数種の花粉膜における各膜層の表面微細構造(林学部門)

この報告は花粉膜における各膜層の表面微細構造についての電子顕微鏡による研究結果の一端である。供試料は5種であり, 実験結果の大要はつぎのとおりである。1.トガサワラ花粉において, perine, ectosexine及びendosexineの3層の表面構造を明らかにした。すなわち, perineは粒状物, ectosexineは平かつ, endosexineは刺状物或いはイボ状物である。2.ツガ花粉において, ectosexine, endosexine及びnectosexineの3層の表面構造を明らかにした。すなわち, ectosexineは指状物, endosexineは刺状物或いはイボ状物, nectosexineはイボ状物である。3.Cupressus goveniana花粉においては, 5層の表面構造を知りえた。すなわち, perineはコンペイトウ型粒状物, ectosexineは刺状物, endosexineはほとんど平かつ, ectonexine及びmesonexineもendosexineと同様である。4.ヒノキ及びカリトリス花粉においては, うえに述べたCupressus goveniana花粉と同様の結果が認められた。5.これまでの実験結果から, この処理法の適用範囲をつぎのように分類した。A)容易なもの;Cunninghamia, Callitris, Thujopsis, Thuja, Chamaecyparis, Cupressus及びJuniperus. B)普通;Taxus, Torreya, Cephalotaxus, Larix, Tsuga及びCryptomeria. C)困難なもの;Picca, Abies及びPinus.The present paper deals with the fine surface structure of the stratified membrane in some pollen grains-Gymnosperm. The materials used in this study are the pollen of 5 species (Pseudotsuga japonica, Tsuga sieboldii, Cupressus goveniana, Chamaecyparis obtusa and Callitris robusta). The summary of the results is as follows : 1. In the pollen of Pseudotsuga japonica, the writer were able to clarify the fine surface structure of 3 layers (perine, ectosexine and endosexine). Namely, perine granular, ectosexine smooth and endosexine spinols or verrucoid. 2. In the pollen of Tsuga sieboldii, we were able to recognise the fine surface structure of 3 layers (ectosexine, endosexine and nectosexine). Namely, ectosexine finger-like projection, endosexine spinolsoor verrucoid, nectosexine verruciod. 3. In the pollen of Cupressus goveniana, we were able to know the fine surface structure of 5 layers. 1st layer (perine orbiculus), 2nd layer (ectosexine spinols), 3rd layer (endosexine almost smooth), 4th and 5th layers (ectonexine and mesonexine are similar to that of endosexine). 4. In the pollen of Chamaecyparis obtusa and Callitris robusta, we have realised the results as like as that of Cupressus goveniana, as the above mentioned. 5. From the experimental results until now, we classify the range of application of this method as follows : A) Good; Cunninghamia, Callitris, Thujopsis, Thuja, Chamaecyparis, Cupressus, and Juniperus. B) Passage; Taxus, Torreya, Cephalotaxus, Larix, Tsuga and Cryptomeria. C) Difficult; Picea, Abies and Pinus

スギ化石花粉の表面微細構造に関する研究

The pollen of plants has the trace of its original form as the fossil in coals and partial sedimentary rocks. It is thought that the pollen grain fallen into peat bog is gradually following up the process of fossilisation in the present time. How the surface structure of the pollen changes in this process, has an important significance for the identification of the fossil pollen in palynology, as well as for the studies on the fossilisation of the pollen. From this point of view, the writers have selected the Alluvial peat as the material, and attempted the observation by means of electronmicroscope based on the replica method. The materials were taken from the peat layer of Tashirogata bog in Kokakeyama national forest, Nibuna, Todoroki village, Yamamoto-gun, Akita prefecture, at the depth of 1.0m from the surface of the bog. The summay of the results is as follows : 1) The surface of the modern pollen of Cryptomeria japonica is covered all over with granules of the "confetto type" (their diameter being about 0.2∿0.8μ). However, on the surface of the fossil pollen of Cryptomeria japonica no granules of the "confetto type" could be detected. From this point of view, it is thought that the granules above mentioned were separated from the surface of the grain in the fossilising process. 2) And next, we were able to clarify that the texture, after the separation of granules of the "confetto type", of both the modern pollen and the fossil pollen is different between the germinal zone and the other parts. This is important for the identification of both the modern and the fossil pollen. Especially, the texture, after the separation of granules of the "confetto type", of the modern pollen shows fine spinuies (G. Z. : 0.1μ and B : 0.1-0.3μ), while that of the fossil pollen shows fine dotted varrucae (G. Z. : 0.1μ and B : 0.1-0.3μ). 3) From the experimental results (optical and electronmicroscopic) as described above, the writers were able to identify the fossil pollen detected in the Alluvial peat as that of Cryptomeria japonica. 4) This is an example of the pollen of Cryptomeria japonica, but if the study of this kind will be advanced in the future, there will be abtained the result important for the identification of genera or species of fossil pollen of many kinds

