珍稀保护植物光叶木兰生殖生物学研究
发布时间：2019-01-01 12:18
【摘要】：光叶木兰(Magnolia dawsoniana)是木兰科木兰属的高大落叶乔木,特产于四川中部大渡河谷及青衣江流域,其自然分布种群数量小,繁殖更新能力弱,是四川省林业厅推荐优先保护的极小种群野生植物之一。生殖是物种繁殖的重要环节,因此对珍稀濒危植物的生殖生物学研究迫在眉睫。因此,本研究以栗子坪国家级自然保护区野生分布的光叶木兰为对象,对其开花过程、开花物候、雌雄蕊发育、传粉特性和种子特征等进行了研究,探讨了濒危原因,研究结果如下：1.光叶木兰开花过程大致可以分为五个阶段：(1)花蕾期；(2)初开期；(3)展瓣期；(4)盛开期；(5)凋谢期；光叶木兰花期2-4月,单株开花持续34-42 d,群落开花持续47-52d,高海拔群落开花时间比低海拔群落晚近半个月。2.开花过程存在二次开合现象,单朵光叶木兰花在第一天花被片展开后,在该天晚上花被片会稍合拢,第二天约10：00左右再次展开,此后,花被片完全保持展开不再闭合,直至脱落。3.光叶木兰雌雄蕊异熟,雌蕊先雄蕊成熟12h；雌蕊及雄蕊的品质都随着时间的推移下降：雌蕊表现为可授性下降,雄蕊表现为花粉生活力下降、萌发时间增长、萌发率降低。花粉量大,可达2,047,500,花粉-胚珠比为2,6546.19,属专性异交,需要传粉媒介。4.光叶木兰访花昆虫少,蜜蜂、蝇、甲虫类、毛蚊科和蓟马科五大类昆虫,访花昆虫访花频率低；花被片、雌蕊柱头黏液、花粉在不同花期吸引的昆虫有所差异,其中受花粉吸引强的昆虫为蜜蜂、蝇和甲虫。5.光叶木兰花托中间部位的部分子房常败育,果实常出现弯曲现象,结实率仅58.57%；种子质量差,饱满种子仅占46.33%,且饱满种子生活力平均60.67%；种子中还有抑制种子发芽的物质存在,不利于种子的萌发。综上所述,导致光叶木兰种群极小的主要原因是需要昆虫为其传粉但访花昆虫种类少且频率低,传粉效率低；花粉生活力低,且柱头可授性时间短；结实率低、种子生活力低且种子含有抑制类物质。
[Abstract]:(Magnolia dawsoniana) is a large deciduous tree of Magnoliaceae. It is specialized in Dadu River Valley and Qingyi River Valley in central Sichuan. Its natural distribution population is small, and its reproduction and regeneration ability is weak. It is one of the small populations of wild plants recommended by Sichuan Forestry Department. Reproduction is an important part of species reproduction, so it is urgent to study the reproductive biology of rare and endangered plants. Therefore, this study studied the flowering process, flowering phenology, pistil and stamen development, pollination characteristics and seed characteristics of Magnolia grandiflora, which was distributed in Liziping National Nature Reserve, and discussed the reasons of its endangerment, such as flowering process, flowering phenology, pistil and stamen development, pollination characteristics and seed characteristics, etc. The results are as follows: 1. The flowering process of Magnolia lanceolata can be divided into five stages: (1) bud stage, (2) initial opening stage, (3) spreading stage, (4) full bloom period, (5) withered period, and (3) flowering stage. The flowering time of the community was 47-52 days. The flowering time of the high altitude community was half a month later than that of the low altitude community. 2. There was a secondary opening and closing phenomenon in the flowering process. After the tepals of a single glossy leaf were spread out on the first day, the tepals would close slightly in the evening of that day, and then again around 10:00 on the next day. After that, the tepals remained completely unfolded and no longer closed. Until it falls off. The quality of pistil and stamen decreased with the passage of time, and the stamen showed decreased pollen viability, increased germination time and decreased germination rate. The amount of pollen is large, up to 2o 047g / 500, the ratio of pollen to ovule is 2 / 6546.19. it belongs to special heterosynthesis and needs pollination medium. 4. The floral visit insects of Magnoliaceae were few, and the insects of honeybee, fly, beetle, trichosphellidae and thripidae had low flower visiting frequency. Tepals, pistil stigma mucus and pollen attract insects at different flowering stages, among which bees, flies and beetles are strongly attracted by pollen. Part of ovary in the middle part of Magnolia grandiflora often aborted, the fruit was often curved, the seed setting rate was only 58.57, the seed quality was poor, the full seed was only 46.33, and the full seed viability was 60.67 on average. There is also a substance in the seed to inhibit seed germination, which is not conducive to seed germination. To sum up, the main reasons for the very small population of Magnolia lanceolata are that it needs insects to pollinate it, but the species and frequency of flowering insects are low, the pollination efficiency is low, the pollen viability is low, and the stigma can be pollinated for a short time. Seed setting rate is low, seed viability is low and seeds contain inhibitory substances.
