Questions 1.The evolution of complex land plants required the development of [many] specific specialized systems and processes, in order to ensure successful land invasion. Discuss this statement and emphasise how the move from the single through the multicelled organism and how the evolution of the supracelled organism influenced the process. Use appropriate diagrams to enhance your answer. 2. As the distance from the apex increases due to the addition of new derivative closer to the apex, so the similarities between older and newly-formed derivatives become less obvious. Many changes occur, some of which are initiated within cells quite close to the meristematic zone in the shoot apex, others much further away from the meristem. Discuss, using suitable examples to illustrate your answer. 3. The process of cell differentiation is said to be ‘irreversible.’ Discuss, and provide suitable examples which demonstrate this irreversible condition which highlight the changes which take place in a post-embryonic angiosperm shoot apex. 4. Write an essay on cell differentiation and maturation in higher plants. Include some discussion on your interpretation of ‘the differentiation process.’

1.A series of complex cell division, cell expansion and cell differentiation processes take place once the foliar buttress has emerged. These processes are initiated by marginal and submarginal initials. Discuss the relationship between these two of initials and explain how they are responsible for the formation of the cell and tissue types found in mature Angiospermous leaves. 2.Development of the leaf is a process that involves division which is first initiated within the apical meristems of plants. Cell division may be synchronous or asynchronous. Given that the monoplex, simplex and multiplex models all undergo similar cell division processes, explain how a foliar buttress would be initiated and differentiated by these three different apical meristems. 3.During the early stages of expansion of a foliage leaf, the major vein network differentiates acropetally; and the minor vein network parallels this, but is initiated first in the leaf apex and in the distal marginal regions of the leaf and then differentiates basipetally. Why is this? 4.Outline the developmental sequences involved in leaf expansion and development, and explain why this process appears to be so complex?

1.Phloem is a complex system of cells that are collecting, transporting or unloading assimilates. Discuss these specific activities in higher plant phloem, and relate them to changes in osmotic and pressure potentials at source and sink, required to ensure transport from source to sink. 2.Translocation involves a number of potential symplasmic and apolasmic steps. Even though apoplasmic and symplasmic phloem loading each have advantages, an apoplasmically-based phloem loading mechanism would advantage plants growing in a competitive environment. Discuss this statement and include in your answer the advantages and disadvantages of these two systems. 3.Write an essay on phloem transport explaining how what we know of phloem structure, lends support to the [variously-proposed] phloem loading [and transport] theories. 4.Leaf expansion and development involves a complex differentiation sequences, which ensure that assimilates are transported and offloaded where needed in strong sink tissues and transported away once these sinks become weak sources. Discuss source to sink transition in relation to leaf differentiation. 5.Higher plants contain xylem and phloem, to accommodate water and carbohydrate transport. Why do plants have, and need such distinct transport systems in the first place?

The process of cell differentiation is said to be ‘irreversible.’ Discuss, and provide suitable examples which demonstrate this irreversible condition which highlight the changes which take place in a post-embryonic angiosperm shoot apex. cell differentiation suitable examples emonstrate demonstrate post-embryonic

Write an essay on cell differentiation and maturation in higher plants. Include some discussion on your interpretation of ‘the differentiation process.’

A series of complex cell division, cell expansion and cell differentiation processes take place once the foliar buttress has emerged. These processes are initiated by marginal and submarginal initials. Discuss the relationship between these two of initials and explain how they are responsible for the formation of the cell and tissue types found in mature Angiospermous leaves. M SI PC PBS VT Epid Xy Ph M marginal, Si Submarginal initial, Epid epidermis, PC procambium, PBS parenchymatous bundle sheath, VT vascular tissue, Xy xylem, Ph phloem

During the early stages of expansion of a foliage leaf, the major vein network differentiates acropetally; and the minor vein network parallels this, but is initiated first in the leaf apex and in the distal marginal regions of the leaf and then differentiates basipetally. Why is this?

Translocation involves a number of potential symplasmic and apolasmic steps. Even though apoplasmic and symplasmic phloem loading each have advantages, an apoplasmically-based phloem loading mechanism would advantage plants growing in a competitive environment. Discuss this statement and include in your answer the advantages and disadvantages of these two systems.

Write an essay on phloem transport explaining how what we know of phloem structure, lends support to the [variously-proposed] phloem loading [and transport] theories.

Leaf expansion and development involves a complex differentiation sequences, which ensure that assimilates are transported and offloaded where needed in strong sink tissues and transported away once these sinks become weak sources. Discuss source to sink transition in relation to leaf differentiation.