• Volume 77, Issue 4

      April 1973,   pages  137-180

    • Impact of photoperiod on seasonal sowing in rice - II. Interaction between short photoperiod and the month of sowing in a late-winterindica rice

      G Misra P A Khan

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      One late-winter variety ofindica rice was sown on the 1st of every month during the period from August 1964 to July 1965. In each month, a set of plants were subjected at the age of 28 days to 8 hr photoperiod for 21 days, and grown thereafter in natural daylength along with untreated controls till flowering and subsequent harvest. Production of tillers, leaves and plant height were significantly reduced by the short-day treatment. The vegetative growth period of the variety was greatly altered by the date of sowing. Control plants remained vegetative till they received in nature a critical nightlength of not less than 11 hr 26 min and an optimum temperature for the pigment (phytochrome) conversion. Thus plants sown during the months February to July came to ear emergence in the following October, plants of August and September sowing came to ear emergence in November, plants sown in October came to ear emergence in December, plants sown in November and December came to ear emergence in March and plants sown in January came to ear emergence in April. The 8 hr photoperiod induced a markedly earlier flowering in the treated plants in all the months of sowing. Grain yield was higher in the control plants than that of the treated plants in all the monthly sowings, while late sowings remarkably reduced the grain yield in the control plants.

    • Correlation between neurosecretion and some physiological functions of the scorpionHeterometrus swammerdami

      Kandula Pampapathi Rao Mohammad Habibulla

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      The diverse types of neurosecretory cells located in the brain and suboesophageal ganglion of the scorpionHeterometrus have shown morphological evidence of activity in relation to diverse physiological functions. Some of the functions investigated were the process of delivery of the young, apolysis, ecdysis, growth, maturation, water relations, diurnal rhythms of locomotor activity and temperature adaptation. Continuous light and continuous darkness reflected change in the activity of specific groups of neurosecretory cells. In this Arachnid also, neurosecretion seems to play a central role in the regulation of many physiological activities as in insects and other organisms.

    • Physiological studies on the effects of hormonal imbalance on the central nervous system - I. Effects of hypophysectomy on certain biochemical parameters in the brain of frog

      S Suryaprabha Kandula Pampapathi Rao

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      The acetylcholinesterase activity, RNA levels, total free amino acids and magnesium content in fore-, mid- and hind-brain were determined in the normal and hypophysectomised frogs (Rana cyanophlyctus). Hypophysectomy results in a marked decrease in the freea−a and in Mg. RNA also decreases significantly, but not to the same degree as thea−a and Mg. But AchE levels do not change significantly although there is a general decrease. It is suggested that the decrease in Mg is a reflection of the ionic imbalance resulting from hormonal imbalance. Hypophysectomy also results in reduced protein synthesis (and/or turnover) in the CNS as indicated by reduced RNA anda−a.

    • Development of endosperm, embryo and seed coat inAmischophacellus axillaris L

      P S Chikkannaiah

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      The endosperm formation is of nuclear type. A persistent chalazal haustorium with prominent processes is present. Compound starch grains are present in abundance in the endosperm cells except in the cells of the outer layer.

      Embryogeny is of Asterad type and is placed under Commelina variation.

      A persistent hypostase and a crushed epistase are present in a mature seed. A collar is formed by the activities of both the nucellus and the integuments.

      The basal region of the seed is filled with mealy endosperm and the collar region is occupied by a massive embryo surrounded by a few disintegrated endosperm cells.

      The seed coat is formed by both the layers of the inner integument and the inner epidermis of the outer integument. The cells of the outer layer of the outer integument in the collar region form a cap crowning the seed.

      Thick cutin is present on the degenerated nucellus and on the outer epidermis of the inner integument.

    • Hybrid vigour in Brinjal

      T V Viswanathan

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      Morphological and yield characters of eight intervarietal hybrids of brinjal were studied to assess the extent of vigour expressed in different parental combinations. The most economic combination was found to be between Muktakeshi × Banaras giant in which the increase in yield was over 100%.


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