The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Kazuhiro Ohba - One of the best experts on this subject based on the ideXlab platform.
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impact of humidity on temperature induced grain sterility in rice oryza sativa l
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 °C, 34/30 °C, 32/24 °C and 30/24 °C day/night air temperatures from late booting to maturity inside sunlit Phytotrons. Increasing both air temperature and RH significantly increased spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their spikelets to increased air temperature and RH. Increased spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to spikelet temperature. Grain sterility increased when spikelet temperature increased over 30 °C while it became completely sterile at 36 °C. The ability of a variety to decrease its spikelet temperature with decreasing RH could be considered as avoidance while the variability in spikelet sterility among varieties at a given spikelet temperature could be considered as true tolerance.
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Impact of humidity on temperature-induced grain sterility in rice (Oryza sativa L)
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 degrees C, 34/30 degrees C, 32/24 degrees C and 30/24 degrees C day/night air temperatures from late booting to maturity inside sunlit Phytotrons. Increasing both air temperature and RH significantly increased spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their spikelets to increased air temperature and RH. Increased spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to spikelet temperature. Grain sterility increased when spikelet temperature increased over 30 degrees C while it became completely sterile at 36 degrees C. The ability of a variety to decrease its spikelet temperature with decreasing RH could be considered as avoidance while the variability in spikelet sterility among varieties at a given spikelet temperature could be considered as true tolerance.
W M W Weerakoon - One of the best experts on this subject based on the ideXlab platform.
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impact of humidity on temperature induced grain sterility in rice oryza sativa l
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 °C, 34/30 °C, 32/24 °C and 30/24 °C day/night air temperatures from late booting to maturity inside sunlit Phytotrons. Increasing both air temperature and RH significantly increased spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their spikelets to increased air temperature and RH. Increased spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to spikelet temperature. Grain sterility increased when spikelet temperature increased over 30 °C while it became completely sterile at 36 °C. The ability of a variety to decrease its spikelet temperature with decreasing RH could be considered as avoidance while the variability in spikelet sterility among varieties at a given spikelet temperature could be considered as true tolerance.
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Impact of humidity on temperature-induced grain sterility in rice (Oryza sativa L)
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 degrees C, 34/30 degrees C, 32/24 degrees C and 30/24 degrees C day/night air temperatures from late booting to maturity inside sunlit Phytotrons. Increasing both air temperature and RH significantly increased spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their spikelets to increased air temperature and RH. Increased spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to spikelet temperature. Grain sterility increased when spikelet temperature increased over 30 degrees C while it became completely sterile at 36 degrees C. The ability of a variety to decrease its spikelet temperature with decreasing RH could be considered as avoidance while the variability in spikelet sterility among varieties at a given spikelet temperature could be considered as true tolerance.
A. Maruyama - One of the best experts on this subject based on the ideXlab platform.
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impact of humidity on temperature induced grain sterility in rice oryza sativa l
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 °C, 34/30 °C, 32/24 °C and 30/24 °C day/night air temperatures from late booting to maturity inside sunlit Phytotrons. Increasing both air temperature and RH significantly increased spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their spikelets to increased air temperature and RH. Increased spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to spikelet temperature. Grain sterility increased when spikelet temperature increased over 30 °C while it became completely sterile at 36 °C. The ability of a variety to decrease its spikelet temperature with decreasing RH could be considered as avoidance while the variability in spikelet sterility among varieties at a given spikelet temperature could be considered as true tolerance.
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Impact of humidity on temperature-induced grain sterility in rice (Oryza sativa L)
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 degrees C, 34/30 degrees C, 32/24 degrees C and 30/24 degrees C day/night air temperatures from late booting to maturity inside sunlit Phytotrons. Increasing both air temperature and RH significantly increased spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their spikelets to increased air temperature and RH. Increased spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to spikelet temperature. Grain sterility increased when spikelet temperature increased over 30 degrees C while it became completely sterile at 36 degrees C. The ability of a variety to decrease its spikelet temperature with decreasing RH could be considered as avoidance while the variability in spikelet sterility among varieties at a given spikelet temperature could be considered as true tolerance.
Rainer Matyssek - One of the best experts on this subject based on the ideXlab platform.
