Seed Vigor Test for the Establishment of Switchgrass

Switchgrass (Panicum virgatum), a high-yielding perennial C4 prairie grass species, is a top candidate as a bioenergy feedstock for cellulosic ethanol production. Seedling establishment is a primary concern given the inherent variability in switchgrass seed dormancy. Determining current states of seed quality in terms of emergence percentage is crucial for a successful stand establishment. A practical seed vigor test was conducted under greenhouse conditions to determine current emergence percentage. Three depths and three media types were conditions evaluated in the vigor test. To find correlation between emergence percentage in greenhouse test conditions and that in field conditions, results from the vigor test were applied in two separate field evaluations. Field evaluations showed that vigor test conditions of field soil at 1-cm depth yielded below the target, suggesting that this condition did not put enough stress on seedling emergence in the greenhouse vigor test. A 20% increase of vigor test results in the field soil/1 cm condition could accurately predict field emergence. Field results suggested that coarse sand at 5-cm accurately predicted field emergence of highly vigorous varieties and that coarse sand at 1-cm and fine sand at 3-cm predicted field emergence in moderately to least vigorous varieties

Iridium Catalyzed Synthesis of Tetrahydro-1H-Indoles by Dehydrogenative Condensation

Novel synthetic routes to the commonly encountered indole motif are highly sought after. Tetrahydro-1H-indoles were synthesized for the first time from secondary alcohols and 2-aminocyclohexanol in the presence of a well-established iridium catalyst using a modified synthetic procedure recently developed for the synthesis of hydrocarbazoles. The catalyst is stabilized by an inexpensive and easy-to-synthesize triazine based PN5P pincer ligand. The reaction proceeds through acceptorless dehydrogenative condensation (ADC) and yields the title compound, dihydrogen, and water and can thus be classified as sustainable synthesis. Overall, five examples, three of which were previously unknown compounds, were prepared. The propitious isolated yields and the mild reaction conditions show the synthetic value of this approach. These tetrahydroindoles can be quantitatively dehydrogenated over a heterogeneous Pd catalyst to yield the corresponding indoles