巻号一覧
61 巻 (2005)
- 4 号 p. 189-
- 3 号 p. 131-
- 2 号 p. 95-
- 1 号 p. 1-
61 巻, 4 号
December
選択された号の論文の5件中1～5を表示しています
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招待総説（英文）
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Walter LARCHER2005 年 61 巻 4 号 p. 189-202
発行日: 2005年
公開日: 2006/12/27
ジャーナル フリーCold and frost are stress factors of widespread occurrence for plants. They damage woody plants due to chilling temperatures in the tropics, by freezing sensitive plants in regions with episodic frosts and temperatures down to -10℃, and by freezing of even tolerant plants in regions with cold winters below -10 and -40℃. The wide range of frost resistances in plants from different climatic zones indicates that the ability to become hardened to freezing has evolved in a stepwise process. There are opinions how an evolutionary acquisition of freezing tolerance could have taken place in the following way: First there is a differentiation of better adapted ecotypes and in the long term a series of functional plant groups develop along climatic gradients. Frequent climatic stress and climatic changes stimulate the selection of new genotypes resistant to climatic extremes. Furthermore, plants exposed to multiple stress factors in their habitat acquire a general cross-tolerance to climatic constraints.
The objective of this review is the understanding of low temperature resistance in woody plants, e.g. stabilization of biomembranes by lipid composition, deep supercooling, and ability to become freezing tolerant during winter dormancy. An over a hundred year long history of investigating frost stress and survival of different plant species has brought about an important understanding of basic processes. Recently antifreeze proteins which slow the freezing processes, and proteins, which protect the protoplasm against low temperature, frost and dehydration have been discovered. Findings that help to explain the mechanisms for coping with low temperature will be applicable to agriculture, horticulture, forestry and bioclimatology.抄録全体を表示PDF形式でダウンロード (3174K)
研究論文（英文）
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三原 義秋2005 年 61 巻 4 号 p. 203-205
発行日: 2005年
公開日: 2006/12/27
ジャーナル フリー環境への配慮から，燃焼排ガスの脱硫・浄化は重要な課題となっているが，世界中の多くの煙突が酸性雨や環境汚染を発生させている。燃焼排ガスは一般的にSO2と水蒸気を含み，酸性雨の形成と同じプロセスで，SO2を水と結合し酸性水にすることで脱硫ができるはずである。そこで，冷却塔を含む細霧噴霧システムを用いて脱硫の検証を行った。燃焼LPガスとSO2ガスは冷却塔の上部から導入した。その結果，排ガスの温度が水温に近づくにしたがい，脱硫率は高まり，100％に近い脱硫率が達成できることが明らかとなった。塩化ビニルフィルムを燃焼させ，Cl2や黒煙を発生させたところ，細霧の噴霧によって黒煙は白煙に変化した。この簡易で安価な改良により，環境汚染と酸性雨を発生させる煙突が姿を消し，煙突の文字も古語とならむことを！。抄録全体を表示PDF形式でダウンロード (574K) -
植山 秀紀2005 年 61 巻 4 号 p. 207-216
発行日: 2005年
公開日: 2006/12/27
ジャーナル フリー中山間地域のように，多様な日射量分布を示す複雑地形地域の日射環境を評価するには，メッシュ図の作成が有効である。そのため，高解像度のメッシュ日射量分布図を作成する手法が開発されたが，高解像度のメッシュ図の作成には，太陽位置毎の直達，散乱日射量の値が必要である。そこで，アメダスの気象観測値を用いて，直達，散乱日射量の時別値の，月平均値，旬平均値，半旬平均値を推定する手法を開発した。本手法ではまず，日照率，降水量そして水平面大気外日射量の時別値を説明変数とする重回帰式により，直達日射の大気透過率の時別値を推定し，直達日射量を求める。そして，渡辺ら（1983）の式を用いて推定した，散乱日射時別値の無次元指標を用いて散乱日射量を求める。
本手法に必要な，大気透過率および無次元指標の推定式は，潮岬気象台における，全天日射と直達日射の1991～2000年の観測値を用いて作成した。本手法による推定値を，日本の11地点にある気象台の観測値と比較したところ，月平均，旬平均，半旬平均のいずれにおいても，RMSEで0.0～0.2 MJ·m-2·h-1の精度で推定できた。さらに，アメダスポイントから6 km離れた中山間域における直達，散乱日射量の観測値と比較したところ，半旬平均値の場合，気象台における値よりも推定精度は劣ったが，月平均値および旬平均値においては，RMSEで0.0～0.2 MJ·m-2·h-1となり，同程度の精度で推定された。抄録全体を表示PDF形式でダウンロード (1164K)
研究論文
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溝口 康子, 大谷 義一2005 年 61 巻 4 号 p. 217-228
発行日: 2005年
公開日: 2006/12/27
ジャーナル フリーPortable infrared CO2 sensors, such as GMT222 (VAISALA) and LI-820 (LI-COR), are often used for soil CO2 efflux measurements; however, in general, these inexpensive small sensors are relatively inaccurate and slow to respond. The output signals are delayed as a result of diffusion processes in the sample cell and internal averaging calculations to ensure stable data output. Accurate estimations of CO2 efflux require calculating the actual increase in CO2 concentration in a chamber without these composite delays.
Laboratory experiments were conducted to determine the response characteristics of several sensors under two different conditions: diffusion and flow-through. The data obtained in the experiments indicated that attachment of a dust filter substantially delayed the sensor response. Furthermore, the sensor response time under the diffusion condition was longer than under the flow-through condition. When the soil CO2 efflux was calculated using a nonlinear regression method, a long response time led to large CO2 efflux estimation errors; for example, a 10% underestimation occurred when CO2 concentrations were measured using GMM222C with a sampling interval of 300 seconds. We developed a backward estimation method for recovering the actual increase in CO2 concentration from the delayed sensor outputs. Correction of the sensor response with the backward estimation provides an effective solution for achieving an accurate estimation of the soil CO2 efflux using inexpensive sensors.抄録全体を表示PDF形式でダウンロード (1310K)
短 報
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丸山 篤志, 桑形 恒男, 大場 和彦2005 年 61 巻 4 号 p. 229-233
発行日: 2005年
公開日: 2006/12/27
ジャーナル フリーThe Plant Area Index (PAI) of rice, measured indirectly using a Plant Canopy Analyzer (PCA), was compared with that measured directly using a leaf area meter to determine the primary factor that causes the PAI to be underestimated on vertically oriented canopies. Comparison measurements were conducted on several growth stages of the rice in three different cropping seasons; i.e., the usual season (from May to September), the early season (from March to July) and the late season (from June to October) in a warm temperate climate.
The ratio of PAI measured using a PCA to directly (PAIPCA/PAID) showed a seasonal variation from 0.62 to 1.07. The lowest values of PAIPCA/PAID (0.62-0.65) were observed near the flowering time of the rice in all cropping seasons, due to the deviation from random distribution of the foliage as a result of vertically oriented leaves, tillers and panicles. A simple method was proposed to correct the PCA measurements by expressing PAIPCA/PAID as a function of the mean tilt angle of the foliage. The corrected values using this function showed good agreement with the directly measured values. The correction method was confirmed by additional comparison measurements conducted in the usual cropping season in the following year.抄録全体を表示PDF形式でダウンロード (781K)
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