Leaf age sturucture at different light conditions was studied for 14 evergreen broadleaved tree species from October 9 to December 27,1989,to clarify differences of leaf longevity among species and light conditions. The patterns of the leaf age compositions of the observed species for each light condition were compared with each other and divided into 4 groups. The species, whose pattern of leaf age composition changed with light condition, changed their position into the group with higher age leaf under more shaded conditions. The mean maximum longevities became longer under more shaded condition for most of the species. Camellia japonica, Cinnamomum insularimontanum, Cleyera japonica, Photinia glabra and Aucuba japonica, grown under a lower tree layer with a shaded environment, were assumed to have a longer leaf longevity than other species. Ilex pedunculosa, Ilex chinensis and Cinnamomum Camphora, found even in the early stage of succession with light environment, were assumed to have a shorter leaf longevity than other species. Quercus glauca, Quercun salicina and Quercus acuta, from among the species possible to dominate in a tree layer of the climax forest, were assumed to have a shorter leaf longevity than other species. The last group of species was assumed not to be adapted to a shaded environment.

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This paper shows the relation of chemical forms of nutrients between river and seawaters in Kagawa prefecture and the Bisan-seto sea and the sea of Harima-nada. We obtained the following results: 1) the ratio of nitrogen of river waters was DIN:DON:PON = 63:17:20 and that of seawaters was DIN:DON:PON = 19:69:12. This means that the chemical forms of nutrients between river and seawaters were different, and 2) the ratio of phosphorus of river water was DIP:DOP:PP = 43:21:36 and that of seawaters was DIP:DOP:PP = 60:16:24.

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In the northeastern Shikoku, the Asan Mountainland, whose southern boundary coincides with the Median Dislocation Line dividing southwestern Japan into the Outer and the Inner Geological Zones, is a recently elevated massif preserving several steps of relatively flat erosion surfaces on its foot.
The writer tried to make clear the Plio-Pleistocene tectonic movement of this mountainland through the study of these erosion surfaces. He classified these surfaces into 3 grouper, where sedimentary remnants are classfied into 6 layers on the northern side and 9 on the southern side of the massif. Moreover, 6 types of the conditions of contact between each surface and other ones are identified. Analysing these geomor-phological factors and fault structures, the writer reaches the following conclusions.
The Asan Mountainland is presumabjy a tilted block with some fresh fault scarps on its southern side as on the northwestern side, and has swollen up as a landwave of pitching with an axis upwarping at its central part linking Inohana with Sarusaka. Thus, the central part of the massif has been brought higher than its western or eastern ends. The movement mentioned above develops a system of radial faults with such depression areas as some parts of Takamatsu and Marugame Plain.
Considering the fresh fault cutting the lowest terrace gravels seen on the southern side of the mountain, this orogenic movement may have continued to grow up to the recent time.

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　陸域から海域への流入負荷量の推定は，主要な流入経路となる河川を中心に行われているが，流域に観測データが揃わない中小河川や沿岸流域を含む場合に，データの豊富な主要河川のみで推定をすると，自然環境や負荷発生源の分布，利水状況等の流域特性の相違が十分に反映されない。そこで，瀬戸内海に流入する岡山，香川流域を対象に負荷発生源から算定した排出負荷量を統合して流入負荷量の推定を試みた。平均的な降水年の2003年では，主要河川に基づく推定に対し，岡山県の児島湖流域，の中小河川を別途推定した場合では，主要河川との比負荷量や流達率の相違が反映され，負荷量は岡山流域で増加，香川流域では減少した。さらに原単位法で発生源別に算定した沿岸流域の排出負荷量を統合した場合では，沿岸流域の工業地帯や市街地の負荷量が反映され，河川データに基づく推定に対し，岡山流域では全窒素，全リン，CODが164，189，121%に増加し，香川流域では全窒素で252%と増加したが，全リン，CODは98，72%と減少し，水質項目による相違も大きかった。観測データと排出負荷データの統合により，流入負荷量の推定精度の向上が図れた。

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讃岐平野は大和・近江平野と並んで条里遺構が顕著に遺されていることで知られている。この条里遺構は土地基盤整備と密接な関係にある。本研究ではこの条里遺構を, 生産を規定する農業基盤の視点から捉えることとした。そこで讃岐平野における条里遺構分布を地理的に把握・計量し, その歴史的背景を古代条里制開拓として究明する一方, その地割がかなり乱れていて, 不整形地割になっていることの原因の解明を行った。また条里遺構地域では地割が不整形であるうえに, 圃場整備が実施困難で整備が遅れているために, 農業の生産性が停滞していることを指摘した。

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1.オオセッカについて過去に発表された文献をもとに,本種の分布および生態をまとめて,本種の保全についての提言を行った。
2.オオセッカは,宮城,東京,神奈川,埼玉,茨城,群馬,千葉,静岡,愛知,香川,徳島,兵庫の1都11県で越冬期に記録され,青森,秋田,宮城,茨城,千葉の4県で確実な繁殖記録があった。
3.今まで確認された生息地のうち,1993年現在,繁殖期の生息が確認されているのは,秋田県八郎潟,青森県内の屏風山地域,岩木川河口,河口,仏沼周辺,北関東の利根川下流域,霞ヶ浦浮島湿原の7ヵ所で,およそ1000個体が現存すると推定されている。
4.オオセッカは,東北地方では4月下旬に渡って来る昆虫食の夏鳥で,一夫多妻の繁殖システムをもち,平均一腹卵数は4.88±0.62(30)卵であった。本種は,いずれの繁殖地においても,ヨシが混在し,下層にスゲやイが存在する2層構造をもつハビタットに生息していた。
5.オオセッカの個体群は大きく変動し,青森県八郎潟や青森県屏風山地域では減少し,青森県仏沼や岩木川河口では個体数は安定し,最近,利根川下流域や霞ヶ浦浮島では増加している。
6.非繁殖期にはヨシ原にひそみ観察しづらいため,越冬期の生態については詳しくわかっていない。
7.オオセッカは,本来,河川敷などの攪乱を受けているハビタットに適応し,好適なハビタットがあれば定着して短期間に高密度の個体群を形成し,ハビタットが不適になれば他の場所へと個体群を移していくという戦略をとっているのかもしれない。
8.オオセッカの保全上必要と考えられる個体群生態学,集団遺伝学および越冬生態についてのデータはまだ不足している。本種の越冬地や渡りの中継地をも含めた総合的な保全を行なっていく必要がある。

