Pvs. Rao et al., BIOTIC AND ABIOTIC ELICITATION OF PHYTOALEXINS IN LEAVES OF GROUNDNUT(ARACHIS-HYPOGAEA L), Physiological and molecular plant pathology, 49(5), 1996, pp. 343-357
Groundnut leaves (cultivar TMV2) infected with the fungal pathogens, C
ercospora arachidicola, Phaeoisariopsis personata and Puccinia arachid
is accumulated 1830, 664 and 162 nmol phytoalexins g(-1) fresh wt., re
spectively, 4 weeks after inoculation, whereas leaves infested with Fr
ankliniella sp. for the same period contained 1.25 nmol phytoalexins g
fresh wt. Spraying abraded leaves with salicylic acid (0.01 M) result
ed in the accumulation of 1270 nmol phytoalexins g(-1) fresh wt. 120 h
after treatment and irradiation of abaxial leaf surfaces with u.v. li
ght (254 nm) for 48 h and incubation in the dark for a further 96 h ca
used the accumulation of 393 nmol phytoalexins g(-1) fresh wt. Compoun
ds with u.v. spectra corresponding to isoflavanones were almost exclus
ively synthesized in response to abiotic elicitors but in leaves infec
ted with fungal pathogens formononetin, daidzein, and medicarpin were
also present, though as minor components. (C) 1996 Academic Press Limi
ted.