摘 要

繁殖适合度是衡量树种适应性的重要指标之一。鹅掌楸作为我国的二级濒危保护树种，开展鹅掌楸属繁殖适合度研究至关重要，对于揭示鹅掌楸濒危因素及种内杂交育种有指导意义。本文对鹅掌楸属种内、种间种子的饱满度、花朵形态特征进行比较分析，旨在比较鹅掌楸属不同树种间、以及同一树种不同种源间的繁殖适合度差异以及造成这一差异的因素。

为了比较鹅掌楸属种间、种内的花部特征，本文以8个鹅掌楸属种源（3个北美鹅掌楸种源和5个鹅掌楸种源）的花朵为材料，分析和比较了8个不同种源鹅掌楸属的花部特征的差异；为了比较分析鹅掌楸属8个不同种源的种子繁殖适合度，我们通过采集其自由授粉种子并使用软x射线摄影法检测了种子的饱满度，在此基础上得出了鹅掌楸属8个不同种源种子的繁殖适合度。主要研究结果如下：

在花部形态特征方面，北美鹅掌楸花萼长度、花瓣长度、雄蕊长度、柱头长度的均值分别为5.49cm、5.41cm、3.58cm、4.07cm；鹅掌楸的花萼长度、花瓣长度、雄蕊长度、柱头长度的均值分别为4.63cm、4.25cm、2.66cm、3.26cm。北美鹅掌楸的花部特征普遍较大于鹅掌楸。但在花药的平均数量上，鹅掌楸的平均花药数量为46.90个，高于北美鹅掌楸的37.25个。在种子饱满度和繁殖适合度方面，北美鹅掌楸的饱满度均值为17.63%，鹅掌楸的饱满度均值为11.40%，北美鹅掌楸的繁殖适合度比鹅掌楸高54.6%。研究结果表明，鹅掌楸属大多数花部形态特征与繁殖适合度呈正相关性，北美鹅掌楸的花朵更大，颜色更鲜艳，可能会吸引更多的传粉昆虫，所以繁殖适合度更高。

关键词：鹅掌楸属；种子饱满度；繁殖适合度；花部形态

The seed plumpness for reproductive fitness analysis of Liriodendron

ABSTRACT

Reproductive fitness is one of the important indicators for measure adaptability between tree species . L.chinense is an endangered tree species in China , therefore, it is very important to know its reproductive fitness. In this study, we take seed plumpness as the reproductive fitness, and we analyzed the interspecific and intraspecific variation of seed plumpness and floral traits between two species of Liriodendron.

In order to compare the floral traits on interspecific and intraspecific of the Liriodendron , the flowers from eight provenances of Liriodendron (three provenances of L.tulipifera and five provenances of L.chinense ) were taken as sample materials, All open-pollinated seeds were collected to detect the seed plumpness by the method of Faxitron UitraFocus60,. The results as follows:

The average length of petal , calyx , stamen , stigma on L.tulipifera are 5.49cm , 5.41cm , 3.58cm , 4.07cm , while the average length of petal , calyx , stamen , stigma on L.chinense are 4.63cm , 4.25cm , 2.66cm , 3.26cm. the floral sizes of L.tulipifera are longer than that of L.chinense. However, the average quantity of anther of L.chinense is 46.90 , while for L.tulipifera , the average quantity of anther is only 37.25. The average value of seed plumpness of L.tulipifera is 17.63%, while for L.chinense , it is 11.40% . It is obvious that the reproductive fitness of L.tulipifera is higher than that of L.chinense. Correlation analysis showed that there are positive correlation between reproductive fitness and floral traits. The flowers of L.tulipifera are bigger than L.chinense , and the color of L.tulipifera are brighter than L.chinense . It may attract more pollinating insects, this results may be used to reveal the underlying mechanisim for the low reproductive fitness of L.tulipifera.

Key words:Liriodendron ; Seed plumpness ; Reproductive fitness ; Floral traits

目 录

1 前言 - 1 -

1.1 鹅掌楸属树种概述 - 1 -

1.1.1 树种特点 - 1 -

1.1.2 地理分布 - 1 -

1.1.3 种群规模 - 2 -

1.2 鹅掌楸属树种种子饱满度 - 2 -

1.2.1 饱满度定义 - 2 -

1.2.2 常用测定方法 - 2 -

1.3 软x射线摄影术的应用 - 3 -

1.3.1 种子的饱满度测定 - 3 -

1.3.2 种子活力检测 - 3 -

1.3.3 种子的机械损伤检测 - 4 -

1.3.4 种子发育过程的观察 - 4 -

1.4 研究目的及意义 - 4 -

2 试验材料与方法 - 5 -

2.1 试验材料来源 - 5 -

2.2 试验方法 - 5 -

2.2.1 样品采集及处理 - 5 -

2.2.2 种子饱满度检测 - 5 -

2.2.3 数据处理 - 6 -

3 结果与分析 - 7 -

3.1 鹅掌楸属种内、种间花部形态特征比较 - 7 -

3.2 鹅掌楸属种内、种间种子饱满度比较分析 - 9 -

3.2.1 2014年鹅掌楸属种内、种间种子的饱满度比较 - 9 -

3.2.2 2015年鹅掌楸属种内、种间种子的饱满度比较 - 10 -

3.2.3 同一种源不同年份种子的饱满度比较 - 11 -

3.2.4 鹅掌楸属树种种间种子饱满度比较 - 12 -

3.3 鹅掌楸属树种种内、种间繁殖适合度比较分析 - 12 -

4 结论与讨论 - 14 -

4.1 花部形态特征与繁殖适合度 - 14 -

4.2 鹅掌楸属种内、种间种子饱满度和繁殖适合度比较 - 14 -

致 谢 - 15 -

参考文献 - 16 -

1 前言

1.1 鹅掌楸属树种概述

木兰科（Magnoliaceae)鹅掌楸属(Liriodendron)植物属于落叶乔木，是一种古老的树种，曾一度发展到鼎盛，第四纪冰川作用后大部分都已灭绝，而今世界上仅残存两种，一种分布于北美，称北美鹅掌楸（L.tulipifera），一种分布于东亚，称鹅掌楸(L.chinense)^［1］。

1.1.1 树种特点