THE TNVESTJGATION OF ACACIA FARNESZANA ESSENTIAL OIL By A. E l-H a m i d i a n d 1. S i d r a k Acacia farnesiana W i 11 d. (Legunziizosae) is a perennial tree of 6-10 ft. with straight spines, much branching carrying yellow flower-heads of characteristic sweet scent when slightly rubbed between the fingers. The tree is naturalised in Sudan where it grows in isolated groups mainly near the Nile in the northern and central Sudan where it is known by the vernacular name "baram". It is cultivated in Egypt under the local name "futna" more than fifty years ago for its essential oil production. It is grown also for the same reason in north Africa, and in the U.S.A. it is known as sweet acacia. The oil was investigated by Schimmel & Co. and by L a F a c e (G u e n t h e r , 1952). They reported the occurrence of several oil components some of which were not definetly established. The present work was carried out to further investigate the oil by means of simple economic chromatographic methods which could be easily applied in regions where the expensive analytical apparatuses and trained technicians are not always available.
Silymarin, synthesized in fruits of Silybum marianum (L.) Gaertn., is a mixture of the three flavonolignans silibinin, silydianin, and silychristin. In the past, silymarin has been used for therapy of hver diseases, but clinical investigations have demonstrated that silibinin is the effective compound (1). Therefore, plant breeding should aim for a genotype with silibinin as its only flavonolignan. Successful selection strategies require basic knowledge of pollination and fertilization mechanisms in Silybum.Greenhouse experiments indicated that S. marianum is a self-fertile species. Even when the anthers with sepals were removed directly after flower elongation a seed set of 35% was observed (2).In order to obtain data on outcrossing ratio under natural conditions, a field experiment was carried out in summer 1992. Three inbred generations (11-13) of the genotype S 26 (with the recessive character "green leaves") and plants of the genotype S 22 (with the dominant character "variegated leaves") were used (3). The monogenic character of the leaf colour allowed early detection of F3-plants derived from cross-pollination. Three plants from each inbred generation of S 26 were transferred to the field and 30 plants of 5 22 were cultivated around the S 26 plants, to enable cross-poffination by insects.Table 1 Ratios of seedlings with green and variegated leaves in the F1-generation. Generation lnflorescence Number of fruits Seedlings with green leaves Seedlings with varieg. leaves Outcrossing ratio F1aofl1b 1+2. 450 379 4 1.06c F1of13 1+2. 450 369 9 2.44 F1 of 13 1+2. 450 359 10 2.79 1 1350 1107 23 2.04 a Generation after the outcrossing experiment. lnhred generation. Values in %.From every plant of each generation, 100 fruits from the first and 50 fruits from the second inflorescence of S 26 were harvested and subsequently the seedlings with green and variegated leaves were counted in the F1 (Table 1).Autogamy was predominant in all inbred generations, but partial xenogamy was also observed. The ratio of outcrossing ranged from 1.06-2.79%, with an average ratio of 2.04These results indicate that S. marianum is a selffertile species with a low outcrossing ratio. This is in con-tradiction to the report by Heinz (4), whobased on morphological studies -communicated that flowers of S. marianum show protandry. After evaluation of five inbred generations she observed inbred-depressions and concluded that S. mananum is an outcrossing species.
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