Questions - Answers

1. Differentiate fibrous roots from adventitious roots.
A:

2. Define "Modification". Mention how root is modified in Banyan tree and Mangroove plants.
A: Any permanent variation or deviation from the normal structure of an organ to perform a special function other than its normal functions is called modification.
Modification of the root in: 
Banyan tree (Ficus bengalensis): Adventitious roots produced from the branches grow positively

geotropic, become stout and fix in the soil. These are called "Prop roots" or "Pillar roots". They give additional mechanical support.
Mangrooves: The root system of these plants do not get sufficient oxygen in the soil as they grow in marshy, swampy areas. So some of the lateral roots grow positively phototropic and grow erect above the soil. These are called "Pneumatophores" and they bear numerous pores called Pneumathodes which help in respiration.
 

3. What type of specialised roots are present in Epiphytes? What is their function?
A: Epiphytes have 3 kinds of specialised roots.
      * Clinging roots 
      * Velamen roots
     * Assimilatory roots
Clinging roots: These are present in Vanda which help in fixation only.
Velamen roots: These are areal, hanging colourless roots with a dead, multi layered, hygroscopic tissue. Their function is to absorb moisture from the atmosphere.
e.g.: Vanda
Assimilatory roots: These are present in Taeniophyllum. They prepare food.

4. How does the Sucker of Chrysanthemum differ from the Stolon of Jasmine?
A:

5. What is meant by pulvinus leafbase? In members of which angiospermic family do you find them?
A: The swollen leaf base is called pulvinus leaf base. It is seen in the members of Leguminaceae.
e.g.: Dolichos, Butea

6. Define "Venation". How do dicots differ from monocots with respect to venation?
A: Veins are made of vascular tissues. The arrangement of veins and veinlets in the lamina of leaf is called Venation. Veinlets form network in dicots. It is called Reticulate venation. In Monocots veins run parallel. It is called Parallel venation.
 

7. How is a Pinnately compound leaf is different from a Palmately compound leaf? Explain with one example each.
A:

8. Which organ is modified to trap insects in insectivorous plants? Give 2 examples.
A:  The leaves are modified into trap leaves to catch, kill and digest insects. e.g.: Nepenthes (pitcher plant), Drosera (Sundew), Dionea (Venus flytrap) and Utricularia (Bladderwort)

9. Differentiate between Racemose and Cymose inflorescences.
A:

10. What is the morphology of cup like structure in Cyathium? In which family it is found?
A:  The cup like structure in Cyathium is made of involucre. It is found in Euphorbiaceae.
e.g.: Poinsettia, Euphorbia.
 

11. What type of inflorescence is found in fig trees? Why does the insect Blastophaga visits the inflorescence of fig tree?
A: The inflorescence in fig trees (Ficus sp) is hypanthodium. It belongs to the family Moraceae. Blastophaga visits its inflorescence to lay the eggs in the female sterile flowers (Gall flowers)

12. Differentiate actimorphic and zygomorphic flower.
A:

13. How do the petals in Pea plant are arranged? What is such type of arrangement called?
A: Corolla of Pea plant is called Papilionaceous corolla. It has 5 petals. The larger, odd petal (Vexillum) is present on the posterior side. It overlaps 2 side petals called wings or alae. They overlap the 2 anterior, fused smallest petals called keel or carina. The over lapping is from posterior end to anterior. It is called "Vexillary aestivation" or Descending imbricate aestivation.

14. What is meant by epipetalous condition? Give an example.
A: If stamens are attached to petals by their filaments it is called epipetalous condition. It is the characteristic feature of Gamopetalae.
       e.g.: Datura, Solanum. It is also seen in a polypetalous family like Malvaceae.
 

15. Differentiate between apocarpous and syncarpous ovary.
A:

16. Define placentation. What type of placentation is found in Dianthus?
A: Arrangement of ovules, attached to the placenta in the ovary is called placentation.
     The ovules in Dianthus (and also in Primrose) are attached to the central axis of multicarpellary, syncarpous and unilocular ovary. It is called free central placentation.
 

