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The physiological role of abscisic acid in the rooting of poplar and aspen stump sprouts
Author(s) -
Blake Terence J.,
Atkinson Susan M.
Publication year - 1986
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1986.tb05070.x
Subject(s) - cutting , abscisic acid , cultivar , biology , botany , horticulture , salicaceae , germination , woody plant , biochemistry , gene
The better rooting performance of stump sprouts offers the means of mass‐producing rooted cuttings of many difficult‐to‐root genotypes. To study the physiological basis of rooting, stem cuttings were taken from stump sprouts of the more readily‐rooted hybrid poplar cultivar DN ( P. deltoides × P. nigra ) and the difficult‐to‐root aspen hybrid cultivar AE ( P. alba × P. tremula ). Seasonal variation in rooting percentage of both the AE and DN cultivars (higher in winter and lower in late summer and fall) of poplar was correlated with higher and lower levels of abscisic acid (ABA), respectively, in fractionated extracts of poplar. The presence of ABA in the purified inhibitory fraction was unequivocally confirmed by (i) co‐chromatography, (ii) gas chromatography‐electron capture detector and isomerization with UV light and (iii) combined negative chemical ionization‐mass spectrometry. Although ABA was identified in the inhibitory fractions of mung bean bioassays of both poplar and aspen extracts, exogenous ABA did not inhibit rooting when applied at physiological concentrations. Since ABA levels were higher in the more readily‐rooted hybrid poplar cultivar DN and were higher in February, close to the time of maximal rooting of cuttings, this suggests that ABA levels may possibly explain clonal and seasonal variation in rooting patterns of poplar stump sprouts. This interpretation is supported by the fact that lower, physiological concentrations increased rooting percentage, root number and root elongation when ABA was added to poplar and aspen cuttings.