Chrono-spatial reproductive phenology of Hook.f. & Thomson ex C.B.Clarke reveals suitability as climate-changing bio-indicator along the Sikkim Himalayan altitude.

Genus under the family Gentianaceae is morphologically and taxonomically distinct with about 14 species from Sikkim Himalayan region. A Chrono-spatial floral phenology study was conducted on from 1580 to 2400 m altitude in West Sikkim Himalayan region. The floral phenology was studied in a field nursery at 1200 m altitude and spatial floral phenology was studied over a 1580-2400 m altitudinal range in the West Sikkim Himalayan region.

Fitness benefits and costs of cold acclimation in Arabidopsis thaliana.

Abstract When resources are limited, there is a trade-off between growth/reproduction and stress defense in plants. Most temperate plant species, including Arabidopsis thaliana, can enhance freezing tolerance through cold acclimation at low but nonfreezing temperatures. Induction of the cold acclimation pathway should be beneficial in environments where plants frequently encounter freezing stress, but it might represent a cost in environments where freezing events are rare.

Natural selection drives clinal life history patterns in the perennial sunflower species, Helianthus maximiliani.

In plants, ecologically important life history traits often display clinal patterns of population divergence. Such patterns can provide strong evidence for spatially varying selection across environmental gradients but also may result from nonselective processes, such as genetic drift, population bottlenecks and spatially restricted gene flow. Comparison of population differentiation in quantitative traits (measured as Q(ST) ) with neutral molecular markers (measured as F(ST) ) provides a useful tool for understanding the relative importance of adaptive and nonadaptive processes in the formation and maintenance of clinal variation.

Transposable element proliferation and genome expansion are rare in contemporary sunflower hybrid populations despite widespread transcriptional activity of LTR retrotransposons.

Hybridization is a natural phenomenon that has been linked in several organismal groups to transposable element derepression and copy number amplification. A noteworthy example involves three diploid annual sunflower species from North America that have arisen via ancient hybridization between the same two parental taxa, Helianthus annuus and H. petiolaris.