Chapter 28, Problem 1TYU

Test Your Understanding

Know and Comprehend

1. Seed plants lack which of the following structure(s)? (a) ovules surrounded by integuments (b) microspores and megaspores (c) vascular tissues (d) a large, nutritionally independent sporophyte (e) a large, nutritionally independent gametophyte

Summary Introduction

Introduction: Seed is a part of plant, which contains an embryo that will give rise to a new plant, stores food material in the form of “endosperm” for the growth of embryo, and seed coat for the protection of seed.

Answer to Problem 1TYU

Correct answer: Seed plants does not possess a “large, nutritionally independent gametophytic” structure. Hence, the correct answer is option (e).

Explanation of Solution

Reason for the correct answer:

Seeds are present inside the ovary, which is known as female gametophyte. The function of female gametophyte is to provide nutrition to a number of ovules that requires a large amount of nutrition. Gametophytes are microscopic in size and have endosperm in it as a reserve food material for the development of plant when the seed is set for the process of germination. Thus, if a nutritionally independent gametophyte is present then the development of the ovules will not be possible, which will result in the deterioration of ovules.

Option (e) is given as “a large, nutritionally independent gametophyte”.

A seed plant does not have a nutritionally independent gametophyte because the gametophyte depends upon the sporophyte for the nutrition. Hence, the correct answer is option (e).

Reasons for the incorrect answers:

Option (a) is given as “ovules surrounded by integuments”.

Seed plants produce ovules which are surrounded by the integuments. Later on, those integuments will result in the formation of seed coat and serve as a protective covering of the seed. Hence, option (a) is incorrect.

Option (b) is given as “microspores and megaspores”.

Seed plants produce both kinds of spores such as microspores (male gamete) and megaspores (female gamete). The condition of producing both types of spores is known as heterospory. Hence, option (b) is incorrect.

Option (c) is given as “vascular tissues”.

Plant body uses vascular tissues for the transport of food materials and water for the proper growth of plant body. Thus, vascular tissues are present in seed plants. Hence, option (c) is incorrect.

Option (d) is given as “a large, nutritionally independent sporophyte”.

Most of the seed plants have a large, nutritionally independent sporophyte. Hence, option (d) is incorrect.

Hence, options (a), (b), (c), and (d) are incorrect.

Conclusion

Nutritionally independent gametophyte is not present in seed plants.