Class 12 Biology

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  What is the number of microsporangia in each lobe of an angiosperm anther? (1) Four (2) Two (3) Eight (4) One The cells of which of the following layers of the anther wall are multinucleated due to endomitosis? (1) Epidemis (2) Endothecium (3) Middle layer (4) Tapetum A typical angiosperm anther is dithecous which means that it is: (1) One lobed and the lobe has two theca (2) Two lobed and each lobe has two theca (3) Two lobed and each lobe has one theca (4) Four lobed and each lobe has two theca Which of the following layers in the wall of an anther nourishes the developing pollen grains? 1. Tapetum 2. Epidermis 3. Endothecium 4. Middle layers Pollen intine is made of: 1. Sporopollenin 2. Cellulose and pectin 3. Ergosterol 4. Phospholipids and cholesterol Pollen grains lose their viability within 30 minutes of their release in: 1. Rose 2. Potato 3. Pea 4. Wheat Pollen grains are shed at which stage? (1) 2 celled  (2) 3 celled (3) Usually at 2-celled, but sometimes 3-celled ...

 Vegetative propagation :  Reproduction by vegetative parts of plants i.e. other than the reproductive parts(flower, Fruit). Vegetative parts= Roots, Stem, Leaves Types : Natural and Artificial Natural methods i) Roots: Buds grow in 2 types of roots(Tap and fibrous) eg: Dahlia, Dalbergia, sweet potato, Asparagus ii) Underground stem (a) Tubers : Potato (b) Bulbs: Onion and Garlic (c) Rhizomes: Banana, Turmeric, Ginger (d) Corms: Colocasia, crocus, Amorphophilus (e) Sucker : Mint, Crysenthemum (f) Runner:Oxalis (g) Stolon:Strawberry, Valisneria (h)Offset: Pistia,Eichhornia