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81.
The ecological roles of stem sprouts and creeping sprouts ofAucuba japonica Thunb. were investigated through comparisons of the population structure at individual and stem level between two sites with
different disturbance histories. Age and size structure of individuals indicated fewer chances for establishment of new individuals
in undisturbed population. Maintenance of population was achieved by stem replacement within a clump and vegetative propagation
with creeping sprouts which adapted to the non-severe disturbances. Rapid recovery by vigorous sprouting and encouraged seedling
recruitment were detected in the disturbed sites. Results of the stem level analysis suggested transformation of stem sprouts
into creeping sprouts. The major role of stem sprouts shifted from the maintenance of individuals to recovery of individuals
by a severe disturbance. These differentiation of ecological roles among stem types, and their flexible changes according
to disturbance regimes were thought to be the reasons whyA. japonica can achieve both the rapid dominance in a disturbed stand and the stable population in a less disturbed stand. 相似文献
82.
Shigeru Yamauchi Katsumi Saitoh Koichiro Sera Yoshihisa Wada Masaaki Kuwahara 《Journal of Wood Science》2008,54(2):162-168
Elemental analysis of wood fuels and ashes from a biomass power plant was carried out using particle induced X-ray emission
(PIXE) to confirm that the ashes can be utilized safely. The power plant produced four types of ash: one cinder and three
fly ashes. Ignition loss tests revealed that the cinder included little unburned carbon, while the unburned carbon concentrations
in the fly ashes were considerably higher. From PIXE analysis, more than 20 elements were found in all the ashes and it was
shown that aluminum, silicon, calcium, potassium, and iron were the major elements in the ashes. In the fly ash collected
in a bag filter, sodium, sulfur, and chlorine were also classified as major elements. Although chromium, arsenic, and lead
were detected in all the ashes, leaching tests indicated that there were no potential problems associated with landfill treatment
of the ashes. It was assumed that temporal fluctuation in the concentrations of major elements in the ashes was not significant.
Nine kinds of waste wood fuels were analyzed by PIXE and 24 elements were determined. Lead was detected in all the woody fuels,
but arsenic was not detected.
Part of this report was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007. 相似文献
83.
Miho Kojima Hiroyuki Yamamoto S. Nugroho Marsoem Takashi Okuyama Masato Yoshida Takahisa Nakai Saori Yamashita Koichiro Saegusa Kenji Matsune Kentaro Nakamura Yoshihiko Inoue Takeshi Arizono 《Annals of Forest Science》2009,66(5):507-507
84.
Koichiro Tanamachi Masayuki Miyazaki Kazuhiro Matsuo Chetphilin Suriyasak Aina Tamada Kiyoshi Matsuyama 《Plant Production Science》2016,19(2):300-308
High-temperature stress during the grain-filling stage reduces grain quality of rice, and this is a serious problem in Japan, especially in the Kyushu region. To solve this problem, various heat-tolerant cultivars have been bred, such as ‘Nikomaru’, ‘Kumasannochikara’, ‘Genkitsukushi’, ‘Sagabiyori’, and ‘Otentosodachi’. When cultivated under high temperature after flowering, these heat-tolerant cultivars had lower percentages of chalky grains than in the heat-sensitive cultivar ‘Hinohikari’. All the heat-tolerant cultivars markedly decreased the nonstructural carbohydrate content in the stem under the high temperature compared to control condition during early grain-filling stage, which is considered to be a common trait of heat tolerance. Notably, ‘Sagabiyori’, ‘Genkitsukushi’, and ‘Nikomaru’ maintained a nucellar epidermis at 17 days after flowering (DAF) under high temperature, whereas the nucellar epidermis disappeared in ‘Hinohikari’. In addition, the expression of AGPS2b, thought to be a rate-limiting enzyme in starch synthesis, in ‘Kumasannochikara’, ‘Otentosodachi’, and ‘Nikomaru’ did not decrease under high temperature, whereas ‘Hinohikari’, ‘Sagabiyori’, and ‘Genkitsukushi’ could not maintain expression of the gene at 17 DAF. Moreover, the expression of Amy3E, a starch-degradation-related gene considered to induce grain chalkiness, in ‘Kumasannochikara’ at 17 DAF was not increased by high temperature. These results suggest that the heat-stress-tolerant cultivars have various mechanisms for dealing with high-temperature stress. 相似文献
85.