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The local meteorological observation was carried out at Takase Basin and the south west slope of Osa Mountain, Kagawa Prefecture on clear-fine day in winter, Jan. 19-21, 1988.
The cold air lake was observed at the bottom of Takase Basin and the thermal belt observed at the slopes of 100-500m of Osa Mountain and 100-200m of Asahi Mountain. The vertical differences of both air and surface temperatures for the typical inversion layer were 6-7°C and about 10°C, respectively, and the thickness of the inversion layer was 80-100m at the basin bottom. In the case of small cold air current, the cooling seemed to be larger, because the air current was easy to stand on the gentle slope. The pan-type distribution of isotherm was recognized at the basin.
The change of wind direction and the frequency of weak wind of 1m/s were higher at the basin bottom. The cold air current of 1 to 3m/s was observed at the slope and its wind speed was relatively heigher at the lower region of the slope. The cold air current seemed to blow from the elevation of about 400m. The stronger the wind speed of the air current was, the higher the air temperature was at the foot of the mountain, however, the air temperature seemed to be constant in the case of wind speed over 3m/s.
The relative humidity and the appearance frequencies of dew and frost were higher at the basin bottom, but lower at the slope and the foot of the mountain in the case of cold air current. The air was dry and its temperature was high at the observation base of 160m in the blowing period of cold air current. The amounts of dew and frost were few, and the latent heat flux by evapotranspiration was occasionally released from the soil surface even at night. As the cold air current blowing from the thermal belt is the warmer wind at the slope and supplies the sensible heat to the crop at the foot of the mountain, its utility is high as meteorological resources along with the thermal belt.

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Osmotic concentrations and NaCl contents of expressed vegetable saps of some halophytes and the conditions of the soils covered with their vegetations were investigated (osmotic concentrations were determined in cryoscopic method), with results as shown in the following table.
As will be seen from the foregoing results, Salicornia herbacea is distinguished from the other plants under investigation not only by the highest osmotic concentration and the greatest amount of NaCl content of its sap but also by the highest salinity of the soil where it grows. From this we may conclude that among the investigated plants, Salicornia herbacea is the strongest, and Statice japonica, Suaeda maritima, and Suaeda japonica are less strong in their halophytic characters.

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阿讃山地に発達するPedimentを検討した結果はつぎのとおりである.
1) Pedimentの発達は地質的には花崗岩の上に讃岐層群が位置することが条件となっている.しかしこれは必要条件ではあるが十分条件ではなく,さらにこれら二つの岩質の境がある高度より高いこと,斜面の侵蝕基準面が安定していることがあげられる.
2) 花崗岩と讃岐層群との境がある高度より低くなるといわゆるtalus slopeが直接段丘やその他の下位の面に続きPedimentはみられなくなり,反対にこの境が高くなるほどPedimentは大きくなっている.
3) 花崗岩類中にホルンヘルスの砂岩などが狭在し,これが鋭敏にPedimentに影響しPedimentが乱されている部分がかなりみられる.
4) 斜面の四要素である山頂平坦面, free face, talus slope, pedimentが明瞭に発達している.
5) Pedimentは瀬戸内沿岸部で標高約40mの段丘に続いており, Pedimentの形成時代はこれらの段丘の形成された時代と時期的に重なる部分があったか,あまり離れない時代に形成された.

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　汽水域は，多種多様な汽水域特有の生物の生息場であるが，人為的環境改変の影響を受けやすい場所であるため，保全や自然再生が課題となっている．本研究では，汽水域において，環境指標として注目されているハゼ類に着目し，瀬戸内海に流入する河川の汽水域においてハゼ類の分布調査をおこない，そのデータを用いて相補性解析をおこなうことにより，保全上重要であると考えられる河川を抽出することを試みた．その結果，瀬戸内海全域を解析対象とした場合は，ランク上位47河川を保全対象に設定すれば，全種の生息地のうちの50％以上をカバーできることが示された．これらの河川に，地方別で解析した際に抽出された18河川を加えた65河川が，瀬戸内海における保全上重要な河川汽水域であるといえる．

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To examine correlations between SS transport L and river discharge Q in Japan, we develop a database for SS and river discharge in Japan under low- and high-flow conditions by collecting previous field data. In addition, we present a new approach to evaluate a sediment rating curve (L=aQ^b) using the database and statistical analysis. The results indicate that the coefficient b was mostly 1.6 to 2.0 which was slightly lower than previous results (b=2). The SS fluxes in mountain rivers were on the whole larger than those in other rivers, showing appreciable dependence of the L-Q relations on land use of watershed. We confirmed the fundamental validity of the present approach through the comparison with observed data.

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