Dissertation > Excellent graduate degree dissertation topics show

The Variation of Flower Morphology in Alternanthera Philoxeroides (Mart.) Griseb and Its Correlates with Habitats

Author: ZhangZuo
Tutor: WangDong
School: Central China Normal University
Course: Botany
Keywords: Alternanthera philoxeroides (Mart.) Griseb. flower pattern feminization of stamen habitats individual age water pH value
CLC: Q944
Type: Master's thesis
Year: 2008
Downloads: 11
Quote: 0
Read: Download Dissertation

Abstract

Alternanthera philoxeroides(Mart.) Griseb,a weedy species in the Amaranthaceae family native to South America,has introduced into China in 1930s.Until now,the plant has become one of vicious invasive weeds in China.Most previous studies focused on its high degree of phenotypic plasticity of vegetative structures,little attention is paid to its variation of flower morphology and its correlates with different habitats.After randomly sampling for six habitats from aquatic to terrestrial in the suburbs of Wuhan City,we analyzed the correlation between flower morphology and different habitats.The results are mainly as follows:1.The flower morphology of A.philoxeroides is highly diverse,and the feminization of stamens is common.Base on the degree of feminization in a flower,we found 6 types of flower.That is:1) 5 stamens in a flower;2) 4 stamens in a flower;3) 3 stamens in a flower;4) 2 stamens in a flower;5) only 1 stamen in a flower,and 6) flower have no stamen.Of them,the quantity of both flowers having 5 stamens and no stamen are much more than others.The feminization of stamen of single stamen varied greatly, and we found 8 types of stamens.That is:1) the stamen grows normally;2) the stamen only has the stigma on the crown;3) the stamen has two stigmas on the crown and the base;4) the filament has expanded,like an ovary,but the filament and the anther have remain;5) the anther has disappeared,the filament has remain,the ovary has already formed and the stigma has divided into two unequal parts,the smaller is incomplete and the larger is normal;6) the filament transform into gynophore but the stamen remain have two stigmas;7) the filament transform into gynophore and the pistil has formed;8) the stamen has transformed into a pistil.Of them,the number of normal stamen and the stamen has transformed into a pistil is much more than other types.2.In bisexual flower the normal pistil produces ovule,but the "pistil" which have transformed from the stamens have no ovule in the ovary.Furthermore,we have not found the mature seed in typical bisexual flower yet.3.The inflorescence characteristics of A.philoxeroides in different habitats showed significant difference.In aquatic habitat,the average number of capitulum on a plant is 1.33,the number of flowers per capitulum is 18.45,the length of peduncle reach to 2.77cm and the capitulum inserted to the top of 4.95th stem node.In hygric habitat,the plant only have one capitulum average,the average number of flowers per capitulum is 23.12,the length of peduncle reach to 2.96cm,and the capitulum inserted to the top of 4.52th stem node. In lime habitat,the average number of capitulum on a plant is 1.27,the number of flowers per capitulum is 19.25,the length of peduncle is 2.28cm and the capitulum inserted to the top of 3.20th stem node.In loess habitat,the average number of capitulum on a plant is 1.11,the average number of flowers per capitulum is 18.50,the length of peduncle is 1.56cm and the capitulum inserted to the top of 5.22th stem node.In sand habitat,the plant only have one capitulum,the number of flowers per capitulum is 19.25,the length of peduncle is only 1.41cm and the capitulum inserted to the top of 4.00th stem node.4.The degree of feminization has significant regression relations with different habitats and the degree of feminization is significantly different in six habitats.In these habitats(blackland,aquatic,hygric,lime,loess and sand),the types of stamen are different.There are eight types of stamen in aquatic,five types of stamen in hygric,four types of stamen in loess,blackland and lime,only two types stamen in sand.5.The effect of the individual age on the degree of feminization is great.The results show that there is significant relations between the individual age and the degree of feminlzation,which indicate the degree of feminization is increasing with individual age correspond.6.We found that A.philoxeroides have the adaptability range for the water pH values which is from 5 to 8.Although the degree of feminization has the significant difference when the water ph values change from 5 to 8,there isn’t the significant regression relation with water ph values.So,we can’t decide the degree of feminization by the water ph values.

The Variation of Flower Morphology in Alternanthera Philoxeroides (Mart.) Griseb and Its Correlates with Habitats

Abstract

Related Dissertations