Embryo sacs of some apomictic species appear normal but containdiploid cells. Suggest a suitable explanation for the condition.
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Draw the diagram of a microsporangium and label its wall layers. Writebriefly on the role of the endothecium.
With a neat, labelled diagram, describe the parts of a mature angiospermembryo sac. Mention the role of synergids.
What are the possible types of pollinations in chasmogamous flowers.Give reasons.
Starting with the zygote, draw the diagrams of the different stages ofembryo development in a dicot.
The generative cell of a two-celled pollen divides in the pollen tube butnot in a three-celled pollen. Give reasons.
Why does the zygote begin to divide only after the division of Primaryendosperm cell (PEC)?
Are parthenocarpy and apomixis different phenomena? Discuss theirbenefits.Hint: Yes, they are different. Parthenocarpy leads to development of seedlessfruits. Apomixis leads to embryo development.
What is polyembryony and how can it be commercially exploited?
Does self incompatibility impose any restrictions on autogamy? Givereasons and suggest the method of pollination in such plants.
Vivipary automatically limits the number of offsprings in a litter. How?
Given below are the events that are observed in an artificial hybridizationprogramme. Arrange them in the correct sequential order in which theyare followed in the hybridisation programme.(a) Re-bagging (b) Selection of parents (c) Bagging (d) Dusting the pollenon stigma (e) Emasculation (f) Collection of pollen from male parent.
List three strategies that a bisexual chasmogamous flower can evolve toprevent self pollination (autogamy).
What is the function of the two male gametes produced by each pollengrain in angiosperms.
How is pollination carried out in water plants?
Are pollination and fertilisation necessary in apomixis? Give reasons.
Which is the triploid tissue in a fertilised ovule? How is the triploidcondition achieved?
Draw the diagram of a mature embryo sac and show its 8-nucleate,7-celled nature. Show the following parts: antipodals, synergids, egg,central cell, polar nuclei.
Name the type of pollination in self-incompatible plants.
What is self-incompatibility?
Which are the three cells found in a pollen grain when it is shed at thethree celled stage?
Can an unfertilised, apomictic embryo sac give rise to a diploid embryo?If yes, then how?
In case of polyembryony, if an embryo develops from the synergid andanother from the nucellus which is haploid and which is diploid?
Name the parts of pistil which develop into fruit and seeds.
Name the common function that cotyledons and nucellus perform.
Name the part of gynoecium that determines the compatible nature ofpollen grain.
Name the component cells of the ‘egg apparatus’ in an embryo sac.
Draw the embryo sac of a flowering plants and label :(a) (i) Central Cell (ii) Chalazal end (iii) Synergids(b) Name the cell that develops into embryo sac and explain how this cellleads to formation of embryo sac.(c) Mention the role played by various cells of embryo sac.(d) Give the role of filiform apparatus.
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Differentiate between microsporogenesis and megasporogenesis. Whattype of cell division occurs during these events. Name the structure formedat the end of these two events.
What will be the fate of following structures in the angiospermic plant?Ovary wall, Ovule, zygote, outer integument Inner integument and primaryendosperm nucleus.
Continued self pollination lead to inbreeding depression. List three devices,which flowering plant have developed to discourage self pollination?
Even though each pollen grain has two male gametes. Why are at least 10pollen grains and not 5 pollen grains required to fertilise 10 ovules presentin a particular carpel?
Name the blank spaces a, b, c and d is the table given below :Item What it represents in the plant(i) Pericarp a(ii) b Cotyledon in seeds of grass family(iii) Embryonal axis c(iv) d Remains of nucellus in a seed.
Name the parts A, B, C and D of the anatropous ovule (Figure 2) givenabove.
Differentiate between geitonogamy and xenogamy.
Among the animal, insects particularly bees are the dominant pollinatingagents. List any four characteristic features of the insect pollinated flower.
Fruits generally develops from ovary, but in few species thalamuscontributes to fruit formation.(a) Name the two categories of fruits.(b) Give one example of each.
Outer envelop of pollen grain made of a highly resistant substance. Whatis that substance? At which particular point the substance is not present?
In angiospermic plant before formation of microspore sporogenous tissueundergo cell division(a) Name the type of cell division.(b) What would be the ploidy of the cells of tetrad?
If the diploid number of chromosomes in an angiospermic plant is 16.Mention number of chromosomes in the endosperm and antipodal cell
Arrange the following in correct developmental sequence :Male gamete, Potential pollen mother cell, sporogenous tissue, Pollengrains, Microspore tetrad.
In same species of Asteraceae and grasses, seed are formed withoutfusion of gametes. Mention the scientific term for such form of reproduction.
Why are pollen grains produced in enormous quantity in Maize?
