Plant Kingdom Definition and Types

Introduction:

• All the plants are placed in the Kingdom- Plantae, according to the five-kingdom classification by R.H. Whittaker.
• The Kingdom- Plantae consists of multicellular plants with eukaryotic organization and chlorophyllous cells.
• Usually, they are autotrophic i.e. prepare their food but a few members are heterotrophic like insectivorous plants which capture and digest insects to get nutrition, for example, Venus flytrap, Bladderwort, etc.
• Some heterotrophic plants are parasites i.e. they live on other plants and absorb water and nutrients from the host body, for example, Cuscuta.
• The eukaryotic cells of plants have chloroplasts which are the plastids in which green-colored pigment chlorophyll is present. They consist of cellulosic cell walls.

Classification of Plant kingdom

- The Plant kingdom is divided into two groups based on their ability to produce seeds. These groups are- Cryptogams (seedless plants) and Phanerogams (seed-bearing plants).
 

• Cryptogams include- Thallophyta, Bryophyta, and Pteridophyta.
• Phanerogams consist of Gymnosperms and Angiosperms.
• Oswald Tippo, University of Illinois 1942, classified plant kingdom into two subkingdoms: Thallophyta (thalloid plant body without distinct alternation of generations and no embryo) and Embryophyta (organ level differentiation of plant body with regular alternation of sporophyte and gametophyte generations and embryo present).
• As we move from Bryophytes to Angiosperms the gametophyte gets reduced, whereas, sporophyte becomes well developed.
• : Plant Kingdom is further classified into subgroups of Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms which is based on the following criteria:
• Plant Body: Presence or absence of well differentiated plant parts like stem, root and leaves.
• Vascular tissue : Presence or absence of complex tissue i.e. Xylem( water and mineral conducting tissue) and Phloem (food translocating tissue)
• Seed formation: Presence or absence of flowers and naked seed or covered seed.

In this chapter we will learn about the following Concepts:

• Biological Systems of Classification & branches of taxonomy
• Algae-
• Bryophytes-
• Pteridophytes-
• Gymnosperm-
• Angiosperm-
• Lifecycle patterns-

Quiz:

Q1. The reproduction in Algae occurs by
(1) Vegetative
(2) Asexual
(3) Sexual
(4) All of these

Q2. Asexual reproduction is the production of different types of spores. Out of that most common is
(1) Carpospore
(2) Zoospores
(3) Basidiospores
(4) Akinetes

Q3. Select the wrong statement.
(1) Isogametes are similar in structure, function and behavior
(2) Anisogametes differ either in structure, function and behavior
(3) In oomycetes female gamete is smaller and motile, while male gamete is larger and non-motile
(4) Chlamydomonas exhibits both isogamy and anisogamy and Fucus shows oogamy

Q4. The gemmae produced by some liverworts function as:
(1) A water gathering structure
(2) A light capturing structure
(3) A sexual structure
(4) An asexual structure

Q5. The plant body of moss (Funaria) is
(1) completely sporophyte
(2) predominantly sporophyte with gametophyte
(3) completely gametophyte
(4) predominantly gametophyte with sporophyte

Q6. Which one is correct about heterosporous pteridophytes?
1. Microspore and megaspores develop into the male and the female gametophytes respectively.
2. The female gametophyte is retained on the parent sporophyte for a variable period.
3. The development of the zygote into the embryo takes place within the female gametophyte.
4. All

Q7. Read the following statements carefully and mark the correct w.r.t. gymnosperms
a. Pollen grains are carried by air currents
b. Pollen tube carries the male gametes to archegonia
c. Ovules are exposed before fertilization but get covered after fertilization
d. They produce same type of spores
1. (a,b&d)
2. (a & b)
3. (a&c)
4. (b & d)

Q8. Select the correct statement(s)
1. Only a few bryophytes are heterosporous
2. Double fertilization is unique to angiosperms
3. Strobili are found in Selaginella & Salvinia
4. Female gametophytes of gymnosperm have an independent free-living existence

Q9. Both bryophytes and pteridophytes:
1. are vascular cryptogams
2. have a dominant sporophyte
3. reproduce only sexually
4. are haplo-diplontic

Q10. Consider the following four statements whether they are correct or wrong
(A) The sporophyte in liverworts is more elaborate than that in mosses
(B) Salvinia is heterosporous
(C) The life-cycle in all seed-bearing plants is diplontic
(D) In Pinus male and female cones are borne on different trees
       The two wrong statements together are :
       1. Statements (A) and (B)
       2. Statements (A) and (C)
       3. Statements (A) and (D)
       4. Statements (B) and (C)

Answer key:

1. (4)
2. (2)
3. (3)
4. (4)
5. (4)
6. (4)
7. (2)
8. (2)
9. (4)
10. (3)