Study the pH and water holding capacity of different soil samples.

AIM: To study the pH and water holding capacity of different soil samples.

REQUIREMENTS: Soil samples, measuring cylinders, funnel, filter papers and pH indicator.

PROCEDURE:

Take 2 funnels and line them with filter paper

Put these funnels in a measuring cylinder

Put the 2 soil samples in  separate funnels

The weight of soil sample should be same in both (25g)

Pour equal amount of water in both funnels (25 ml)

Let the water drip in the cylinder

Not the volume of water collected

OBSERVATIONS:

The volume of water collected in cylinder of sample A was more than sample B

Also, the pH of sample A was higher

Calculations:

Volume of water retained by soil = Vol. of H2O poured-Vol. of H2O collected in cylinder

Water holding capacity = (Vol of H2O retained/Vol of H2O required) x 100

CONCLUSION:

Soil sample A is roadside soil and sample B is garden soil as sample B has more water holding capacity.

PRECAUTIONS:

The water should be poured slowly

The measuring cylinders should be properly calibrated.

Study and identify the transverse section of testes and ovary through permanent slides.

Aim: To study and identify the transverse section of testes and ovary through permanent slides.

Requirements: Permanent slides of transverse section of Testes and ovary, microscope

Observation:

T.S of Mammalian Testes

The mammalian testes are covered with a thick fibrous tissue called tunica albuginea

The testes consist of a many seminiferous tubules embedded in the interstitial tissues.

Various types of cells are present from outside towards the lunar in the following order:-

Spermatogonia(2n)———>Spermatocytes ( ) ———>Sepermatids———>Spermatozoa(n) i.e. sperms

Between the germinal cells, pyramidal shaped cells called Sertoli cells are present

A large number of sperms have their head embedded in the Sertoli cells.

The interstitial tissue has Leydig cells which produce testosterone.

T.S. of Mammalian Ovary

A mammalian ovary is a solid structure bounded germinal epithelium followed by a thick layer of fibrous tissue called tunica albuginea.

The ovary consists of the outer cortex and inner medulla.

The medulla consists many rounded or oval bodies called ovarian follicles at various stages of development.

The development of follicle is as follows:-

10 follicle——>20 follicle—–>30 follicle—->Graffian follicle—–>corpus luteum

The cortex contains round and mature follicles along with corpus luteum.

Precaution:

Handle the microscope with care

Use find adjustment for better focus

You can also get Class XII Practicals on BiologyPhysics, and Physical Education.

Study Pollen Germination on a Slide

Aim:  To study pollen germination on a slide.

Apparatus and materials required: Fresh seasonal flower slides, microscope, beaker, cavity slide, boric acid, sucrose.

Procedure:

Prepare a nutrient solution by dissolving 10g sucrose and 10 mg boric acid in 100 ml water.

Take a few drops of this solution on a clear slide, dust a few pollen grains from the stamen of a mature flower in it.

Obverse the slide under the microscope after 5 minutes. Keep observing the slide regularly after intervals of half an hour.

Observations:

In a nutrient solution or nutrient-rich medium, the pollen grains germinate. The tube/vegetative cell enlarges and comes out the pollen grains through one of the germ pores to form a pollen tube. The generative cell nucleus soon passes into it and dives to make 2 sperm nuclei (male gametes). Each male gamete is lenticular to spherical in outline.

Precautions:

Flowers should be freshly picked

Use a clear cavity slide to observe pollen grain

 

You can also get Class XII Practicals on BiologyPhysics, and Physical Education.