BOTANY LABORATORY PRACTICAL (PLANT ANATOMY AND MORPHOLOGY) - O.A. SHEVCHUK - 2014

THE FLOWER

TOPIC 9. SEED TYPES. STRUCTURE OF MONOCOT AND DICOT SEEDS

General notes. Seeds are the Organs of reproduction and dissemination of seed plants (spermatophytes). There are five seed types depending on where reserve nutrients are stored: in the endosperm, nucellus, embryo, both endosperm and nucellus, or both endosperm and embryo. Seeds with and without endosperm are the most widespread and commonly utilized in agricultural practice. Therefore, special attention should be given to studying their Structure and origin.

Seeds of dicotyledonous plants have specific structural features. Unlike monocots, a dicot seed consists of two main parts: the seed coat and the embryo. It lacks a specialized nutritive tissue like the endosperm, where reserves are typically stored. In dicots, reserve nutrients are stored in the cotyledons of the embryo, or in the perisperm and embryo. Typically, the seed coat is free and does not fuse with the pericarp.

Objective: to compare the seed structure of monocots and dicots.

Material and equipment: pre-soaked caryopses of cultivated oat (Avena sativa), durum wheat (Triticum durum), seeds of common bean (Phaseolus vulgaris), field pea (Pisum sativum), sunflower (Helianthus annuus), corn (Zea mays), corn cockle (Agrostemma githago), acorn of English oak (Quercus robur), permanent Microscope slides of longitudinal caryopsis sections, as well as corn cockle seeds, charts, and laboratory equipment.

Tasks

1. Examine The structure of endospermic seeds in various plant species. Identify their constituent parts.

2. Examine and study the structure of non-endospermic seeds in the common bean.

3. Examine and study the structure of non-endospermic seeds in the English oak. Indicate their constituent parts.

4. Study the different seed types.

5. Examine seeds with perisperm using the corn cockle as an example.

Label the diagrams and draw Conclusions.

Conclusion

Self-Assessment Questions

1. How are seeds formed, and what process precedes their development?

2. Which PARTS OF THE ovule give rise to the seed coat, embryo, and endosperm?

3. What are the criteria for seed Classification?

4. What is the Water/144.html">Origin of the perisperm, and how does it differ from the endosperm?

5. What are the hilum, raphe, and micropyle?

6. What is the Structural Organization of the bean and oat embryos?

7. What function do the cotyledons perform in beans versus oats?

8. What are the coleoptile, coleorhiza, and epiblast?

9. In which part of a bean seed are nutrients stored?

10. From which part of the ovule does the seed coat develop?

11. What is the chromosome set of embryo Cells?

12. From which part of the Ovary does the pericarp form?

13. Does an oak seedling bring its cotyledons above the soil surface?

14. Does a common bean seedling bring its cotyledons above the soil surface?