Volume 65, Issue 3
March 1967, pages 83-134
pp 83-93 March 1967
A detailed micropetrological study of symplektites from some selected rock types of Madurai District, Madras State, has been made by the author. It is suggested that the symplektites, observed in the garnetiferous cordierite biotite schist of Ganguvarpatti, are due to the effects of stresses and the ionic diffusions caused by them, while those in the anorthosites and norites of Oddanchatram area are attributed to replacement and recrystallization respectively.
pp 94-102 March 1967
1. The nervous system of femaleSaccharicoccus sacchari Cockerell is described in detail.
2. The nervous system of this mealybug is of a typical coccid type comprising a brain or supra-oesophageal ganglion and a thoracicoabdominal ganglion.
3. The brain lies anterodorsad to the oesophagus, while the thoracico-abdominal ganglion beneath the oesophagus.
4. The two ganglia are connected by a pair of circumoesophageal connectives which pass around the oesophagus.
5. The brain gives rise to three pairs of nerves which innervate the antennae, the ocelli and the mouth region.
6. The thoracicoabdominal ganglion gives rise six pairs of nerves, five of which innervate mainly the thoracic region and the last or sixth pair the abdominal region.
7. No ganglia or nerve representing a sympathetic nervous system were found.
pp 103-105 March 1967
pp 106-107 March 1967
pp 108-110 March 1967
pp 111-113 March 1967
pp 114-118 March 1967
Anatomy of normal and tetracot seedlings are described. Normal seedling has dimerous and tetracot seedling trimerous root structure. Both seedlings have unilacunar double trace type of cotyledonary node while the foliar node is trilacunar. The root-hypocotyl-cotyledon vasculature and epicotyl vasculature are independent. Polycotyly in this case is due to splitting.
pp 119-125 March 1967
Twelve organic compounds were studied in respect to their effect on the activity and production of protopectinase (PP) and polygalacturonase (PG) enzymes ofAlternaria tenuis. Onlyα-naphthol, oxidised pyrogallol, tannic acid and extract of heart wood ofAcacia catechu (kattha) were found to be effective inhibitors for the activity of PP and PG enzymes. Apart from these chemicalsp-benzoquinone, hydroquinone and 1:2:5:8-tetrahydroxyanthraquinone were also found to reduce the production of enzymes in the culture medium. No definite relation between the inhibitory effect of the chemicals with either the growth of the fungus or germination of the spores was recorded.
It was observed that the chemicals required some reaction time to cause effective inhibition of the enzymes.
pp 126-134 March 1967
The structure, distribution and ontogeny of sclereids in the male and female cones have been found to be very similar in eight species ofCupressus, namelyC. macrocarpa, C. goveniana, C. funebris, C. lusitanica, C. knightiana, C. sempervirens, C. torulosa, andC. lindleyi and in someJuniperus species,i.e., J. chinensis, J. formosana, J. procera, and one unidentified species. There are no sclereids in the vegetative parts. The sclereids exhibit polymorphism. The ontogeny of different types of sclereids is the same in all the species. A parenchyma cell in the ground tissue of the female cone scale or in the microsporophylls differentiates as a sclereid initial, develops branching, undergoes “secondary sclerosis” and results in the formation of a thick-walled sclereid. The taxonomic importance of these sclereids is also discussed.