Plant, acidity tolerance composition

There is much controversy, at least in Europe, concerning genetic modification of plants. The three major crops affected so far are maize, soyabean and rapeseed. All of these, in addition to their other uses, are sources of oil. The reasons for modification in all these cases are related to herbicide tolerance and resistance to insects. For the varieties generally available at present, there is no known difference from non-modified strains with respect to fatty acid composition, oil yield, tocopherol level, or the level of any other minor oil constituent. 

Their results, however, have important implications in emphasizing the caution which must be exercised when fatty acid compositions are assumed on the basis of quantification at a particular development period. More dramatic differences in the fatty acid data were found by Kuiper and Stuiver (1972) in a study of drought tolerance and earliness in spring. They noted the presence of large amounts (80% of total acids) of long-chain cyclopropane fatty acids in sulfolipid of early spring cow parsley. The cyclopropane acids disappeared by May. These authors suggested that these unusual compositions may be related to the ability of plants to withstand extreme conditions. 

To detennine whedier die same genes control fatty acid composition in die seed oil and in polar lipids of different tissues, we compared die overall fatty acid composition of seeds, roots and leaves (Table 1, Table 2). Deficiencies in C18 2 and C18 3 desaturation were not restricted to (he seeds. The mutations were also expressed in roots and leaves. Modifications of leave lipids were low in comparison to roots indicating changes in extrachlorplast lipids. A substantial reduction of C18 3 and concomitant increase of C18 2 was observed in die roots of all low C18 3 mutants. For membrane function diis substitution of C18 3 by C18 2 seems to be tolerated Goe 9 and cv. Apollo have no deficiencies in plant development and they are high yielding. 

The fatty acid composition of membrane lipids is important during the development of cold tolerance of many plants [1] often because increases in the proportion of polyunsaturated lipids retain the fluidity of membranes. For example, there is a correlation between the different degrees of winter hardiness and membrane lipid composition in Norway spruce [2]. There is also an inverse seasonal relationship in Norway spruce between short chain (C 2 u) saturated and unsaturated C g fatty acids in certain lipid classes [3]. 

---