NCERT Class 11-Biology: Chapter – 5 Morphology of Flowering Plants Part 6 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Long Answer Type Questions

Question 1:

Distinguish between families Fabaceae, Solanaceae, Liliaceae on the basis of gynoecium characteristics (with figures) , Also write economic importance of any one of the above family.

Answer:

Difference of Fabaceae, Solanaceae and Liliaceae
FabaceaeSolanaceaeLiliaceae
Ovary superior, mono carpellary, unilocular with many ovules, style singleBicarpellary obligately placed, syncarpous; ovary superior, biloculaer with many ovules, axileTricarpellary anycarpous, ovary superior, trilocular with many ovules; axile placentation
Fabaceae
Solanaceae
Liliaceae
Fabaceae
Solanaceae
Liliaceae

Economic Importance of Fabaceae –

Many plants belonging to the family are sources of pulses (gram, arhar, sem, moong, soyabean; edible oil (soyabean, groundnut) ; dye (Indigofera) ; fibres (sunhemp) ; fodder (Sesbania, rifolium) , ornamentals (lupin, sweet pea) ; medicine (muliathi) .

Economic Importance of Solanceae –

Many plants belonging to this family are source of food (tomato, Brinjal, potato) , spice (chilli) ; medicine (belladonna, ashwagandha) ; fumigatory (tobacco) ; ornamentals (petunia) .

Economic importance of Liliaceae –

Many plants belonging to this family are good ornamentals (tulip, Gloriosa) , source of medicine (Aloe) , vegetables (Asparagus) , and colchicine (Colchicum autumnale) .

Question 2:

Describe various stem modifications associated with food storage, climbing and protection.

Answer:

The stem may not always be typically like what they are expected to be.

They are modified to perform different functions like:

(i) Food storage – Underground stems of potato, ginger, turmeric, zaminkand, Colocasia are modified to store food in them.

(ii) Climbing – Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb such as in gourds (cucumber, pumpkins, watermelon) and grapevines.

(iii) Protection – Axillary buds of stems may also get modified into woody, straight and pointed thorns. Thorns are found in many plants such as Citrus, Bougainvillea. They protect plants from browsing animals.

Question 3:

Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?

Answer:

Difference of Stolon, Offset and Rhizome
S. no.StolonOffsetRhizome
1.These are underground stems which spread to new niches and when old plants die, new are formed. It is a creeper.A lateral branch with short internodes and each node bearing a rosette of leaves and a tuft of roots is found in aquatic plantsRhizome is underground stem growing parallel to soil surface which is differentiated from roots in having scale leaves and axillary buds and helps in vegetative propagation.
2.Example – StrawberryExample – Pistia, EichhorniaExample – Ginger Turmeric