Morphologically and physiologically diverse fruits of two Lepidium species differ in allocation of glucosinolates into immature and mature seed and pericarp

Abstract

The morphology and physiology of diaspores play crucial roles in determining the fate of seeds in unpredictable habitats. In some genera of the Brassicaceae different types of diaspores can be found. Lepidium appelianum produces non-dormant seeds within indehiscent fruits while in L. campestre dormant seeds are released from dehiscent fruits. We investigated whether the allocation of relevant defence compounds into different tissues in different Lepidium species may be related to the diverse dispersal strategy (indehiscent and dehiscent) and seed physiology (non-dormant and dormant). Total glucosinolate concentration and composition were analysed in immature and mature seeds and pericarps of L. appelianum and L. campestre using high-performance liquid chromatography. Moreover, for comparison, transgenic RNAi L. campestre lines were used that produce indehiscent fruits due to silencing of LcINDEHISCENCE, the INDEHISCENCE ortholog of L. campestre. Total glucosinolate concentrations were lower in immature compared to mature seeds in all studied Lepidium species and transgenic lines. In contrast, indehiscent fruits of L. appelianum maintained their total glucosinolate concentration in mature pericarps compared to immature ones, while in dehiscent L. campestre and in indehiscent RNAi-LcIND L. campestre a significant decrease in total glucosinolate concentrations from immature to mature pericarps could be detected. Indole glucosinolates were detected in lower abundance than the other glucosinolate classes (aliphatic and aromatic). Relatively high concentrations of 4methoxyindol-3-ylmethyl glucosinolate were found in mature seeds of L. appelianum compared to other tissues, while no indole glucosinolates were detected in mature diaspores of L. campestre. The diaspores of the latter species may rather depend on aliphatic and aromatic glucosinolates for long-term protection. The allocation patterns of glucosinolates correlate with the morpho-physiologically distinct fruits of L. appelianum and L. campestre and

How Does Changing Environment Influence Plant Seed Movements as Populations of Dispersal Vectors Decline?

“…These substances may influence fruit/seed size, shape, texture, composition, and dehiscence property, which may indirectly influence the diversity of seed dispersal modes and distribution. The morphological and physiological characteristics of seeds or spores play important roles in determining the fate of seeds in unpredictable habitats [ 23 ]. Further, the dehiscence characteristic may help plants escape extreme environmental conditions through long-distance dispersal [ 106 ].…”

Maize Grain Germination Is Accompanied by Acidification of the Environment

“…Thus, seeds need protection. It is well-known that the pericarp/testa also represents a protective tissue that functions as a physical barrier and chemical defence against pathogens and herbivores [37,38]. This was specifically shown for maize grains in which polyphenolic components in the pericarp mediated resistance against Aspergillus flavus (a saprotrophic and pathogenic fungus) and Spodoptera frugiperda (fall armyworm, a pest) [39,40].…”