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Free and bound abscisic acid in relation to water potential in aging cotyledons of Lupinus albus
Author(s) -
Elkinawy Mahasen
Publication year - 1983
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.1399-3054.1983.tb02778.x
Subject(s) - abscisic acid , lupinus , botany , biology , cotyledon , dry weight , horticulture , chemistry , biochemistry , gene
To evaluate the capacity for biosynthesis of abscisic acid (ABA) in the cotyledons of developing plants of Lupinus albus L. (= L. termis Forssk.) cv. Giza 1, and the physiological role which the compound may perform during senescence, the levels of free and bound forms of ABA have been estimated in conjunction with the natural changes in the water potential of the tissues during a period of 18 days after sowing. In the cotyledons of the dry seeds, the bound form of ABA is about three times as abundant as the free form. Peaks of the free ABA occur on days 3 and 8, when the water potential reaches minimum values of –1060 and –950 kPa respectively. Since the concentration of the bound ABA does not drop during days 1–8, it is suggested that the peaks of free ABA are due to synthesis in the expanding cotyledons in response to the two water potential minima. During the post expansion period (days 9–18), free ABA appears to be released from a bound form as a consequence of decreased synthetic activity and increased tissue deterioration. The remarkable increase in the rate of the dry weight loss which immediately follows each peak of ABA suggests the involvement of ABA in the senescence of the cotyledons by speeding up the translocation of nutrients to the developing axis.