Environmental Factors Affecting Yield

Jerusalem artichoke thrives under a wide range of growing conditions. However, yields can be greatly affected by environmental factors, including solar radiation, temperature, length of the growing season, and rainfall. 

Biology and Chemistry of Jerusalem Artichoke Helianthus tuberosus L. 

In a modeling study of Jerusalem artichoke productivity, foliage dry matter content was found to be a linear function of annual intercepted radiation (Allirand et al., 1988). Yearly productivity variations in France, in terms of biomass, were also explained in great measure by differences in the absorption of solar radiation (Barloy, 1988b). 

In contrast to the tubers, the stems and leaves of Jerusalem artichoke are readily killed by frost. Therefore, if the tops are required for fodder or other uses, they must be cut prior to the first frost. The tubers are harvested after the tops have been killed by frost, to ensure that sufficient nutrients have been translocated to the tubers. Frost also enhances the sweetness of the tubers, raising sugar yields for certain industrial applications and improving their flavor for culinary usage. 

Nevertheless, Jerusalem artichoke has been successfully cultivated in many tropical regions. Plants are much smaller and mature earlier, yielding smaller and fewer tubers than in temperate regions. However, because growth rates are faster near the equator, two consecutive crops can potentially be produced. In the tropics, Jerusalem artichoke is preferably grown at altitudes of around 300 to 750 m, although in India it is cultivated up to altitudes of 3,600 m (CAB International, 2001). 

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N. E. Peters, Evaluation of Environmental Factors Affecting Yields ofMcjor Dissolved Ions of Streams in the United States, U.S. Geological Survey Water-Supply Paper 2228, U.S. Geological Survey, Reston, Va., 1984. 

So far, much research has gone into finding new synthetic routes, new products and novel selective syntheses, and in the analysis of important factors affecting yield and in some cases selectivity. However, other practical constraints relevant to process development for industrial-scale synthesis have to be tackled. For example, new insights are needed to develop cost-effective, stable, and selective PT catalysts (especially effective immobilized triphase catalysts). Other relevant factors include the recovery and recycle of the PT catalyst, catalyst decomposition, environmental issues such as catalyst toxicity, and ease of product recovery. Catalyst costs are not very high when quats are used, as against the more expensive crown ethers or cryptands. In most cases, the overall process is more than cost-effective since PTC allows the use of cheap alternative raw materials, prevents the use of costly dipolar solvents, is less energy intensive (due to lower temperatures) than alternative methods, alleviates the need... 

A second scan of Callistemon tissue examining a sample collected from the same plant two months later in the season is shown in Figure 3 (solid line). This curve has the same overall shape as the earlier scan, but metabolic rates are somewhat lower and r, , is shifted to a higher temperature. Similar shifts in properties with plant age, nutrient stress, or other environmental factors affecting plant yields can equally well be studied with these methods. 

The above show that both the quantum yield and fluorescence lifetime can be modified by any factor that affects the relative contributions of the nonradiative (k) and radiative (F) decay processes. As described in Section 2.2, these factors include environmental factors such as solvent polarity, ionization and... 

Mesocarp—fruit ratio is largely genetically determined and is little affected by environmental factors. Fruit—bunch ratio depends mainly on the efficiency of pollination. Oil-mesocarp ratio depends in part on the ripeness of the fruit, since oil is only synthesized during the later stages of fruit development. There is also considerable variation in oil-mesocarp of bunches from the same progeny harvested at different times of the year (23). It has also been shown that application of potassium fertilizer leads to a reduction in the oil-bunch ratio (24) but the increase in fruit yield in response to potassium was more than enough to compensate for the reduced oil-bunch ratio. 

Plant cell culture is useful in laboratory and in industry because it allows plant natural products to be produced in a relatively controlled manner, and provides a supply of plant material that is not affected by sourcing problems, such as environmental, seasonal, geographical, and political factors.Also, plant cell culture allows for the tweaking and rearrangement of secondary metabolite biochemical pathways in order to produce novel metabolites, and to increase target compound yields, as well as allowing derivatives to be formed by introduction of analogs of natural intermediates.Plant cell culture can be performed with callus and suspension cultures, as well as with shoot cultures and hairy root cultures. These latter two approaches are especially useful when a metabolite is found to be produced more readily in differentiated cells. 

In spite of these difficulties, many quantitative studies on sets of values reveal trends in the change of hemicellulosic composition related mainly to a particular factor. A study of, for example, the effect of growth on hemicellulosic composition must, however, yield quantitative values that are affected by uncontrolled environmental influences throughout the period of growth. A similar remark would relate to most studies designed to investigate correlations between any other factor or influence on hemicellulosic composition. 

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