花粉膜の表面構造に関する電子顕微鏡的研究 VI : 裸子植物篇 1

The writers have been engaged in the electronmicroscope investigations on the fine structure of pollen membrane, based on the replica method, and they already published the reports I∿V on their results. The series of this study is, from now on, to be divided into the part of gymnospermae and that of angiospermae. The present report gives the fine structure of the surface of pollen membrane of 5 species, as the 1st report treating the part of gymnospermae. The summary of the results is as follows : 1. Pollen of Cycas revoluta THUNB. : in the dorsal view, the surface of pollen membrane is scattered with many irregularly round-shaped concaves (perhaps small openings), and the protrusions among them show the pattern of fine waves. The longer diameter of the concaves is about 0.2∿0.3μ. In the ventral view, the almost same pattern as in the dorsal view is recognised, but it has the tendency to some decline. On the surface of the germinal furrow are recognised protrusions of irregular meshes. The width of the protrusions is about 0.2∿0.4μ. 2. Pollen of Ginkgo biloba LIN. : on the surface of pollen membrane are arranged irregular protrusions, which are covered all over with linear projections. The tops of these linear projections are pointed, and show spinule-like features. The height of the linear projections in the dorsal view is about 0.1∿0.2μ, and their length is irregularly between 0.2 and 2.0μ. The surface of the membrane of germinal furrow is dotted with spinules or granules, and with faint linear projections at the same time. The length of the linear projections is about 0.2∿1.0μ, the height of the spinules about 0.1∿0.2μ and the diameter of granules about 0.5μ. 3. Pollen of Podocarpus Nagi PILG. : the surface of the body shows the protrusions of the "cauli-flower type", and from their surface are projected fine spinules about 0.1μ long. Besides, the surface of air-filled bladders is comparatively smooth, but we can recognise fine spinules as in the case of the body. The germinal furrow shows an irregularly elliptical form, and on its surface are found the spinules, which are finer than those on the surface of the body. Among the spinules are recognised irregular protrusions. 4. Pollen of Keteleeria Davidiana BEISSN. : the surface of the body is covered with the protrusions of the "cauli-flower type", and some of the protrusions show the similar forms to those of pila. The surface of the protrusions has fine spinules (about 0.1μ) projected from it, and is dotted with small openings (about 0.1μ). Also, we could recognise fine spinules (their height is about 0.1∿0.3μ) and small openings (their diameter about 0.1μ) on the surface of air-filled bladders. 5. Pollen of Pseudolarix Kaempferi GORD. : the surface of the body is covered with the protrusions of the "cauli-flower type", and fine spinules (their height is about 0.1μ) are projected from their surface. Also, the surface of air-filled bladders is irregularly uneven, and is dotted all over with fine spinules (their height is about 0.1∿0.2μ) and small openings (their diameter about 0.1μ)

花粉膜の表面微細構造によるツガ及びカナダツガの類別について(林学部門)

