramets (culms) of a genet flower and die in off-years, whereas other culms of the same genet do not flower synchronously, the genet can still survive blooming in an off-year and could particip...

The lotus (Nelumbonaceae: Nelumbo Adans.) is a highly desired ornamental plant, comprising only two extant species, the sacred lotus (N. nucifera Gaerten.) with red flowers and the American lotus (N. lutea Willd.) with yellow flowers. Flower color is the most obvious difference of two species. To better understand the mechanism of flower color differentiation, the content of anthocyanins and th...

The number of pods per plant and the number of seeds per pod are the most variable yield components in winter oilseed rape (WOSR). The production of a seed is the combination of several physiological processes, namely formation of ovules and pollen grains, fertilization of the ovules and development of young embryos, any problem in these processes may result in seed abortion or pod abortion. Bo...

Atmospheric CO2 and tropospheric O3 are rising in many regions of the world. Little is known about how these two commonly co-occurring gases will affect reproductive fitness of important forest tree species. Here, we report on the long-term effects of CO2 and O3 for paper birch seedlings exposed for nearly their entire life history at the Aspen FACE (Free Air Carbon Dioxide Enrichment) site in ...

BACKGROUND AND AIMS Nymphaea thermarum is a member of the Nymphaeales, of one of the most ancient lineages of flowering plants. This species was only recently described and then declared extinct in the wild, so little is known about its reproductive biology. In general, the complete ontogeny of ovules and seeds is not well documented among species of Nymphaea and has never been studied in the s...

to evaluate the effect of gamma rays on the seeds and amounts of nitrogen on growth and yield of chamomile (chamomilla recutita synonym matricaria chamomilla), a factorial experiment was conducted based on randomized complete block design with three replications at the research farm of agriculture college of shahid-beheshti.-urmia in 2010. treatments were gamma rays from cobalt-60 on chamomile ...

Reproductive meristems and embryos display dormancy mechanisms in specialized structures named respectively buds and seeds that arrest the growth of perennial plants until environmental conditions are optimal for survival. Dormancy shows common physiological features in buds and seeds. A genotype-specific period of chilling is usually required to release dormancy by molecular mechanisms that ar...

The molecular mechanisms underlying the initiation and maintenance of the embryonic pathway in plants are largely unknown. To obtain more insight into these processes, we used subtractive hybridization to identify genes that are upregulated during the in vitro induction of embryo development from immature pollen grains of Brassica napus (microspore embryogenesis). One of the genes identified, B...