Volume 88, Issue 3
May 1979, pages 175-252
pp 175-182 May 1979
A knowledge of the distribution patterns of stable elements in the environment is an essential pre-requisite for understanding the problems of radioactive pollution. In this paper the data obtained under natural conditions of the environment in the case of potassium, calcium, magnesium, iron, copper, zinc, cobalt, manganese, strontium, lithium and uranium are presented. A method for elimination of the interference from phosphate in the estimation of calcium and strontium in plant materials is also described.
pp 183-188 May 1979
The various appendages (sepals, petals, stamens and carpels) in the flower ofAntirrhinum are initiated in a centripetal sequence. The five sepal primordia are initiated in a rapid succession as discrete units. The calyx tube is formed due to the fusion of marginal meristems of adjacent sepal primordia. The corolla tube is also initiated by the fusion of marginal meristems at the back of stamen primordia. In the later stage of development, it extends in length by zonal growth. Of the five stamen primordia formed, the posterior one develops into a staminode. The septum, which bears placentae, grows from the summit of the floral apex as in typical axile placentation.
pp 189-193 May 1979
Three cytotypes (2n = 18; 2n = 27; 2n = 36) ofCynodon dactylon were found to occur in Punjab plains. Evidences from biochemical analyses were sought to distinguish these otherwise morphologically indistinguishable cytotypes. It was observed that the presence or absence of β-alanine and threonine in the flag leaves could be effectively used as a marker. Tetraploids had highest acid invertase activity which was accompanied with higher concentrations of hexoses and always with reduced concentration of sucrose. Acid invertase activity was least in triploids. Tetraploids were richer in protein content than triploids and had almost double the quantity present in diploids.
pp 195-201 May 1979
Morpho-anatomical studies of leaves of two cultivars ofPolyscias balfouriana Bailey (Araliaceae) reveal that while the mutation in both the cultivars has occurred in L2, the detailed pattern of variegation in the two cultivars is quite different from each other due to displacement phenomenon of normal green and mutated colourless layers.
pp 203-212 May 1979
The results from a study of the relationships between external productive features of millable canes and quality characters as well as anatomical differences of stem in relation to both yield components and quality factors in 16 clones ofSaccharum involving rinded and rindless samples are discussed in this paper. The wide variations recorded for the various characters studied brought out the diversity in the genotypes besides indicating the relative importance of certain attributes in production and quality breeding, where cane weight and sucrose content play a leading role. The study revealed the major contribution of rind to fibre content and the value of appropriate levels of fibre as also the need for examining the different physical characteristics of the fibre which are conducive to both high levels of sucrose storage potential and better milling quality. From anatomical studies, varietal differences were recorded, but neither the smallest nor the largest cell volume was associated with extreme levels of fibre, brix or sucrose content.
pp 213-217 May 1979
The development of endosperm conforms to the Scutellaria type of Schnarf. Variations in the plane of early cell divisions in the development of endosperm have been recorded. The embryogeny usually conforms to the Capsella variation of Onagrad type, sometimes Chenopodiad type and rarely Ruta variation of Onagrad type.
pp 219-224 May 1979
Differentiation and structure of phloem are described in adventitious root, bulbous stem, foliage and storage leaf of the bulb ofAllium sativum. Differentiation of protophloem occurs very close to the root apex. At maturity sieve elements appear enucleate. In the root, each of the tetrarch group of phloem has three to six metaphloem sieve elements. Sieve element with persistent nucleus occurs very rarely. Sieve elements of dormant clove show dormancy callose which disappears soon after the germination of the clove.
pp 225-228 May 1979
The presence of methyl eugenol in the oil and the difficulty experienced in its separation was considered to be a negative attribute in theCymbopogon flexuosus (var. RRL-59). A mutation breeding programme was initiated to rectify this inherent defect. A massive screening of irradiated vegetative slips of this essential oil-bearing plant resulted in the isolation of a methyl-eugenol deficient mutant. Our results show that once the methyl eugenol is absent from the oil, the oil as such closely resembles the oil of citronella (Java type) and can be a good substitute for the same. This investigation supports the view that beneficial mutations at specific gene loci once isolated in a vegetatively propagated species can be easily stabilised and propagated.
pp 229-242 May 1979
Three novelties collected from Tamil Nadu (Madras State) are described and illustrated of which one belongs to the sectionSulcati and the other one toFlavescentes of the subgenusPycreus. The third novelty comes under the sectionDiffusi of the genusCyperus proper. The new taxon described under sectionSulcati seems to be remarkable in view of the fact that it possesses a characteristic and a peculiar type of epicarpic surface markings. The vegetative anatomy of these three novelties is also presented here which speaks for their distinctness in this respect.
pp 243-247 May 1979
Mating behaviour ofCyclosorus parasiticus studied from isolate, pair and composite populations showed potentially intergametophytic mating behaviour and capacity for intragametophytic selfing which helps in wide distribution of the species in different environmental niches. The study also indicates lesser genetic diversity inC. parasiticus.
pp 249-252 May 1979
The influence of three levels of nitrogen on the incidence of sheath rot disease of paddy caused bySarocladium attenuatum was studied under field conditions using one resistant (Bhavani) and one susceptible (Kannaki) variety. Nitrogen nutrition of the host influenced the disease incidence. The total and OD phenols were much less in the susceptible variety than in the resistant variety. Further, Bhavani had less quantities of soluble carbohydrates, total nitrogen, ammoniacal nitrogen and protein nitrogen. Phenols accumulated in the infected plants, while the reducing and non-reducing sugars and different nitrogen fractions decreased.