この報告は, 花粉膜の表面微細構造によるツガ及びカナダツガの類別について述べるものである。供試料は, Micropeuce (Eutsuga)に属するツガ及びカナダツガの2種である。実験方法は, 筆者が1956年来適用しているMethylmethacrylate carbon 2段replica法によつた。実験の結果, 下記の諸点を明らかにすることができた。1.ツガ花粉 : cap及びgerm furrowの表面は不規則に配列した隆状突起によつておおわれ, さらにそれより大きさの異なつた指状物が突出し, その間にごく小数ながらイボ状物の存在が認められる。とくに指状突起物は軟弱なためか, 曲りやすく, しかもほとんどはく離しない。一方, marginal ridgeとgerm furrowの連結部の膜面は, 微小なしかも不規則な突起物によつておおわれている。これはcap及びgerm furrowの表面と全く異なつた構造を呈している。また, Photo. 3に示した如く, germ furrowの中央部にnarbeの存在を確認することができた。narbeの表面は, へいかつである。指状突起物の長さは約0.3∿2.1μ, 連結部膜面の突起物の長さは約0.1∿0.2μ, またnarbeは長径約7.5μである。2.カナダツガ花粉 : capの表面は花野菜型の隆起でおおわれ, その表面には微小な刺状突起をそなえている。またgerm furrowの表面には, 大きさの異なつた粒状隆起が存在し, さらにその表面には微小な刺状紋を有しており, 粒状隆起の間には不定形の隆起が認められた。capとgerm furrowの連結部の模面構造はツガ花粉と同様である。Photo. 6に示したように, ツガにみられたnarbeが見出しえられなかつた花野菜型隆起部上の刺状紋の長さは約0.1μであり, 粒状突起物の直径は約2.4∿2.0μで, またその表面に存在する刺状紋の長さは約0.1μである。以上述べた諸点で明らかなように, ツガ及びカナダツガ花粉の微細構造は, いちじるしく異なつている。なおPhoto. 7に示したイボ状構造は, ectosexineより下の層の表面構造である。筆者は, ツガ花粉のsexineは3つの異なつた表面構造をもつ層から成り立つているのであろうということを推定した。The present paper deals with the classification between Tsuga Sieboldiana and Tsuga canadensis, based on the fine surface structure of pollen membrane. The matrials used in this study are the pollen of 2 species, such as Tsuga Sieboldii CARR. and Tsuga canadensis CARR. belonging to Micropeuce (Eutsuga). The experimental method depends upon the methylmethacrylate-carbon 2 stage replica, which was used by the author since 1956. As the result of the electronmicroscopic investigation, he could clarify the following points. 1. Pollen of Tsuga Sieboldii CARR. : the surface of cap and germ furrow is covered all over with irregularly arranged protrusions, and finger-like projections which are different in sizes, rising from their surface. Especially, their projections are pliant, probably on account of their delicate nature, and they cannot, in most cases, be separated from the surface of the grain. Besides, the surface of the combined parts between marginal ridge and germ furrow of the grain is covered with fine and irregular projections. As shown in Photo 1,we can seen the different structure of the surface pattern of cap, and germ furrow. As given in photo. 3,he could recognise the existence of narbe in the central part of germ furrow. The surface of narbe is very smooth. The length of finger-like projection; about 0.3∿2.1μ, the length of projection of surface membrane in the combined parts; about 0.1∿0.2μ, and long diameter of narbe; about 7.5μ. 2. Pollen of Tsuga canadensis CARR. : the surface of cap is covered all over with protrusions of the "cauli-flower type", and they are possessed of projection of fine spinules on its surface. Also, on the surface of germ furrow were seen grain-like projections in different sizes, and fine spinules on its surface. Moreover, protrusion of amorphus in that of grain-like projection were recognised. The structure of the combined part of cap and germ furrow are similar to those of Tsuga Sieboldii pollen. As given in photo. 6,there is no find of narbe as are found in Tsuga Sieboldii pollen. The length of spinules (on protrusions of the "cauli-flower type"); about 0.1μ, diameter of grain-like projection; about 0.4∿2.0μ, and the length of the spinules existed in their surface; about 0.1μ. As mentioned above, it is clearly seen that the fine structure between the pollen of Tsuga Sieboldii and of Tsuga canadensis were considerably different. Moreover, the verrucate structure as given in photo. 7 shows the surface structure of the under layer of ectosxine in sexine stratification. It has been estimated that sexine of Tsuga Sieboldii pollen consist of three layers each different in the fine surface structure

