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Volume 2013 (2013)
- Issue 116 Pages 116_1･･･
- Issue 115 Pages 115_1･･･
Volume 2013, Issue 115
Displaying 1-6 of 6 articles from this issue
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Original Articles
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Yoshiya Shiraki, Hajime Takeda, Tamotsu Okamoto, Nobuhiro Kita2013 Volume 2013 Issue 115 Pages 115_1-115_9
Published: June 30, 2013
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSWe investigated the periodic changes in the 137Cs concentration of tea plants (new shoots, old leaves, twigs, branches, trunks and roots) cultivated in an ordinary tea field management style without pruning grown in Kanagawa Prefecture from May 25th, 2011 to July 25th, 2012. There was a tendency for the 137Cs concentration of old leaves, twigs and branches to be decreased. The decrease of the 137Cs concentration in the tea plants was caused by rainfall, loss of leaves from plucking and skiffing and defoliation. As no periodic changes of the 137Cs concentration were observed in trunks and roots, it was suggested that the 137Cs in the new shoots translocated from old leaves, twigs and branches.
Furthermore, it was considered that the transition of the 137Cs concentration of old leaves, twigs and branches under ordinary tea field management without pruning could be represented as an exponential function within days after 25 May 2011.View full abstractDownload PDF (1254K) -
Yoshiya Shiraki, Hajime Takeda, Tamotsu Okamoto, Nobuhiro Kita2013 Volume 2013 Issue 115 Pages 115_11-115_19
Published: June 30, 2013
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSWe exmamined the radioactive cesium translocation from old leaves and stems to new shoots by using uncontaminated tea nursery stocks that were sprinkled with the contaminated first crop of processed tea extracts manufactured at the Kanagawa Agricultural Technology Center Hokuso Region Office in 2011. The radioactive cesium was detected in the new shoots and the ratio of radioactive cesium concentration (137Cs concentration/ 134Cs concentration) was 1.31. It was considered that as the ratio of radioactive cesium concentration of new shoots was almost equal in that of contaminated tea extracts (1.35), and that of old leaves (1.45), and stems (1.28) 1 day after being sprinkled, the radioactive cesium sprinkled on the old leaves and stems translocated to new shoots. On the other hand, it was clear that the radioactive cesium deposited on the surface of old leaves and stems was remarkably reduced by rain. Furthermore, we investigated the radioactive cesium distribution of branches and trunks in matured tea bushes. It was clear that the radioactive cesium existed not only in the bark and cambium of branches and trunks but also their xylem nineteen months to twenty-one months after fallout.View full abstractDownload PDF (1149K)
Short Communications
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Yoshiya Shiraki, Hajime Takeda, Tamotsu Okamoto, Nobuhiro Kita2013 Volume 2013 Issue 115 Pages 115_21-115_25
Published: June 30, 2013
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSWe conducted this study to reduce radioactive cesium in tea plants that had been contaminated eleven or thirteen months earlier. The results obtained were as follows:
1) High-pressure washing was applied to tea leaves, twigs and branches contaminated with radioactive cesium at 7.5MPa of 1,200L/10a. However, no reduction of the amount of radioactive cesium was observed.
2) Tea branches contaminated with radioactive cesium were soaked in 1% acetic acid solution(pH=3.52), 1% sodium chloride solution(pH=6.84),1% sodium hypochlorite solution(pH=8.67) and 1% sodium carbonate solution(pH=10.77) for 5 minutes respectively and they were then washed in water after they had dried. However, no reduction in the amount of radioactive cesium was observed.
These results suggested that the radioactive cesium would exist not only on the surface of old tea leaves and branches but also in the innner part of them.View full abstractDownload PDF (1067K) -
Tomoyoshi Kondo, Kimiaki Murai, Masakazu Shiwa2013 Volume 2013 Issue 115 Pages 115_27-115_31
Published: June 30, 2013
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSIn recent years, trimming and pruning of the canopy of tea plants have been performed every year after the second crop, resulting in the accumulation of large quantities of pruned shoots (litter) in the space between hedges. The nitrogen fertilizer applied in the space between the hedges could not reach the soil easily because of accumulation of this litter, and we believe that it became a factor in the decline in the efficiency of fertilizer application. Therefore, in a tea field in which fertilizer was applied over the accumulated litter in the space between hedges, we analyzed the amount of inorganic nitrogen in the soil and the contribution rate of the nitrogen fertilizer in flush seasons by using the 15N-tracer method, and we investigated the influence of this litter on the fertilizer application efficiency.
The amount of inorganic nitrogen in the soil remained low in the tea field, even when ammonium sulfate and rapeseed oil cake were used. The 15N contribution rate of the second flush was 4.8% and the utilization rate of the nitrogen fertilizer in the first and second flush was 3.8%; these values were lower than those in a tea field without litter. Consequently, it was thought that the litter accumulated after trimming and pruning in the space between hedges might have been a factor responsible for the decline in fertilizer application efficiency.View full abstractDownload PDF (1249K) -
Yuzo Mizukami, Atsushi Nesumi, Atsushi Takahashi, Kenta Nakajima, Hiro ...2013 Volume 2013 Issue 115 Pages 115_33-115_36
Published: June 30, 2013
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSThe Japanese green tea cultivar ‘Saitama42’ has characteristic aroma such as the cherr y tree’s leaf. Aroma extract dilution analysis has revealed that 6 odorants namely linalool, 3-methylnonane-2,4-dione, β-damascenone, indole, coumarin and vanilline were the most prevalent odorants in ‘Saitama42’.View full abstractDownload PDF (1131K)
Note
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Aogu Nakayama2013 Volume 2013 Issue 115 Pages 115_37-115_48
Published: June 30, 2013
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSDownload PDF (1282K)
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