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The Commons in an Age of Global …, Jan 1, 2004
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
I ntroduetion IN a detailed communication 2 from this Experiment Station the leading generalisati... more I ntroduetion IN a detailed communication 2 from this Experiment Station the leading generalisation arrived at was the following: " The critical study has brought one special feature to prominence, viz., that the winter season in the temperate regions is represented in a general way by the summer season in the tropics in introducing a general depression of physiological activities in the plant of which respiration can be taken as a measure. It appears that the prevailing high temperatures and enhanced rates of transpiration during this season (summer) subject the plant to as severe conditions for living as those obtained in the winter season in the temperate regions under an exactly opposite set of circumstances."
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
At the normal atmospheric pressure of carbon dioxide the intensity of assimilation increases meas... more At the normal atmospheric pressure of carbon dioxide the intensity of assimilation increases measurably with the intensity of illumination upto 68,760 metre candles in radish leaves in the sub-tropics. At a ten time atmospheric concentration of carbon dioxide the rate of assimilation continues to increase with the intensity of illumination to a slightly higher illumination intensity of 72,197 metre candles. Depression in the photosynthetic activity of radish leaves appears to occur for the first time at a light intensity more than twice the average sunlight in the winter months in these regions. An appreciable time factor sets in at a light intensity of 1,80,000 metre candles. This depression in the photosynthetic rate appears to be connected with the inactivation of chloroplasts and is capable of reversal under reduced light intensity provided the exposure to the higher light intensity has not been prolonged. The threshold light intensity for photosynthesis is in the neighbourhood of 4,000 metre candles for radish leaves in these regions. The minimal and optimal cardinal points herein mentioned though characteristic of the winter season in the sub-tropics should not necessarily apply to the temperate regions where the plants are adapted to lower intensities of light in contrast to the high illumination conditions obtaining in these regions.
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
The march of assimilation from day to day in a young leaf for twenty days—the period of physiolog... more The march of assimilation from day to day in a young leaf for twenty days—the period of physiological activity of a radish leaf in the laboratory—is deduced from the separate time-assimilation curves of mature and old leaves. Under the natural pressure of carbon dioxide in the atmosphere, assimilation of radish leaves increases continuously upto 29°C. more or less in conformity with the Van’t Hoff’s law, the coefficient of increase being 2·26. The maximum assimilation attainable under the atmospheric conditions of carbon dioxide is reached at 30°C. From 30 to 34°C. the first observed value of assimilation attained is of the same order but at and beyond 30°C. this initial value of photosynthesis abates in successive hours. While the first evidence of time factor is available at 30°C. its pronounced influence is manifested not till 37°C. when the disparity between the first and second hourly reading is striking. At 29°C. it is possible to reach a higher sustained pitch of assimilation in time by increasing the partial pressure of carbon dioxide in the environment. Assimilatory activity in the radish leaf becomes extinct at a temperature of 47·4°C. and does not commence at a temperature lower than 12·6°C. in these regions. This behaviour is contrasted with that of Cherry Laurel, recorded by Matthaei working in the temperate regions who found the threshold value for photosynthesis to be −6°C., and ascribed to the ecological adaptation of the plants to higher temperatures in these regions.
The Commons in an Age of Global …, Jan 1, 2004
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
I ntroduetion IN a detailed communication 2 from this Experiment Station the leading generalisati... more I ntroduetion IN a detailed communication 2 from this Experiment Station the leading generalisation arrived at was the following: " The critical study has brought one special feature to prominence, viz., that the winter season in the temperate regions is represented in a general way by the summer season in the tropics in introducing a general depression of physiological activities in the plant of which respiration can be taken as a measure. It appears that the prevailing high temperatures and enhanced rates of transpiration during this season (summer) subject the plant to as severe conditions for living as those obtained in the winter season in the temperate regions under an exactly opposite set of circumstances."
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
At the normal atmospheric pressure of carbon dioxide the intensity of assimilation increases meas... more At the normal atmospheric pressure of carbon dioxide the intensity of assimilation increases measurably with the intensity of illumination upto 68,760 metre candles in radish leaves in the sub-tropics. At a ten time atmospheric concentration of carbon dioxide the rate of assimilation continues to increase with the intensity of illumination to a slightly higher illumination intensity of 72,197 metre candles. Depression in the photosynthetic activity of radish leaves appears to occur for the first time at a light intensity more than twice the average sunlight in the winter months in these regions. An appreciable time factor sets in at a light intensity of 1,80,000 metre candles. This depression in the photosynthetic rate appears to be connected with the inactivation of chloroplasts and is capable of reversal under reduced light intensity provided the exposure to the higher light intensity has not been prolonged. The threshold light intensity for photosynthesis is in the neighbourhood of 4,000 metre candles for radish leaves in these regions. The minimal and optimal cardinal points herein mentioned though characteristic of the winter season in the sub-tropics should not necessarily apply to the temperate regions where the plants are adapted to lower intensities of light in contrast to the high illumination conditions obtaining in these regions.
Proceedings of The Indian Academy of Sciences - Section A. Part 3, Mathematical Sciences, 1935
The march of assimilation from day to day in a young leaf for twenty days—the period of physiolog... more The march of assimilation from day to day in a young leaf for twenty days—the period of physiological activity of a radish leaf in the laboratory—is deduced from the separate time-assimilation curves of mature and old leaves. Under the natural pressure of carbon dioxide in the atmosphere, assimilation of radish leaves increases continuously upto 29°C. more or less in conformity with the Van’t Hoff’s law, the coefficient of increase being 2·26. The maximum assimilation attainable under the atmospheric conditions of carbon dioxide is reached at 30°C. From 30 to 34°C. the first observed value of assimilation attained is of the same order but at and beyond 30°C. this initial value of photosynthesis abates in successive hours. While the first evidence of time factor is available at 30°C. its pronounced influence is manifested not till 37°C. when the disparity between the first and second hourly reading is striking. At 29°C. it is possible to reach a higher sustained pitch of assimilation in time by increasing the partial pressure of carbon dioxide in the environment. Assimilatory activity in the radish leaf becomes extinct at a temperature of 47·4°C. and does not commence at a temperature lower than 12·6°C. in these regions. This behaviour is contrasted with that of Cherry Laurel, recorded by Matthaei working in the temperate regions who found the threshold value for photosynthesis to be −6°C., and ascribed to the ecological adaptation of the plants to higher temperatures in these regions.