Successional changes in mycorrhizal type in the pioneer plant communities of a subalpine volcanic desert on Mt. Fuji, Japan

Isolated island-like plant communities dominated by the perennial herb Polygonum cuspidatum are typical pioneer vegetation in the subalpine volcanic deserts of Japan. To study the relationship between mycorrhizal associations and plant community development, we conducted a survey of the mycorrhizal status of plants in subalpine island communities in a volcanic desert on Mt. Fuji. Roots of 45 native species, belonging to 23 families, were collected from island communities at 3 different successional stages: (I) pioneer communities dominated by P. cuspidatum, (II) mixed communities of herbs and grass, and (III) mixed communities of herbs and shrubs. Arbuscular mycorrhiza (AM) was the predominant mycorrhizal type in the early stages of community successions (I and II). P. cuspidatum, which had previously been reported as a non-mycorrhizal species, formed AM at the study site. In the later stage (III), 5 mycorrhizal types, AM, ecto-, ericoid, arbutoid and orchid mycorrhizal, were observed. Seven woody species had two types of mycorrhizas (AM and ectomycorrhiza). High spore densities of AM fungi were observed in the soil of the island communities, whereas few spores were observed in bare ground without vegetation cover. The average colonization levels of the AM fungi were within a wide range of 0.1 to 72%, independent of successional progress. These data show that marked increases in mycorrhizal types occur during the succession of island communities, although AM is the predominant mycorrhizal type throughout the successional process

Mycorrhizal status of alpine plant communities on Mt. Maedake Cirque in the Japan South Alps

To clarify the mycorrhizal status of alpine plants, we sampled roots of 33 species from 15 families growing on Mt. Maedake Cirque in the Japan South Alps. Ericoid mycorrhiza, ectomycorrhiza and arbuscular mycorrhiza (AM) were observed in the study site. Colonization classified as ericoid mycorrhizal was observed with Phyllodoce aleutica, Tripetaleia bracteata, Vaccinium uliginosum, Rhododendron aureum, Arcterica nana and Shortia soldanelloides f. alpina, and ectomycorrhizal colonization with Pinus pumila and Polygonum viviparum. AM plants were found in species belonging to the following families: Compositae, Geraniaceae, Ranunculaceae, Rosaceae, Gramineae, Liliaceae, Violaceae, Crassulaceae, Gentianaceae and Campanulaceae. AM was the predominant mycorrhizal type in the study site and average colonization levels of AM fungi were within a wide range of 1.2 to 76.1%. In conclusion, mycorrhizal associations were observed in most (91%) of the plant species examined under the severe climate conditions of the study site

CODESTREAM DOMAIN SCRAMBLING OF MOVING OBJECTS BASED ON DCT SIGN-ONLY CORRELATION FOR MOTION JPEG MOVIES

ABSTRACT This paper proposes a moving objects scrambling method for Motion JPEG movies that consists of two parts: a moving objects detection based on DCT sign-only correlation (DSOC) and a partial scrambling. DSOC is the correlation of the positive and negative signs of DCT coefficients. Utilizing the codestream structure of Motion JPEG movies and the relation between motion and DSOC, the proposed moving objects detection is achieved in codestream domain. The proposed scrambling is also achieved in codestream domain by inverting signs of DCT coefficients that each sign is independently encoded as one bit. The codestream domain processing in this method serves low processing time and keeps coding efficiency. Moreover, the proposed method completely descrambles scrambled codestreams to the original without any knowledge on the position and shape of moving objects. Simulation results show the effectiveness of the proposed method

Soil microbial succession along a vegetation development sequence in a volcanic desert on Mount Fuji, Japan

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月18日（金） 統計数理研究所 3階リフレッシュフロ

Efficient Collusion Attack-Free Access Control for JPEG 2000 Coded Images

This paper proposes an efficient access control method for JPEG 2000 coded images with multiple dimensions of hierarchical scalability. An access control method is required to 1) be resilient to collusion attack and 2) manages less number keys from the perspective of the key management cost. The proposed method is resilient to collusion attack and manages only one key. Moreover, the proposed method reduces the length of managed key in comparison with the conventional methods satisfying above two requirements. This feature serves an efficient key management.APSIPA ASC 2009: Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference. 4-7 October 2009. Sapporo, Japan. Poster session: Image, Video, and Multimedia Signal Processing 1 (5 October 2009)