Plant Kingdom Test 5

Being photosynthetic they increase the level of dissolved oxygen in their immediate environment.

Gymnosperms are plants with produce seeds but lacks flower. These are non flowering plants. They produce naked seeds.

The plant shown above is cycas. This plant belongs to division cycadophyta and family cycadceae. It is diecious and native to India.

Bryophytes are called as amphibians of plant kingdom as bryophytes can grow in both land andwater. Water is essential for completion of life cycle. So, they are called amphibians of plant kingdom.

All seed-bearing plants i.e.,gymnosperms and angiosperms follow diplontic alternation of generation.

Plant body of Ulothrix and Spirogyra, is gametophytic (haploid), they produce zoogametes (n) which fuses to form zygosporic (2n) diploid, which is a resting spore. Onset of favourable condition zygospore undergoes reductional division, or meiosis to produce zoo- meiospores

Species of Sphagnum, a moss, provide peat that has long been used as fuel.

Unlike bryophytes and pteridophytes, in gymnosperms the male and the female gametophytes do not have an independent free-living existence.

The yellow or brown spots which have sporangia in fern are called sori. Spores are produced inside these sporangia to start gamotophytic haploid life.

Megasporangium of seed plants are called ovule. Ovule is present inside the ovary which terminates into seeds on ripening. It represent female reproductive unit.

Green algae usually have a rigid cell wall made of cellulose.

Bryophytes are also called amphibians of the plant kingdom because these plants can live in soil but are dependent on water for sexual reproduction.

Fern spore germinate to form a leafy structure called prothallus. On prothallus, male and female gametophyte germinate and produce respective germ cells.

In Gymnosperms, cross pollination is mainly accompanied by wind. The pollen grains are produced in large quantity and generally lighter.

Angiospermic plants have roots to hold the soil and remain erect. Similarly Rhodophytes have holdfast by which they remain attached with substratum to absorb water and minerals.

Phaeophyceae possess chlorophyll a, c, carotenoids and xanthophylls. They vary in colour from olive green to various shades of brown depending upon the amount of the xanthophyll pigment

These plants can live in soil but are dependent on water for sexual reproduction. They usually occur in damp, humid and shaded localities.

The cones bearing megasporophylls with ovules or megasporangiaare calledmacrosporangiate or femalestrobili.

Adaptation is essential for survival of organism. The greatest extent of adaption in various environmental conditions is found in Angiosperms. Angiosperms are found in all kind of environment and altitudes.

Fusion of two polar nuclei with one male gamete is called triple fusion. Primary endosperm nucleus is formed by this product of triple fusion that divide mitotically to form endosperm.

Fusion between one large, non-motile (static) female gamete and a smaller, motile male gamete is termed as oogamous.

Archegoniophore occurs in Marchantia that develop on the thallus of Marchantia plant. Archegoniophoreproducegametes for alternation of generation.

In gymnosperms, male and female cones are formed that produce male and female gametes. So, cone of gymnosperms represents thereproductive organs.

The pollen tubes enter the embryo-sac where two male gametes are discharged. One of the male gametes fuses with the egg cell to form a zygote (syngamy). The other male gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus (PEN).

Phloem of angiosperms contain companion cells but other vascular plants lacks companioncells in their phloem cells. Phloem transport food form leaves to all other parts of plants.