Std 12th Biology Board Practical Expt 4
4. Study of pollen germination on slide.
HSC Std 12th Subject Biology Maharashtra State Board Syllabus Practical Experiment No 4. Study of pollen germination on slide. with ansewers pdf MCQs
Std 12th Biology State Board Practical with Answer
Experiment No 04
Date :
Pollen groins ore the mole reproductive units produced in the anther lobe of stamens, producing pollen tube carrying male gametes, on germination.
Aim: To study the process of pollen germination on slide while observing under the compound microscope.
Requirements:- Flower of CatImranthus (periwinkle) or Helianthus (Sunflower) or Hibiscus (shoe flower). cavity slide/ gloss slide, cover slips, compund microscope, sucrose crystals (Table sugar), etc.
Principle:-
Pollen grain after deposited over the stigma absorbs water and nutrients from the stigma and germinates to produce male gumetophyte showing pollen tube with two non-motile male gametes and a larger vegetative nucleus.
Figure:-
Fig. Pollen grain showing pollen germination
Procedure:-
1. A nutrient medium is to be prepared using 20grams of sucrose in 100 ml of water.
2. Take a few drops of this solution preferably on a cavity slide and dust a few pollen grains from mature, dehisced anther.
3. Place cover slip carefully.
4. Observe the slide under compound microscope after every five minutes continously for 30 minutes.
Observation:-
1. In the nutrient medium, the pollen will germinate and pollen tube comes out through germ pore.
2. It is due to enlargement of tube cell and stretching of the intine, pollen tube comes out and grows.
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महाराष्ट्र राज्य माध्यमिक व उच्च
माध्यमिक शिक्षण मंडळ, पुणे फेब्रुवारी-मार्च २०२४ माध्यमिक
शालान्त प्रमाणपत्र (इ.१०वी) व उच्च माध्यमिक प्रमाणपत्र (इ.१२वी) परीक्षा अंतिम
वेळापत्रक ▪HS
परीक्षा ▪SSC
परीक्षा |
Inferences:-
The pollen grain is uninucleate (has one nucleus) in the beginning. At the time of liberation, it becomes 2 celled, with a small generative cell and a vegetative cell.
In the nutrient medium, the pollen grain germinates. The tube cell enlarges and comes out of the pollen grain through one of the germ pores to form a pollen tube. The tube nucleus descends to the tip of the pollen tube. The generative cell also passes into it. It soon divides into two male gametes.
6. Name the nutrient element which plays a major role in pollen germination
Sucrose provides nutrition in the germ tube for its growth as a pollen tube.
7. Draw a well labelled diagram of male gametophyte in Angiosperms as observed by you.
4. Triporate pollen grain is commonly found in
a. monocot plants
b. dicot plants
c. ptendophytes
d. gymnosperms
Answer -b. dicot plants
5 How many prothallial cells develop during development of male gametophyte in Angiosperms?
a. One prothallial cel!
b. No prothallial cell
c. Egual to number of gametes produced
d. Equal to number of tube cells produced
Answer -b. No prothallial cell
6. Uniporate or monocolpate pollen grain is found in
a. monocot plants
b. dicot plants
c. gymnosperms
d. pteridophytes
Answer -a. monocot plants
Observe the slide and draw the diagram.
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