S. Geetha et al., Sclerospora graminicola- and arachidonic acid-induced autofluorescence in downy mildew resistant and susceptible genotypes of pearl millet, ANN AP BIOL, 133(2), 1998, pp. 219-226
Autofluorescence of downy mildew resistant and susceptible cells of pearl m
illet seedlings undergoing hypersensitive reaction (HR) upon Sclerospora gr
aminicola-inoculation and arachidonic acid (AA)-treatment was studied. Two-
day-old seedlings of a highly resistant (IP 18296) and a highly susceptible
(23D(2)B) genotype of pearl miller were either inoculated with zoospore su
spension of S. graminicola or treated with AA for 24 h. The coleoptiles wit
h hypersensitive necrotic spots were processed by the standard procedure, a
nd the tissues were subjected to fluorescence microscopy. A differential ac
cumulation of autofluorescent compounds in resistant and susceptible pearl
millet genotypes was observed with most accumulation occurring in resistant
cells treated with AA. The variation in the degree of fluorescence and the
spatial accumulation of autofluorescent compounds among the two inoculated
/treated genotypes is discussed.