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Deposition of callose in relation to abscission of citrus leaves
Author(s) -
Jaffe Morecai J.,
Goren Raphael
Publication year - 1988
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.1399-3054.1988.tb05841.x
Subject(s) - callose , abscission , petiole (insect anatomy) , botany , biology , chemistry , cell wall , hymenoptera
When leaves of Citrus sinensis (L.) Osbeck cv. Shamouti senesce, they become more susceptible to abscission and the proximal 2 mm of their lamina‐petiole abscission zones exhibit callose deposition. The degree of senescence, assayed with the DAR‐WIN image processor (Telewski et al. 1983), was positively correlated in a linear fashion with callose deposition. Explant of non‐senescing leaves were observed. Excision of the leaf at the stem‐petiole junction induced callose deposition throughout the petiole, but not in the lamina. Callose deposition began immediately upon excision and reached a maximum at 3 h. It then decreased slightly and remained at the same level for up to 5 days. Exogenous compounds that decrease callose deposition, e.g. laminarase and 2‐deoxy‐D‐glucose, inhibited the rate of abscission of explants. Compounds that promote callose deposition, e.g. uridine diphosphoglucose and mannose, increased the rate of abscission of explants. Exogenous callose, e.g. laminarin, increased the rate of abscission. It is not known how callose might be causally involved in promoting abscission.