Determination of the genetic structure of remnant Morus boninensis Koidz. trees to establish a conservation program on the Bonin Islands, Japan

Background  

Morus boninensis, is an endemic plant of the Bonin (Ogasawara) Islands of Japan and is categorized as "critically endangered" in the Japanese red data book. However, little information is available about its ecological, evolutionary and genetic status, despite the urgent need for guidelines for the conservation of the species. Therefore, we adopted Moritz's MU concept, based on the species' current genetic structure, to define management units and to select mother tree candidates for seed orchards.     

Effect of height-to-diameter ratio on stem stiffness of sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) cultivars

The lumber from sugi plantations in Japan displays large intra- and intertree variation in mechanical properties, even within a stand. These variations seem to be induced by the effects of the characteristics of cultivars as well as the effects of growth traits on mechanical properties. Therefore, the effects of growth traits on mechanical properties per cultivar need to be precisely examined. In this study, we focused on the effects of growth traits, especially height-to-diameter ratio (H/D ratio), on stem stiffness per cultivar. Sixteen cultivars were classified into three groups according to the relationships between stem stiffness and growth traits. In cultivars that showed a close correlation between growth traits and stem stiffness, it was assumed that stem stiffness could be controlled to a certain extent by silvicultural practices using the H/D ratio as an indicator. In cultivars that showed a weak correlation between growth traits and stem stiffness, selecting cultivars for the production of logs with higher mechanical properties seemed to be effective; in this study, Kumotoshi, Tanoaka, and Edanaga were found to be suitable. Tree age and site index may be important factors for producing wood with higher mechanical properties.     

Differences in Muscle Fiber Recruitment Patterns between Continuous and Interval Exercises

We evaluated differences in muscle fiber recruitment patterns between continuous and interval training to develop an optimal training program for Thoroughbred horses. Five well trained female thoroughbred horses (3–4 years old) were used. The horses performed two different exercises on a 10% inclined treadmill: 90%VO₂ max for 4 min (continuous) and 90% VO₂ max for 2 min × 2 times with 10-min interval (interval). Muscle samples were obtained from the middle gluteal muscle before and immediately after the exercises. Four muscle fiber types (type I, IIA, IIA/X, and IIX) were immunohistochemically identified, and the optical density of periodic acid Schiff staining (OD-PAS) in each fiber type and glycogen content of the muscle sample were determined by quantitative histochemical and biochemical procedures, respectively. No significant differences were found in the OD-PASs and glycogen contents between the continuous and interval exercises, but the decreases in OD-PAS of fast-twitch muscle fibers were obvious after interval as compared to continuous exercise. Interval exercise may be a more effective training stimulus for the glycolytic capacity of fast-twitch muscle fiber. The data about muscle fiber recruitment can provide significant insights into the optimal training program not only for thoroughbred horses, but also for human athletes.     

Localization of eNOS in the olfactory epithelium of the rat

Nitric oxide (NO) is a free radical and produced from L-arginine by nitric oxide synthase (NOS). Since NO is recently suggested to be involved in olfactory perception, the expression of eNOS, an isoform of NOS, was examined in the rat olfactory epithelium. The activity of NADPH-diaphorase was also examined as a marker of NOS. In the dorsomedial region of the nasal cavity, intensely positive reactions for NADPH-diaphorase were observed in the entire cytoplasm of sensory cells (olfactory cells). By immunohistochemistry, intensely positive reactions for eNOS were also found in the dorsomedial region of the nasal cavity. These reactions were observed on the free border of the olfactory epithelium. By immunoelectron microscopy, positive reactions for eNOS were found in the cilia of olfactory cells. In addition, in situ hybridization analysis of the olfactory epithelium revealed the expression of eNOS mRNA in the olfactory cells. These results indicate the presence of eNOS in the olfactory cells of the rat, and differential expression of eNOS in the olfactory epithelium depending on the regions of the nasal cavity. In addition, NO produced by eNOS may be involved in olfactory perception in the cilia of olfactory cells.     

The absorption and translocation of amino acids and amides in rice plant

It has been well known that the inorganic nitrogen compounds used as the common nitrogen source for the growth of higher plants can be replaced by some organic nitrogen compounds such as amino acids or amides. According to GHOSH and BURRIS (1), who investigated the effect of some amino acids as the nitrogen source, alanine, asparagine, glutamate and histidine were better nitrogen sources than ammonia for clover and tomato plants. For tobacco, however, nitrate and ammonia were superior to all organic nitrogen compounds used. RATNER et al. (2). made the same kind of study by using corn and sunflower plants and reported that the plants could grow with glycine, aspartate, glutamate and arginine, but all of them were inferior to inorganic nitrogen as the nitogen source.     

Effect of nitrogen sources on the chemical components in young plants

Nitrogen nutrition has great influences not only on the yields, but also on the chemical components of the plants. Nitrate nitrogen is generally found to be superior to ammonium nitrogen as the nitrogen source for higher plants (1). As reported in the previous paper (2), young plants of sugar beet grown with the culture solution containing a high level of ammonium nitrogen developed the symptom of ammonia toxicity. To make clear the mechanism of ammonia toxicity, comparative studies on the absorption and the assimilation of ammonium- and nitrate-nitrogen in higher plants at young stages of growth were carried out.     

Characteristics and classification of an unirrigated anthropogenic-alluvial soil found in the Kumamoto Plain

In Japan anthropogenic-alluvial soils excluding irrigated rice soils are lagging for behind other genetic soil types in pedological investigations. Although there are some investigations of anthropogenic-alluvial soils used for mulberry plantations, orchards, vegetable gardens, and seeding beds for trees, the main object of these investigations is not pedological. Kanno et al. (1) reported that unirrigated anthropogenic-alluvial soils used for vegetable growing in the Chikugo Plain resemble the “Alochthonous brown warp soil” defined by Kubiena (2). First of all, it is of great importance to accumulate general data for unirrigated anthropogenic-alluvial soils and to develop the classification principles for them. Classification problems will be settled in accordance with the accumulated data. This paper deals with characteristics of an unirrigated anthorpogenic-alluvial soil found in the Kumamoto Plain and with classification principles for it. These principles have almost never been described for a pedological standpoint in Japan.