Mulch and groundcover effects on soil temperature and moisture, surface reflectance, grapevine water potential, and vineyard weed management.

The objectives of this research were to identify alternatives to glyphosate for intra-row (under-trellis) vineyard floor management and to evaluate the potential for intra-row and inter-row (alleyway) groundcovers to reduce vegetative vigor of 'Marquette' grapevines (Vitis spp.) in a southeast Nebraska vineyard. The experiment was a randomized factorial design with five intra-row treatments (crushed glass mulch [CG], distillers' grain mulch [DG], creeping red fescue [CRF], non-sprayed control [NSC], and glyphosate [GLY]) and three inter-row treatments (creeping red fescue [CRF], Kentucky bluegrass [KB], and resident vegetation [RV]). Treatments were established in 2010-2011 and measurements were conducted during 2012 and 2013 on 5- and 6-year-old vines. Soil temperatures were mostly higher under mulches and lower under intra-row groundcovers, compared to GLY. Weed cover in CG, DG, and CRF treatments was the same or less than GLY. At most sampling dates, inter-row soil moisture was lowest under KB. Intra-row soil moisture was highest under DG mulch and lowest under CRF and NSC; CG had the same or lower soil moisture than GLY. Surprisingly, we did not detect differences in mid-day photosynthetically active radiation (PAR) reflectance, despite visual differences among the intra-row treatments. Mid-day vine water potential did not differ among treatments. We concluded it is not necessary to maintain a bare soil strip under established vines in this region, where soil fertility and moisture are non-limiting.

Resveratrol compounds inhibit human holocarboxylase synthetase and cause a lean phenotype in Drosophila melanogaster.

Holocarboxylase synthetase (HLCS) is the sole protein-biotin ligase in the human proteome. HLCS has key regulatory functions in intermediary metabolism, including fatty acid metabolism, and in gene repression through epigenetic mechanisms. The objective of this study was to identify food-borne inhibitors of HLCS that alter HLCS-dependent pathways in metabolism and gene regulation. When libraries of extracts from natural products and chemically pure compounds were screened for HLCS inhibitor activity, resveratrol compounds in grape materials caused an HLCS inhibition of >98% in vitro. The potency of these compounds was piceatannol>resveratrol>piceid. Grape-borne compounds other than resveratrol metabolites also contributed toward HLCS inhibition, e.g., p-coumaric acid and cyanidin chloride. HLCS inhibitors had meaningful effects on body fat mass. When Drosophila melanogaster brummer mutants, which are genetically predisposed to storing excess amounts of lipids, were fed diets enriched with grape leaf extracts and piceid, body fat mass decreased by more than 30% in males and females. However, Drosophila responded to inhibitor treatment with an increase in the expression of HLCS, which elicited an increase in the abundance of biotinylated carboxylases in vivo. We conclude that mechanisms other than inhibition of HLCS cause body fat loss in flies. We propose that the primary candidate is the inhibition of the insulin receptor/Akt signaling pathway.

In vitro rejuvenation of woody species.

Juvenility and phase change in woody plant species exert profound impacts on plant morphology and the ability of explants to be successfully propagated in vitro. Morphological characteristics such as leaf shape modifications, thorniness, and the inability to initiate flowers are associated with juvenility. Physiological maturity, that is the ability to reproduce sexually, is reached by many woody species only after many years of juvenile growth. As a result, micropropagation of woody species has historically been difficult with many plant species proving to be exceedingly recalcitrant. The importance of juvenility and its impact on successful vegetative reproduction in vitro has therefore received much research attention. In vitro technologies that have been demonstrated to induce rejuvenation include meristem culture, chemical treatments, pruning and hedging, forcing new growth, and taking advantage of epicormic buds, grafting and micrografting, and somatic embryogenesis. Applications of these technologies are discussed in this chapter.