• Volume 91, Issue 5

      October 1982,   pages  371-472

    • Effect of water stress and sucrose on opening and longevity of flowers in gladiolus

      I V Ramanuja Rao H Y Mohan Ram

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      The percentage of buds opening and flower longevity as affected by the availability of water and sucrose to out spikes of gladiolus were studied. Uptake of sucrose solution and fresh weight changes in spikes were dependent on sucrose concentration. Marked reduction in uptake and fresh weight occurred when polyethylene glycol (peg) was used as the stressing agent. In comparison.peg failed to induce any significant change in the percentage of flower buds opening. Sucrose was essential for opening since the buds that failed to open in the control were caused to open in sucrose. Induced water stress did not curtail flower longevity at any given concentration of sucrose. Thus flower opening and longevity in gladiolus appear to be limited more by the availability of sucrose than water.

    • Petal venation inTrigonella (papilionaceae)

      Mohini Gupta

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      Petal venation of nine species ofTrigonella has been worked out. A positive correlation has been found between length or area and the number of dichotomies but no correlation is found with breadth. In all the species corolla is of simple type exceptT. polycerata in which it is of medicagoid type. Among the different types of anastomosesC andD types are of most frequent occurrence and other types are species specific with a low range of variation.

    • Responses of cotton-cultivars to long day conditions

      J G Bhatt M R K Rao

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      Flowering of cultivated varieties of cotton belonging toG. arboreum, G. herbaceun andG. hirsutum was delayed by over 14 hrs of daylength because of increase in number of days for square formation. The long day treatment in general increased height, production of fruiting branches, leaf area and dry weight per plant. The number of fruiting forms, bolls retained, yield of seed cotton and fruiting coefficient decreased under long day conditions. These characters were affected more in upland varieties and short day Cambodia derivatives. The most ofG. arboreum andG. herbaceum varieties became more vegetative in growth but their boll number and yield per plant increased.

      Since the varieties 1998 F (G. hirsutum) and Gaorani 1111 (G. arboreum) were tolerant to long photoperiod and grew satisfactorily, it is suggested that these may be used as donor parents for improving the quality of cottons grown in northern India.

    • Seed germination and seedling establishment of two closely relatedSchima species

      Ram Boojh P S Ramakrishnan

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      Seed germination ofS. khasiana from Upper Shillong andS. wallichii from Shillong, Umsaw and Burnihat in Meghalaya, north-eastern India, and seedling establishment and growth of these species/populations in reciprocal cultivation were studied. Seeds lost viability and germinability gradually within a year when stored at 5 cm below the soil surface under natural conditions or at 20°C in the laboratory. Storage at 0°C permitted retention of 15–25% viability. Seeds germinated better on the surface layers (0–2 cm) of the soil.S. khasiana had a lower temperature optimum (15°C) of germination while the populations ofS. wallichii had a higher temperature optimum (20/25°C). At a temperature of 30°C, the lower altitude population ofS. wallichii from Burnihat gave higher germination than the high altitude population from Shillong. A given species/population ofSchima gave better seedling establishment and growth in its own natural habitat as compared to the introduced populations from the other altitudinal sites. This is indicative of the close adaptation of the natural populations to their habitat and ecotypic differentiation in this species.

    • Anther and pollen development in cotton haploids and their parents

      S S Mehetre

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      Development of anther tapetum from premeiotic stages to pollen formation was studied in six x-ray induced haploids ofGossypium hirsutum, three interspecific F2 haploids, and one natural haploid of each ofG. hirsutum andG. barbadense, and the observations were compared with those of their respective parents, a genetic male sterile, a male fertile and a cytoplasmic male sterile line ofG. hirsutum. Significant differences were recorded for number of anthers per flower, pollen size, pollen viability and number of microspores produced byPMC. Anther development in haploids was normal. Anther dehiscence was also normal in some haploids. Non-dehiscent anthers could be mostly attributed to the formation of immature pollen grains. Normal development of anthers and degeneration of tapetum occurred in the parents and in the genetic fertile line. Contrastingly no degeneration of tapetum was noticed in the cytoplasmic male sterile line.

