Butenolide from plant-derived smoke functions as a strigolactone analogue: Evidence from parasitic weed seed germination

AbstractThe main germination active compound in smoke, 3-methyl-2H-furo[2,3-c]pyran-2-one (butenolide), has structural similarities with strigolactones that function as germination stimulants for root parasitic plants such as Orobanche spp. and Striga spp. (Scrophulariaceae). Consequently, we tested whether butenolide also functions as a germination stimulant for parasitic weeds. Butenolide stimulated germination of both Orobanche minor and Striga hermonthica to similar levels as the synthetic strigol analogue GR24 and was effective at similar concentrations (10−5 to 10−11 M). Both butenolide and GR24 were more effective than the synthetic strigol analogue Nijmegan-1. Across eight further Orobanche spp., and for species from the root parasitic genera Cistanche, Conopholis and Lathraea, butenolide also had a similar level of activity to GR24. These results suggest that the germination stimulatory activity of butenolide may result from analogy with strigolactones

Ranges of critical temperature and water potential values for the germination of species worldwide: Contribution to a seed trait database

Germination is the first essential stage in crop and food production, as well as for the establishment of trees and regeneration of wild species. Temperature and water potential are the primary environmental factors that control germination in all species, and affect both the rate and final percentage germination. A comprehensive description of intra- and inter-variations between groups of species (perennials and annuals, trees, grasses, crops and wild species) helps understand where these species are currently able to grow on earth and will be in the future. By collecting germination trait data on 243 species from the literature and unpublished data, we provide a wide spectrum of species’ seed germination traits, in the form of a set of parameter values describing germination responses to variations in temperature and water potential. Major differences in germination traits were seen to depend on the climatic conditions where the species grow or originated, with species able to germinate on ice and others unable to germinate below 18 °C. By contrast, within the different plant groups, similar ranges of threshold values were found, linked to the species geo-climatic origin. Crops however germinate faster, their range of threshold temperatures and water potential values is wider, and some crops have higher optimum and maximum temperatures as well as lower water potential threshold values. This is likely the result of human selection for rapid germination and for species able to grow in the wide range of environmental conditions where agriculture was developed. Our analyses revealed correlation between traits: negative correlations appeared between germination speed and temperature thresholds, and between temperature and water potential thresholds. The collected data also form a valuable database, enabling plant establishment to be better taken into account in modeling and simulation studies of vegetation boundaries (wild or cultivated) under changing land-use and climate

The climatic challenge: which plants will people use in the next century?

More than 31,000 useful plant species have been documented to fulfil needs and services for humans or the animals and environment we depend on. Despite this diversity, humans currently satisfy most requirements with surprisingly few plant species; for example, just three crops – rice, wheat and maize – comprise more than 50% of plant derived calories. Here, we synthesize the projected impact of global climatic change on useful plants across the spectrum of plant domestication. We illustrate the demographic, spatial, ecophysiological, chemical, functional, evolutionary and cultural traits that are likely to characterise useful plants and their resilience in the next century. Using this framework, we consider a range of possible pathways for future human use of plants. These are centred on two trade-offs: i) diversification versus specialization in the range of species we utilize, and ii) substitutionof the species towards those better suited to future climate versus facilitating adaptation in our existing suite of dominant useful plants. In the coming century, major challenges to agriculture and biodiversity will be dominated by increased climatic variation, shifting species ranges, disruption to biotic interactions, nutrient limitation and emerging pests and pathogens. These challenges must be mitigated, whilst enhancing sustainable production to meet the needs of a growing population and a more resource intensive standard of living. With the continued erosion of biodiversity, our future ability to choose among these pathways and trade-offs is likely to be diminished

Seasonality effects on plant phenology and seed ecology in Oritrophium peruvianum (Asteraceae), a threatened tropical alpine species

Abstract Oritrophium peruvianum (Lam.) Cuatr. (Asteraceae) is a threatened perennial herb, endemic to the tropical alpine zone of the Andean paramos and used for medicinal purposes. In this study, its population structure, phenological patterns and seed viability and germination were analysed. In all of the three investigated populations, the proportion of flowering plants was smaller than that of non-flowering. Size structure differed among populations, with two following a normal and one a left-skewed distribution, with a higher percentage of young plants. Flowering was spread throughout the rainy season, with fruiting intensity highest at the end of the rainy season and at the beginning of the dry season. Seedling emergence was limited and appeared to be independent of the season, indicating opportunities for continuous seedling emergence and mortality throughout the year. Seed viability was higher in seeds collected at the end of the dry season compared with those harvested at the end of the rainy season. Laboratory studies suggest that under natural conditions, germination timing is likely to be independent from the season