SADASIVAN, Toppur Seethapathy
Elected 1945; Council Service: 1946-49, 1956-76; President:
1971--73;Vice-President: 1965-70; Secy.: 1956-58
Emeritus Prof., Univ. of Madras
b. 22 May 1913, Madras s.
T. Seethapathy and Kanakammal m. Radha,
three d

Edn.: Univ. of Madras: BSc. 34; Univ. of Lucknow: MSc. 36; Univ. of London: PhD. 40, DSc. 55. Career: Univ. of Lucknow, Dept. of Botany: Demonstrator 40-41; Fruit and Vegetable Preservation Lab., Lyaupur: Microbiologist 41-44; Univ. of Madras, Centre for Ad-vanced Studies in Botany: Director/Prof. 44-73; CSIR, Plant-based Lab.: Consultant 73-76; Birbal Sahni Professor, Lucknow 77-80; Vidyashram, Kodaikanal: Chairman 82. Fellow, INSA. Sundar Lal Hora Medal 73; Bhatnagar Prize 60; Padma Bhushan 74. Sc. Work in Plant Pathology. Worked on model host-parasite systems and followed up the biochemical changes in the host plants as the disease syndrome progressed. While working on the toxin pyriculol produced by this blast fungus demonstrated permeability changes in the host tissues. Furthermore it was demonstrated for the first time that the toxins of the fungus induced 'green islands' in rice leaf tissues. Work on the cotton wilt problem caused by the soil inhabiting fungus Fusarium vasinfectum led to a better understanding of rhizosphere effect where the role of root exudates in promoting the growth and survival of specific pathogens became well established. First ever demonstration of the fungal toxin fusaric acid in vivo led to designating this toxin as a vivotoxin and was advanced by the group. Put forward definitive evidence of ionic imbalance in wilted plants in the form of excessive excretion and enhanced transpiration resulting in loss of potassium and accumulation of divalent cations. The other host-parasite system studied was the blast disease of rice caused by the air-borne fungus Pyricularia oryzae.

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