Question

Over the semester, there have been two main threads in the course. The first was the various adaptations from parenchyma cells to advanced sieve tubes and vessels. The second was from the most simple land plants liverworts to the angiosperms. Across both threads, I’ve discussed changes in lifecycles, the adaptation of thallose gametophytes to sporophytes with true leaves. The reduction of the gametophyte portions of the life cycles from being dominant to being reduced to pollen as also been discussed. Across both sections of the semester, you’ve been exposed to at least 250 new vocabulary terms.

To tie up the major concepts, I’m requesting that you explain those two related threads of material in one paper. In short, take the most simple of plants, and through increased complexity (and in some cases, this is a reduction), tell the story of land plants from liverworts to angiosperms.

It is a 500 to 750 work assignment basically summing up and tying up loose ends of all that you learned this semester. This is about one-page maximum. You may use drawings and sketches or flow charts etc to get your point across. Basically painting a map from parenchyma to trees. Basic to complex. Remember this is in place of an exam.

Answer 1

From the given information:

The kingdom plantae is divided into five divisions namley-

1. Algae:as we know the life is originated in water, so plants are also from water called Division algae.it is a auatic divison .

2. Bryophyta: from this the next division is evolved called bryophyta - The plant body is thalloid green in natutre  , growing in the colder moisty habitat . the cell of thallus is parenchymatous in natutre . the whole thallus is made up of parenchyma cells . the parenchyma cells are the thin wall cells with cellulose and hemicellulose deposition in cell wall. the main function is to stored the food material in it. As we focus on bryophyta , there is constant water supply to plants [by rhizoids ], so tha green thallus is produce food material phosynthetically and need a huge storage . so the plant body is parenchymatous simpley . the moss of bryophta are not thalloid , their plant body is differentiated into central axis [equal to stem] , rhizoids and leaves. here the transver section of stem shows the smaller parenchyma core in center surrounded by larger parenchyma cells.

3. Pteridophyta: the next evolution is of division pteridophyta . this is famous as a first vascular plant on land . here the plant body is differntiated into root, stem and leaves . eventhough it is abundantly growing in the colder habiatat , moisty condition of soil is not a compulsory character. as the body grow vertically it need proper anchoring into the soil . For that the strong tissue started to develop. As there is is moderate water , and water should reach away from soil to particular height of plant , her the water conducting tossues xylem is developed. xylem is a dead tissue made up of sclerenchymatoous tissue with cellulose and lignin deposition in the cell wall. xylem provides strengh to the stem to astand firmly on the land. In this group two types of function performed by different cells , parenchyma food storage and secondary metabolite storage. And Xylem for support to stem and conduction of water. these two tissues present in all the parts of plant

4. gymnosperm: from pteridophyta , gymnosperm is developed , a huge tall [111 feet] tree on earth evolved in mesozoic era. As they are tall means xylem and phloem is definately present in highly evolved condition . And secondary growth is also noticed which continuously producing these two complex tissues. collenchyma type of simple tissue is also developed in this group which help to tensil strengh and elasticity to stem . In the pholem complex pholem vessels are present but companion cell and pholem sieve tube is absent. In xylem complex the xylem vessels are absent but xylem trachieds are present. these complex tissues are also present in roots. [tap root]​​​​​​​

5. angiosperm: Angiosperm is highly evolved division which developed a solid tree which is usefull for funiture making. this is because the tree has well developed complex phloem tissue complex with four types of cell - phloem parenchyma, phloem sive tube , phloem companion cell and phloem fibers [also called bast fibres]. where as the xylem comples tissue is also made up of four types of cell - Xylem parenchyma, Xylem trachieds , Xylem vessels and Xylem fibers. THe solid Woody stem of Angiosperm is because of xylem vessels . The well developed root system [tap and fibrous] also made up of these two complex tissue. Xylem is again divided into small sized early developed protoxylem and larged sized mature metaxylem. In the leaves also there are diffent types of tissues developed as compare to thalloid of bryophyta.

as we go upper upper level we found the secondary growth in kingdom plantae. Which again responsible for tissue variation.

Bryophyta is the simplest on so having only parenchyma through out thalloid plant body

Pteriodphyta develope primitive type of xylem , phloem and concept of vascular bundles .

Gymnosperm deveoped in huge tree with secondary growth cambium collenchyma parenchyma and sclerenchymatous hypodermis on stem .

Angiosperm is highly evolved showing varieties of tissue, with secondary growth cambium collenchyma parenchyma and sclerenchymatous hypodermis on stem. as well as palisde tissue, secretory tissues ans so on

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