Effect of soil type and climatic conditions on the growth and flowering phenology of three Oxalis species in the Western Cape, South Africa

Generally, invasive plant species havewide environmental tolerance that enables them to exploit various climatic conditions and soil types, allowing them to invade new habitats easily. In the Cape Floristic Region, South Africa, the diversity of flowering plants can in part be ascribed to variation in these habitat characteristics that limit their distribution. Climate change has been predicted to bring warmer and drier conditions to the region, with possible influences on the climatic barriers that influence species distributions. We tested the effects of soil type and climate on the growth and flowering of the non-weedy Oxalis tomentosa, and the two weedy species Oxalis purpurea and Oxalis pes-caprae on an altitudinal gradient. The three species, all native to the region, exhibit a range of tolerances to environmental conditions: the first is habitat specific whereas the others are both well known indigenous weeds that have wider tolerance. The results showed that O. purpurea tolerates a variety of conditions well, whereas O. pes-caprae is more restricted by soil type, but would potentially profit from future climatic changes. O. tomentosa, when removed from its native habitat, was stressed under all conditions. These results suggest that habitat-restricted species will be threatened if the predicted level of climate change occurs, while invasive weeds will profit. Studying species responses to different environmental conditions is essential in determining future distributions

Soluble redox-active polymetallic chains [{Ru-0(CO)(L)(bpy)}(m)](n) (bpy=2,2 '-bipyridine, L = PrCN, Cl-; m=0,-1): electrosynthesis and characterization

Electrochemical and spectroelectrochemical techniques were employed to study in detail the formation and so far unreported spectroscopic properties of soluble electroactive molecular chains with nonbridged metal-metal backbones, namely, [{Ru-0(CO)(PrCN)(bpy)}(m)](n) (m = 0, -1) and [{Ru-0(CO)(bpy)Cl}(m)](n) (m = -1, -2; bpy = 2,2'-bipyridine). The precursors cis-(Cl)-[Ru-II(CO)(MeCN)(bpy)Cl-2] (in PrCN) and mer-[Ru-II(CO)(bpy)Cl-3](-) (in tetrahydrofuran (THF) and PrCN) undergo one-electron reductions to reactive radicals [Ru-II(CO)(MeCN)(bpy(center dot-))Cl-2](-) and [Ru-II(CO)(bpy(center dot-))Cl-3](2-), respectively. Both [bpy(center dot-)]-containing species readily electropolymerize on concomitant dissociation of two chloride ligands and consumption of a second electron. Along this path, mer-to-fac isomerization of the bpy-reduced trichlorido complex (supported by density functional theory calculations) and a concentration-dependent oligomerization process contribute to the complex reactivity pattern. In situ spectroelectrochemistry (IR, UV/vis a has revealed that the charged polymer [{Ru-0(CO)(bpy)Cl}(-)](n) is stable in THF, but in PrCN it converts readily to [Ru-0(CO)(PrCN)(bpy)](n). An excess of chloride ions retards this substitution at low temperatures. Both polymetallic chains are completely soluble in the electrolyte solution and can be reduced reversibly to the corresponding [bpy(center dot-)]-containing species