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An Agrobacterium tumefaciens-mediated transformation system was developed for Artemisia annua L. Using this system a cDNA encoding farnesyl diphosphate synthase (FDS placed under a CaMV 35S promoter) was transferred into A. annua via A. tumefaciens strain LB4404. Leaf or leaf discs were used as explants to be infected with A. tumefaciens and an optimal(More)
Caffeoyl-coenzyme A (CoA) O-methyltransferase (CCoAOMT) has been proposed to be involved in an alternative methylation pathway of lignin biosynthesis. However, no direct evidence has been available to confirm that CCoAOMT is essential for lignin biosynthesis. To understand further the methylation steps in lignin biosynthesis, we used an antisense approach(More)
We demonstrate a great simplification in the long-standing problem of measuring optical frequencies in terms of the cesium primary standard. An air-silica microstructure optical fiber broadens the frequency comb of a femtosecond laser to span the optical octave from 1064 to 532 nm, enabling us to measure the 282 THz frequency of an iodine-stabilized Nd:YAG(More)
We present the general theory of clean, two-dimensional, quantum Heisenberg antiferromagnets which are close to the zero-temperature quantum transition between ground states with and without long-range Néel order. While some of our discussion is more general, the bulk of our theory will be restricted to antiferromagnets in which the Néel order is described(More)
Using an iodine-stabilized He-Ne laser as a transfer oscillator, we compare absolute measurements of the optical frequency from a traditional frequency synthesis chain based on harmonic generation and from the frequency division technique of an ultrawide bandwidth femtosecond frequency comb. The agreement between these two measurements, both linked to the(More)
Leaf senescence in many plant species is associated with increased oxidative damage to cellular macromolecules by reactive oxygen species (ROS). Since ROS levels and their damage products in many plants are known to increase during senescence, it is possible that these changes are due to a decline in the levels of certain antioxidant enzymes. Using specific(More)