Share Answer In angiosperms presence of vessels is not an universal feature as there are certain angiosperms where vessels are absent e.g. Wintera, Trochodendron etc. Secondary growth is increase in the girth or diameter of axis (root and stem) of the plant by formation of secondary tissue by the activity of lateral meristein. <br /> It occurs in dicotyledons of angiosperms and gymnosperms. But in monocotyledons of angiosperms the primary plant body is complete in it and doesnt produce any secondary tissue. <br /> Autotrophic plants are those which synthesise their organic food themselves by the process of photosynthesis. But certain angiospermic plants have heterotrophic mode of nutrition, e.g. Rafjlesia, Orobanche, Striga are root parasites. <br /> But double fertilization is universal in all angiosperms. It involves fusion of one male gamete with the egg cell and another male gamete with the diploid secondary nuclei.

Share Answer Spermatophyta includes seed bearing plants and this includes gymnosperms and angiosperms. Acacia and sugarcane both are angiosperms. Pinus and Cycas both are gymnosperms. Rhizopus belongs to kingdom fungi and Tritcum is an angiosperm. Ginkgo is gymnosperm and Pisum is an angiosperm. So Ginkgo and Pisum correctly represent the grouping spermatophyta.

Share Answer Eichler divided plant kingdom into two sub- kingdoms cryptogamae and phanerogamae. All plants without flowers and seeds are included in the sub-kingdom cryptogamae whereas phanerogamae includes plants which bear flowers and seeds. <br /> Cryptogams are further classified into three divisions. Thallophyta, Bryophyta and Pteridophyta. Spore bearing plants such as mosses and ferns belong to cryptogams because instead of reproducing by flowers and seeds they reproduce by means of spores.

Share Answer physiologically differentiated sex organs

Share Answer Seed producing plants belong to spermatophyta. It includes gymnosperms and angiosperms. Seed habit or seed formation originated in gymnosperms. It requires the retention of megasporangium or the only on the parent plant and non-shedding of megaspore, development of integument and in site formation of female gametophyte. <br /> All these features developed in gymnosperms and angiosperms. Thallophytes, bryophytes and pteridophytes lack these features and thus do not reproduce by producing seeds. <br /> Fern and Funaria belong to pteridophytes and bry ophytes respectively so they do not reproduce by producing seeds.

Share Answer Angiosperms are highly evolved and well adapted land plants. They have both vessels and tracheids in xylem for better conduction of water. Roots are modified into tap roots, adventitious roots, pneumatophores etc. to suit the desired climate. <br /> Sex organs are highly developed, sporophylls are organized into flowers and the flowers are highly coloured or modified to attract pollinators at different times and places insect pollination is more prevalent because it is more efficient and leads to less wastage of pollen grains as compared to wind pollination. <br /> So the flowers are made attractive to attract a variety of insects. Seed are more protected as they are enclosed inside a fruit. All these adaptations have made angiosperms more adaptive in diverse habitats.

Share Answer Diversification in plant life appeared due to long periods of evolutionary changes. Algae and bryophytes have thalloid plant body with no differentiation into root, stem and leaves. They had no vascular tissues but later in pteridophytes vascular tissues (xylem and phloem) developed and plant body became differentiated into root, stem and leaves. <br /> But the vascular tissues lack vessels and companion cells and they reproduce by spores. In gymnosperms seed habit developed but the seeds are not enclosed inside fruit. In angiosperms vessels and companion cells are present, flowers are present and seeds are enclosed inside fruits. Thus the path of evolution is from algae to bryophytes to pteridophytes to gymnosperms and finally to angiosperm.

Share Answer Cycas is an evergreen palm like plant. It belongs to order cycadales of gymnosperms. The plant body is sporophytic differentiated into root, stem and leaves; sexual reproduction is of oogamous type takes place by the fusion of distinct male and female gametes. The male and female gametes are formed by the germination of microspores and megaspores which are borne on microsporophylls and megasporophylls. <br /> These microspores germinate to form male gametophyte that produces male gametes. The male gametes of Cycas are largest (300 jx) in nature, visible to naked eye, oval in form and top shaped. It is spirally coiled in the anterior half with thousands of small cilia. <br /> After fertilization the ovule is connected into a seed. In the endosperm of seed lies a well developed embryo having two cotyledons, a plumule and a radicle.

Share Answer Flagellation is the arrangement of flagella over the body surface of a bacterial cell. Peritrichous flagellation has flagella all over the surface of a bacterial cell e.g. E. coli. <br /> Ginkgo belongs to order ginkgoales of gymnosperms. It is called living fossil because it is the single living genus in a big fossilized order. Macrocystis belongs to class phaeophyceae. It is the largest perennial alga, about 40- 60 m in size. Wolffia is the smallest flowering plant. Rhizophore is a leafless, colourless, positively geotropic elongated structure that grows down from the point of bifurcation of stem. It occurs in Selaginella.

Share Answer Stele is a column containing vascular tissues which is surrounded by pericycle and separated from ground tissue by endodermis. <br /> Siphonostele is medullated protostele or protostele with central non-vascular pith. Leaf gaps are absent. Siphonostele is of two types: <br /> In Ectophloic siphonostele, central pith is surrounded successively by xylem, phloem, pericycle and endodermis. In amphiphloic siphonostele there is central pith and xylem is surrounded on either side by phloem, pericycle and endodermis. It is found in Osmunda and Equisetum.