Volume 40, Issue 4
October 1954, pages 89-123
pp 89-101 October 1954
The megalopæ ofO. platytarsis andO. cordimana were for the first time successfully reared in the laboratory to the first crab stage.
The megalopæ of the two species differ in size, colour, shape of telson and number of setae on the last pleopod.
The megalopæ of both species burrow in the sand of the intertidal zone before metamorphosing into the first crab stage.
A key for the identification of the megalopæ and the first crab stages of the two species is given.
pp 102-109 October 1954
Glœsporium psidii was isolated from die-back of guava trees. A detailed study of the symptoms, the amount and extent of damage has been recorded. It was found that severity of the disease increased from middle of August to beginning of October.
The pathogenicity of the organism was established and it has been found that it can readily attack the young tender shoots, injured leaves, flowers and buds. It failed to attack mature twigs and leaves.
It has been established that mummies are produced if buds and flowers are infected at an early stage.
The fungus can live in dormant condition for about 21/2–3 months. It subsequently resumes its activity and develops the rot when the fruits ripen.
None of the fungicides so far tried could control the disease fully but the application of 3:3:50 bordeaux mixture and ·22% or ·33% peronox gave encouraging results.
pp 110-115 October 1954
Photometric determinations of Desoxyribonucleic acid in the haploid nuclei of the female gametophyte and diploid nuclei of nucellar cells show that the former have half the amount of DNA found in the latter and appear to establish a regular correspondence between the amount of DNA in the nucleus and its ploidy.
pp 116-123 October 1954
In order to assess the efficiency of different P-carriers it is necessary to know not only how it affects the total supply of available phosphate but also the rate at which the phosphate is released in an available form for the use of the plants.
On the basis of the above two factors the results of these studies may now be summarised as under:-
From the point of view of the total supply of available phosphorus, superphosphate as well as bone meal are almost four times as efficient as rock phosphate in the Karjat soil. Whereas the rate of supply of phosphates goes on decreasing in the case of superphosphate, that in the case of bone meal shows a continuous increase. As regards the effect of different soil amendments when used in conjunction with the phosphatic fertilisers, the total available phosphorus as well as its rate of supply is adversely affected when sulphur is applied along with superphosphate. The organic soil amendments have not produced any effect on the total as well as on the rate of supply of available phosphorus when they are added along with superphosphate. Whereas the addition of sulphur along with either rock phosphate or bone meal has increased the availability of phosphorus, the organic amendments do not seem to have any effect, mohua flowers on the other hand having depressed the rate of release of phosphorus when applied with bone meal.