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Effects of salicylhydroxamate on respiration, seed germination and seedling growth in Avena fatua
Author(s) -
Upadhyaya Mahesh K.
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.tb01260.x
Subject(s) - avena fatua , germination , seedling , respiration , shoot , sodium azide , biology , alternative oxidase , avena , salicylhydroxamic acid , horticulture , botany , biochemistry
The effects of inhibitors of alternative respiration [salicylhydroxamate (SHAM) and propyl gallate (PG)] on germination, seedling growth and O 2 uptake in Avena fatua L. (wild oats) were studied. SHAM did not inhibit germination or O 2 uptake prior to germination. SHAM‐sensitive (alternative) respiration, therefore, cannot be a pre‐requisite for germination. Following germination, both chemicals inhibited seedling growth with the root being more susceptible than the shoot. SHAM concentrations that inhibited root growth by 90 to 95%, inhibited O 2 uptake of 1 cm root apices by less than 15%. While sodium azide (a cytochrome‐oxidase inhibitor; 1 m M ) alone inhibited O 2 uptake by only 40 to 50%, in the simultaneous presence of SHAM (or PG), O 2 uptake was inhibited by 90 to 99%. Thus: 1) respiration of wild oat seedling root apices is predominantly cytochrome‐mediated and incomplete inhibition of O 2 uptake in the presence of azide alone is due to diversion of electrons to the alternative pathway and 2) even though these roots have little alternative respiration, they maintain the capacity to support a much greater flux of electrons via this path way. SHAM and PG at concentrations (0.05 to 0.4 m M ) which inhibited O 2 uptake significantly in the presence (but not in the absence) of azide had little effect on root growth suggesting that an effect(s) other than that on respiration is involved in the inhibition of root growth at higher concentrations. The effect of SHAM on wild oat root growth is not selective as it also inhibits growth of a number of crop species.