Volume 61, Issue 2
February 1965, pages 63-123
pp 63-70 February 1965
pp 71-80 February 1965
pp 81-89 February 1965
From a study of the total iron (FeT), acid-soluble iron (FeS) and chlorophyll in the leaves of cane varieties, the fraction of iron bearing relation to chlorophyll (active iron, FeA) and that not related to chlorophyll (residual iron, FeR) have been calculated. FeR appears to bear relation to the growth of the cane varieties. A study of the variation of FeR/FeA ratio seems to be of help in determining whether the tendency of the plant, at a particular time, is more towards growth or accumulation of sucrose. It is shown that the factorf=FeR × FeS/FeA2 can serve as an index in the characterisation of cane varieties, in relation to early or late ripening character, even at an young age of 5 months.
pp 90-97 February 1965
Dissolved oxygen mg. per litre and the population ofMoina dubia per litre of the sample collected over a long period in the experimental sewage oxidation pond and a medium polluted tank (Gandhisagar) show that the population ofMoina dubia is not affected to any degree by low dissolved oxygen content.
It is seen experimentally that at higher dissolved oxygen levels mortality results due to oxygen asphyxiation. The increase in the dissolved oxygen and the mortality rate is directly proportional.
pp 98-108 February 1965
In the present investigation vascular anatomy of the node and flower of three species ofNajas—N. graminea, N. flexilis, andN. guadalupensis—have been studied. The leaves are one-traced in all the three species. InN. graminea although both the staminate and pistillate flowers appear to be subtended by the lowermost leaf of a node but the behaviour of vascular tissue shows that they are terminal on a branch system.
The male and female flowers ofNajas are represented by a single stamen and pistil respectively and are enclosed in a bottle-shaped spathe. InN. graminea the staminate flower is nacked. The vascular supply of gynoecium consists of a single bundle which gives off a very small dorsal trace inN. flexilis before entering the base of the solitary ovule which is described as basal. It appears that the so-called basal ovule inNajas too as in many other cases is a derived one. The presence of two stigmas gives some indication towards the pseudomonomerous and bicarpellary nature of the gynoecium.
pp 109-120 February 1965
The grassesPanicum repens, Brachiaria mutica, Leersia hexandra, Digitaria sanguinalis orDigitaria setigera do not seem to serve as collateral hosts forPiricularia oryzae Cav. pathogen of blast disease of rice. The pathogens studied exhibited distinct host specificity.
The isolates ofPiricularia onPanicum repens, Brachiaria mutica andDigitaria setigera have been identified asformae specialis ofPiricularia grisea (Cke) Saccardo. The accommodation of the isolates ofPiricularia onDigitaria sanguinalis, Oryza sativa andLeersia hexandra asPiricularia grisea, andPiricularia oryzae and asPiricularia leersiae respectively, is accepted.
pp 121-123 February 1965