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The relationship between the
total flavans (biflavan, catechin, epicatechin and
oligomer flavans) and the graft-take in walnut was studied. Total flavans were
determined by thin layer chromatography in the phloem tissues of annual shoots.
Content of total flavans and percentage graft-take were recorded from November
1997 to October 1998. Following chip-budding, grafted plants were exposed to
controlled conditions for one month. The total flavan contents ranged from
10.8mg g^–1 in March to 14.1mg g^–1 in May. Graft-take
percentages varied from 32% in June to 100% in February. A negative correlation
(r = –0.618) was found between total flavan content and graft-take.

Other
flavans (biflavan, epicatechin and oligomer flavans) in the upper, middle and
lower portions of the graft union were also detected in phloem tissues sampled
15 days, 30 days, 45 days and 60 days after grafting. Flavans increased below
the union and decreased in the upper portion. The results suggested that
graft-take in walnut might also be affected by the flavan content of annual
shoots.

South African Journal of Botany 2003, 69:
292–294