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Advances in understanding ozone impact on forest trees: Messages from novel phytotron and free-air fumigation studies
Environmental Pollution, 2010Co-Authors: Rainer Matyssek, Thorsten E. E. Grams, David F. Karnosky, Gerhard Wieser, Kevin E. Percy, Elina Oksanen, Mark E. Kubiske, David E. Hanke, Hans PretzschAbstract:Recent evidence from novel phytotron and free-air ozone (O3) fumigation experiments in Europe and America on forest tree species is highlighted in relation to previous chamber studies. Differences in O3 sensitivity between pioneer and climax species are examined and viewed for trees growing at the harsh alpine timberline ecotone. As O3 apparently counteracts positive effects of elevated CO2 and mitigates productivity increases, response is governed by genotype, competitors, and ontogeny rather than species per se. Complexity in O3 responsiveness increased under the influence of pathogens and herbivores. The new evidence does not conflict in principle with previous findings that, however, pointed to a low ecological significance. This new knowledge on trees' O3 responsiveness beyond the juvenile stage in plantations and forests nevertheless implies limited predictability due to complexity in biotic and abiotic interactions. Unravelling underlying mechanisms is mandatory for assessing O3 risks as an important component of climate change scenarios.
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seasonal ozone response of mature beech trees fagus sylvatica at high altitude in the bavarian forest germany in comparison with young beech grown in the field and in Phytotrons
Environmental Pollution, 2000Co-Authors: M Baumgarten, H Werner, K H Haberle, Lisa Emberson, P Fabian, Rainer MatyssekAbstract:Abstract Mature beech trees (Fagus sylvatica) grown at two different altitudes in the Bavarian forest were compared with young beech trees grown at nearby field sites or in Phytotrons for their macroscopic and physiological responses to different ozone (O3) exposures. Cumulative O3 exposure expressed as the sum of hourly mean concentrations above the canopy ranged between 100 and 150 μl l−1 h, with the vertical O3 profiles at the higher altitude site being enhanced by 30%. O3 profiles at all sites were reduced by up to 20% with increasing depth within and beneath the canopy. The leaf discoloration that developed in the absence of premature leaf loss was similar in the sun foliage of mature and young trees (including plant grown in the phytotron). Injury became apparent at low O3 exposures, expressed as accumulated hourly means over a threshold of 40 nl l−1 (AOT40
Per Lea - One of the best experts on this subject based on the ideXlab platform.
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The effect of temperature on sensory quality, chemical composition and growth of carrots (Daucus carota L.). III. Different diurnal temperature amplitudes
Journal of Horticultural Science & Biotechnology, 1999Co-Authors: Hans J. Rosenfeld, Ragnar T. Samuelsen, Per LeaAbstract:SummaryData from experiments with carrots grown in Phytotrons under different day and night temperatures at two locations in Norway and three harvesting dates were treated by means of Principal Component Analysis (PCA). No effect of the single temperature amplitudes were found, the significant main effects were due to the mean temperature levels of 12 and 188C, location and harvest date. The PCA visualized the effect of mean temperature level on sensory, chemical and physical variables. Differences between the two groups were mainly caused by variation in sensory variables, the first group being characterized by high score for whiteness, sweetness, acidic taste, crispness, juiciness, glucose, fructose and root length. The other group had a high score for colour, odour, overall taste and flavour parameters, firmness, dry matter, sucrose, a and b-carotene, root weight and root diameters.
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The effect of temperature on sensory quality, chemical composition and growth of carrots (Daucus carota L.) I. Constant diurnal temperature
Journal of Horticultural Science & Biotechnology, 1998Co-Authors: Hans J. Rosenfeld, Ragnar T. Samuelsen, Per LeaAbstract:SummaryThe carrot cv. Panther FT grown in Phytotrons at 9,12 15,18 and 21°C constant diurnal temperatures at two locations, As (59°40’N) and Tromso (69°39’N), and harvested at two dates was evaluated for sensory attributes, chemical composition and morphological variates. Significant temperature effects were detected for most sensory, chemical and physical variables. High growing temperatures (18 and 21°C) favoured colour, bitter tasting flavour components, firmness and the dry matter, sucrose and carotene content of the roots, whereas low growing temperature (9 and 12°C) heightened sweet taste, acidic taste, crispness, juiciness, and the fructose and glucose content. The longest roots were obtained at 9 and 12°C, the highest root weights at 12 and 15°C. Principal component analysis (PCA) revealed clear differences in the sensory profile of carrots grown at high and low temperatures, expressed by the first three principal components which together explained 81% of the variation in sensory variables. PCA o...