渐危植物鹅掌楸的授粉率及花粉管生长

中国科学院大学学报

渐危植物鹅掌楸的授粉率及花粉管生长

黄双全,郭友好,陈家宽

收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1998-07-10 发布日期:1998-07-10
通讯作者: 黄双全

Pollination Rates and Pollen Tube Growth in a Vulnerable Plant, Liriodendron chinense (Hemsl.) Sarg. (Magnoliaceae)

HUANG Shuang-Quan, GUO You-Hao, CHEN Jia-Kuan

Received:1900-01-01 Revised:1900-01-01 Online:1998-07-10 Published:1998-07-10
Contact: HUANG Shuang-Quan

摘要/Abstract

摘要：

对鹅掌楸Liriodendron chinense 3个自然居群连续3年直接统计落置柱头上的花粉量，其中

61.9％以上的柱头接受了花粉。每柱头上的平均花粉量为4.4～42.6粒，明显超过胚珠数2。授粉率是

结实率的6～8倍，鹅掌楸结实率低的主要原因可能不是由于花粉的限制。落置柱头的花粉几乎均可萌

发，少数花粉管穿过花柱道，经珠孔端进入胚囊，暗示花粉间存在着强烈的竞争。授粉率和柱头上的平

均花粉量与结实率呈正相关(R＝0.77，R=0.69)。在柱头上人工授同株和异株的花粉，花粉管生长速

率看不出明显差异，到达胚珠的时间在48～60 h之间。花开花药未裂时柱头上落置较高比例的花粉，

由于先期到达柱头的花粉最有可能受精，表明鹅掌楸有异交为主的繁育系统。人工处理包括套袋、套

网、去除花被片，其结实率大大降低，而去雄后的结实率接近自然传粉结实率支持了这一观点。

关键词: 鹅掌楸, 授粉率, 花粉竞争, 繁育系统

Abstract:

The limited seed production of insect-depended plant, Liriodendron chinense was

once considered to be pollen-limited and insufficient cross pollination. In this study, we

counted pollen grains deposited on stigmas in three populations in Guizhou, Hunan and Zhe-

jiang provinces of China respectively. Over 61.9% stigmas were pollinated. From 1994 to

1996, the mean number of pollen grains on each stigma ranged from 4.4 to 42.6, much

more than ovules(2) in each pistil. Based on observations of three years, both the pollination

rate and pollen quantity on stigmas significantly affected seed set. When flowers opened

without stamens dehiscencing at the early stage of anthesis, stigmas received considerable

quantity of pollen grains. Pollen grains from different sources were able to germinate and

pollen tube growth rates were not greatly variable. It is very likely that pollen grains arrived

first would fertilize eggs. Since only several pollen tubes went through the stylar canal, the

potential pollen competition may exist. In this case, there would be strong selection on floral

syndrome which benefit early insect visits. Pollen grains from the early visits would have a

greater chance to fertilize ovules than those from later visits, which implies that cross pollina-

tion is the predominant breeding system of this plant. The conclusion was also confirmed by

following four artificial experiments. Three treatments, including flowers bagged, netted or

with the perianth removed, all reduced seed set clearly, but flowers with the stamens re-

moved (emasculation)had a higher seed production by open pollination. As the rates of de-

posited stigmas in three populations were 6～8 times more than full seed set, we consider

that lower seed production in this plant may not mainly be due to pollen limitation.

Key words: Liriodendron chinense, Pollen deposition, Pollen competition, Breeding system

黄双全,郭友好,陈家宽. 渐危植物鹅掌楸的授粉率及花粉管生长[J]. 中国科学院大学学报.

HUANG Shuang-Quan, GUO You-Hao, CHEN Jia-Kuan. Pollination Rates and Pollen Tube Growth in a Vulnerable Plant, Liriodendron chinense (Hemsl.) Sarg. (Magnoliaceae)[J]. .