Narcissus is an economically important crop with a large number of species, hybrids and/or varieties in cultivation. It is one of the most popular ornamental plants. The Netherlands is among the... Show moreNarcissus is an economically important crop with a large number of species, hybrids and/or varieties in cultivation. It is one of the most popular ornamental plants. The Netherlands is among the top producers of Narcissus in the world. The ornamental value of Narcissus is quite well known but they can also be a valuable resource of natural compounds. Among these compounds, galanthamine has been successfully commercialized as medicine for the treatment of early to mild Alzheimer’s Disease (AD). The characteristic symptoms of this disease are loss of memory and impairment of multiple cognitive and emotional functions. The objective was to find out how galanthamine levels could be enhanced to convert this floricultural crop into a medicinal crop. There are different factors that influence the production of galanthamine and other metabolites in the bulbs. Effect of various factors such as preanalytical methods, bulb location and age along with effect of biotic and abiotic factors on the growth and yield were studied. From the results, it is evident that factors have detrimental effect on the total bulb yield and galanthamine levels. Show less
Jasmonates (JAs) are crucial plant signaling molecules that regulate defense responses against wounding, insects and necrotrophic pathogens. The biosynthesis of JAs is regulated by a positive... Show moreJasmonates (JAs) are crucial plant signaling molecules that regulate defense responses against wounding, insects and necrotrophic pathogens. The biosynthesis of JAs is regulated by a positive feedback loop. This thesis reveals the transcriptional regulatory mechanism behind this positive feedback loop in Arabidopsis. The studies show that the bHLH-domain transcription factors MYC2, MYC3 and MYC4 positively regulate most JAs biosynthesis genes directly and by controlling the expression of ORA47 gene, encoding a regulator of JAs biosynthesis. Show less
