Volume 80, Issue 5
November 1974, pages 197-252
pp 197-206 November 1974
Early ontogeny of leaf has been described for brinjal and chilli. Both the plants show middle, submarginal type of growth. However, in brinjal the derivatives of the marginal initial, sometimes, divide periclinally. Thus, two types of marginal growth—middle submarginal type, and mixed type of marginal and submarginal types—hitherto a new report, have been reported in brinjal. Venation of the blade of the leaf and vein endings in particular have been studied. Extension cells are found between one vein and the vein ending of the another vein.
pp 207-215 November 1974
The embryology and seed development ofDactyliandra welwitschii Hook. f., a monotypic species of Cucurbitaceae, is studied. The inferior, tricarpellary, unilocular ovary with parietal placentation bears anatropous, bitegmic and crassinucellate ovules singly at the tip of each lobe of the bifid placenta. The deep seated megaspore mother cell undergoes meiosis to form a linear tetrad of megaspores. The chalazal megaspore is functional and embryo sac development follows the Polygonum type. Fertilization is porogamous and pollen tube is persistent.
Endosperm is nuclear with a short chalazal haustorium. The wall formation is progressive and the haustorium remains coenocytic. Embryogeny is of the Asterad type. The testa develops from the outer integument alone while the inner degenerates soon after fertilization. The mature seed coat comprises the seed epidermis, 8–10-layered sclerotic hypodermis, main sclerenchymatous layer of vertically elongated astrosclereids, aerenchyma and the inner zone.
pp 216-221 November 1974
This paper presents descriptions of six hyphomycetes from litter. Two new species,Pyricularia vandalurensis andSpadicoides aggregata are described. Four other species,viz., Circinotrichum fertile Pirozynski and Hodges,Endophragmia alternata Tubaki and Saito,E. atra (Berk. & Br.) M. B. Ellis andPericonia sacchari Johnston are reported for the first time from India.
pp 222-225 November 1974
A toxin produced byColletotrichum capsici, pathogen of turmeric leaf spot disease has been found to alter the cell permeability of turmeric leaf tissue even at very low concentrations. This led to leaching of large quantities of water soluble constituents. The possibility of the involvement of a toxin in the pathogenesis is discussed.
pp 226-228 November 1974
pp 229-239 November 1974
Trichogramma semblidis (Auriv.) has been recorded from eggs ofTabanus macer Bigot in India. Some aspects of the biology of this parasite have been studied. Males ofT. semblidis exhibit dimorphism, that is, alate and apterous forms are produced, the incidence of apterous forms depending on the host eggs from which they are reared. Males reared fromTabanus eggs are almost exclusively apterous. Dimorphism was studied using eggs of four unnatural hosts, namely,Achaea janata L.,Heliothis armigera Hübn.,Corcyra cephalonica St. andPhthorimaea operculella Zeller. Fewer apterous males were produced from eggs ofAchaea andCorcyra, than from those ofHeliothis andPhthorimaea, but it appears that quality of nutrition in the host egg controls dimorphism.
Fecundity per parental female was highest whenCorcyra eggs were used but proportion of female progeny was highest whenHeliothis eggs were used. When offered a choice between the above four hosts,T. semblidis females showed a marked preference for eggs ofAchaea, whileCorcyra andHeliothis were preferred to eggs ofPhthorimaea. Corcyra eggs, however, though smaller were preferred to those ofHeliothis.
Apterous and alate males were found to be comparable with regard to mating behaviour and inseminating capacity. On an average 14·8 and 16 females were inseminated by an apterous and alate male respectively. Field parasitism was recorded in three areas of the Mandya District (Karnataka State) from October 1970 to January 1971.
pp 240-252 November 1974
Mycobacterium tuberculosis H37Rv possesses an enzyme (referred to as ‘Y enzyme’) which catalyses in the presence of INH and NAD, the formation of a product, which turns yellow on acidification. The requirements for the reaction, such as enzyme concentration, INH concentration, etc., have been standardized. The substrate specificity of the enzyme with respect to INH and NAD has been determined. The reaction is specific for the INH-sensitive strain and is totally absent in INH-resistant strains. Furthermore, the ‘Y enzyme’ shows some characteristic features of a peroxidase in its requirement for oxygen and sensitivity to inhibition by various reagents. The requirements of this enzyme which is involved in the action of isoniazid inM. tuberculosis H37Rv is described for the first time.