TiPlasmids are used as transformation vectors

Its ability to transform plants has made A. tumefaciens an excellent tool for integrating foreign genes in their functional state in a plant genome. It was necessary, however, to modify Ti-plasmids before they could be used as vectors (Fig. 22.14). The genes for auxin and cytokinin synthesis were removed to prevent tumor growth in the transformed plants. Since synthesis of an opine is unnecessary for a transgenic plant and would be a burden on its metabolism, the genes for opine synthesis were...

Xenobiotics are detoxified by conjugation

Toxic compounds produced by the plant or which are taken up (xenobi-otics, including herbicides) are detoxified by reaction with glutathione. Catalyzed by glutathione- transferases, the reactive SH group of glutath-ione can form a thioether by reacting with electrophilic carbon double bonds, carbonyl groups, and other reactive groups. Glutathione conjugates (Fig. 12.6) synthesized in this way in the cytosol are transported into the vacuole by a specific glutathione translocator against a...

Mechanized agriculture usually necessitates the use of herbicides

About 50 of the money spent worldwide for plant protection is expended for herbicides. The high cost of labor is one of the main reasons for using herbicides in agriculture. It is cheaper and faster to keep a field free of weeds by using herbicides rather than manual labor. Weed control in agriculture is necessary not only to decrease harvest losses by weed competition, but also because weeds hinder the operation of harvesting machineries fields free of weeds are a prerequisite for a mechanized...

Nitrogen fixation enables plants to use the nitrogen of the air for growth

In a closed ecological system, the nitrate required for plant growth is derived from the degradation of the biomass. In contrast to other plant nutrients (e.g., phosphate or sulfate), nitrate cannot be delivered by the weathering of rocks. Smaller amounts of nitrate are generated by lightning and carried into the soil by rain water (in temperate areas about 5 kg N ha per year). Due to the effects of civilization (e.g., car traffic, mass animal production, etc.), the amount of nitrate, other...

The cell wall gives the plant cell mechanical stability

Nanocellulose Fiber

The difference between plant cells and animal cells is that plant cells have a cell wall. This wall limits the volume of the plant cell. The water taken up into the cell by osmosis presses the plasma membrane against the inside of the cell wall, thus giving the cell mechanical stability. The cell walls are very complex structures in Arabidopsis about 1,000 genes were found to be involved in its synthesis. Cell walls also protect against infections. The cell wall consists mainly of carbohydrates...