# 紅藻門[编辑]

| 红藻门 化石时期：
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| --- |
|  |
| 江蓠属
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| 科学分类  |
| 域： | 真核域 Eukaryota |
| 演化支： | 多貌生物 Diaphoretickes |
| 演化支： | CAM  |
| 演化支： | 原始质体生物 Archaeplastida |
| 门： | **红藻门 Rhodophyta** Wettstein, 1922 |

**红藻門**（學名：*Rhodophyta*），是含有藻红素的一門藻類，屬於多細胞、真核細胞的生物；約有7000种。

幾乎所有的紅藻都生活在海洋中，他們生長在漲潮線以下的岩石上或較深的水中，有些物種可以在250公尺深的海裡生長。紅藻多营附着生活，不产游动细胞。

紅藻不具有根莖葉構造，但它在海洋中的生存深度超过任何植物。紅藻的顏色來自稱為藻红素的色素，其紅色遮掩了葉綠素的顏色。

紅藻生殖产生孢子和异形配子，都不具有鞭毛；雌性生殖器称果胞，上有一延长部分——受精丝，精子不能游动，随水流至果胞，与受精丝接触受精；除部分物种外，大部分存在世代交替现象。

## 系统地位

红藻是原始色素体生物的一支，其在原始色素体生物中的系统地位仍不明确，主要的观点如下表：

| 湯瑪斯·卡弗利爾-史密斯研究组
 | 帕特里克 J. 基林研究组
 | 阿拉斯泰尔 G. B. 辛普森研究组
 | Fabien Burki研究组
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| 原始色素体生物
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皮胆虫

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红藻

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绿色植物

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灰藻

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隐藻

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
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皮胆虫

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红藻

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隐藻

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灰藻

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绿色植物

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 原始色素体生物
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皮胆虫

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红藻

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灰藻

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绿色植物

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隐藻

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 原始色素体生物
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灰藻

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绿色植物

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隐藻

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皮胆虫

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红藻

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## 繁殖

红藻的生殖方式有无性生殖和有性生殖。

在无性生殖生活史中，红藻将孢子释放到水中。如果孢子遇到合适的基质（substrate），就将附着在其上开始生长。

红藻的有性生殖生活史较为复杂。较简单的一种生活史涉及到单倍的配子体和二倍的孢子体两个阶段，配子体上，雄性生殖结构产生的雄配子是不动精子（spermatangium），不具备鞭毛，借助水流移动；红藻的雌性生殖结构称为果孢（carpogonium），其上具有称为受精丝（trichogyne）的突起，用于接受精子。精子接触到受精丝并结合后，雄核经由受精丝向下移动到雌核并与之融合，形成的二倍体受精卵，受精卵有丝分裂产生果孢子（carpospore）。果孢子从亲本配子体释放到水中，附着在某处生长为孢子体，孢子体通过孢子减数分裂产生单倍体孢子。单倍体孢子又会发育为配子体，从而完成孢子体－配子体两个世代的世代交替。

大部分红藻的生活史具有三个世代的交替，这种生活史与上一种生活史的主要区别在于，精子和卵细胞结合后，受精卵并不直接分裂产生果孢子，而是通过反复进行有丝分裂，产生第三个世代，二倍体的果孢子体（carposporophyte）。果孢子体并不独立生活，只附着在亲本配子体上，并从配子体上吸收养分进行生长，果孢子体成熟后，进行有丝分裂产生果孢子，并从果孢子体释放到水中，附着在某处生长为二倍体的四分孢子体（tetrasporophyte），再进行减数分裂，产生四分孢子（tetraspore），发育成配子体。这些红藻从而完成了配子体－果孢子体－四分孢子体三个世代的世代交替。

## 參考資料