Coix 属の改良に関する育種学的研究 (III) : Coix 属及び Zea 属の花粉膜の表面構造について

筆者らは現在改良試験を実施中であるCoix属のハトムギ, ジュズダマ及びそのF_1雑種, 更にその四倍体植物の花粉を, Zea属のトウモロコシ花粉と共に薬品処理による花粉膜の光学顕微鏡的観察と, Carbon Replica法の適用による花粉膜の表面微細構造の電子顕微鏡的観察を行い, 両者の比較を行つた。1.光学顕微鏡的観察 光顕像においては, 供試植物の花粉の間には, 花粉粒の大きさ以外に形態学的差異は観察されなかつた。発芽孔は一つであり, 花粉膜はextineが薄くintineが厚く観察された。また発芽帯周辺は一般に厚膜であり, 花粉の変形, 壌裂は極の方に多い。発芽帯には乳状突起が観察された。2.電子顕微鏡的観察 電顕像による花粉のextexineの微細構造は, 供試花粉ではいづれも微細なspineによつておおわれ, 各種間に明らかな差は認められない。ただCoix, Zea両属間にはspineの大きさにおいて, Coix属内の各種間には形状においてやや差が認められるようである。発芽帯の状態は, トウモロコシでは乳状突起の中心に, spineをもつ隆起部が発達し, ハトムギ及びジュズダマでは共にこの隆起部はなく, わづかなうねりをもち, なお乳状突起には不規則に少数のspineが点在していた。しかし, このspineをもつ隆起部は, F_1及び四倍体植物においては著しく発達していた。発芽帯の孔径は, 四倍体は二倍体に比して著しく大きかつた。一般にCoix属とZea属の花粉表面構造の間には, きわめて高度の類似性が認められた。The morphology of pollen is investigated as a main section of palynology. In the present time the studies on the surface structure of pollen are paid special attention to make progress of the pollen analysis. The present paper deals with the results of microscopic and electromicroscopic investigations on the surface structure of the pollen membrane. The materials used in this studies are the pollen of Zea mays, Coix Ma-Yuen, C. Lacryma-Jobi, F_1 plant (C. Ma-Yuen×C. Lacryma-Jobi), 4x F_1 plant and 4x C. Ma-Yuen. The pollen used in the microscopic observation was treated by HCI and NaOH previously and electromicroscopic observation was based on the carbon replica method. 1. Microscopic observation : The morphological difference of pollens between the material plants was not recognized except the diameter of these pollen grains. The pollen of Zea and Coix plant are apaturate pollen similarly other gramineae plants. The extine of pollen membrane was thin but the intine was observed very thickly, These pollens have thick membrane around a germinal zone, for that reason the transformation and the bursting of pollen occurs near the pole of pollen, In germ pore of pollen grain the papilla was observed slightly. 2. Electromicroscopic observation : According to electromicroscopic observation, the extexine of pollen membrane was covered with fine spinules, there were no significant differences between the material plants on the surface structure of the pollen membrane. It is, however, obviously to the slight difference were recognized in the size of spine between the genus Coix and Zea, and in the shape of spine between the each plants in genus Coix. In the state of germ pore, there are fairly different between the material plants. In the germ pore of Zea pollen, the protrusion with fine spinules was well-developed in the central part of papilla, on the contrary, in the Coix Ma-Yuen and C. Lacryma-Jobi a few spines are dotted irregularly on the whole surface of slight concaved papilla. The protrusion with fine spinules was not found in the other pollen of C. Ma-Yuen and C. Lacryma-Jobi. But the protrusion was well-developed in the pollen of F_1 plant, 4x F_1 plant and 4x C. Ma-Yuen. The diameter of germ pore of 4x Coix pollen was larger as compared with that of 2x Coix pollen. As the results of these experiment it wes revealed generally that the similarity between the surface structure of pollen membrane of genus Coix and Zea was very closely

コナラ成熟林における繁殖器官各部の乾物生産と種子生産における花粉粒及びめ花数の関係(林学部門)

樹齢100∿150年生のコナラ成熟林において1982,83年の繁殖器官各部の生産量を測定し, 考察した。この林分斜面は南向きで急傾斜(平均34度)である。花粉以外の各部生産量はリタートラップ法により, 花粉は開やく前の雄花序につく花粉量調査を併用し, 乾重と個数について推定した。乾物生産量は1982年が300kg/ha・y, 1983年750kg/ha・yで, 雄性も雌性の部分も1983年の方が多く, とくに種子の増加が著しかった。豊作年には乾物生産量全体に占める雌性部分の割合が高く(55%), 凶作年には低かった(20%)。1983年の種子豊作は開花しため花数が増加したこと(2.6倍)と結実率が高かったこと(2倍増加)によりおこった。この結実率の増大は花粉粒の生産個数のそれ(1.2×(10)^⇾1.6×(10)^no./ha・y)に対応していた。一方, め花数に対する花粉粒数の比には両年度の違いは小さく, これはスギ, ヒノキ, オニグルミの林分で認められている結果と一致した。Annual production rates (by dry weight and number) of each component of reproductive organs in a Konara oak (Quercus serrata THUNB.) mature stand, which consisted of trees 100-150 years old, were measured in 1982 and 1983 and analyzed. The slope of the studied stand faced south and was steep (mean inclination : 34°). Production rates per 1-ha stand for each component except pollen were determined using ten litter traps (each measuring 0.5×0.5m), while for pollen, this was done together with measurement of the amount of pollen contained in catkin samples before anther opening. The dry matter production rate of all reproductive parts including pollen in 1982 and 1983 amounted to 300 and 750kg/ha・y, respectively; the increase in 1983 was recognized in both male and female parts, especially acorns. In abundant crops the proportion of female parts to the total production was high (50%), while in poor crops, the proportion was low (20%). The higher production of acorns in 1983 compared with 1982 was caused by an increase in both the potential number of female flowers (2.6 times) and the ratio of fruits which matured (2 times). Changes in the seed-maturing ratio, i.e., the proportion of female flowers developing into mature and sound acorns, was related to the pollen production rate, which varied from 1.2×(10)^ to 1.6×(10)^ grains/ha・y. Little difference between the two years in the ratio of the number of pollen grains to female flowers was found, which agreed with our previous findings for Sugi (Cryptomeria japonica), Hinoki (Chamaecyparis obtusa) and Siebold walnut (Juglans ailanthifolia) stand

