Timbuktu or to study. By 1300, the population increased to 10,000 and kept increasing until it reached about 50,000 in the 1500s. There is insufficient rainfall in the Timbuktu region for purely rain-fed agriculture and crops are therefore irrigated using water from the River Niger. The main agricultural crop is rice. African floating rice ("Oryza glaberrima") has traditionally been grown in regions near the river that are inundated during the annual flood. Seed is sown at the beginning of the rainy season (June–July) so that when the flood water arrives plants are already in height. The plants grow up to in
12-oxophytodienoate reductase 12-oxophytodienoate reductase 12-oxophytodienoate reductase (OPRs) is an enzyme of the family of Old Yellow Enzymes (OYE). OPRs are grouped into two groups: OPRI and OPRII – the second group is the focus of this article, as the function of the first group is unknown, but is the subject of current research. The OPR enzyme utilizes the cofactor flavin mononucleotide (FMN) and catalyzes the following reaction in the jasmonic acid synthesis pathway: This reaction occurs in peroxisomes in plants. Several isozymes have been discovered, with varying substrate stereospecificity: three in "Lycopersicon esculentum", 13 in "Oryza sativa", and five in "Arabidopsis thaliana".