17. What is meant by parthenocarpic fruit? How is it useful?
A: If a fruit is formed from the ovary without fertilisation, it is called parthenocarpic fruit. The phenomenon is called parthenocarpy. The fruits are seedless. e.g.: Banana, Pine-apple.
    These are useful as they contain more fleshy edible part without seeds.
 

18. What is the type of fruit found in Mango? How does it differ from that of coconut?
A: The fruits in mango and coconut are drupe.

19. Why certain fruits are called false fruits? Name 2 examples of plants having false fruits?
A: If a fruit is formed the ovary along with other parts of the flower like thalamus and pedicel it is called false fruit.  e.g.: Cashew, Apple, Strawberry.
* In Anacardium occidentale (cashew) pedicel becomes fleshy, false fruit. It bears true fruit at the tip.
*  In Pyrus malus (Apple), thalamus becomes fleshy, juicy edible false fruit. It encloses true fruit.
 

20. Name any two plants having single seeded dry fruits.
A: All dry, indehiscent fruits are single-seeded.
    i) Caryopsis: The pericarp and seed coat are fused.
         e.g.: Grass (Rice, Wheat, Jowar etc.)
    ii) Nut: The pericarp and seed coat are free. Pericarp is woody.
         e.g.: Cashew
 

21. Define schizocarpic dry fruits. Give an example.
A:  Dry fruits which burst but do not liberate seeds are called schizocarpic fruits. They burst and liberate one seeded mericarps.  

e.g.:  Acacia arabica.
* The fruit in it bursts transversely in the region of constrictions. The fruit is called lomentum.

22. Define mericarp. In which plant you find it?
A: A one-seeded, dry, piece of schizocarpic fruit liberated after bursting is called mericarp.
        e.g.: Acacia arabica, Mimosa
 

23. What are aggregate fruits? Give 2 examples.
A: Fruits formed from apocarpous pistil are called aggregate fruits. Number of fruitlets are formed from such pistil and all are attached to a common stalk like a bunch. It is called Etaerio.
       e.g.:  Annona squamosa (Custard apple)
 

24. Name a plant that has a single fruit developing from the entire inflorescence. What is such a fruit called?
A: The fruit formed from entire inflorescence is called multiple fruit or compound or composite fruit.      

e.g.: Pine-apple (Ananas sativus)
        Jack fruit (Aetocarpus integrifolia)
        Fig (Ficus carica)

25. What is meant by scutellum? In which type of seeds it is present?
A: The cotyledon in monocot seeds is called scutellum. It is shield shaped.
      e.g.: Maize, Rice

26. Define endospermic and non endospermic seeds with examples.
A: In angiosperms, after double fertilisation 
     i) Zygote develops into embryo and
     ii) Primary Endosperm Nucleus develops into endosperm.
     iii) Ovule becomes seed.
* Endosperm supplies food to the developing embryo.
* After seed formation if endosperm is still left, it is called endospermic or albuminous seed.
     e.g.: Rice, Wheat, Maize, 
             Cocos, Datura, Annona etc.
* If endosperm is completely consumed for the development of embryo, the seed is called
     non-endospermic or exalbuminous seed.
      e.g.: Bean, Pea, Red gram etc.

27. Justify the statement: "Underground parts of plants are not always roots".
A: Underground parts of plants need not be roots always. They may also be stem parts.
     All underground stem modifications look like roots under the soil but they are all stems 
     due to the following characters.
* Presence of scale leaves
* Nodes and internodes
* Presence of axillary and terminal buds
* Presence of adventitious roots.
 

28. Describe any two special types of inflorescence.
A: Some types of inflorescence called special types of inflorescence because:
* They are confined to some plants or some families only.
* Arrangement of the flowers remain special.
* Opening of the flowers also remains special.
There are 3 kinds of inflorescence:
  i) Cyathium        ii) Verticillaster          iii) Hypanthodium

Cyathium: It is confined to Poinsettia and Euphorbia (Euphorbiaceae). The inflorescence is enclosed by an involucral cup bearing nectary on it. The flowers are pedicellate, bracteate and achlamydous (naked), unisexual and monoecious.
* A single female flower is central in position and comes out of the involucral cup. It bears tricarpellary syncarpous gynoecium.
* It is surrounded by 5 scorpioid cymes, each with many bracteate, pedicellate, male flowers with single stamen. Flowers are produced in centrifugal succession. The inflorescence looks like a single flower.

