Inhibition of Orobanche crenata Seed Germination and Radicle Growth by Allelochemicals Identified in Cereals

Orobanche crenata is a parasitic weed that causes severe yield losses in important grain and forage legume crops. Cereals have been reported to inhibit O. crenata parasitism when grown intercropped with susceptible legumes, but the responsible metabolites have not been identified. A number of metabolites have been reported in cereals that have allelopathic properties against weeds, pests, and pathogens. We tested the effect of several allelochemicals identified in cereals on O. crenata seed germination and radicle development. We found that 2-benzoxazolinone, its derivative 6-chloroacetyl-2-benzoxazolinone, and scopoletin significantly inhibited O. crenata seed germination. Benzoxazolinones, l-tryptophan, and coumalic acid caused the stronger inhibition of radicle growth. Also, other metabolites reduced radicle length, this inhibition being dose-dependent. Only scopoletin caused cell necrotic-like darkening in the young radicles. Prospects for their application to parasitic weed management are discussed. © 2013 American Chemical Society.This research is supported by projects FP7-ARIMNet-MEDILEG and AGL2011-22524 (cofinanced by FEDER funds).Peer Reviewe

Predictability of Keeping Quality for Strawberry Batches

Postharvest life of strawberries is largely limited by Botrytis cinerea infection. It is assumed that there are two factors influencing the batch keeping quality: the Botrytis pressure and the resistance of the strawberry to infection. The latter factor will be discussed in this article. A colour model is presented that describes the development of red colour and anti-fungal function of individual strawberries over time. The model was fitted to colour data from strawberries grown at two different nutrient densities (EC) and stored per batch at 5, 10 or 16 °C and constant vapour pressure deficit after harvest. A batch was defined as all strawberries from one EC and one harvest. Spoilage per batch was recorded daily during storage. The fitted initial spoilage per batch was found to relate to the fitted average amount of precursor of both the colour and the anti-fungal compounds. Batch keeping quality could be derived from the initial batch colour distributions for the low nutrient batches. Also, batch keeping quality correlated highly with the time between harvest dates for the low EC batches. An explanation for the ability to link colour distributions to keeping quality without having to use a term describing the pH is presented from pigment HPLC measurements of sub-batches. Indications that the colour distributions of high EC batches may be subject to substantial co-pigmentation are presented. For a practical implementation of predicting keeping quality of batches additional research is needed, especially regarding different Botrytis pressures between greenhouses