生殖器官の生産量からみたシイ林の有性生殖(林学部門)

松尾大社(京都市嵐山)の境内のシイ成熟林において, リタートラップ法で1986年∿1989年の生殖器官の生産量(林分当たり)を測り, また花粉生産量は開花前の雄花序当たり花粉量を基に推定した。これらの諸量を検討し, 有性生殖についてえた主な結果は次の通りである。花粉生産量は重量(218∿359kg (ha)^ (yr)^)では最大クラス, 粒数(64.2∿103×(10)^(ha)^ (yr)^)では突出して多く, しかも年次変動が小さかった。この莫大な花粉数は, しかし, 胚珠数に見合ったものであった(花粉/胚珠の数比, 4.1∿8.3×(10)^5)。花粉粒は小形であるから(1.94∿4.30×(10)^mg), 同化産物の花粉への流れは節約されている。開花年ごとの乾物量は1609∿1803kg (ha)^で, 雄性と雌性の部分量は逆比例の関係にあった。年度ごとの乾物生産量は1237∿2204kg (ha)^ (yr)^の範囲で, これは種子の並作∿凶作の年の値である。この生産量の多少と各部分の割合との間には, 一定の傾向はなかった。これは種子成熟に2カ年を要することに関係がある。また, 当年生と1年生の部分の生産量は等しくなる年が多かった。結実率は低いが(5.5%∿10.6%), ほかの種と大略等しい。年々の種子数は結実率と並行して推移し, 総雌花数も種子生産に関係があるようだ。種子対投資の重量比は種子の並作年に3倍, 凶作年6倍で, これはほかの重力散布種子の種の値と一致した。In a mature stand of Shii chinkapin (Castanopsis cuspidata SCHOTTKY) at Matsuotaisya shrine, Arashiyama, Kyoto, annual production rates of reproductive organs were studied using 20 litter traps (each 50cm×50cm in mouth area) in 1986-1989,and those of pollen were estimated by multiplying the number of fallen male catkins per ha per year by the mean amount of pollen per catkin before anthesis. The main results were as follows. The pollen production rate of 218-359kg d. w. (ha)^ (yr)^ was one of the highest among other species, and that of 64.2-103×(10)^(ha)^ (yr)^ was by far the largest number; moreover, these showed small year-to-year fluctuations. Such a huge number of pollen grains, however, was balanced by the number of ovules in a stand (numerical ratio of pollen grains to ovules : 4.1-8.3×(10)^5). The light pollen grains (1.94-4.30×(10)^mg d. w.) save the assimilation products invested in pollen formation. Dry matter of reproductive organs by the year of anthesis was within the range 1609-1803kg d. w. (ha)^, and those of male and female parts were inversely proportional to each other. Annual production rates were within the range 1237-2204kg d. w. (ha)^ (yr)^, equivalent to values in years of average to poor seed crop. There was no relationship between the annual production rates (by weight) of male and female parts, because fruit maturation requires two growing seasons. In three years among four, the 0-and 1-yr-old parts showed equal dry weight allocation. Seedmaturing ratios or numerical ratios of mature nuts to total female flowers were small (5.5%-10.6%), being approximately equal to those of other species. The year-to-year trend in nut production (by number) parallelled those of seed-maturing ratio and the number of female flowers. Mean nut weight vs. assimilation products necessary for producing a single nut, calculated by dividing the drymatter production rate of overall parts by the number of nuts, was 1 : 3 in a year with an average seed crop, and 1 : 6 in a year with a poor crop. This seed production effort was similar to those of five other barachorous species

