PLANT KINGDOM
PLANT KINGDOM: Eukaryotic, multicellular, chlorophyll containing and having cell wall, are grouped the area Plantae, popularly known as plant kingdom.
Phylogenetic system
of bracket grounded on evolutionary relationship is presently used for
classifying plants.
Numerical Taxonomy
use computer by assigning law for each character and assaying the features.
Cytotaxonomy is
grounded on cytological information like chromosome number, structure and
geste.
Chemotaxonomy uses chemical ingredients of plants to resolve
the confusion.
PLANT KINGDOM
PLANT KINGDOM
Thallophyta- Comprises the simplest plants which retain undifferentiated or thallus like forms, reproductive organs single celled called gametangia. It includes only Algae.
ALGAE
PLANT KINGDOM
Characteristic of
Algae
• Plants body is
thallus, which may be unicellular, social, filamentous or parenchymatous.
• Generally submarine but a many are also plant in wettish
terrestrial territories like tree caddies, wet jewels, wettish soiletc.
• Vascular tissues and mechanical tissues are absent.
PLANT KINGDOM
• Reproduction is
vegetative by fragmentation, asexual by spore conformation (zoospores) and
sexual reproduction by emulsion of two gametes which may be Isogamous
(Spirogyra), Anisogamous (Chlamydomonous) or Oogamous (Volvox).
• Life cycle is colorful-haplontic, diplontic or diplohanlontic.
Economic significance-
(i) A number of brown
algae (Laminaria, Sargassum) are used as food in some countries.
(ii) Fucus and
Laminaria are rich source of Iodine.
( iii) Laminaria and Ascophyllum have antibiotic parcels.
(iv) Alginic acid is
attained from Fucus and Sargassum, which is used as mixes.
BRYOPHYTES – They're non-vascular mosses and liverworts that grow in wettish shady region.They're called amphibians of plants area because these plants live on soil but dependent on water for sexual reproduction.
Characteristic
features-
• Live in damp and
shady territories, plant to grow during stormy season on damp soil, jewels,
walls etc.
• The dominant phase
or plants body is free living gametophyte.
• Roots are absent
but contain rhizoids
• Vegetative reproduction is by fragmentation, tubers,
gemmae, kids etc. coitus organs are multicellular and jacketed. Antheridium and
archegonium produce male and womanish gametes called antherozoids and egg or
oospore.
• Sporophyte is sponger on gametophyte.
Liverworts
The thallus is
dorsiventral flattened, dichotomously fanned with or without splint-such like
accessory.
Unicellular rhizoids,
multicellular scales and fully parasitic sporophyte or sporangium.
Asexual reproduction takes place by fragmentation thallus or
conformation of technical structure called gemmae. Gemmae are green,
multicellular, asexual kids, which develops in small containers called gemma
mugs. The gemmae becomes detached from the parent body and germinate to form
new individualities.
During sexual reproduction
male and female sex organs are produced on same thallus or different.
The sporophyte is
discerned into bottom, seta and capsule.
Mosses
The gametophyte of mosses consists of two stages-the first
stage is protonema stage, which develops directly from spores and creeping,
green, constantly filamentous. The alternate stage is the lush stage, which
develops from secondary protonema as side cub having upright, slender axes
bearing spirally arranged leaves.
Vegetative reproduction
by the fragmentation and budding in secondary protonema. A coitus organ
develops on lush shoots.
Sporophytes in mosses are more advanced and correspond of bottom, seta and capsule. Common exemplifications are Funaria, Polytrichum, Sphagnum etc.
Pteridophytes
They're seedless vascular plants that have sporophytic plants
body and invisible gametophyte. Sporophytic plants body is discerned into true
stem, roots and leaves.
Vascular tissue are present
but vessels are absent from xylem and companion cells and sieve tube are
absent.
Sporophytes bear
sporangia that are subtend by splint like accessories called sporophylls. In
some plants (Selaginella) compact structure called strobili or cone is formed.
Sporangia produce
spores by meiosis in spore mama cells. Spores germinate to produce
multicellular thalloid, prothallus.
Gametophyte bears male and womanish coitus organ called
antheridia and archegonia. Water is needed for fertilisation of male and female
gametes.
Most of Pteridophytes
produce spores are of analogous kind (homosporous) but in Selginella and
Salvinia, spores are of two kinds (heterosporous) larger called megaspore that
produce womanish gametophyte and lower microspore that produce male gametes.
Gymnosperms
• Gymnosperms are
those plants in which the ovules aren't enclosed inside the ovary wall and
remain exposed before and after fertilisation.
• They're imperishable and woody, forming either backwoods
or trees. Some are veritably large (Sequoia sempervirens) and others are
veritably small (Zamia pygmia).
• Stem may be
unbranched (Cycas) or fanned (Pinus). Root is valve. Leaves may be simple or
emulsion.
• They're
heterosporous, produce haploid microspore and megaspore in male and womanish
Strobili independently.
• Male and female
gametophytes don't have independent free-living actuality. Pollination occurs
through air and zygote develops into embryo and ovules into seeds.
• Illustration-Pines, Cycus, Cedrus, Ginkgo etc.
Angiosperms
Pollen grain and
ovules are developed in technical structure, flower. Seeds enclosed inside the
fruits.
Size varies from
nearly bitsy Wolfia (0.1 cm) to altitudinous tree Eucalyptus ( further than
100m).
Double fertilisation-
Each pollen grain produce two male gametes. One gametes fuse with egg to form embryo, Syngamy and other gametes fuse with two polar capitals to form endosperm, triadic fission. Since fertilisation takes place doubly so, it's called double fertilisation.
Alternation of generation
Different plants
groups complete their life cycles in different patterns.
Angiosperms complete their life cycle in two phases-a
diploid sporophytes and haploid gametophyte. The two follows each other. This
miracle is called alternation of generation.
(a)
Haplontic-Saprophytic generation is represented by only the one-celled zygote.
Meiosis in zygote results into haploid spores to form gametophytes, which is
the dominant vegetative phase. Illustration-Volvox, Spirogyraetc.
(b) Diplontic-Diploid
sporophytes is dominant, independent, photosynthetic plants. The gametophyte is
represented by single to many celled. All seed bearing plants fall under this
order.
(c)
Haplo-diplontic-Both phases are multicellular and intermediate condition is
present. It's present in Bryophytes and Pteridophytes.
