Showing papers by "Annamalai University published in 1969"

Photosynthetic Studies With Leaf Cell Suspensions From Higher Plants

Abstract: A technique for obtaining intact mesophyll cell suspensions derived from higher plant leaves is described A large number of taxonomically unrelated plants were found suitable for cell ;extraction' including several plant species from monocotyledonous groupThe absorption spectra of leaf cells in suspension differed only slightly from that of Chlorella cells The higher plant cells respired and photosynthesized in aqueous solutions very much like algal cell suspensions Only osmotically intact cells photosynthesized maximally and their activity was stimulated by 2 to several fold by the addition of bicarbonate to the medium The isolated cells when stored at low temperature with proper aeration maintained their initial activity for a minimum of 9 hr Cells stored at the room temperature (27 +/- 2 degrees ) lost their activity rather rapidly The isolated cells were physiologically intact as tested by their metabolic response to diverse inhibiting chemicals and growth regulating substances

Photosynthetic efficiency in rhizophoracean mangroves with reference to compartmentalization of photosynthetic pigments

Abstract: Photosynthetic pigments are localized in protein complexes of chloroplast membranes and their role in photosynthesis has long been established but their efficiency has not been measured in many species. The photosynthetic efficiency of four rhizophoracean mangroves, Rhizophora apiculata, R. mucronata, Bruguiera cylindrica and Ceriops decandra was studied in randomly collected propagules from Pichavaram mangrove forest (southeast coast of India) by estimating the concentration of photosynthetic pigments in protein complexes of the thylakoid membrane. Reaction centre chlorophyll (RC-chl) was maximum in B. cylindrica and minimum in R. mucronata. Of the total amount of chlorophylls, RC-chl constitutes about 50%. The light harvesting complex chlorophyll (LHC-chl) was highest in C. decandra and lowest in R. mucronata. Net photosynthesis was found to be higher in B. cylindrica and lower in R. mucronata with the respective CO2 fixation of 20.52 and 10.83 μmol m-2s-1. A positive correlation was obtained between RC-chl and net photosynthesis. The stomatal conductance to CO2 influx was also found to be high and low in B. cylindrica and R. mucronata respectively. We refer the chlorophylls present in the reaction centre and light harvesting complex as “ membrane bound chlorophyll” and propose to use this as an index for measuring the productivity of mangrove species

Production of organic acids by soil micro-organisms

Abstract: Micro-organisms of the rhizosphere soils in respect of four plant speciesviz sesbania, cowpea, sorghum, and finger millet and those of the non-rhizosphere soil (control) maintained under pot culture conditions were incubated for a fortnight in liquid media containing glucose and the relative amounts and nature of the organic acids produced were investigated by pH changes and chromatographic studies respectively. Micro-organisms with the rhizosphere of all the four plant species produced greater amounts of acids than those of the non-rhizosphere soil. Rhizosphere micro-organisms with legumes produced greater amounts of acids than those with non-legumes. However no qualitative differences were observed in the organic acids produced by the rhizosphere micro-organisms of the four plant species investigated as well as those of non-rhizosphere soil.

Seasonal Variations in Foraminiferal Abundance and their Relation to the Substrate in Vellar Estuary, Madras

Abstract: Seasonal differences in the abundance of the benthic Foraminifera of the estuary are shown to be related to the standardized nomenclature of the sediment types relative to sand silt and clay. The area with almost sandy substrate in November 1967 yields the lowest foraminiferal number due to the strongest currents caused by the floods observed in October 1967. The finest sediments and weaker currents are associated with the higher foraminiferal numbers in March and April 1968. The most accommodative substrate for a higher foraminiferal number is found to be silty-clayey-sand, in which silt is dominating over clay.