To study the pollen germination and growth of pollen tube in a pollinated pistil (in Portulaca / grass).

                      II. CORE EXPERIMENTS

                               EXPERIMENT 1

OBJECT

To study the pollen germination and growth of pollen tube in a pollinated pistil (in Portulaca /

grass).

REQUIREMENTS

Fresh pollinated flowers of Portulaca/grass, glass slide, coverslip, needles, forceps, brush, dropper, safranine,

glycerine, petridish, water, blotting paper, microscope etc.

PROCEDURE

1.

Take out the pollinated carpel from the flower of Portulaca/grass and place it on a glass slide in a drop of water. Gently tease it with the help of needles or pick up the carpel from the flower and cut a longitudinal section of it. Place the section on a glass slide in a drop of water.

Fig. 1.1. Pollen germination. A. Pollen grains germinating on stigma (a teased preparation).

B. Growth of pollen tube in the carpel (L.S.).

2.Pour a drop of safranine on the teased carpel or its section and wash it with water.

3.Put a drop of glycerine and cover the teased carpel or its section with coverslip. Remove the extra glycerine

with blotting paper Observe the preparation under the high power of microscope and draw the diagrams of different stages of pollen germination.

OBSERVATION

Differents stages of germination pollen are observed in the stigma and style regions of the carpel. Some pollen  are in their initial stage of germination others have quite long pollen tube containing tube nucleus and two male nuclei.

PRECAUTIONS

1.Only pollinated carpels should be selected for the experiment.

 2.Teasing should be done gently, so that the pollen tubes are not ruptured.

3.Excess of glycerine/water should be removed by blotting paper.

VIVA VOCE