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The roots of Pennisetum typhoides decomposing in normal field conditions, in sterilized soil inoculated with 15 rhizosphere fungi and in field soil maintained at various moisture levels produced vanillic acid. 3-4-dihydroxy benzoic acid and hydroxy cinnamic acid. These acids proved toxic to the rhizosphere fungi and seeds and seedlings of certain crop plants. Out of 15 rhizosphere fungal species inoculated to the soil only 6 could induce the release of toxins, moreover, the phytotoxic substances were detected from the washing of the roots collected only on the 30th day. The moisture range which showed liberation of toxins was 20-70 per cent. The time of liberation of acids in different set s varied. These were, however, frequently liberated from washings collected from roots decomposed for 15. 30 and 45 days.

Leaf-surface mycoflora of three ornamentals - Impatiens balsamina L., Rheoes discolor L. and Lochnera rosea (L.) Reichb., in relation to foliar application of aqueous solution of 5,0% urea has been studied. In the former two plants the application of urea enhanced the my00flora whereas in the latter an adverse effect was observed for phyllosphere region. In phyUoplane region of L. rosea, however, a promotive effect was exhibited in sprayed plants. The urea in this concentration also proved slightly toxic to L. rosea.

Sixty seven fungal species from the nonrhizosphere (NR), rhizopshere (RS) and cortical (RPC) and steler (RPS) parts of rhizopshere of crown (RC), middle (RM) and distal (RD) regions of decomposing roots of Pennisetum typhoides Burm. f.) Stapf. et Hubb. were isolated during December to June, 1970-72. The number of fungal species gradually decreased from NR—RPS in horizontal and RC—RD in vertical regions. The fungal population was always higher in RS of different depths than in corresponding NR regions. The amino acids and sugar components of the roots showed a direct correlation with the fungal population. The amount of cellulose, hemicellulose and lignin components of roots gradually decreased from December to June. Root-washing collected from RC, RM and RD regions exhibited the presence of vanillic acid and 3-4 dihydroxy benzoic acid during March and April. It also exerted an adverse effect on the 10 rhizosphere fungi during this period. pH and moisture contents showed a poor correlation with the fungal population cxcept during summer months. Phycomycetes with species of Deuteromycetes obtained in the first phase were followed by Deuteromycetes along with few Ascomycetes in the second phase. In the last Deuteromycetes with some slerile mycelia were isolated. Aspergilli were the most numerous throughout the present investigation.

This paper presents the results of study the effect of rhizosphere of Pennisetum typhoides on the soil fungistasis. The fungistasis of three different regions of the root has been investigated in relation to rhizosphere effect.

The present paper deals with the succession of fungi on the root regions of living Pennisetum typhoides. The presence and amounts of amino acids and sugars in root exudates (July to October) and root extracts (July to November) have been studied.