Experiment No 5

Estimation of viability of embryo

by Quick test and to determine

effect of heat on enzyme activity

5

Experiment

Material and Chemicals

Overview

Introduction

Procedure

Observations

1

2

3

4

Introduction

EnzymeEnzymes are large biological molecules

responsible for the thousands of chemical inter conversions that sustain life.

Nature of Enzymes

Specificity of Enzyme

Structure of Enzymes

Mechanism of Action

Role of Enzymes in plant growth

Effect of heat on Enzymes

Reactions without Enzymes

Germination percentage is a good measure of seed quality.

One disadvantage of conventional germination tests is that they require a waiting period of two weeks or more.

The Tetrazolium test is a quick chemical test that can be conducted in a short period of time with minimal equipment. 

Tetrazolium Test : Quick test

Initially the Tetrazolium solution is colorless but changes to red when it comes into contact with hydrogen, derived from enzymes in the respiration process.

Embryos showing active respiration are considered "viable" and turn red. 

The darker the color the greater the respiratory activity in the seed. 

Light pink color indicates a seed with reduced viability when compared to a seed that stains dark red.

Experiment

Apparatus and Chemicals

Beakers Burner Soya bean seed Potato Forceps Tetrazolium

Procedure Dissolve 1 gram of Tetrazolium in 20 ml of distilled water.

Take the Potato slices in two beakers. In which one are boiled and other have un boiled potatoes.

Add Tetrazolium solution in them.

The un boiled potato will show reddish color while no reaction occur in boiled potato slices.

Observe change in color due to reaction of tetrazolium.

In order to observe presence of enzyme in seeds, soak the soya bean seeds in water for one hour.

Cut it into two equal halves, so that embryo can become visible.

Boil some soya bean seeds and cut into two equal halves.

Put the seeds into separate test tubes and add tetrazolium solution

Observe change in color of seed.

Observation

Heat effects embryo, which ultimately effects enzyme and tetrazolium does not show reddish color after reaction.

Viable seeds

Non -viable seeds

A- Classification of viable and non viable seeds by Tetrazolium test: 1-6(Viable) ,7-16 (Non viable)

B- Mature embryo

A B