- Xanthophyta, or yellow-green algae, is a division of algae that includes 375 species across 75 genera. They range from single-celled flagellates to simple colonial and filamentous forms. - They are mostly found in freshwater but some occur in marine and soil environments. Their cells contain chlorophyll a and beta carotene and store food as oils and fats. - One example is the class Vaucheria, which contains about 70 species. Vaucheria have bladder-like coenocytic thalli that are differentiated into underground rhizoidal and aerial vesicular portions.

1. XANTHOPHYTA
Yellow green algae

2. Presented by:
Sohail Hashmi
Presented to:
Dr Umair Ahmed Awan

3. CONTENTS
01
02
03
Introduction
Genral account
Evolution
Classification04

4. SECTION 1
introduction and genral
account

5. INTRODUCTION
• Yellow-green algae or the Xanthophyceae are an important group of
algae
• Most live in fresh water, but some are found in marine and soil
habitats
• They vary from single celled flagellates to simple colonial and
filamentous forms
• Oil and fats are usual reserve food products
• The division includes 375 species and 75 genera

6. Characteristics of Class Xanthophyceae (Yellow Green Algae)
• Mostly fresh water and unicellular
• Cells are eukaryotic with silica and pectin in the cell wall
• Chief pigments include chlorophyll a and e, beta carotene, neoxanthin and
violaxanthin
• Reserve food includes chrysolaminarin and oils,Starch and pyrenoids absent
• Sexual reproduction is isogamous, anisogamous or oogamous
• Zoospore formation is common
• Male gametes are flagellate
• Flagella are heterokont (unequal)
• Life cycle is mostly haplontic

7. C l i c k h e r e t o a d d t o t h e t i t l e

8. Pigments
• Xanthophyte chloroplasts contain the photosynthetic pigments
• chlorophyll a
• chlorophyll c
• β-carotene
• carotenoid diadinoxanthin
• Unlike other heterokonts, their chloroplasts do not contain
fucoxanthin, which accounts for their lighter colour
• Their storage polysaccharide is chrysolaminarin
• Xanthophyte cell walls are produced of cellulose and hemicellulose

9. Classification
• The species now placed in
the Xanthophyceae were
formerly included in the
Chlorophyceae
• In 1899, Lüther created the
group Heterokontae for green
algae with unequal flagella
• Pascher (1914) included the
Heterokontae in the
Chrysophyta
• In 1930, Allorge renamed
the group as Xanthophyceae Vaucheria

10. Classification
• Xanthophyceae have been divided into the following four orders
in some classification systems:
• Order Botrydiales
• Asterosiphon
• Botrydium

11. Order Mischococcales
• Botrydiopsis
• Botryochloris
• Bumilleriopsis
• Chlorellidium
• Mischococcus
• Monodus
• Ophiocytium
• Pleurochloris

12. Order Tribonematales Pascher
• Bumilleria
• Heterococcus
• Heterothrix
• Tribonema
• Order Vaucheriales
• Vaucheria

13. Lüther system of classification
• Classification according to Lüther (1899)
Class Heterokontae
Order Chloromonadales
Order Confervales
Classification according to Pascher
 Heterokontae
 Heterochloridales
 Heterocapsales

14. Evolutionary perspective
• Three major evolutionary lines can be traced among the Xanthophyta
I. One line may have developed from an unicellular motile ancestry giving rise to
non-motile unicells which may be solitary or colonial
II. Another tendency is to produce a tubular, or siphonaceous form
III. While the third one is leading to the formation of multicellular filamentous
type

15. Reproduction
1. Vegetative reproduction
• the reproduction in filamentous form oocur by fragmentation
• unicellular forms divided by simple division

16. Asexual reproduction
• They form one or more zoospores in each cell.Zoospores are
biflagellated.The flagella have unequal length.The longer flagella is
tinsel type and shorter flagellum is whiplash type
• aplanospores are also produced in some bacteria
• Sexual reproduction
• sexual reproduction is rare in this group.sexual reproduction is
oogamous or sometimes isogamous type
• in case of oogamous antheridia and oogonia are produced

17. examples
i. Unicellular motile form e.g Chloramoeba,heterochloris
ii. Palmelloid forms e.g Chlorosaccus,chlorogolea.
iii. Dendroid forms e.g Mischococcus
iv. Rhizopodial forms e.g Stipitococcus
v. Coccoid form e.g Chlorobotrys

19. Thallus
• The plant body is bladder like unicellular,coenocytic and
yellowish green
• It is differentiated into underground rhizoidal portion and an
aerial vesicular portion
• The thallus is surrounded by a tough cellulose cell wall .Just
inner to the cell wall is present a layer of cytplasm which
surrounds a large central vacuole
• Starch formation is totally absent

20. Vaucheria
• One example of a relatively common Xanthophyta is the class Vaucheria
that gathers approximately 70 species
• whose structure consists of several tubular filaments, sharing its nuclei
and chloroplasts without septa
• They live mainly in freshwater, although some species are found in
seawater spreading along the bottom like a carpet

23. Thank you