@article{oai:kpu.repo.nii.ac.jp:00005204,
 author = {齋藤, 秀樹 and Saito, Hideki},
 journal = {京都府立大學學術報告. 農學, The scientific reports of Kyoto Prefectural University. Agriculture},
 month = {Dec},
 note = {興聖寺(京都府宇治市)境内のシイ林においてリタートラップ法で継続8年間にわたって生殖器官の生産量(林分当たり)を測定し, また花粉については開花前の雄花序当たりの花粉量をもとに推定した。本報告は種子成熟に2か年を必要とするシイ林での生殖器官生産の豊凶周期とその誘因を中心にとりまとめたものである。主な結果はつぎのとおりである。1) 2生育期間をかけて生産される生殖器官の乾物収量は, 開花年ごと463.4&acd;2792.0(平均1607.8)kg (ha)^<-1>の範囲にあった。雄性および雌性部分収量の豊凶は3年周期であらわれたが, 両部分を合わせた全収量には明らかな周期は認められなかった。雄性と雌性部分の占める割合は全収量に関連しており, 雄性部分は30%(豊作年)&acd;90%(凶作年)の範囲で変動した。2)同化産物が1年間に生殖器官の生産に使われた量, すなわち乾物生産速度は611.4&acd;3031(平均1677)kg (ha)^<-1> (yr)^<-1>であった。生産速度が1500kg (ha)^<-1> (yr)^<-1>をこえた年は8年間に5回もあり, 1000kgをきった年はわずかに1回であった。この莫大な同化産物の投資は, シイが暖温帯に生育しているために可能であると考えた。3) i年次から始まる雄性部分生産速度は凶&xrarr;並&xrarr;豊の順で増加し, 雌性は並&xrarr;凶&xrarr;豊(i-1年次からは豊&xrarr;並&xrarr;凶)で, 逆列の周期であった。生殖器官全体の生産速度に対する雄性の占める割合は, i+1年次を基準にすると大&xrarr;中(平均)&xrarr;小(雌性は小&xrarr;中&xrarr;大)のサイクルで変化した。4) i年次の生殖器官の生産速度(i年次の雄性部分とi-1年次の雌花に由来する部分の生産速度との和)がi+1年次の開花量を決め, その開花量がi+2年次の雌性の生産速度に影響を与えていた。この結果, 生産速度の豊凶周期は3年, 大豊作は3の倍数の年周期であらわれることがわかった。これはシイの隔年結実である。種子も同様の周期であった。5)林分当たりの花粉数(生産速度)はほかの樹種に比べて突出して多かった。しかし, この値は胚珠数と釣り合っていた(胚珠当たり3&acd;4×(10)^5粒)。6)生殖器官の生産に投資された同化産物量のうちで種子に分配されたのは0%&acd;40%(平均20%)であった。種子生産には種子重の2.7&acd;3.9倍のコスト(種子当たり0.682&acd;0.981g)を払っていた(凶作年は除外)。7)雄花序の約95%は開花した。雌花は未熟果実として1年目に35%前後, 2年目55%&acd;60%, 合わせて88%&acd;95%が落果した(凶作年は除外)。結実率は雌花の0.4%&acd;12%の範囲にあり, これは生殖器官の乾物収量の増加に伴って高くなった。未熟果実はほとんど成長せずに落下しており, 平均でみて成熟果実重量の3&acd;5%であった。種子および生殖器官全体の豊凶は雌花数に左右されるが, 結実率の少しの変化が生産速度に影響することがわかった。, In a mature stand of Shii chinkapin (Castanopsis cuspidata SCHOTTKY) at Kohsho-ji temple, Uji, Kyoto, the annual yield (per ha) of sexual organs was studied using 10 litter traps (each 50cm×50cm in mouth area) during eight consecutive years, and that of pollen was estimated by multiplying the number of fallen male catkins per ha per yr by the mean amount of pollen per catkin before flowering. We focused mainly on cyclic periodicity and its causes in the yield of sexual organs of Shii chinkapin, which requires two growth seasons for nut maturation. The main results were as follows. 1) Dry-matter yield of sexual organs produced during two years was in the range 463.4-2792.0 (mean : 1607.8)kg (ha)^<-1> in each year of flowering. Heavy crops of male and female components occurred at intervals of three years. However, no periodicity in the total crop of either was recognized. The percentage proportion of male components to total sexual organs for dry-matter yield varied from 30% (productive year) to 90% (unproductive year), increasing with decreasing total crop. 2) Annual production rates, or assimilation products, invested in the production of sexual organs were in the range 611.4-3031 (mean : 1677)kg (ha)^<-1> (yr)^<-1>. Productive years with more than 1500kg (ha)^<-1> (yr)^<-1> occurred five times in an 8-yr period, and an unproductive year with less than 1000kg (ha)^<-1> (yr)^<-1> occurred only one. I considered that the large assimilation products of the study stand resulting from a favorable climate site (moist and warm-temperate zone) permitted this huge and frequent investment in production of sexual organs. 3) The sequence of production rates of male components when starting at year i was light&xrarr;medium&xrarr;heavy, and that of female (including nuts), medium&xrarr;light&xrarr;heavy (heavy&xrarr;medium&xrarr;light for starting at year i-1), the two sequences being reversed. The percentage dry weight of male components to production rates of total sexual organs changed in the sequence large&xrarr;medium&xrarr;small when a year started at i+1 (for female, small&xrarr;medium&xrarr;large). 4) Production rates of sexual organs at year i (sum of production rates of male components at year i and those of components derived from female flowers at year i-1) set flowers bearing in the following year i+1,and this was closely related to production rates of female components at year i+2. These relationships meant that heavy production of sexual organs occurred at an interval of three years, and that very heavy production appeared at intervals based on a multiple of three because of the yearly fluctuation of seed maturity. This 3-yr cyclic periodicity results in alternate-year bearing for Shii chinkapin. 5) The pollen production rate of 13.1-86.9 (mean : 49.5)×(10)^<12> (ha)^<-1> (yr)^<-1> was by far the largest number among other species. Such a huge number among other species. 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 : 3-4×(10)^5). 6) Dry matter allocated to nut production among assimilation products invested in sexual organs was in the range 0%-40% (mean : 20%). The assimilation product necessary for producing a single nut was 0.682-0.981g per nut. The cost of nut production was 2.7-3.9 times per nut (excluding a very light year). This seed production effort was similar to those of other barachorous species. 7) Male catkins of about 95% were opened every year. Female flowers of about 35% fell in the first year, and those of 55%-60%, in the second year, the total number of immature fruits reaching 88%-95% of all female flowers (excluding a very light year). Seed-maturing ratios were in the range 0.4%-12% of the numbers of all female flowers, and increased with the increase in yield of sexual organs. Little growth of immature fruits was recognized, corresponding to 3%-5% of},
 pages = {1--18},
 title = {シイ林における 8 年間の生殖器官生産の年次変動周期(林学部門)},
 volume = {45},
 year = {1993},
 yomi = {サイトウ, ヒデキ}
}