The Life Cycle of Chara, a Fresh Water Green Alga

This animated short film is a look at the life history of Chara, a close relative of embryophytes (land plants). A life history is the series of growing and reproductive changes an organism undergoes throughout its life. Chara is a genus in the fresh water green algal family Characeae, commonly called stoneworts or musk grasses. For this video, the morphology of Chara rusbyana was studied by using a living culture and by consulting the botanical literature. A key difference between the life history of land plants and the Characeae is that alternation of generations is found in land plants but not in the Characeae. Given that the Characeae are close relatives of land plants, understanding their life history is valuable to our ever-broadening knowledge of the early evolution of land plants.
Narration Text:
In this freshwater pond, a close cousin of land plants is about to begin its life cycle. It is in the family of algae called the Characeae.
We will begin with the zygospore, a dormant zygote deposited here by its mother plant previous year.
The single cell within contains starchy nutrients from its mother that feeds its infantile growth. Before dividing even once, the diploid zygote undergoes meiosis… or so we think, as this has yet to be confirmed.
Humans are diploid. Meiosis occurs before fertilization in order to create haploid gametes from our diploid genome, forming a diploid zygote that then undergoes mitosis.
Chara rusbyana is haploid. Meiosis occurs after fertilization in order to create its haploid genome from a diploid zygote, formed by haploid gametes that were created by mitosis.
Either way, this mixes the parents’ genomes and creates completely new gene combinations in the offspring - the evolutionary benefit of sexual reproduction.
What emerges from the top of the spore coat is a single haploid cell. At its first division, the larger cell becomes the root-like rhizoid and the smaller cell the green photosynthetic filament.
The green filament bulges and first grows a whorl of five simple branchlets. The apex continues to grow until another whorl appears with yet another contained within it, and another… and another.
After the first whorl of 5 branchlets, most of the plant body is covered by rows of cells forming a protective cortex.
Eventually, some nodes will grow axillary buds that become new apices and branch off of the main plant body.
Some Characeae, such as this Chara rusbyana grow more adventurous branches that extend centimeters from the plant. These Grovesian Branches propagate the plant.
Over the course of the season the alga well establishes itself.
Our plant happens to be a male. Fortunately a female seems to be growing nearby.
And by now they have grown near enough to have sex.
We know our plant is male by its orange sperm-producing organs called Antheridia.
Inside of this Antheridium, filaments of cells propagate by mitosis - their cytoplasm becoming sperm, which swim free upon maturity.
The 8 scutum cells then open to release the batch into the water.
The female alga has also been busy growing its egg cell structures, the Oogonia. The Oogonium consists of a large egg cell surrounded five twisted cortex cells and five tip cells at the top entrance.
A single sperm finds its way to the top of the oogonium where it swims in to fertilize the egg, creating a diploid zygote. The Oogonium stores starch around the zygote and forms a calcified shell for protection. The zygospore then falls from the mother plant to the pond floor awaiting the Spring.
It will then undergo meiosis to mix its parents’ genes and keep one of the four mixed copies for itself and repopulate this pond once again in the spring.

[@carleypekelder9397]

This is super well done and very clear. Good job. I'm having trouble finding videos to study for my Biology of Algae class and this was the only one even remotely relevant or helpful. Thanks a lot.

[@chitrakshrathore1662]

Same here boi

[@chitrakshrathore1662]

Wanna learn more

[@savannahyoung1246]

Dude..why was this so pretty?! I loved it!!

[@pathikritmanna9571]

Amazing! Thanks a lot!

[@adibanaj2686]

Very good vedio

[@wrestpinpeace]

This is amazing

[@miramiramiraa]

I'm spooked by the background music, srsly

[@liveyou8569]

haha

[@arunima713]

very helpful💗

[@gurubharathi8645]

10y ago but still useful ❤

[@mdshahid7695]

Pls continue with this type Video

[@meghanakoligapogu9511]

Brilliant explanation

[@sudhirkumaryadav655]

Nice and very informative video

[@mdshahid7695]

Awesome....

[@naureenkhan5404]

Beautifully explained👍

[@elitemaster8245]

Woww amazing . Perfect . Stunning.

[@botanyinformationorstudy8670]

beautiful animation 😍😍

[@vijayalakshmi76sakthivel69]

Clear cut vedio Thanks for making and please make more vedios in botony and Keep rocking

[@FizzFixx]

thanks sir

[@warriorfutured6707]

Thanks🙏🙇 it will really help in my test

[@hbl9587]

This video is very helpful for me thanks

[@EjazKhan-it3ro]

thanks ! it's very helpful ...

[@Yooopinky]

It's very good

[@wcdeich4]

What is the life cycle of the green thread algae found in aquariums?

[@safepancake7551]

I never knew there were primitive plants in the water so much like land plants, I just assumed they were like algae, with multicellularality evolving on land

[@dolmalhamu6000]

perfect

[@wahajuddin2323]

The background music is so scary

[@rohitnorke8738]

i want life cycle of chara in hindi ,please make video know

[@RobStewart1085]

I don't have the resources to make a video in Hindi. However, I put the narration text in the video description. I hope it translates well for you. Thank you for your support!

[@gemianita1939]

so,u mean to say that both antheridium and oogonium originate from the same plant?

[@RobStewart1085]

In C. rusbyana, the antheridium and oogonium do not originate from the same individual plant. C. rusbyana is a dioecious species. However, many species in the genus Chara are monoecious. Many of these will also grow their antheridia and oogonia conjoined on the same branchlet node. In order to prevent self-fertilization, these monoecious species often use separate timing for the release of sperm and the maturity of the oogonia.

[@qiuyiyu1727]

Meiosis occurs after fertilization. TENET.

[@jamilyjuraszek]

isso aqui é elite

[@loveguru5962]

nice

[@wikissum-n-why7146]

perfecte

[@DarkAngel48565]

I studied that its monoecious.

[@RobStewart1085]

Many species of Chara are monoecious. C. rusbyana in particular though is dioecious and relatively hard to find. My professor gave me a sprig of C. rusbyana from his master culture to observe growing. It was a dioecious male culture consisting of one robust, asexually-reproducing individual. Genetic data has also confirmed it is one individual.

[@NatetheNintendofan]

it's chara But she replaces flowey

[@shanthala1345]

Lit

[@suryakantprajapati1647]

In handi undrestant

[@amirelfatimi8275]

Like se devi dare biodiversità vegetale

[@anamelesscommenter9700]

Why? WHY do I think of Undertale?!

[@canceledthissucks1745]

Sure I do!

[@RobStewart1085]

Sorry, wrong Chara. Also, not the NHL player.

[@baluluckyrishitha]

as chara ishaploid algae how it show sexual dimorphism

[@RobStewart1085]

The male plants have red to orange antheridia. The female plants have white, grey, or black oogonia. The color of the oogonia can indicate whether it is immature, mature, or has been fertilized. Color does vary between species and genera.

[@Lazybones593-32]

Er er er undertale

[@buck9668]

Charophyte reproduction