    • Changes in proteins, amino and keto acids in different seedling parts ofCyamopsis tetragonolobus Linn. during growth in light and darkness

      Prem Gupta D Mukherjee

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      Comparative changes in protein, free amino and keto acids have been studied in different seedling parts ofCyamopsis tetragonolobus plants in light and dark. Endosperm recorded higher level of free amino acids in darkness than in light, while a low concentration of protein was exhibited both, in light and dark. The breakdown of soluble protein was more in darkened cotyledon due to higher protease activity. The large increase in the free amino acids in the hypocotyl during seedling growth in the dark may be due to its restricted capacity to incorporate all the amino acids into proteins. Root samples from light recorded higher soluble protein as well as a higher free amino acid pool. α-Oxoglutaric acid (α-oga) was recorded in low levels and at few growth stages in both light and dark. In light raised cotyledon samples, the dominating keto acids are phosphoenolpyruvate and pyruvic acid. Low levels of oxaloacetate in light, like α-oga, indicate its rapid utilization during growth, but its accumulation in the dark may suggest sluggish protein synthesis thus sparing the utilization towards the synthesis of amino acids. Utilization of asparagine and glutamine was also affected in dark.

    • Effect of ridge gourd pollen on zoospore germination ofPseudoperonospora cubensis and its significance in epidemiology

      Amarnatha Shetty H S Shetty K M Safeeulla

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      Ridge gourd pollen has a stimulatory effect on the germination ofPseudoperonospora cubensis. The rate and percentage germination of zoospores increased in the presence of pollen leachates. Spraying of leaves with a mixture of pollen and sporangial suspension enhanced the development of lesions. Early germination of zoospores in the presence of pollen proved advantageous for infection as it provided a prolonged favourable infection period. The results are discussed in relation to the epiphytoties of the disease during flowering period.

    • Leaf proteinase and nitrate reductase activities in relation to grain protein levels and grain yield in four species of grain amaranth

      K Ramamurthy Naidu Y Seethambaram V S Rama Das

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      The relationship of leaf nitrate reductase (nr) and proteinase activities to the grain protein level and grain yield was investigated in four species of grain amaranth (Amaranthus hypochondriacus, A. caudatus, A. cruentus andA. edulis). A strikingly positive correlation between the leaf proteinase activity and the grain protein content was found.A. edulis with higher grain protein level possessed high leaf proteinase activity, whileA. hypochondriacus, with relatively lower grain protein content had lower leaf proteinase levels. Although there was no definite correlation between the leaf proteinase levels and the grain yield, the integrated leafnr activity was positively correlated with the grain yield. The total nitrogen content per plant seems to be dependent on the extent of root growth and the levels ofnr activity in leaves.

    • Cell division inStaurastrum gracile Ralfs. under the scanning electron microscope

      Vidyavati

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      Staurastrum gracile Ralfs. was grown in Chu’s No. 10 culture medium, in a culture cabinet at 18–20°C with 16 hrs light and 8 hrs dark period. The cells exhibited polymorphism. The cells were fixed and their division and growth was examined under the scanning electron microscope.

    • Leaf surface studies of some medicinal salvias

      H P Sharma Usha Shome

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      Scanning electron microscopic studies on the leaves of 8 medicinal salvias comprising mainly surface ornamentation of the various epidermal cells and the appendages, provide useful parameters to distinguish one species from another. Some of the distinguishing features of the species studied are:Salvia cabulica Benth.—Striated lower epidermis, etomatal ledges broad and smooth;S. lanata Roxb.—Abaxial side completely covered over by a thick coat of trichomes;S. macrosiphon Boiss.—verrucose trichomes with constricted joints;S. moorcroftiana Wall.—longitudinal folds on basal cells of trichomes;S. officinalis Linn.—curved cylindrical trichomes, cells over veins with characteristic longitudinal ridges, gland stalk very long;S. plebeia R. Br.—basal cells of trichomes transversely striated;S. pratensis Linn.—verrucose trichomes and series of irregular folds on lower epidermis;S. spinosa Linn.—smooth collapsible hairs, folds on general surface similar toS. pratensis.

    • Morphological and histochemical changes in the egg and zygote ofLagerstroemia speciosa. I. Cell size, vacuole and insoluble polysaccharides

      P Raghavan V J Philip

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      InLagerstroemia speciosa, the decrease in size of the egg and its micropylar vacuole immediately after fertilization is followed by a progressive and marked expansion of the cell. Thepas-positive cell wall material in egg is confined to the micropylar half. Soon after fertilization, but before completion of decrease in size of the zygote, its cell wall grows in thickness. A complete wall is not formed around the zygote. The bulk of the insoluble polysaccharides in the cytoplasm is localized at the chalazal pole of the egg and zygote. Following fertilization, the size and number of starch granules in the egg cytoplasm significantly increased followed by a decrease and again an increase during zygote development. The morphological changes in the egg following fertilization are probably related to the osmolarity of the cell and of the vacuole which would account for the change in cell size.

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