全 文 ：Effects of Extracts from Gracilaria lemaneiform on
Microalgae
LU Hui-ming1,2, LIAO Xiao-jian3, YANG Yu-feng1,2*, XU Shi-hai3
1 Institute of Hydrobiology, Jinan University,
2 Key Laboratory of the Eutrophication of Water Body and Red Tide Control, Department of Education of
Guangdong Province
3 Department of chemistry, Jinan University, Guangzhou 510632,China
Key words：Gracilaria lemaneiform; Skeletonema costatum; allelopathy; semi-effective concentration; eutrophication
大型海藻龙须菜浸出组分对中肋骨条藻的化感抑制作用
卢慧明 1,2，廖小建 3，杨宇峰 1,2*，徐石海 3
1 暨南大学 水生生物研究中心，
2 水体富营养化与赤潮控制广东省教育厅重点实验室，
3 暨南大学 化学系， 广州 510632
【摘要】 研究了龙须菜乙醇浸出组分对中肋骨条藻的化感抑制作用。结果显示，浸出组分对中肋骨条藻产生明显
抑制作用,且微藻的生物量迅速减少。当龙须菜浸出成分浓度为42mgL-1时，相对抑制率为50％，即半效应浓度（EC50）。
龙须菜对赤潮藻产生明显的化感抑制作用，延缓了富营养化水体中赤潮藻的爆发，从而使龙须菜具有控制中肋骨条
藻赤潮发生的潜在价值。
关键词：龙须菜；中肋骨条藻；化感作用；半效应浓度；富营养化
中图分类号：Q178.53 文献标识码：A 文章编号：1008-8873(2008)05-424-03


1 Introduction

Plants interact among themselves physically, but
more often by chemical means. One such chemical
interaction is allelopathy and one such chemical
substance is allelochemical. In the First World
Congress on Allelopathy [1], allelopathy was defined as
‘Any process that involves secondary metabolites
produced by plants, algae, bacteria and fungi that
influence the growth and development of biological
systems’. Some aquatic macrophytes show allelopathy
to other microalgaes, and can reduce biomass of
microalgaes by releasing allelopathic compounds [2].
This present works is to study effects of G.
lemaneiform and assess the potential of the seaweed G.
lemaneiform.




收稿日期：2008-09-10 收稿，2008-10-10 接受
基金项目：国家基金－广东省联合重点基金（U0633006）,863 项目（2007AA09Z436）,广东省高校重点项目（2007129）
作者简介：卢慧明 (1981－)，男，博士研究生，河北石家庄人，研究方向：海洋环境与赤潮。
*通讯作者，E-mail: tyyf@jnu.edu.cn
第 27 卷 第 5 期 生 态 科 学 27(5): 424-426
2008 年 10 月 Ecological Science Oct. 2008
2 Materials and Methods
2.1 Collection of samples
Samples of G. lemaneiform were collected from the
Nan Ao Island, Guangdong Province.

2.2 Alga culture
The axenic strain of G. lemaneiform was obtained
from the Algae Culture Collection, Institute of
Hydrobiology, Jinan University. Prior to the initiation
of the experiments, short-term batch cultures of G.
lemaneiform were grown in 100 ml conical flasks
filled with 60ml f/2 medium. Light source was supplied
by fluorescent tubes of one side with a daylight similar
emission. Spectrum (60µmolm–2 s–1) at 12:12L/D cycle.
The temperature was maintained at 20±1℃ in an
air-conditioned growth chamber. Cells in the
exponential growth phase were collected from batch
cultures and used as the inocula for the following
experiments.

2.3 Preparation extracts of G. lemaneiform
G. lemaneiform (2.3kg dry weight) was cut into
uniform lengths (2 cm). These fragments were
immersioned in anhydrous alcohol (40kg) for 30d. The
extracts were concentrated to 50 ml at 50℃under
reduced pressure in an evaporator. The concentrated
extract (50ml) was filtered through a Whatman GF/C
filter. These extracts were then stored at -20°C until
required.

2.4 Data processing
The relative inhibitory rate of extracts from
G.lemaneiform on algae growth[3].
IR(%)＝(1-T/C)×100% (1)
IR－relative inhibitory rate, T－treatment group, C
－control group
3 Results and Discussion
3.1 Effect of extracts from G. lemaneiform on algae
growth
Model of logistic suitable for control algae growth,
however treatment algae growth suffered a certain
influence and growth curve also has changed. And the
concentration of algae is at the low level all the time.
The result shows that allelochemical could significantly
inhibit algae growth (p＜0.01). 42mgL-1 of extracts
from G. lemaneiform shows that the relative inhibitory
rate is 50% (EC50) [4].

3.2 Effect of extracts from G. lemaneiform on algae
cell morphology
The micro-measurement indicates that the cell
volume of the treatment algae is bigger than that of the
control,
unclear borders and the color of the cells is hardly
removed. From which we can infer that cell structure is
lysed gradually.
3.3 discussion
The growth of S. costatum at corresponding initial
cell density is significantly reduced in the presence
extracts of G. lemaneiform. In general, most coexistence
studies have demonstrated allelopathic effect of many
macrophytes on algae [5-6], but the mechanism is poorly
understood. Studies using Escherichia coli liposomes
have shown that the effect of terpenes on the structural
and functional properties of biological membranes was
directly related to accumulation in these membranes, the
effect was independent of the structural features of the
molecules [7]. Effects included swelling of the
membrane bilayer, changed in membrane fluidity and
increased passive flux of protons. Other studies have
shown that terpenes have the ability to disrupt or
penetrate lipid structures [8].
In conclusion, allelopathy is a quite complex system
engineering problem, which relates to many index
factors of signals transduction pathway, action site,
ablation of allelochemical substances, changes in cell
structure and organelle.
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426 生 态 科 学 Ecological Science 27 卷