台灣樟科植物開花授粉生物學之研究

The Floral and Pollination Biology of Lauraceae in Taiwan

范義彬(Yi-Bin Fan)

指導教授 ： 楊平世

國立臺灣大學/生物資源暨農學院/昆蟲學研究所/博士(2006年)

https://doi.org/10.6342/NTU.2006.02522

摘要

樟科植物(Lauraceae)是台灣森林中重要的組成樹種，本研究在瞭解樟樹(Cinnamomum camphora (Linn.) Presl.)、紅楠(Machilus thunbergii Sieb et Zucc)、山胡椒(Litsea cubeba (Lour.) Pers.)及長葉木薑子(Litsea acuminata (Blume) Kurata)開花生物學及其授粉生物學，並探討植物與訪花昆蟲間共同演化的關係。
樟樹(Cinnamomum camphora (Linn.) Presl.)為聚繖花序，兩性花，花期為3-4月；每朵花直徑5.52±0.58㎜，單花壽命6.45±1.41天；花粉數3170.7顆；花開放後夜間不閉合，花藥隨後開裂夜間不閉合；日夜皆有訪花昆蟲，共計5目23科65種昆蟲，以雙翅目(Diptera)11科33種最多，鱗翅目(Lepidoptera)5科15種次之，其他還有鞘翅目(Coleoptera)5科11種，半翅目(Hemiptera)2科3種，膜翅目(Hymenoptera)3科3種。訪花昆蟲即是其潛在可能的授粉昆蟲，但以雙翅目的蠅類為最重要；天然結實率1.23±2.89﹪。
紅楠(Machilus thunbergii Sieb et Zucc)為聚繖花序，兩性花，花期為2-3月；每朵花直徑10.32±0.73㎜，單花壽命4.24±1.08天；花粉數9273.6顆；花開放後閉合；日夜皆有訪花昆蟲，日間訪花昆蟲較多，訪花最頻繁的時段是09:00~15:00，紅楠訪花昆蟲共計5目21科34種昆蟲，以雙翅目11科22種最多，膜翅目5科9種、鱗翅目3科3種、鞘翅目1科3種、革翅目(Dermaptera)1科1種。其訪花昆蟲即是其潛在可能的授粉昆蟲，但以膜翅目的蜜蜂(Apis spp.)和雙翅目的蠅類為最重要；天然結實率5.98±11.11﹪。
山胡椒(Litsea cubeba (Lour.) Pers.)為繖形花序，單性花雌雄異株，花期為2-3月；雄花花序直徑9.20±0.82㎜，小花直徑3.73±0.77㎜，單花壽命13.03±4.52天，花粉數7786.8顆；雌花花序直徑8.11±0.85㎜，小花直徑2.28±0.35㎜，單花壽命15.68±4.90天。花開放後夜間不閉合，花藥隨後開裂夜間不閉合，日夜皆有訪花昆蟲。山胡椒訪花昆蟲有4目36科108種，以鞘翅目16科39種最多，鱗翅目7科33種次之，雙翅目7科24種、膜翅目6科12種。雄株訪花昆蟲共計4目33科77種昆蟲，以鞘翅目16科36種最多，鱗翅目6科16種次之，雙翅目6科15種、膜翅目5科10種；雌株共計4目16科44種昆蟲，以鱗翅目5科17種最多，鞘翅目 4科12種、雙翅目4科12種次之，膜翅目3科3種昆蟲。雌雄共同的訪花昆蟲計3目7科13種昆蟲，以鞘翅目4科9種最多，雙翅目2科3種次之，鱗翅目1科1種。往來於雌雄花之間者有鞘翅目的菊虎、金花蟲，雙翅目的食蚜蠅、鱗翅目的夜蛾和尺蛾，其主要授粉昆蟲；天然結實率29.76±19.90﹪。
蜜蜂(Apis spp.)不造訪樟樹花，且僅在山胡椒、長葉木薑子雄花上訪花，對山胡椒、長葉木薑子授粉並無貢獻，是盜粉者。
長葉木薑子(Litsea acuminata (Blume) Kurata)為繖形花序，單性花，雌雄異株，花期為6-7月；雄花花序直徑9.86±1.24㎜，花粉數14130顆；雌花花序直徑6.92±0.82㎜。花開放後夜間不閉合，花藥隨後開裂夜間不閉合，日夜皆有訪花昆蟲。長葉木薑子的訪花昆蟲有4目29科66種，以鱗翅目11科25種最多，雙翅目8科16種次之，膜翅目5科14種，鞘翅目5科11種。雄株訪花昆蟲共計4目26科59種昆蟲，以鱗翅目11科25種最多，雙翅目6科13種次之，膜翅目4科11種，鞘翅目5科10種；雌株訪花昆蟲共計4目9科16種，以膜翅目2科7種最多，雙翅目3科5種次之，鱗翅目3科3種、鞘翅目1科1種昆蟲。往來於雌雄花之間者有3目6科8種(2種蠅、3種蜂、2種蝶、1種蛾)，以鱗翅目3科3種、膜翅目2科3種最多，雙翅目1科2種。是其主要授粉昆蟲；天然結實率22.88±23.17﹪。
總而言之，山胡椒和長葉木薑子(單性花雌雄異株)以結實率來說，較樟樹和紅楠(兩性花雌雄同株)的繁殖為成功。雖然山胡椒和長葉木薑子(單性花雌雄異株)的授粉模式較樟樹和紅楠(兩性花雌雄同株)單純。