樹幹の振動および固定がハンノキ属 2 種の成長におよぼす影響(林学部門)

落葉広葉樹ハンノキ属の2樹種の若木について, 3とおりの機械的刺激 : 振動, 固定, および自然(対照)を樹幹に与えて, 約1生育期間の成長への影響を調べた。実験結果を要約するとつぎのとおりである。1)振動によって樹高成長は減少, 直径成長は増加し, そしてH/Dは減少した。生枝下部の幹断面積成長は, 振動で下方ほど著しく促進された。しかし樹冠内では振動の影響はあらわれない。固定すると生枝下部で減少し, 樹冠内での増加が著しい。2)処理期間中の年輪成長幅は, 振動方向の増加が樹幹全体であらわれた。この傾向は下方ほど大きい。3)根重および根の割合は振動によって増加した。とくに支持根で著しい傾向があり, しかも振動方向に発達して耐振動性が大きくなった。4)全樹体, 地上部, 幹枝葉の各重量に対する処理の影響はばらばらであったが, 振動で乾物生産が減少することはなかった。幹枝葉のしめる割合は振動によって顕著な変化があらわれない。T/Rはヤシャブシで処理効果がなく, ヤマハンノキの実験では振動自然>固定で各10%差だった。The effects of three mechanical stimulations : shaking, staying, and free-swaying (control), on the growth and development of young alder trees were studied. The period of the treatments was from 72 to 108 days. The summary of the results are as follows. 1) The shaking reduced height growth, enhanced diameter growth, and consequently decreased the ratio of height to diameter. Stem crosssectional area increment on clear bole was markedly increased by shaking, with the increase toward the stem base. The stayed trees showed a pronounced upward shift of increment, at the expense of downward stem parts. 2) Trees responed to unidirectional shaking by producing larger diameter increment along the shaking direction throughout their length, with increasing on the lower stem. 3) The effects of shaking affected growth by altering weight and percentage of roots, especially for larger roots more than 0.2cm in diameter. The root system was reflected by the development in direction to the stem shaking. 4) Although the evident tendency of the effects of the mechanical treatments on the dry weight of stem, branches, leaves, above-ground parts, and a whole tree has not become visible, the shaking did not reduced dry matter production. With the exception of root growth, the shaked and stayed trees did not alter the distribution of dry weight of each organ within the tree. The ratio of above-ground parts to root of a Alnus firma tree was not affected by shaking, but for A. hirsuta var. sibirica, the value resulted in decrease for shaken trees and in increase for stayed. 5) In the stayed treatment where A. hirsuta var. sibirica trees were prevented from swaying throughout their length, the stem bending was observed after the tree stakes were removed. Mean bulk density of stems spaned a range from 0.37g/(cm)^3 for shaking to 0.31g/(cm)^3 for staying

シイ林における生殖器官各部の生産量と種子生産に影響する要因(林学部門)