                               

Verticillaster: It is seen in Lamiaceae (Labiatae).
 e.g.: Leucas, Leonatis
* The stem is erect, quadrangular
* Phyllotaxy is opposite. Leaves have shorter petioles.
* Flowers are subsessile and bisexual
* Two dichasial cymes are produced in the axils of opposite leaves.
* Each dichasial cyme is added with a monochasial, scorpioid cyme on either side.
* Thus there are 2 dichasial cymes and 4 scorpioid cymes in total.
* Two groups of flowers produced in the axils of opposite leaves unite to form a false
    whorl around the node. This false whorl which looks like a ball is called verticillaster.

            

Exercises

1. In which plant, the underground stem grows horizontally in soil and helps in perennation?
A: The underground stem grows horizontally in under the soil in Zingiber, Curcuma (Turmeric), Musa, Canna etc.
 Perennation means: Underground stem lives inside the soil even under unfavourable conditions for any number of years and produces a new plant, when conditions become favourable.
 

2. Needle like phylloclades are found in which plant?
A: Evergreen stems meant for photosynthesis in Xerophytes of arid regions are called phylloclades. They are needle like in Casuarina.
 

3. Why do plants like Nepenthes trap insects?
A: Some plants grow in Nitrogen deficient soils. They do not have the genetic machinery to synthesise their proteins. So they depend on insects. Their leaves modify to trap insects, kill and digest for their nitrogen requirements.
e.g.: Nepenthes (Pitcher Plant), Dionea (Venus fly trap), Drosera (Sundew) and Utricularia (Bladderwort)

4. What is the characteristic inflorescence found in members of Asteraceae?
A: Head inflorescence (Anthodium or Capitulum) is found in the members of Asteraceae (Compositae). It looks like a single flower and highly advanced inflorescence.
 

5. Can you name a plant that has less number of flowers in its inflorescence?
A: The inflorescence with less number of flowers is solitary cyme. It has one flower only. It is seen in Hibiscus (axillary) and Datura, Cotton (terminal).
 

6. Which family shows naked flowers?
A: Flowers without perianth are called achlamydous or naked flowers. These are found in Cyathium inflorescence of Euphorbiaceae family.
 

7. In which flowers of the fig trees does the insect Blastophaga lay its eggs?
A: Blastophaga, the pollinating insect in Hypanthodium inflorescence of Ficus trees (Fig) lays its eggs in Gall flowers (Female, sterile, middle flowers).
 

8. What type of symmetry is shown in the flowers of Canna?
A: The flowers of Canna can not be cut into two similar halves by any vertical plane passing through the centre. So these are asymmetrical.

9. On which side of the flower do the flowers of Pea have the keel petals?
A: Keel petals or carina are smallest in the corolla of Fabaceae flowers. They are united in the form of boat and present towards anterior side. The side of flower towards bract is called anterior side.
 

10. What is the ratio of overlapping margins of petals to overlapped ones in imbricate aestivation?
A: There are 5 overlapping margins, 5 overlapped margins in imbricate aestivation of Cassia and Gulmohur. So the ratio is 5 : 5 = 1 : 1
 

11. How many Ovules are found attached in basal placentation?
A: Only one ovule.
 

12. Which part of the flower in Cashew plant forms the false fruit?
A: The petiole becomes fleshy false fruit in Cashew (Anacardium occidentale)
 

13. Which plant has hard, stony endocarp and fleshy edible mesocarp?
A: The fruit in Mangifera indica (Mango) is a drupe. The endocarp is hard and stony. Mesocarp is fleshy, juicy, sugary, succulent and edible.

14. What is the morphology of "Spathe" in Spadix inflorescence?
A: It is the large, basal, modified bract meant for protection.
 

15. What is the type of fruit known if it develops from apocarpous ovary of a single flower?
A: The fruit developed from the apocarpous ovary is called Aggregate fruit. In it, many fruitlets (equal to the number of carpels) are attached to a common stalk and form Etaerios.