關鍵字

樟樹 ； 紅楠 ； 山胡椒 ； 長葉木薑子 ； 樟科 ； 開花生物學 ； 授粉生物學 ； 共同演化

並列摘要

The family Lauraceae contains the most dominant species in Taiwan’s natural hardwood forest and is considered one of the most important families in Taiwan. This study was focused on the florescence and pollinating biology of four widely distributed species of Laurel family, Cinamomum camphora (Linn.) Presl., Machilus thunbergii Sieb et Zucc, Litsea cubeba (Lour.) Pers. and Litsea acuminata (Blume) Kurata, in Taiwan’s broadleaf forests and the co-evolution relationship between those plants and related insects.
Cinamomum camphora (Linn.) Presl. is characterized by inflorescence cryme and hermaphroditism. The average flower size, longevity and average number of pollen grains were 5.52±0.58mm, 6.45±1.41 days and 3170.7 grains respectively. The blooming season was from March to April and flowers and stamens are open no matter day and night when blooming. Totally 65 insect species of 23 families of 5 orders were observed. Their taxonomic composition were: Diptera (11 families, 33 species), Lepidoptera (5 families, 15 species), Coleoptera (5 families, 11 species), Hemiptera (2 families, 3 species) and Hymenoptera (3 families, 3 species). Insect visitors to the blossoms were the potential pollinators and flies are the most important ones. Natural fruit-set rate was 1.23±2.89﹪.
Machilus thunbergii Sieb et Zucc is characterized by inflorescence cryme and hermaphroditism. The size of flower, longevity of individual flower and the average number of pollen grains is 10.32±0.73 mm, 4.24± 1.08 days and 9273.6 grains respectively. The blooming season is in the spring from February to March, flowers and stamens will close after opening, and insects visit the blossoms day and night, especially during 09:00~15:00. There were totally 34 species insects of 21 families from 5 orders were recorded to visit flowers of M. thunbergii. Their taxonomic composition were: Diptera (11 families, 22 species), Lepidoptera (3 families, 3 species), Coleoptera(1 families, 1 species), and Dermaptera (1 families, 1 species). Insect visitors were the potential pollinators and honeybees (Apis spp.) and flies were the most important ones. Natural fruit-set rate was 5.98±11.11﹪.
Litsea cubeba (Lour.) Pers. is characterized by inflorescence umbel and dioecism. Blooming season is from February to March. Male inflorescence diameter was 9.20±0.82 mm and small flower diameter was 3.73±0.77mm; the longevity of individual flower were 13.04±4.52 days and the number of pollen grains was 7786.8. While size of female inflorescence diameter, small flower diameter and longevity of individual flower were 8.11±0.85 mm, 2.28±0.35 mm and 15.68±4.90 days respectively. Flower and stamens are open all the day when blooming. Their insect visitors include 108 species of 36 families from 4 orders. Their taxonomic composition were: Coleoptera (16 families, 39 species), Lepidoptera (6 families, 33 species), Diptera (7 families, 24 species) and Hymenoptera (6 families, 12 species). 77 species of 33 families from 4 orders have been observed visiting male flowers of L. cubeba. They were: Coleoptera (16 families, 36 species), Lepidoptera (5 families, 16 species), Diptera (6 families, 15 species) and Hymenoptera (5 families, 10 species). There were 44 species of 16 families from 4 orders visited the female flowers of L. cubeba. They were: Lepidoptera (5 families, 17 species), Coleoptera (4 families, 12 species), Diptera (4 families, 12 species) and Hymenoptera (3 families, 3 species). The major pollinating insects flying between male and female flowers include Cantharidae and Chrysomelidae (Coleoptera), Syrphidae (Diptera), Noctuidae and Geometridae (Lepidoptera). Natural fruit-set rate was 29.76±19.90﹪.
In addition, honeybees (Apis spp.) have been verified not visiting flowers of C. camphora and female flowers of L. cubeba and L. acuminata. Therefore they are pollen robbers rather than pollinators.
Litsea acuminata (Blume) Kurata is characterized by inflorescence umbel and dioecism. It will bloom in June and July. The average size of male and female inflorescence diameter is 9.86±1.24 mm and 6.92±0.82 mm respectively. It has 14130 grains of pollen in average. Flowers and stamens are also open in both daytime and nighttime when blooming. Their insect visitors include 66 species of 29 families from 4 orders. Their taxonomic composition were: Lepidoptera (11 families, 25 species), Diptera (8 families, 16 species) , Hymenoptera (5 families, 14 species) and Coleoptera (5 families, 11 species). There were 59 species of 33 families from 4 orders visited male flowers of L. acuminata. They were: Lepidoptera (11 families, 25 species), Diptera (6 families, 13 species). Hymenoptera (4 families, 11 species) and Coleoptera (5 families, 10 species). There were 16 species of 9 families from 4 orders visited the female flowers of L. acuminata. They were: Lepidoptera (3 families, 3 species), Coleoptera (1 families, 1 species) and Diptera (3 families, 5 species). There were 8 species of 6 families from 3 orders visiting both male and female flowers, major pollinating insects were: Lepidoptera (2 families, 3 species), Hymenoptera (2 families, 3 species) and Diptera (1 families, 2 species). Natural fruit-set rate was 29.76±19.90﹪.
In conclusion, the reproduction of L. cubeba and L. acuminata （dioecism） is much more successful than C. camphora and M. thunbergii’s（hermaphroditism） in the fruit-set even though the pollination mode of L. cubeba and L. acuminata （dioecism） is simplier than C. camphora and M. thunbergii’s（hermaphroditism）.

並列關鍵字

Cinnamomum camphora ； Machilus thunbergii ； Litsea cubeba ； Litsea acuminata ； Lauraceae ； floral biology ； pollination biology ； coevolution

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