Plant Kingdom Test - 83

(d) Gymnosperms
Explanation: Cones are salient features of gymnosperms. Moreover, gymnosperms are well adapted to extreme conditions.

The cell walls of red algae (Rhodophyceae) are chemically made of cellulose, pectin and poly sulphate esters. Pectin extracted from the cell wall is used as an ingredient in jellies and ice-creams.
So, the correct answer is Statement 1 is incorrect but statement 2 is correct.

Plant life began in water and gradually evolved to establish itself on land. These plants emerged from green algae or Chlorophyceae members like Chlamydomonas, Volvox, etc that produced motile, flagellated gametes for sexual reproduction in water.

In Angiosperms Endosperm is Triploid, in gymnosperms it is haploid.

Adiantum is a pteridophyte, where the fronds (leaves) arise directly from the rhizome. Sometimes, to propagate the plant vegetatively. The leaf or the frond bends towards the soil. When the leaf tip touches the soil, it gives rise to new plant creating a walking like appearance. 

Volvox is a genus of chlorophytes, a type of green algae. It exists as a grand spherical colony. Each little alga within the colony bears two flagella, whip-like hairs. The cells have eye spots, more developed near the anterior, which enable the colony to swim towards light. The individual algae in some species are interconnected by thin strands of cytoplasm, called as protoplasmates.

Red tide is caused by algal bloom. The algal blooms decrease the oxygen content of the water. It is caused by microscopic algae, Karenia brevis and can kill large numbers of fish and other sea life including dolphins and manatees and can make shellfish poisonous to humans. K. brevis produces airborne toxins that can cause respiratory irritation. Red tide can cause skin irritations. So, the correct answer is option C.

Cladophora is cosmopolitan in temperate and tropical regions, occurring in freshwater, brackish and marine conditions. The various species are found intertidally in wave-exposed to very sheltered habitats, in brackish pools, lagoons and mudflats and in more or less eutrophic freshwater streams and lakes with pH > 7. 

Pyrenoids occur in many of the algae and are associated with the chloroplasts. In algae, pyrenoids are the sites of carbohydrate (typically starch) storage. Starch and iodine react to produce a deep blue-black colour, so staining a thin algal prep with iodine will indicate the presence of pyrenoids. Spirogyra is a filamentous green alga in which the chloroplast has a characteristic spiral shape. In this photograph, you can see the chloroplast coiling against the outer edge of the cells. The numerous small round blobs along the edges of the chloroplast are the pyrenoids. The larger, faint blobs (they look like out-of-focus regions) that take up most of the volume of the cells in the filaments on the right are the nuclei, which are suspended in the interior of the cells. The pyrenoids of algal cells may arise by a number of means. In some instances, mature pyrenoids may divide within a cell, giving rise to 2 or more daughters (Manton,1966), whilst in certain brown algae new pyrenoids arise as lateral outgrowths ofthe chloroplast in the region of old pyrenoids. A de novo formation of pyrenoids is known to occur in Tetracystis excentrica and Oedogonium cardiacum.