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प्रश्न
A scientist removed some cells from the growing point of a plant and placed it in a suitable medium leading to the formation of a shapeless lump of mass X. X is then transferred to another medium which stimulates it to develop roots. When X with developed roots is placed in a yet another medium, then it develops shoots to form tiny plantlets. These plantlets can then be transplanted in pots or soil where they can grow to form mature plants.
(a) What is the shapeless lump of mass X known as?
(b) What name is given to this method of producing new plants?
(c) The growth medium used in this method contains plant nutrients in the form of a 'jelly'. Name this jelly.
(d) What is the general name of chemicals used to stimulate the growth of plant cells and development of roots and shoots?
(e) Name any two plants which are produced by this method.
(f) State any two advantages of this method of producing plants.
(g) What is the other name of this method [other then that given in (b) above]?
उत्तर
(a) The shapeless lump of mass X is known as callus.
(b) This method of producing new plants is known as tissue culture.
(c) The jelly is called agar.
(d) The chemicals used to stimulate the growth of plant cells and fasten the development of roots and shoots are called plant hormones.
(e) Orchids and dahlia are two flowering plants that are propagated by this method.
(f) The main advantage of this technique is that it is extremely fast, and the plantlets are obtained in a few weeks. Secondly, this method produces disease-free plantlets.
(g) The other name of this technique is micropropagation.
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संबंधित प्रश्न
Study the following diagrams showing various stages of binary fission in Amoeba:
The correct sequence of these diagrams should be:
(A) I, IV, III, II, V
(B) I, III, IV, II, V
(C) I, II, IV, III, V
(D) I, II, III, IV, V
How are the modes for reproduction different in unicellular and multicellular organisms?
The unicellular organism which reproduces by budding is :
(a) Spirogyra
(b) Hydra
(c) Planaria
(d) Yeast
An organism having a whip-like structure at one end which reproduces by the process of binary fission is :
(a) Hydra
(b) Paramecium
(c) Leishmania
(d) Plasmodium
When the branches of a plant growing in the field are pulled towards the ground and a part of them is covered with moist soil (leaving the tips of the branches exposed above the ground), then after some time new roots develop from the parts of branches buried in the soil. On cutting these branches from the parent plant, new plants are produced from the cut parts of branches which had developed roots.
(a) What is this method of propagation of plants known as?
(b) What type of branches should a plant have to be able to be propagated by this method?
(c) Name any two plants which are grown for their flowers and propagated by this method.
(d) Name any two plants which are grown for their fruits and propagated by this method
(e) Name one plant which gets propagated by this method naturally by forming runners (soft horizontal stems running above the ground).
Differentiate between the following:
Cutting and grafting
A student has to observe a permanent slide of binary fission in Amoeba. Find the correct sequence of steps given below for focussing the object under a microscope.
(a) Place the slide on the stage, look through the eye-piece and adjust the mirror to get proper illumination.
(b) Focus the slide sharp using fine adjustment screw
(c) Look through the eye-piece and raise the objective lens using coarse adjustment screw till the object is focussed.
(d) Look through the eye-piece and move the slide till the object is visible.
(A) d, c, b, a
(B) a, b, d, c
(C) a, d, c, b
(D) a, c, d, b
Draw a labelled diagram in proper sequence to show budding in hydra.
Write four lines on the following: Layering
Asexual reproduction occurs by __________ cell division.
