Bücher von Basel Khraiwesh

Säata jest jedn¿ z najwäniejszych ro¿lin säatowych uprawianych na ¿wiecie. Azot (N) jest najcz¿stszym sk¿adnikiem od¿ywczym w produkcji ro¿linnej, wiadomo, ¿e dodatek N jest rozprowadzany w ro¿linie, frakcja stäa w glebie, wymywana do zwierciad¿a wody lub denitryfikowana do atmosfery. Dlatego te¿ käda technika, która poprawia efektywno¿¿ absorpcji N przez ro¿lin¿, szczególnie w przypadku ro¿lin o p¿ytkich korzeniach, ostatecznie zmniejszy ilo¿¿ strat N i wp¿yw na ¿rodowisko. Z drugiej strony, cz¿¿¿ wch¿oni¿tego N mo¿e by¿ gromadzona w postaci azotanów. Oko¿o 70% cäkowitej ilo¿ci azotanów spo¿ywanych przez ludzi pochodzi z warzyw. G¿sto¿¿ sadzenia, poziom nawadniania i praktyki nawo¿enia s¿ s¿abo zbadane, a wp¿yw ró¿nych form N na jako¿¿ säaty (zw¿aszcza zawarto¿¿ azotanów) i na ¿rodowisko jest w du¿ej mierze nieznany. Dlatego te¿ niniejsza ksi¿¿ka pokäe najlepsz¿ form¿ azotu, rozstawy ro¿lin i poziom nawadniania, które zapewniaj¿ najwy¿szy plon i maksymalny procent odzysku azotu oraz zapewniaj¿ jako¿¿ säaty pod wzgl¿dem najmniejszego poziomu akumulacji azotanów w li¿ciach, na który wp¿yw maj¿ forma azotu, rozstawy ro¿lin i poziom nawadniania.

Lettuce is one of the most important salad crops grown in worldwide. Nitrogen (N) is the most frequent nutrient in crop production, it is well known that added N is distributed into the plant, the fixed fraction in the soil, leached into the water table or denitrified into the atmosphere. Therefore any technique that improves the N absorption efficiency of the plant especially that of shallow-rooted plants will eventually reduce the amount of N loss and the impact on the environment. On the other hand, some of the absorbed N could be accumulated as nitrate. About 70% of total consumed nitrate by people come from vegetables. Planting density, irrigation level and fertilization practices are poorly studied and the effects of different N forms on lettuce quality (especially nitrate content) and on the environment are largely unknown. So this book will show the best nitrogen form, plant spacing and irrigation level, which provide the highest yield and maximum percentage of nitrogen recovery and provide lettuce quality in terms of the least nitrate accumulation level in leaves as affected by nitrogen form, plant spacing and irrigation level.

RNA interference (RNAi) is a mechanism regulating gene transcript levels by either transcriptional gene silencing (TGS) or by posttranscriptional gene silencing (PTGS), which acts in genome maintenance and the regulation of development. This book show the role of Dicer proteins in the moss Physcomitrella patens, which has four Dicers (DICER-LIKE 1a (DCL1a), DCL1b, DCL3 and DCL4). The Physcomitrella patens was chosen because the dual functions of Dicers in miRNA biogenesis and target cleavage are separable in this species. Using targeted knockout-mutants of Physcomitrella patens, it was shown that DCL1a is required for miRNA biogenesis and DCL1b is required for miRNA-induced target RNA cleavage. Based on these data from Physcomitrella patens a model is proposed for the gene-specific control of transcription factors upon dysfunctions of the RNAi machinery. Similar control mechanisms could be exist in other eukaryotes as well. Also this book provide evidence that artificial miRNAs (amiRNAs) can be used as an alternative tool for studying gene functions in Physcomitrella patens.