Question

Pick out the wrong statement-
a. Double fertilization is unique to gymnosperms and monocotyledons
b. Sequoia, a gymnosperm, is one of the tallest trees.
c. Phaeophyceae members possess chlorophyll a, c, carotenoids and xanthophylls
d. Moss is gametophyte which consists of two stages namely, protonema stage and leafy stage

Answer 1

Hint: Double fertilization is the process which occurs in both monocots and dicot plants. The Sequoia is the tallest tree known. The algae belonging to phaeophyceae are rich in chlorophyll, carotenoids and xanthophylls. And the moss in their life cycle contains two stages.

Complete answer:
> Double fertilisation is absent in case of gymnosperms. It occurs both in monocotyledon and dicotyledon plants. In the double fertilization process, one female gamete unites with two male gametes. One of these male gametes fertilizes the egg forming a zygote and the other unites with two polar nuclei for the formation of an endosperm. Option (a) is incorrect as Double fertilization is unique to gymnosperms and monocotyledons, and double fertilization only occurs in angiosperms.

> The option (b) Sequoia, a gymnosperm, is one of the tallest trees is correct. Sequoia is a gymnosperm and is one of the tallest trees found. It is a Redwood tree, whose scientific name is Sequoia sempervirens. It is generally located at the coast of Oregon and Northern California. Their height can reach above 300 feet. These trees contain tracheids. The tracheids are a common feature which is observed among the gymnosperms. They help in transporting water upto a greater distance. This is the reason why they can grow much in height.

> The option (c) Phaeophyceae members possess chlorophyll a, c, carotenoids and xanthophylls is correct. The Phaeophyta , also called brown algae are mainly characterized by the photosynthetic pigments present in them. Which are chlorophyll-a and chlorophyll-c, β carotene, fucoxanthin, violaxanthin, diatoxanthin and other xanthophylls. They also contain an excess of carotenoid in them.

> The (d) Moss is a gametophyte which consists of two stages namely, protonema stage and leafy stage is also a correct option as the life cycle of a moss is the gametophyte containing two stages. The first stage is the protonema stage, which is developed directly from a spore. They are a creeping, green, branched and filamentous stage. The second stage of the life cycle of moss is the leafy stage, which are developed from the secondary protonema. These are developed as a Lateral bud and they contain an upright slender axis which bears spirally arranged leaves.

Hence, The correct answer is option (A).

Note: The process of double fertilization provides stimulus to a plant as the ovary develops into a fruit. By the fusion of a male and a female haploid gametes, a diploid zygote is formed and this zygote develops into an embryo. This embryo further gives rise to a new plant. The gymnosperms are devoid of ovaries, and the male and female gametophytes are present on their cones itself. While the angiosperms have the gametophytes as a part of the flower. Hence, the process of pollination in gymnosperms occurs with the help of wind. That is the reason why the gymnosperm does not exhibit double fertilization.