Early planting contributed to increased soybean yields in the U.S. Because a double-cropping system dominates in southwestern Japan, early planting is not performed; it is thus unclear how much the yield potential could be increased by early planting. To address this question, we planted seven U.S. and five Japanese cultivars on around 20 May (early planting), measured the agronomic traits, including yield, yield components, and oil and protein contents, and compared these traits with those of the same cultivars planted on around 20 July (normal planting). In the early planting, the yields of the U.S. cultivars were 322–453 g m?2, whereas the highest yield among the Japanese cultivars was only 315 g m?2, which is significantly lower than those of the top five U.S. cultivars, indicating the adaptability of U.S. cultivars to early planting. The increases in yield obtained with early planting were 99–199 g m?2 and ?26–144 g m?2 for the U.S. and Japanese cultivars, respectively. The yield obtained by early planting was positively correlated with the pods m?2, seeds pod?1, and oil contents, but negatively correlated with the sterile pod rate, 100 seed weight and protein content. In the early planting, the U.S. cultivars had greater pods m?2, seeds pod?1 and oil content and less sterile pod rate, 100-seed weight, and protein content than the Japanese cultivars. These results suggest that early planting can increase the yield in southwestern Japan, if cultivars with agronomic traits observed in the U.S. cultivars of this study are grown. 相似文献
86.
87.
Photoperiod-sensitive cytoplasmic male sterility in wheat with Aegilops crassa cytoplasm 总被引:17,自引:0,他引:17
Summary
Triticum aestivum cv. Norin 26 with Aegilops crassa, Ae. juvenalis or Ae. vavilovii cytoplasm (all D2 type) has been studied relative to its photoperiodic response of male sterility and fertility restoration patterns. Alloplasmic lines of Norin 26 with a D2 type cytoplasm showed almost complete male sterility under long-day conditions (15 h), but high male fertility under short-day conditions (14.5 h). No significant influence of temperature on reduction in male fertility was observed. Thus, this type of male sterility is called photoperiod-sensitive cytoplasmic male sterility (PCMS). The PCMS is expressed in the form of pistillody of stamens. Histological studies revealed that there were incomplete ovule-like structures instead of tapetal cells and pollen grains in the pistillate stamens. The floret differentiation stage of the plant is the stage that is sensitive to photoperiod. The PCMS can be used as a new means for hybrid wheat production, named two-line system. The PCMS line is maintained and multiplied by self-fertilization under short-day conditions, and hybrid seed can be produced by crossing the PCMS line with a pollinator line under long-day conditions. In contrast to the system of hybrid wheat production using the T. timopheevi cytoplasm, the present system requires only PCMS and pollinator lines.Abbreviation CS
Chinese Spring
- N26
Norin 26
- PCMS
photoperiod-sensitive cytoplasmic male sterility 相似文献
88.
黄土高原植被与空气负离子关系的研究 总被引:3,自引:1,他引:2
选择黄土高原常见造林树种,分别对不同林分及植被类型进行空气负离子水平研究。空气负离子浓度以及空气清新度大体为:针叶林明显高于阔叶林;油松林夏季优于秋季;不同植被类型由高到低依次为:花卉绿地>林地>宜林荒草地>裸露地>水泥广场;坡向对空气负离子浓度影响差异不显著。 相似文献
89.
Seed exudates collected from three cultivars (cv. Hokkaikintoki, Himetebou, and Kurodane-kinugasa) of common bean ( Phaseolus vulgaris L.) were fractionated based on several physicochemical properties, and the nutrient substances in the fractions effective for Rhizobium proliferation were determined. Regardless of the common bean cultivars, the low molecular weight and high polarity fraction showed the most beneficial effect on Rhizobium proliferation. After further separation of the low molecular weight and high polarity fraction, the promoting effect was detected in the non-ionic and the cationic plus ampho-teric subtractions. Although the amount of sugars or amino acids exuded from a seed was, respectively, similar in all the cultivars except for the sugars in Kurodanekinugasa, the content of these compounds per seed-weight was inversely proportional to the seed size. Ten sugars and twenty-one amino acids were, respectively, identified in the non-ionic and cat-ionic plus amphoteric subtractions, and there were some differences in the composition of these substances between common bean cultivars. 相似文献
90.
Miyuki Iizuka Yasuhiro Arima Tadashi Yokoyama Koichiro Watanabe 《Soil Science and Plant Nutrition》2013,59(2):219-225
Sufficient rhizobium population in the rhizosphere of legume seedlings is required for early and enough setting of root nodules. Potential of seed and seedling root exudates for proliferation of Bradyrhizobium japonicum PNT119 was evaluated in the soybean cvs. Enrei and Tachinagaha. In both cultivars, seed exudates showed a higher potential than root exudates. In the seed exudates, a low-molecular high-polarity fraction including sugars and amino acids showed a higher potential than both high-molecular fraction and low-molecular low-polarity fraction. The correlations between the sugar or amino acid contents of seed exudates and the number of root nodule primordia at 7 d after sowing were investigated among 12 soybean cultivars. When seeds were inoculated with a low rhizobium density, a high correlation coefficient was detected between them. However, there was no positive correlation in the plants inoculated with a high rhizobium density. These results suggest that the amount of low molecular substances in the seed exudates determines the number of root nodule primordia through rhizobium proliferation around seed and young roots when the rhizobium density is the limiting factor. The genetic trait relating to seed coat secretion should be considered as a possible key factor contributing to adequate root nodulation in soybean seedlings cultivated in fields with a low rhizobium density. 相似文献