【学位授予单位】：四川农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S685.99
本文编号：2397553
[Abstract]:(Magnolia dawsoniana) is a large deciduous tree of Magnoliaceae. It is specialized in Dadu River Valley and Qingyi River Valley in central Sichuan. Its natural distribution population is small, and its reproduction and regeneration ability is weak. It is one of the small populations of wild plants recommended by Sichuan Forestry Department. Reproduction is an important part of species reproduction, so it is urgent to study the reproductive biology of rare and endangered plants. Therefore, this study studied the flowering process, flowering phenology, pistil and stamen development, pollination characteristics and seed characteristics of Magnolia grandiflora, which was distributed in Liziping National Nature Reserve, and discussed the reasons of its endangerment, such as flowering process, flowering phenology, pistil and stamen development, pollination characteristics and seed characteristics, etc. The results are as follows: 1. The flowering process of Magnolia lanceolata can be divided into five stages: (1) bud stage, (2) initial opening stage, (3) spreading stage, (4) full bloom period, (5) withered period, and (3) flowering stage. The flowering time of the community was 47-52 days. The flowering time of the high altitude community was half a month later than that of the low altitude community. 2. There was a secondary opening and closing phenomenon in the flowering process. After the tepals of a single glossy leaf were spread out on the first day, the tepals would close slightly in the evening of that day, and then again around 10:00 on the next day. After that, the tepals remained completely unfolded and no longer closed. Until it falls off. The quality of pistil and stamen decreased with the passage of time, and the stamen showed decreased pollen viability, increased germination time and decreased germination rate. The amount of pollen is large, up to 2o 047g / 500, the ratio of pollen to ovule is 2 / 6546.19. it belongs to special heterosynthesis and needs pollination medium. 4. The floral visit insects of Magnoliaceae were few, and the insects of honeybee, fly, beetle, trichosphellidae and thripidae had low flower visiting frequency. Tepals, pistil stigma mucus and pollen attract insects at different flowering stages, among which bees, flies and beetles are strongly attracted by pollen. Part of ovary in the middle part of Magnolia grandiflora often aborted, the fruit was often curved, the seed setting rate was only 58.57, the seed quality was poor, the full seed was only 46.33, and the full seed viability was 60.67 on average. There is also a substance in the seed to inhibit seed germination, which is not conducive to seed germination. To sum up, the main reasons for the very small population of Magnolia lanceolata are that it needs insects to pollinate it, but the species and frequency of flowering insects are low, the pollination efficiency is low, the pollen viability is low, and the stigma can be pollinated for a short time. Seed setting rate is low, seed viability is low and seeds contain inhibitory substances.
【学位授予单位】：四川农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S685.99
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1 孙燕;珍稀保护植物光叶木兰生殖生物学研究[D];四川农业大学;2015年
，本文编号：2397553
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