Volume 38, Issue 6
December 1953, pages 215-249
pp 215-230 December 1953
pp 231-234 December 1953
The pectin content of frenchbean plants infected withM. phaseoli was 50% less than that of correspondingly healthy plants.
That the loss of pectin in the diseased frenchbean plants was due to pectolytic enzyme activity of the pathogen was proved byin vitro studies on cut bits of potato with enzymic extracts of the fungus.
pp 235-241 December 1953
The number of genera of fungi developing from colonised root pieces depends on the concentration of the surface-sterilising agent used and the duration of the treatment given.
For the development of the maximum number of genera of fungi, treatments of 2 minutes immersion each in 0·04%para-nitrophenol and 0·1% HgCl2 (Fred and Waksman’s formula) and 10 minutes immersion in a 1 in 14 aqueous suspension of CaOCl2 have proved superior to several other chemicals known to be weakly bacteriostatic or bactericidal.
Fusarium spp. andMacrophomina phaseoli (Rhizoctonia bataticola) are the primary and dominant colonisers on autoclaved and freshly excised surface-sterilised root pieces buried in Udamalpet soil.
I am indebted to Prof. T. S. Sadasivan for guidance and to the authorities of the Women’s Christian College, Madras, for the subbatical leave during which this investigation was undertaken at this University.
pp 242-249 December 1953
The titratable acidity andpH of leap sap ofTamarindus indica Linn. have been determined under various conditions. The T.A.N.’s of leaves of different ages have been determined and they show an increase with increasing age until in the oldest leaves again there is a slight fall. The T.A.N. values of different age groups have been determined at various hours during the day and it has been found that there is no diurnal fluctuation in acidity in any of the groups. The T.A.N. of leaves of Group I has been determined in the various months of the year. The titratable acidity is highest in the winter months and lowest in summer months. ThepH shows a decrease with increasing age until in the oldest leaves again it increases with age. The buffering capacity of the leaf sap is of a high order.