京都盆地をとりまく低山帯のシイ5林分を対象にして1982,83年の林分あたり雄花, 花粉, 果実の生産量(乾重と個数)をトラップ法で調査し, 開花∿種子散布の過程を解析した。花粉生産量は既報4樹種より多く, 粒数では2.6×(10)^ha^y^を記録した。雄花の生産量は林分の生育段階の進行に伴い増加するが, 果実にはこの傾向が認められない。生殖器官全体の生産量は10資料のすべてが1t ha^y^をこえ, うち3林分は3∿5.5t ha^y^に達した。1982年開花に由来する生殖器官部分の乾物割合は雄性 : 雌性が1 : 1の3林分と1 : 3の2林分にわかれ, この関係は花粉粒数P/め花数Fの比によって整理できた。前者3林分のめ花数には2倍の較差があるが結実率(21%)は等しかった。P/F比が前者の半分しかない後者2林分では結実率が高い林分(31%)と低いもの(17%)とがあった。若い林分ではP/F比が小さいが, 結実率は高い傾向がみられる。シイ種子生産を決定する要因にはめ花数と結実率の二つが認められた。Annual production rates (per 1-ha stand; by dry weight and number) of catkins, pollen and fruits of five chinkapin (Castanopsis cuspidata SCHOTTKY) stands in the mountain zone around the Koyto Basin were measured in 1982 and 1983 using litter traps, and analyzed from the process of flowering to seed dispersal. The pollen production rates were larger than those of the four species previously reported, i.e., Japanese red pine, Cryptomeria, Chamaecyparis and Siebold walnut; the maximum value reached 2.4×(10)^ grains/ha・y. Catkin production increased with developing growth stage of stands, while fruit production varied among stands. Ten estimations (five stands in two years) of the production rates of all reproductive organs including pollen showed values of over 1t/ha・y, in which all six estimations for three stands amounted to between 3 and 5.5t/ha・y. The distribution ratio of male and female organs within the total dry matter production of parts derived from flowering in 1982 was 1 : 1 for three Stands B, D and E, and 1 : 3 for two Stands A and C, corresponding to the ratio of the number of pollen grains (P) to female flowers (F). In the former stands, a two-fold difference in the numbers of female flowers was recognized, while there was no difference in the seed-maturing ratio (21%), i.e., the proportion of female flowers developing into ripe and sound nuts. Of the latter stands having half the P/F Ratio of the former, young Stand A showed a high ratio (31%) while Stand C showed a low ratio (17%). It was concluded that the seed-maturing ratios in mature stands are related to the P/F Ratio, while in young stands, the former tends to be high in spite of a low P/F Ratio

東向き及び西向き斜面のミズナラ老齢林における花粉, 雌花及び種子生産の比較(林学部門)

林分1haあたりの雄花序, 花粉, 雌花及び種子の生産量(乾重と個数)について, 老齢ミズナラ林分の東向き斜面と西向き斜面とを比較検討し, 種子生産に関係する要因を考察した。各部分の生産量はトラップ法で測定し, 花粉については開花前の雄花序試料に含まれる花粉量と林分の開花雄花序数をかけて推定した。調査は1984年と85年に行った。両年度は種子豊作年と判断した。両林分の2年間の乾物生産は450∿500kg/ha・yrで, ここに占める雄性部分の割合は東向き林分が1/4,西向き林分は1/8であった。種子生産は西向き林分の方が多く, これは雌花数が多いためであった。種子生産の年変化は結実率に支配され, 雌花数自体の変化は無関係であった。この結実率は, 雌花に対して花粉の生産が多い年度に高くなった。花粉/種子の数比に年変化が認められなかったことから, 花粉生産量が結実率をとおして種子生産を支配したといえる。花粉/種子の数比は, 種子生産の少い東向き林分(19×(10)^6個)の方が西向き林分(5∿6×(10)^6個)より4倍程度多いが, 両林分の結実率は等しかった。このように, 向かい合って接する東向き及び西向き林分における雄性と雌性部分の生産量及び両者の両割合は異ることがわかった。A comparison of east- and west-facing slopes with regard to the production rates of male flowers, pollen, female flowers and seeds in aged stands of Japanese white oak (Quercus mongolica FISCH. var. grosseserrata REHD. et WILS.) was made and the factors affecting seed production were discussed. Annual production rates (by dry weight and number) per 1-ha stand for each reproductive component except pollen were determined using ten litter traps (each 50cm×50cm in mouth area), while for pollen, this was done together with measurement of the amount of pollen contained in catkin samples before anther opening. The study was conducted in 1984 and 1985,years in which the seed crop was abundant. Dry-matter production rates for all reproductive parts including pollen in the two stands for the two study years were in the range of 450∿500kg/ha・yr, the proportion of male parts being one-fourth for the east-facing stand and one-eighth for the west-facing one. Seed production of the west-facing stand was higher than that of the east-facing one, due to the number of female flowers. Yearly changes in seed production were dependent on the seed-maturing ratio, i.e., the numerical ratio of sound acorns to female flowers, and not on the number of female flowers. The high seed-maturing ratio corresponded to the year in which a large amount of pollen was available for fertilization. Judging from the negligible difference between the two years in the numerical ratio of pollen to seeds, i.e., the number of pollen grains necessary for the formation of one acorn, seed production appears to be dependent on the number of pollen grains released into the air. There were no differences between the two stands in the seed-maturing ratio, while the numerical ratio of pollen to seeds in the east-facing stand (19×(10)^6), which had a low seed production, was about four times higher than that in the west-facing stand (5-6×(10)^6). Remarkable differences between the two stands, either neighboring or face to face, were found in the numerical proportion of male to female parts