PLANT KINGDOM
IMPORTANT POINTS
Fungi, monerans, protists were earlier included in plant Kingdom but not now. BGA is not an algae anymore
Various Systems of classification
Earlier systems were based on gross morphology like habitat,
colour, no. & shape of leaf
Artificial system Natural system Phylogenetic system
Based on natural affinities among
Based mainly on vegetative characters Most acceptable, based on
organisms & consider external, internal,
(easily affected) or on the androecium evolutionary relationships, organism
ultra structure, anatomy, embryology,
structure. Eg- Linnaeus classification of s belonging to Same taxa have
photochemistry. Eg- George Bentham
plants based on no. Of androecium. common ancestor.
& Joseph Dalton Hooker classification
It had drawbacks like it separated
of flowering plants
closely related species, were based on
few characters & equal weightage
given to vegetative & sexual characters
DIFFERENT KINDS OF TAXONOMY
NUMERICAL CHEMOTAXONOMY
TAXONOMY
Chemical constituents of
Based on observable
the plant to resolve confusions
characters using computers
(no. & codes are assigned to
each character) each
character is given equal
CYTOTAXONOMY
importance. Based on
chromosome no.,
structure, behaviour
ALGAE/THALLOPHYTA
INTRODUCTION ECONOMIC IMPORTANCE SIZE & FORM REPRODUCTION
They are chlorophyll bearing simple They fix 1/2 of the total CO2, They are Chlamydomonas( microscopic
thalloid, autotrophic & largely aquatic primary producers & is energy source unicellular), volvox( colonial), ulothrix &
for aquatic animals Fg- PORPHYRA, VEGETATIVE: By fragmentation. Each
(both fresh & marine) org. Some algae LAMINARIA, SARGASSUM are used as food. spirogyra(filament ous), kelps (massiv fragment develops into thallus
form association with fungi(lichen). Algin (brown algae) & carrageen (red e marine form)
algae) produce hydrocolloids (water
with animals (on sloth bear) holding subst.) Agar is produced from ASEXUAL: By production of zoospores
Geledlum & gracilaria. Chlorella & (motile)
spirullina are used as space food
(SCP-Single cell protein)
SEXUAL: By fusion of 2 gametes
Isogamous Anisogamous Oogamous
Gametes are similar in size Gametes are different in size but of same capability Female gamete is non motile but male is
1) if motile- chlamydomonas to move Eg- some species of chlamydomonas motile Ey- volvox, fucus
2) if nonmotile- spirogyra i.e. Udorina
TYPES OF ALGAE
Chlorophyceae /green algae: Plant body is unicellular/colonial/ filamentous. Possess chl-a & b. Possess different shapes.
Have stored food as starch or oil. Have pyrenoid(starch synthesis) body in chloroplast for storing protein. Inner cell wall->cellulose &
outer wall->pectose. Vegetative rep.=> fragmentation, spores. Asexual =>by zoospores. Sexual =>isogamy, anisogamy, oogamy.
Found in fresh, brackish, salty water. Have 2-8 equal & apical flagella
Eg-chlamydomonas, volvox, ulothrix,s pirogyra, chara
Phaeophyceae /brown algae: Branched, filamentous (ectocarpus). Have chl a,c,xanthophylls, caroteins. Have stored food
as laminarin or mannitol. Have cellulosic cell wall. Have gelatinous covering of ALGIN. Plant parts are Holdfast,stipe, frond.
Vegetative-> by fragmentation. Asexual-by zoospores (heterokont) sexual-> by iso,aniso,oogamy. Gametes are pyriform
(pear shaped) & bear a laterally placed flagella. Found rarely in fresh water, mostly in brackish & salt water. Have 2 unequal lateral
flagella. Cellulose, pectin & polysulphate esters are found in cell wall.
Eg-Ectocarpus, dictyota, laminaria, sargass um,fucus, kelps
Rhodophyceae /red algae: They are multicellular. Have red pigment r-phycoerethrin. Found in warmer areas & occur in
all light regions. Stored food is floridean starch which is similar to amylopectin & glycogen in structure. Vegetative-> frag.
Asexual-> nonmotile spores Sexual->oogamous by non motile spores. Found some in fresh & brackish water but most in salt water.
Do not have any flagella.
Eg-polysiphonia, porphyra, glacilaria, geledium
BRYOPHYTES
(AMPHIBIANS OF PLANT KINGDOM)
Live in soil but dependent on water for sexual repro. Play important role in plant succession on bare rocks/soil They also have
INTRODUCTION thalloid like body but more differentiated than algae. Main members of bryophytes are mosses
Sex organs are multicellular and jacketed. Male sex organ -> Anthridium (antherozoid) Female sex organ -> archaegonium
(eggcell) SEX ORGANS
It is thallus like, prostrate & erect. Have rhizoids in place of roots. Lack true root, stem, leaf but may possess structure like
STRUCTURE/PLANT BODY them. Main plant body is haploid (gamatophytic cause produces gametes)
Antherozoids (n) released in water come in contact with archaegonium/egg(n) -> zygote (2n)
->sporophyte(2n) -> spores(n) -> germination -> gametophyte(n) FERTILISATION & DEVELOPMENT
Some mosses provide food for herbaceous mammals, birds, other animals. Species of sphagnum, a moss provide peat
ECONOMIC that have long been used as fuel, and because of their capacity to hold water used as packing material for
transshipment of living material. Mosses with lichens are first to colonise rocks & hence are of great ecological
IMPORTANCE importance. Act as Decomposers of rocks making suitable for growth of higher plants. Form green matts &
prevents soil erosion.
Plant body is thalloid & thallus is dorsiventral & closely appressed to substrate. Leafy members have tiny leaf in rows
looking like stem. Perform ASEXUAL by fragmentation or gemmae formation & SEXUAL as sex organs are present on
same or diff. thalli. Sporophyte is consist of foot + setae + capsule. Spores are produced within capsule. They have LIVERWORTS
free living gametophyte & sporophyte is parasitised on it. Eg- marchantia,
Predominant stage is gametophyte. Consists of 2 stages- >protonema & leafy. Protonema develops from spore, creeping
MOSSES green, branched & frequently filamentous stage. Leafy develops from sec. protonema as a lateral bud,consist of spirally
arranged leaves (this stage contains sex organs). Perform ASEXUAL by fragmentation & budding in sec. protonema or
SEXUAL by antheridia, archaegonia. After fertilisation zygote develops into sporophyte. They have elaborate mechanism
of spore dispersal. Eg-funaria, sphagnum, polytrichumriccia
