自然教育園におけるシュロ成熟個体群の開花・結実動態(1980-2001)

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1. I researched the flowering and fruiting dynamics in the population of mature individuals of Trachycarpus fortunei in the Institute for Nature Study in order to estimate the seed supply ability in the population of T. fortunei in the Institute for Nature Study. The field survey carried out from 1987 to 2001. 2. A few individuals of T. fortunei above 1m in stem height flowered in the Institute for Nature Study. And the rates of maturity increased rapidly in the individuals above 2m in stem height. Above 4m in stem height, most individuals were occupied in the mature individuals. 3. The numbers of mature individuals of T, fortunei increased slowly at the speed of 4 individuals per a year from 1980 to 1987,because many mature and semi-mature individuals were cutting from 1980 to 1983. From 1987 to 1995,the numbers of mature individuals increased constantly at the speed of 30-40 individuals per a year. But the numbers of mature individuals decreased from 1995 to 1996. From 1996 to 2001,the numbers of mature individuals increased again at the speed of 30-40 individuals per a year. 4. The development of inflorescence or infructescence was inhibited heavily between 1987 and 1996. But this inhibition decreased after 1999. The percentage of the numbers ofactual fruiting females per the number of mature individuals from 1987 to 1996 decreasedbelow half of the percentage in 1980. But the percentage increased from 1996 to 2001. And from 1996 to 2001,the numbers of fruits of a female increased too. Therefore, the females with 1,000 fruits were appeared in 2001. 5. The process of flowering or fruiting in the mature individuals of T. fortunei was inhibited by the animal species at each stage of the period generating inflorescence, theperiod developing inflorescence, the period developing infructescence. I recognized the evidence that the production of inflorescence was inhibited by the destruction of the top of stem of T. fortnei at the period generating inflorescence. I recognized the loss of flowers by the destruction of inflorescence in the period develo pinginflorescence. I recognized that the numbers of fruits of a female attacked by parasitic species decreased in the period developing infructescence. 6. It seems that the mature individuals more than about 80% have the ability to generate inflorescence. In 1987,1995,1996,the destruction of the top of stem of T, fortnei by Corvus macrorhynchos inhibited to generate inflorescence in many mature individuals of T, fortnei. 7. The inflorescence of 45.5%-71.8% of individuals flowering at the survey was destroyedpartly or completely in the time before and after bloomed. 21.89%-66.8% of individualsflowering at the survey had lost inflorescence completely (44.2%-99.3% of the individuals that inflorescence had destroyed). Therefore, the numbers of fruits of a female of T. fortnei decreased due to this destruction of inflorescence. But the numbers of fruits of a female increased from 1999. It seems that the inflorescence of individuals flowering at the survey was destroyed by C. macrorhynchos. But there is no report that anyone observed the destruction of inflorescence of T. fortnei by C. macrorhynchos. 8. The numbers of females flowering at the survey decreased due to the destruction of inflorescence. And the numbers of females with actual infructescence was 20%-40% of the numbers of individuals with inflorescence destroyed partly and non-destroyed at the survey. 9. The numbers of fruits of a female decreased due to the attack by the larvae of Geisha distinctissima. The numbers of fruits of a female decreased below the half of numbers of fruits of a normal female in the year when the top of stem in many individuals was destroyed hard. 10. The supply ability of seeds in the population of T. fortunei in the Institute for Nature Study had not increased due to the destruction of inflorescence, the parasitism and another inhibiting factors during the last two decades. But potential seed supply abili
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自然教育園におけるシュロ成熟個体群の開花・結実動態(1980-2001)

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