It may be that the different alleles have different expression in tissues where sulfur assimilation is more active, such as roots and leaves.
Thus, depending on the main site, shoots or roots, of N reduction and assimilation, the tissues would present distinct δN values.
As the major transport carbohydrate in plants, sucrose links carbon assimilation in source tissues to carbon utilization in sink tissues [ 18, 33].
Earthworm activity such as digestion, assimilation, excretion, and tissue breakdown affects nutrient mineralization.
Chlorate has also been demonstrated in tissue culture to reduce sulfur assimilation pathway activity [ 35] and is a dead-end inhibitor of ATP sulfurylase from P. chrysogenum [ 36].
This gene has been functionally associated with ammonia assimilation in vascular tissues of seedlings [ 35, 54].
Based on these observations, it appears that the MYB1 genes of pine and spruce may regulate phenylpropanoid metabolism as well as nitrogen assimilation in various plant tissues.
The expansion of the GSIIE gene family coincides with the development of vascularization of land plants and maybe correlated with the partitioning of nitrogen assimilation between below and above ground tissue (see Additional file 3).
Ozone is known to oxidize leaf tissues after entering stomata, resulting in decreased carbon assimilation and crop yield.
In plant tissues, citrate also supplies carbon skeletons for NH4+ assimilation via the glutamine synthetase (GS) and glutamate synthase (GOGAT) pathway (Chen and Gadal 1990; Agata 2008).
By contrast, a role for hFNR has been characterized for supplying reducing power in non-photosynthetic tissue to a variety of metabolic processes including nitrate assimilation.
