Japanese Journal of Tropical Agriculture
Online ISSN : 2185-0259
Print ISSN : 0021-5260
ISSN-L : 0021-5260
Volume 51 , Issue 2
Showing 1-6 articles out of 6 articles from the selected issue
  • Chukichi KANEDA
    2007 Volume 51 Issue 2 Pages 41-45
    Published: June 01, 2007
    Released: March 19, 2010
    JOURNALS FREE ACCESS
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  • Ninh Thi PHIP, Hiroshi NOJIMA, Toru TASHIRO
    2007 Volume 51 Issue 2 Pages 46-53
    Published: June 01, 2007
    Released: March 19, 2010
    JOURNALS FREE ACCESS
    Angelica acutiloba Kitagawa, Touki, is a medicinal plant belonging to the Apiaceae family. Flowering is characterized by a series of sequentially formed umbels producing seeds. The present study was carried out to analyze the effect of the umbel order and umbellet position on: (i) seed production characteristics, (ii) seed germination, (iii) seedling emergence, and (iv) seedling growth. The results showed that seed development and maturity occurred earlier in the order of primary>secondary>tertiary umbels. Accordingly, the seed weight value was higher in the order of primary>secondary>tertiary umbels, but was not different among the umbellet positions. Seeds were mainly produced on the secondary umbels. The seed germination percentage was very high (>90%) at the optimum temperature, and the seedling emergence percentage was high (>70%) under greenhouse conditions. Seed germination and seedling emergence were not affected by the umbel order and umbellet position. The values of the growth parameters (i.e. leaf area, root diameter, shoot and root dry weight) were significantly higher in the seedlings obtained from seeds on the primary umbel than in those from seeds on the secondary and tertiary umbels. The umbellet position did not affect seedling growth. Seed production, development and seedling growth were affected by the umbel order. The primary umbel produced the heaviest seeds and subsequently the most vigorous seedlings. However, a small amount of seeds was produced on the primary umbel. It is suggested that harvesting the seeds on the primary and secondary umbels at around 9 weeks after the first flowering is most important for high-quality seed production.
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  • Akira MIYAZAKI, Yoshinori YAMAMOTO, Kazuki OMORI, Hardaning PRANAMUDA, ...
    2007 Volume 51 Issue 2 Pages 54-58
    Published: June 01, 2007
    Released: March 19, 2010
    JOURNALS FREE ACCESS
    Leaf photosynthetic rate (PR) and related characters in sago palms were determined under field conditions at three different locations in Indonesia: Kendari, Bogor and Jayapura. The results were as follows: First, diurnal changes in PR revealed that the maximum values of PR in sago palms were in the range of 25-27 mg CO2 dm-2 h-1 in a palm after trunk formation that was grown in Kendari, values which were much higher than those recorded at younger stages in previous reports (8-15 mgCO2 dm-2h-1) . The PR values in palms prior to trunk formation that were grown in Bogor were in the range of 16-18 mg CO2 dm-2h-1. Similar values were observed for the average PR of some folk varieties grown in Jayapura (17.2 mg CO2 dm-2h-1) . Second, the PR was saturated at the light intensity of about 500 μE m-2s-1, suggesting that low light saturation plays an important role in maintaining the levels of CO2 fixation required for a high starch yield under the low light conditions caused by the canopy cover. Third, the PR was closely related to the mesophyll conductance (Gm), an indicator of CO2 fixation ability: the decrease in the PR values of the lower leaves was due to the decrease in Gm. However, the lower PR values recorded in Bogor than those in Kendari were associated with stomatal conductance (Gs), rather than with Gm.
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  • Yoki ASANO, Hisashi OBATA, Mari FUJII, Yasushi ENOMOTO, Yasuhiro SUGIM ...
    2007 Volume 51 Issue 2 Pages 59-65
    Published: June 01, 2007
    Released: March 19, 2010
    JOURNALS FREE ACCESS
    To evaluate the feeding value of roll bale silage from knotgrass (Paspalum distichum L.) grown in paddy fields with a very large application of nitrogen fertilizer, fermentative quality, nitrite and nitrate contents and palatability were investigated. These characteristics of the roll bale silage from knotgrass were compared with those of four kinds of silage from Miyazaki in Experiment 1, and then the effect of monthly harvesting and ensiling between July and September on the characteristics of the prewilting roll bale silages from knotgrass and bahiagrass (Paspalum notatum Flügge) was examined in Experiment 2. Knotgrass silage showed a fermentative quality characterized by a higher pH value (5.1), a higher relative content of acetate (47%), and a much lower ratio of volatile basic nitrogen to total nitrogen (VBN/TN, 2.4%) than those of other silages, along with undetectable levels of nitrite and nitrate. The ingestion behavior by cow was observed. The roll bale silages from knotgrass ensiling in July, August and September showed pH values of 5.2, 5.7 and 5.3, relative contents of lactate of 79%, 27% and 55%, relative contents of acetate of 16%, 50% and 45%, and VBN/TN ratios of 7.9, 25.8 and 12.7, respectively, indicating that the fermentative quality of knotgrass silage changed with the harvesting and ensiling dates. Also, the fermentative quality tended to improve with the decrease in the moisture contents of the silages by prewilting. The nitrite and nitrate contents of all the knotgrass silages were less than 0.02% due to decrease in the original contents of 50% to more than 90% during the ensiling process. There was no decrease in the palatability of knotgrass silage in relation to the feeding value. In conclusion, roll bale silage from knotgrass grown in paddy fields with a very large application of nitrogen fertilizer offers a potential in terms of feeding value.
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  • Yoshimi YONEMOTO, Tatsushi OGATA, Naoko KOZAI, Orwintinee CHUSRI, Hiro ...
    2007 Volume 51 Issue 2 Pages 66-69
    Published: June 01, 2007
    Released: March 19, 2010
    JOURNALS FREE ACCESS
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  • Naoko KOZAI, Ikuo KATAOKA, Tomohiro KONDO, Shun AMEMIYA, Hirokazu HIGU ...
    2007 Volume 51 Issue 2 Pages 70-72
    Published: June 01, 2007
    Released: March 19, 2010
    JOURNALS FREE ACCESS
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