Dissect and display floral whorls. Dissect anther and take T.S. or V.S. of ovary to show pollen grains and locules of ovary, respectively
Practical Notebook Biology Standard XII
Biology
Answeres
Practical Notebook
Standard XII
Class-12th
science
10. Dissect and display floral whorls. Dissect another and take T.S. or V.S. of the ovary to show pollen grains and locules of the ovary, respectively.
Aim:
To dissect given flowers to study and display different whorls. Dissect anther and ovary to show a number of locules (chambers).
Requirements: -
Flowers such as Brassica or Hibiscus. Forceps, razor blade, slides, two needles, coverslips, dissecting microscope, paper, etc. Ced
Procedure: -
Observe different floral whorls such as calyx, corolla, androecium, and gynoecium. Take out each floral whorl carefully and arrange them in proper ascending order on white paper. Count the members of each whorl and also note down, if there is cohesion or adhesion between the members of the same whorl or different whorls. Mount the anthers on the slide and observe them under a lens or dissecting microscope. Take a transverse section of each of the anther and T. S. / V. S. of the ovary with the help of a sharp blade and mount them on a slide in a drop of water, separately.
Observe under a dissecting microscope and count the number of chambers in another ovary. Draw diagrams of the members of each whorl and sections of anther and ovary. Note down your observations as - Hibiscus flower: • Epicalyx - There are 5-7 free bracteoles. Calyx - 5 sepals, green, gamosepalous, valvate aestivation. Corolla - 5 petals, polypetalous, large, red-colored, and showy, twisted aestivation. Androecium - Many stamens, showing monadelphous condition. (Filaments are fused to form hollow staminal tubes but anthers free.) Anthers are monothecus and kidney-shaped. Note the color, shape, and ornamentation of pollen grains. . . Gr 345 • • 015 .. Gynoecium - Pentacarpellary, syncarpous (5 carpels - fused), ovary - superior and pentalocular five chambers) with axile placentation, style passes through hollow staminal tube, stigma - 5 free capitates. 45
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