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Embryonic control of isocitrate lyase activity in the megagametophyte of ponderosa pine seeds
Author(s) -
MURRAY EDWARD W.,
ADAMS ROBERT E.
Publication year - 1980
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.1399-3054.1980.tb08641.x
Subject(s) - isocitrate lyase , biology , incubation , enzyme assay , embryo , germination , glyoxylate cycle , enzyme , botany , incubation period , biochemistry , genetics
A previous report (Bilderback 1974) presented evidence for embryo enhancement of isocitrate lyase (threo‐L, isocitrate glyoxylate lyase, EC 4.1.3.1) activity in the megagametophytes of stratified germinating Pinus ponderosa Laws. var. ponderosa seeds. Our data indicate that the rate of increase in specific activity of this enzyme was greater during the first four days under germination conditions in ponderosa pine megagametophytes from which embryos had been excised than in megagametophytes with embryos left in situ for a 12‐day incubation period. Enzyme activity also increased more rapidly in megagametophytes with embryos removed after 2 days incubation than in those that retained their embryos for the full incubation period. Although rate of increase in enzyme activity was greater in embryoless megagametophytes than in those retaining their embryos, highest levels of activity ultimately occurred in the latter. Thus embryo presence was associated with inhibition of the rate of development of enzyme activity but it was also responsible for a pattern of sustained enzyme activity. These phenomena were not dependent on stratification. Possible reasons for differences between certain aspects of our study and the above cited report are discussed.