垂柳有性生殖初步研究
时间:2020-06-21 15:23 来源:毕业论文 作者:毕业论文 点击:次
| 摘要 垂柳（Salix babylonica）是分布广泛，生命力强的高大乔木或灌木，因形态美丽常常用于景观栽植，垂柳的有性生殖目前研究的还比较少，本文将通过对观察其开花动态及花部特征、统计单花花粉量及单花胚珠数、测定柱头可授性、估算结实率、种子萌发率及种子寿命等等进行初步研究，以期为垂柳的人工栽培提供一些简单的科学理论依据和建议。研究结果表明：垂柳为雌雄异株植物，进行的是异花传粉，花期为 3 月初至 4 月的中旬，雄花单花花粉量大约在 1000 至56400 之间的，雌花单花胚珠数一般是 4个，雌蕊柱头可授性可持续 15天左右，强弱程度为前期强而后期弱；结实率平均为 80%左右，种子的萌发率特别高，一般都在 95%以上，种子在常温下的寿命约为 10天左右。 综上所述，垂柳进行有性生殖来繁衍后代，而垂柳种子不休眠即可发芽，常温下寿命也不长，因此在人工栽培的时候要注意时间的把握，可以采取低温保存的方式使种子被动休眠以延长种子的寿命。 51411 毕业论文关键词 垂柳 有性生殖 雌雄异株 结实率 萌发率 寿命 Preliminary studies on the sexual reproduction of Weeping willows(Salix babylonica) Abstract Weeping willows are widely distributed, strong vitality of tall trees or shrubs, often used for landscape planting because of beauty. The studies on the sexual reproduction of Weeping willows still a bit less at present. This article will observe the dynamics of flowering and characteristics of floral, statistics the numbers of single flower pollen and ovules, determine stigma receptivity, estimate setting rate, seeds germinatin and life, to provide a simple scientific theory and suggestion for artificial cultivation of willows. Research indicates that: Weeping willows are dioecious plants and conducting cross-pollination. Florescence from early March to April in mid, the amounts of single flower pollen for male flowers are among 1000 to 56400,the amounts of single flower ovules for female flowers usually to 4, The stigma receptivity can continue about 15 days, the strength is strong in the early and weak in late; the setting rate is about 80%, the seeds germination is very high, generally more than 95%.Seeds of life there are about 10 days. In summary, Weeping willows by sexual reproduction to produce offspring, seeds germination can jump over dormancy. Also the seed life is not long under normal temperature conditions. So we should grasp the time when cultivating, make the seeds passive dormancy by cryopreservation to prolong the life of the seeds. Key words Weeping willow; sexual reproduction; dioecious; setting rate; germination rate; life 目录 摘要I Abstract.II 表清单.IV 1引言.1 1.1植物繁殖生物学.1 1.2柳属植物1 1.3垂柳研究进展.2 1.4本实验研究的目的与意义.3 2研究地点与实验材料4 2.1研究地点概况.4 2.2试验材料4 3垂柳有性生殖研究5 3.1方法与过程.5 3.1.1垂柳开花动态及其花部形态的观察5 3.1.2统计单花花粉数量和单花胚珠数量5 3.1.3柱头可授性的测定5 3.1.4结实率的估算6 3.1.5果序和种子的观察6 3.1.6种子的萌发率和寿命6 3.2结果与分析.7 3.2.1垂柳的开花动态及其花部形态7 3.2.2单花花粉数量和单花胚珠数量的统计14 3.2.3柱头的可授性测定.16 3.2.4结实率的估算.18 3.2.5果序和种子的观察.19 3.2.6种子的萌发率和寿命20 (责任编辑：qin) |