Pollen grains of water pollinated species have a special characteristics forprotection from water. What is that?
Give the scientific name of a plant which came to India as a contaminantwith imported wheat and causes pollen allergy.
In a young anther, a group of compactly arranged homogenous cells wereobserved in the centre of each microsporangium. What is the name givento these cells?
Explain the development of embryo in a dicotyledonous plant with neatly labeleddiagrams.
Give any three advantages of sexual incompatibility.
Enlist the advantages offered by seeds to angiosperms.
Describe the structure of a pollen grain.
What relationship exists between a species of moth and Yucca plant?
Which type of pollination ensures the arrival of genetically different pollengrains to stigma?
Differentiate between chasmogamous and cleistogamous flowers
State the characteristics of insect pollinated flowers.
What is polyembryony?
Why do most zygotes develop after certain amount of embryo is formed?
Name one plant each where pollination occurs with the help of (1)a) Water.b) Bats
What is sporopollenin?
What do you understand by double fertilization?
Explain the formation of an embryo sac with diagrams.
Explain the structure of an anatropous ovule with a neat labeled diagram?
What is triple fusion? Where does it occur?
Explain the stages involved in the maturation of a microspore into a pollen grain.
Differentiate between microsporogenesis and megasporogenesis.
State any one advantage and disadvantage of pollen grains to humans.
Why are cleistogamous flowers invariably autogamous?
How are the cells arranged in an embryo sac?
Why pollen grains can remain well preserved as fossils?
Describe the structure of a microsporangium with a neatly labeled diagram.
Why is emasculation done in the process of hybridization?
What is microsporogenesis?
Define parthenocarpy.
What is funiculus?
What kind of structures is formed at the end of microsporogenesis andmegasporogenesis?
i) Why is zygotes dominant for sometime in fertilized ovule.ii) What is polyembryony? Give an example.iii) In fruits, what is formed from following parts :-a) Ovary wall b) Outer integument c) Inner integument d)zygotee) primary endosperm f) Ovary g) Nucellus
How dose pollination takes place in salivia. List any four adaptationsrequired for such type of pollination.
“Incompatibility is the natural barrier in fusion of gamete”. Justify thisstatement.
List the advantages of pollination to angiospermic plants?
Draw a well labeled diagram of longitudinal section of pistil showing pollengermination?
What is apomixis? What is its importance?
Name the part of plant producing seed & fruit after fertilization.
Why apple is called a false fruit. Which part of plant forms the fruit?
Name the part of an angiosperm flower in which development of male &female gametophyte takes place.
Trace the events that would take place in flower from the time of Pollen grainof species fall on stigma up To completion of fertilization.
Trace the development of megasporocyte into mature ovule.
i) Explain the structure of a maize grain with the help of a diagramii) Why cannot we use the term maize seeds for maize grains?
Mention two strategies evolved lay flowers to prevent self-pollination
Draw a labeled diagram of mature embryo sac & label the followingi) Egg cell ii) Antipodal cells iii) Synergids iv) Polar nuclei
What are cleistogamous flowers? Can cross – pollination occurs incleistogamous flowers. Give reason?
Why are pollen grains produced in enormous quantity in maize?
Give an example of Bat – Pollinated flower.
Which are the nuclei that fuse to form endosperm?
Describe the post-fertilization changes taking place in a flowering plant?
Trace the development of microsporocyte into mature pollen grains.
List any three differences between wind pollinated flower & insect –pollinated flower.
Why is process of fertilization in flowering plants referred to as doublefertilization?
Draw a diagram of L.S. of an anatropous ovule of an Angiosperm & label thefollowing parts :-(i) Nucellus (ii) Integument(iii) Antipodal cells (iv) Secondary Nucleus.
Differentiate between Geitonogamy & Allogamy.
Mention the scientific term for the type of pollination which ensures GeneticRecombination.
How many haploid nuclei and haploid cells are present in femalegametophyte of angiosperm?
Name the type of cross pollination in Vallisneria & Bougainvillea.
What is apomixis and what is its importance?
Explain the role of tapetum in the formation pollen-grain wall.
If one can induce parthenocarpy through the application of growth substances, which fruits would you select to induce parthenocarpy and why?
What is meant by emasculation? When and why does a plant breeder employ this technique?
Why is apple called a false fruit? Which part(s) of the flower forms the fruit?
Differentiate between:
(a) Hypocotyl and epicotyl;
(b) Coleoptile and coleorrhiza;
(c) Integument and testa;
(d) Perisperm and pericarp.
Why do you think the zygote is dormant for sometime in a fertilized ovule?
What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
What is bagging technique? How is it useful in a plant breeding programme?
What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?
Mention two strategies evolved to prevent self-pollination in flowers.