Life Sciences Commons^™

Senecio Conrathii N.E.Br. (Asteraceae), A New Hyperaccumulator Of Nickel From Serpentinite Outcrops Of The Barberton Greenstone Belt, South Africa, Stefan Siebert, Nadine Carol Schutte, Stoffel Pieter Bester, Dennis Mmakgabo Komape, Nishanta Rajakaruna

Biological Sciences

Five nickel hyperaccumulators belonging to the Asteraceae are known from ultramafic outcrops in South Africa. Phytoremediation applications of the known hyperaccumulators in the Asteraceae, such as the indigenous Berkheya coddii Roessler, are well reported and necessitate further exploration to find additional species with such traits. This study targeted the most frequently occurring species of the Asteraceae on eight randomly selected serpentinite outcrops of the Barberton Greenstone Belt. Twenty species were sampled, including 12 that were tested for nickel accumulation for the first time. Although the majority of the species were excluders, the known hyperaccumulators Berkheya nivea N.E.Br. and B. zeyheri …

Edaphic Adaptation Maintains The Coexistence Of Two Cryptic Species On Serpentine Soils, Jenn M. Yost, Teri Barry, Kathleen M. Kay, Nishanta Rajakaruna

Biological Sciences

• Premise of the study: Divergent edaphic adaptation can contribute to reproductive isolation and coexistence between closely related species, yet we know little about how small-scale continuous edaphic gradients contribute to this phenomenon. We investigated edaphic adaptation between two cryptic species of California wildflower, Lasthenia californica and L. gracilis (Asteraceae), which grow in close parapatry on serpentine soil.

• Methods: We reciprocally transplanted both species into the center of each species’ habitat and the transition zone between species. We quantified multiple components of fitness and used aster models to predict fitness based on environmental variables. We sampled soil across the …

The Edaphic Factor And Patterns Of Variation In Lasthenia Californica (Asteraceae), Nishanta Rajakaruna, Bruce A. Bohm

Biological Sciences

Transectional studies of Lasthenia californica in the Jasper Ridge Biological Preserve (Stanford University) have documented the existence of two races (A and C) based upon flavonoid chemistry, achene morphology, allozymes, and flowering time differences. The two races coexist on a serpentine outcrop and have maintained a sharply defined pattern of distribution for a period of at least 15 yr. The present study has revealed significant differences in the physical and chemical features of the soils harboring the two races. Soils at the lower ends of the transects, where race A plants grow, have higher pH, cation exchange capacity, relative water …